I have too much solar for house load most of the year, but not enough on some winter months.
?The amount of solar does not matter what controls what is bad for your batteries is the charge controller, if you want to maximize the life of your LiFePo4 batteries you would have the charge controller stop charging say around 98% full. ? On a typical summer day my charge controller stops excepting a charge around 3:00 pm the solar cells just go open circuit the rest of the day. ?
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On May 23, 2020, at 2:15 PM, 63urban <63urban@...> wrote:
? Hi I am a long term lurker. I am building some test platforms and hope to eventually come away with a fully electric small live aboard.
Is there such a thing as too much solar? My point being if tour batteries are right full 90% of the time? Will this be hard on batteries?
I realize this is not a problem most folks are faced with but in my application it could happen because of lack of movement and use.
Thanks
Nick
Sent from my Samsung Galaxy smartphone.
-------- Original message -------- From: James Sizemore <james@...> Date: 2020-05-23 10:30 a.m. (GMT-05:00) Subject: Re: [electricboats] 39' sloop conversion
A cycle is generally a large draw down of your battery, under 20% to nearly full again. It takes many small draw downs to say 90% and back to nearly full again to equal one ¡°real¡± cycle. ?As for If solar or A generator while under way, Is counting against your cycles. Probably not if no charging and or drawdown is happening, if your batteries are not gaining or losing any charge then the internal resistance is higher then the resistance of your loads, so all the power from solar is going directly to loads. ?The battery really can not tell the difference between that and doing nothing. With the caveat that they would notice some fluctuations or ripples in the voltage. ?
Generally speaking it takes 100 of small draw downs and recharges to equal one cycle lost. ?You are a probably losing more capacity to just plan calendar life lose then from cycle life lose is most situations with LiFePo4, when not doing large drawdowns to under 20% back to full, they maintain they Capacity very well. ?
My pack is now 10 years old, I have lived aboard for over eight years of there life using them as a house bank (many small drawdowns to say 90-85% daily, and have Cruised the last 2 years meaning large draw downs a couple of times a month when I switch anchorages/marines as I travel. Generally I only draw them down to a little less then 50% on most travel days. ?But occasionally go down as far as 30%. ?I like to keep plenty of reserve capacity incase things don¡¯t go well. ?After 10 years, I have no measurable difference in there rated capacity.
What follows is ¡°internet theory¡± ?Some of that amazing lack of capacity lose may be do to Winston manufacturing ?there 1000ah cells with some reserve capacity. Meaning they may have Really been 1010 ah Cells originally. ?Most cell manufacturers no longer under rate there cells anymore. ?When large prismatic cells where new, they where a little over engineered for warranty purposes, but once the manufacturers had real word data on actual reliability they did less over engineering. ?
But either way my Winston LiFePo4 cells are still delivering like new performance ten years later. ?
On May 23, 2020, at 9:23 AM, Robert McArthur <rjmcarthur@...> wrote:
? Something I have wondered about hybrids and use of regular solar plus gensets... If you are going along and using power from the battery, and each moment there¡¯s some solar going in and you are running a genset so that¡¯s going in to the battery too: a battery has a certain number of cycles that it¡¯s good for (¡°good¡± being relative, but let¡¯s pretend it means that it still retains a useful amount of charge). The manufacturer may say a particular battery may be good for ¡°2000 cycles¡°. But given at every moment you are taking out, say, 100amps, while at the same time putting in 100amps (let¡¯s say), how much does that eat into the ¡°cycles¡± if you do that hour after hour, day after day?
Now what if you¡¯re pulling 100amps from a pack and that after an hour it takes The battery to 50% without anything going in (nice quiet motoring). At the start of the hour you start your oversized genset which, over the next hour, replaces the original 100amps AND the 100amps that the motor is using while the genset was running. So at the end of the second hour the battery is full. Then you run another hour quietly. Rinse and repeat. Under that scenario, are you eating into the cycle lifetime of the battery by 12 times every day? More? Less?
I¡¯m happy to assume LiFePO4 if that helps answer :).
Thanks Rob On 17 May 2020, at 11:36 pm, MATT <msteverson@...> wrote:
?Hello all, I'm a longtime lurker, this is my first post, so please, be gentle.
We have lived on our 39' sloop for about 5 years now and are ready to convert to hybrid...this is the plan I've come up with and am looking for your critical analysis.
The boat is a custom build. It displaces about 18000 lbs all full, has a 3/4 length "scheel" keel, and only draws about 50".? We currently have a very good running yanmar 3gm30f that turns a 17" 2 blade max prop.? We've put in about 20k nm over the past few years and she solidly averages 6kts.? The engine is in the middle of the boat under the galley sink and makes A LOT of noise and stink and we're sick of it.? We've got a little extra time and money so we think this project could go a long way.
The plan
- 48V 12KW Thunderstuck ME1616 kit - currently its on backorder - with a 3:1 gear reduction
- About 15kw lithium battery bank (right now Thunderstruck has Valence 1.6kw batteries used for $350 each, so 8 of these, and the VC1 BMS they sell, I think would be easy to install and work well.)
- A 3.5-4kw diesel generator that is PURELY for recharging batteries using the thunderstruck TSM2500 kit with 2 chargers.? This should get me 70amps at 48volts running from 240VAC.? This is important because we live at anchor in the PNW year round.? We often have a long way to go with no wind, or sun and generally avoid marinas.? I will buy this used or rebuilt to save dollars.
- Run existing loads off of a DC-DC converter
- We have 500W of PV installed with 12V Victron charge controllers?that keeps up with our daily usage.? I would like to get them putting electrons into the 48v bank and?am wondering if there is a work-around with DC to DC converters or something so I don't have to buy all new CCs.??
I will be doing this install myself.? I'm confident with basic stuff like solar installs and alternators but this project will be a little out of my comfort range, I'm very much looking forward to it.? What is most important to me is to keep the system as simple and user friendly as possible mostly for resale purposes.??
Any advice/comments/questions/trashtalk would be appreciated.??
Matt
|
I came across one of my posts from 2010 where I did some regen calcs that may be helpful.
Larry,
As the most visible "regen naysayer" here, the link that you provided completely supports my previous premise.
According to the Whoosh site "... And since we average 5-6 kts, that's over 100 amp/hrs/day ¨C for us quite possibly 150 amp/hrs/day ¨C that is available for running the radar at night, making water with offshore water quality, feeding the SSB radio, and keeping the iPod charged..." So what does this mean? They get 100-150Ah at 12V in 24 hours, that's 1200-1800Wh in 24 hours or 50-75W at 5-6kts. They do say that the harvested water power is sufficicient for house loads, a statement that I wholeheartedly agree with.
My statement is (and always has been) that regen at speeds around 5kts is not a viable source of charging for a traction battery bank. The speed is important because most displacement auxilliary sailboats between 27-32 feet (optimal for a 5kW electric drive) have a hard time hitting sustained runs above 6 kts. For this size boat, average sailing speeds of about 5.5kts is more realistic.
So let's say that you use 4kWh of energy out of your 10kWh battery bank, that's about 10-12nm at 4kts in most of our boats. How far would you have to sail using the system described by Whoosh to bring your batteries back to full charge, assuming that you are using no electrical power in the mean time? Generating 75W at 6kts, that's 12.5Wh/nm. So 4kWh will take 320nm of sailing at 6kts and will take over 53 hours. Slow down to 5kts under sail and the recharge distance is up to 400nm and will take 80 hours. If you have a 12V house load of only 2A, the recharge times and distances double.
Ignoring house loads, the ratio of drive distance (at 4kts) to regen distance (at 5kts) is about 1 to 40. Motor one mile at 4kts (15 minutes) and you need to sail 40 miles at 5kts (8 hours) to get the charge back. If you use a radio, autopilot or lights, the ratio gets worse.
So regen works, but is not as effective at recharging your traction batteries as some drive vendors would like you to believe.
Fair winds,
Eric
Marina del Rey
Hide quoted text
?
--- In electricboats@..., "Larry Doyle" <ldoyle@...> wrote:
Here's to those NaySayers that say regen doesn't work. Here's some boats that are doing it using towed gens as well as the free wheeling the prop/dc motor in regen mode.
www.svsarah.com/Whoosh/WhooshPacificPrepTowGenerator.html
|
Thanks for the positive feedback. ?I have no interest in publishing a book, I already have a good job, and I am good with making my information available as ¡°open source¡±.
The gear reduction is new, the motor bolts directly to it, and is a ratio of 2.55/1.
Since propellers are listed by diameter then pitch, the 13x15.5 is 13 inches in diameter with a 15.5 inch pitch. ?The 224 marking is the Acme part number.
You can see by the pricing from reputable vendors, prismatic cells are going for essentially the same price as they were 10 years ago. ?And the prices quoted on their websites do not include tax, shipping, etc. ?I am using autonomous mini-bms units that shunt excess charging current to help top balance the pack. ?They can also be wired to disable the charger in over-voltage situations on individual cells and de-power the drive in under-voltage situations, but I have not bothered to install that wiring. ?Still no problems after 10 years. ?I wish you the best with the pricing that ¡°sounds to good to be true¡±, sometimes those deals do come true, I hope that your purchase is one of those.
The only two instruments that I have for my drive is the Clearview display for the Sevcon Gen4 controller and the previously mentioned E-xpert Pro HV battery monitor. ?I find that both instruments are highly configurable and I believe them to be very accurate and precise (google accurate versus precise to clarify the difference, if desired). ?I get all of the information that I need without much extra complexity. ?I also use a hand-held digital multimeter to measure individual cell voltages during my annual ¡°health check¡±.
I think that covers most of the questions so far. ?
Fair winds,
Eric
|
Re: Measured Performance data sheet
I really like seeing real data.? Thanks to all who have shared.? I have collected data as I have found it from various sources on the interewebs and plotted it for what it's worth.? See attached screen grab of my spreadsheet.??
Dan Pfeiffer
?
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On 2020-05-23 9:59 am, THOMAS VANDERMEULEN wrote:
Eric,
I agree with Patrick ... incredibly useful.
I've asked a follow-up question elsewhere, but will ask it here too, where it seems more to the point of the post topic.
What is the reduction ratio of your transmission?? [At least, in your photos, it appears that you have some sort of transmission or reduction between the motor and prop shaft.]
I've also already noted elsewhere that you're running a 4-blade wheel of 13" x 15.5" dimensions.? [Also a very helpful detail for verifying 3rd party prop estimating tables.]
Thanks in advance for the additional detail ... I would just like to work out the prop shaft speed to go with prop information.
[-tv]
Tom VanderMeulen
Grace O'Malley
Cape Dory 27
Monroe, MI
|
Re: Measured Performance data sheet
I really like seeing real data.? Thanks to all who have shared.? I have collected data as I have found it from various sources on the interwebs and plotted it for what it's worth.? See attached screen grab of my spreadsheet.??
Dan Pfeiffer
|
Re: Somebody help Capt. John
Thanks for the reply, cables from batteries are 00 pacer and look proper for application to the breaker, shunt, solenoid, from there to the wire looks like 10ga pacer with spades that fit the lugs, the same to the motors which are comparative in size to the motor leads. I'm starting to think the motors, or props are undersized or something like that. I see your point, at some point going from 00 cable to10ga is a bottleneck however I have monitored the 10ga wire temps and they don't seem to heat up as much as the motors, but are the motors to hot at 146F? Each are on separate systems and both produce very equal numbers.
Hummmmm?
|
Hi I am a long term lurker. I am building some test platforms and hope to eventually come away with a fully electric small live aboard.
Is there such a thing as too much solar? My point being if tour batteries are right full 90% of the time? Will this be hard on batteries?
I realize this is not a problem most folks are faced with but in my application it could happen because of lack of movement and use.
Thanks
Nick
Sent from my Samsung Galaxy smartphone.
toggle quoted message
Show quoted text
-------- Original message -------- From: James Sizemore <james@...> Date: 2020-05-23 10:30 a.m. (GMT-05:00) Subject: Re: [electricboats] 39' sloop conversion
A cycle is generally a large draw down of your battery, under 20% to nearly full again. It takes many small draw downs to say 90% and back to nearly full again to equal one ¡°real¡± cycle. ?As for If solar or A generator while under way, Is counting against your cycles. Probably not if no charging and or drawdown is happening, if your batteries are not gaining or losing any charge then the internal resistance is higher then the resistance of your loads, so all the power from solar is going directly to loads. ?The battery really can not tell the difference between that and doing nothing. With the caveat that they would notice some fluctuations or ripples in the voltage. ?
Generally speaking it takes 100 of small draw downs and recharges to equal one cycle lost. ?You are a probably losing more capacity to just plan calendar life lose then from cycle life lose is most situations with LiFePo4, when not doing large drawdowns to under 20% back to full, they maintain they Capacity very well. ?
My pack is now 10 years old, I have lived aboard for over eight years of there life using them as a house bank (many small drawdowns to say 90-85% daily, and have Cruised the last 2 years meaning large draw downs a couple of times a month when I switch anchorages/marines as I travel. Generally I only draw them down to a little less then 50% on most travel days. ?But occasionally go down as far as 30%. ?I like to keep plenty of reserve capacity incase things don¡¯t go well. ?After 10 years, I have no measurable difference in there rated capacity.
What follows is ¡°internet theory¡± ?Some of that amazing lack of capacity lose may be do to Winston manufacturing ?there 1000ah cells with some reserve capacity. Meaning they may have Really been 1010 ah Cells originally. ?Most cell manufacturers no longer under rate there cells anymore. ?When large prismatic cells where new, they where a little over engineered for warranty purposes, but once the manufacturers had real word data on actual reliability they did less over engineering. ?
But either way my Winston LiFePo4 cells are still delivering like new performance ten years later. ?
On May 23, 2020, at 9:23 AM, Robert McArthur <rjmcarthur@...> wrote:
? Something I have wondered about hybrids and use of regular solar plus gensets... If you are going along and using power from the battery, and each moment there¡¯s some solar going in and you are running a genset so that¡¯s going in to the battery too: a battery has a certain number of cycles that it¡¯s good for (¡°good¡± being relative, but let¡¯s pretend it means that it still retains a useful amount of charge). The manufacturer may say a particular battery may be good for ¡°2000 cycles¡°. But given at every moment you are taking out, say, 100amps, while at the same time putting in 100amps (let¡¯s say), how much does that eat into the ¡°cycles¡± if you do that hour after hour, day after day?
Now what if you¡¯re pulling 100amps from a pack and that after an hour it takes The battery to 50% without anything going in (nice quiet motoring). At the start of the hour you start your oversized genset which, over the next hour, replaces the original 100amps AND the 100amps that the motor is using while the genset was running. So at the end of the second hour the battery is full. Then you run another hour quietly. Rinse and repeat. Under that scenario, are you eating into the cycle lifetime of the battery by 12 times every day? More? Less?
I¡¯m happy to assume LiFePO4 if that helps answer :).
Thanks Rob On 17 May 2020, at 11:36 pm, MATT <msteverson@...> wrote:
?Hello all, I'm a longtime lurker, this is my first post, so please, be gentle.
We have lived on our 39' sloop for about 5 years now and are ready to convert to hybrid...this is the plan I've come up with and am looking for your critical analysis.
The boat is a custom build. It displaces about 18000 lbs all full, has a 3/4 length "scheel" keel, and only draws about 50".? We currently have a very good running yanmar 3gm30f that turns a 17" 2 blade max prop.? We've put in about 20k nm over the past few years and she solidly averages 6kts.? The engine is in the middle of the boat under the galley sink and makes A LOT of noise and stink and we're sick of it.? We've got a little extra time and money so we think this project could go a long way.
The plan
- 48V 12KW Thunderstuck ME1616 kit - currently its on backorder - with a 3:1 gear reduction
- About 15kw lithium battery bank (right now Thunderstruck has Valence 1.6kw batteries used for $350 each, so 8 of these, and the VC1 BMS they sell, I think would be easy to install and work well.)
- A 3.5-4kw diesel generator that is PURELY for recharging batteries using the thunderstruck TSM2500 kit with 2 chargers.? This should get me 70amps at 48volts running from 240VAC.? This is important because we live at anchor in the PNW year round.? We often have a long way to go with no wind, or sun and generally avoid marinas.? I will buy this used or rebuilt to save dollars.
- Run existing loads off of a DC-DC converter
- We have 500W of PV installed with 12V Victron charge controllers?that keeps up with our daily usage.? I would like to get them putting electrons into the 48v bank and?am wondering if there is a work-around with DC to DC converters or something so I don't have to buy all new CCs.??
I will be doing this install myself.? I'm confident with basic stuff like solar installs and alternators but this project will be a little out of my comfort range, I'm very much looking forward to it.? What is most important to me is to keep the system as simple and user friendly as possible mostly for resale purposes.??
Any advice/comments/questions/trashtalk would be appreciated.??
Matt
|
Re: Measured Performance data sheet
I appreciate the focus on data and am interested to add to it later this summer.?
Out of curiosity - Having no formal seafaring training, is there a canonical text/protocol/reference on how to perform sea trials for new equipment? I¡¯m thinking things like checklist of environmental conditions to note, guidance on distance, any procedures on which tolerances to push etc? I can deduce the bounds I want to test or gain confidence in, but I¡¯m curious where one goes to learn a little deeper.?
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On May 23, 2020, at 08:53, Larry Brown <elcapitanbrown@...> wrote:
? 13" with 15.5 pitch? ?Or 15.5" with 13 pitch? On May 23, 2020, at 11:05 AM, THOMAS VANDERMEULEN <tvinypsi@...> wrote:
?Eric,
I agree with Patrick ... incredibly useful.
I've asked a follow-up question elsewhere, but will ask it here too, where it seems more to the point of the post topic.
What is the reduction ratio of your transmission?? [At least, in your photos, it appears that you have some sort of transmission or reduction between the motor and prop shaft.]
I've also already noted elsewhere that you're running a 4-blade wheel of 13" x 15.5" dimensions.? [Also a very helpful detail for verifying 3rd party prop estimating tables.]
Thanks in advance for the additional detail ... I would just like to work out the prop shaft speed to go with prop information.
[-tv]
Tom VanderMeulen
Grace O'Malley
Cape Dory 27
Monroe, MI
|
Re: Measured Performance data sheet
13" with 15.5 pitch? ?Or 15.5" with 13 pitch?
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Show quoted text
On May 23, 2020, at 11:05 AM, THOMAS VANDERMEULEN <tvinypsi@...> wrote:
?Eric,
I agree with Patrick ... incredibly useful.
I've asked a follow-up question elsewhere, but will ask it here too, where it seems more to the point of the post topic.
What is the reduction ratio of your transmission?? [At least, in your photos, it appears that you have some sort of transmission or reduction between the motor and prop shaft.]
I've also already noted elsewhere that you're running a 4-blade wheel of 13" x 15.5" dimensions.? [Also a very helpful detail for verifying 3rd party prop estimating tables.]
Thanks in advance for the additional detail ... I would just like to work out the prop shaft speed to go with prop information.
[-tv]
Tom VanderMeulen
Grace O'Malley
Cape Dory 27
Monroe, MI
|
Re: Somebody help Capt. John
The answer to that question has nothing to do with how hard you push your motors, and every thing to do with your wire gauge and fuse size. ?If the system was properly installed then your motors top usage draw should be well under the cable gauge used and the fuses should be rated to protect the wires not the motors. Meaning if the system was properly install, then you should be able to run the motor continuously at max load, and the cables if properly sized should stay under the rates sheathing temperature. ?
You should measure the length of you Cables to and from the motor controllers and the traction battery. Then note the wire gauge then uses an ABYC wire gauge chart to make sure they can handle the continuous max load draw. ?
You can find such charts all over the internet, here is one snatch from google for example:?
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On May 23, 2020, at 10:55 AM, john winterrowd via groups.io <sailorboy55577@...> wrote:
. I want to know how hard I can push with out blowing fuses or melting wires?
|
Re: Measured Performance data sheet
Eric,
I agree with Patrick ... incredibly useful.
I've asked a follow-up question elsewhere, but will ask it here too, where it seems more to the point of the post topic.
What is the reduction ratio of your transmission?? [At least, in your photos, it appears that you have some sort of transmission or reduction between the motor and prop shaft.]
I've also already noted elsewhere that you're running a 4-blade wheel of 13" x 15.5" dimensions.? [Also a very helpful detail for verifying 3rd party prop estimating tables.]
Thanks in advance for the additional detail ... I would just like to work out the prop shaft speed to go with prop information.
[-tv]
Tom VanderMeulen
Grace O'Malley
Cape Dory 27
Monroe, MI
|
Here is an example of a Winter month when Solar is not as reliable and I moved a few times causing significant capacity draw down. ?Lowest battery draw down was 50%. Again blue line battery charge level, red bars house loads, yellow Solar charging. Not shown is generator usage which there would have been on the 8th and 28th do to insufficient solar gain.?
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Show quoted text
On May 23, 2020, at 10:46 AM, "james@..." <james@...> wrote:
? The below image shows my typical house usage when at anchor, the blue line is battery charge state mostly fluctuating from high 80¡¯s to 99% state of charge. The read line is house daily usage and yellow is solar charging.?
On May 23, 2020, at 10:30 AM, James Sizemore <james@...> wrote:
? A cycle is generally a large draw down of your battery, under 20% to nearly full again. It takes many small draw downs to say 90% and back to nearly full again to equal one ¡°real¡± cycle. ?As for If solar or A generator while under way, Is counting against your cycles. Probably not if no charging and or drawdown is happening, if your batteries are not gaining or losing any charge then the internal resistance is higher then the resistance of your loads, so all the power from solar is going directly to loads. ?The battery really can not tell the difference between that and doing nothing. With the caveat that they would notice some fluctuations or ripples in the voltage. ?
Generally speaking it takes 100 of small draw downs and recharges to equal one cycle lost. ?You are a probably losing more capacity to just plan calendar life lose then from cycle life lose is most situations with LiFePo4, when not doing large drawdowns to under 20% back to full, they maintain they Capacity very well. ?
My pack is now 10 years old, I have lived aboard for over eight years of there life using them as a house bank (many small drawdowns to say 90-85% daily, and have Cruised the last 2 years meaning large draw downs a couple of times a month when I switch anchorages/marines as I travel. Generally I only draw them down to a little less then 50% on most travel days. ?But occasionally go down as far as 30%. ?I like to keep plenty of reserve capacity incase things don¡¯t go well. ?After 10 years, I have no measurable difference in there rated capacity.
What follows is ¡°internet theory¡± ?Some of that amazing lack of capacity lose may be do to Winston manufacturing ?there 1000ah cells with some reserve capacity. Meaning they may have Really been 1010 ah Cells originally. ?Most cell manufacturers no longer under rate there cells anymore. ?When large prismatic cells where new, they where a little over engineered for warranty purposes, but once the manufacturers had real word data on actual reliability they did less over engineering. ?
But either way my Winston LiFePo4 cells are still delivering like new performance ten years later. ?
On May 23, 2020, at 9:23 AM, Robert McArthur <rjmcarthur@...> wrote:
? Something I have wondered about hybrids and use of regular solar plus gensets... If you are going along and using power from the battery, and each moment there¡¯s some solar going in and you are running a genset so that¡¯s going in to the battery too: a battery has a certain number of cycles that it¡¯s good for (¡°good¡± being relative, but let¡¯s pretend it means that it still retains a useful amount of charge). The manufacturer may say a particular battery may be good for ¡°2000 cycles¡°. But given at every moment you are taking out, say, 100amps, while at the same time putting in 100amps (let¡¯s say), how much does that eat into the ¡°cycles¡± if you do that hour after hour, day after day?
Now what if you¡¯re pulling 100amps from a pack and that after an hour it takes The battery to 50% without anything going in (nice quiet motoring). At the start of the hour you start your oversized genset which, over the next hour, replaces the original 100amps AND the 100amps that the motor is using while the genset was running. So at the end of the second hour the battery is full. Then you run another hour quietly. Rinse and repeat. Under that scenario, are you eating into the cycle lifetime of the battery by 12 times every day? More? Less?
I¡¯m happy to assume LiFePO4 if that helps answer :).
Thanks Rob On 17 May 2020, at 11:36 pm, MATT <msteverson@...> wrote:
?Hello all, I'm a longtime lurker, this is my first post, so please, be gentle.
We have lived on our 39' sloop for about 5 years now and are ready to convert to hybrid...this is the plan I've come up with and am looking for your critical analysis.
The boat is a custom build. It displaces about 18000 lbs all full, has a 3/4 length "scheel" keel, and only draws about 50".? We currently have a very good running yanmar 3gm30f that turns a 17" 2 blade max prop.? We've put in about 20k nm over the past few years and she solidly averages 6kts.? The engine is in the middle of the boat under the galley sink and makes A LOT of noise and stink and we're sick of it.? We've got a little extra time and money so we think this project could go a long way.
The plan
- 48V 12KW Thunderstuck ME1616 kit - currently its on backorder - with a 3:1 gear reduction
- About 15kw lithium battery bank (right now Thunderstruck has Valence 1.6kw batteries used for $350 each, so 8 of these, and the VC1 BMS they sell, I think would be easy to install and work well.)
- A 3.5-4kw diesel generator that is PURELY for recharging batteries using the thunderstruck TSM2500 kit with 2 chargers.? This should get me 70amps at 48volts running from 240VAC.? This is important because we live at anchor in the PNW year round.? We often have a long way to go with no wind, or sun and generally avoid marinas.? I will buy this used or rebuilt to save dollars.
- Run existing loads off of a DC-DC converter
- We have 500W of PV installed with 12V Victron charge controllers?that keeps up with our daily usage.? I would like to get them putting electrons into the 48v bank and?am wondering if there is a work-around with DC to DC converters or something so I don't have to buy all new CCs.??
I will be doing this install myself.? I'm confident with basic stuff like solar installs and alternators but this project will be a little out of my comfort range, I'm very much looking forward to it.? What is most important to me is to keep the system as simple and user friendly as possible mostly for resale purposes.??
Any advice/comments/questions/trashtalk would be appreciated.??
Matt
|
The below image shows my typical house usage when at anchor, the blue line is battery charge state mostly fluctuating from high 80¡¯s to 99% state of charge. The read line is house daily usage and yellow is solar charging.?
toggle quoted message
Show quoted text
On May 23, 2020, at 10:30 AM, James Sizemore <james@...> wrote:
? A cycle is generally a large draw down of your battery, under 20% to nearly full again. It takes many small draw downs to say 90% and back to nearly full again to equal one ¡°real¡± cycle. ?As for If solar or A generator while under way, Is counting against your cycles. Probably not if no charging and or drawdown is happening, if your batteries are not gaining or losing any charge then the internal resistance is higher then the resistance of your loads, so all the power from solar is going directly to loads. ?The battery really can not tell the difference between that and doing nothing. With the caveat that they would notice some fluctuations or ripples in the voltage. ?
Generally speaking it takes 100 of small draw downs and recharges to equal one cycle lost. ?You are a probably losing more capacity to just plan calendar life lose then from cycle life lose is most situations with LiFePo4, when not doing large drawdowns to under 20% back to full, they maintain they Capacity very well. ?
My pack is now 10 years old, I have lived aboard for over eight years of there life using them as a house bank (many small drawdowns to say 90-85% daily, and have Cruised the last 2 years meaning large draw downs a couple of times a month when I switch anchorages/marines as I travel. Generally I only draw them down to a little less then 50% on most travel days. ?But occasionally go down as far as 30%. ?I like to keep plenty of reserve capacity incase things don¡¯t go well. ?After 10 years, I have no measurable difference in there rated capacity.
What follows is ¡°internet theory¡± ?Some of that amazing lack of capacity lose may be do to Winston manufacturing ?there 1000ah cells with some reserve capacity. Meaning they may have Really been 1010 ah Cells originally. ?Most cell manufacturers no longer under rate there cells anymore. ?When large prismatic cells where new, they where a little over engineered for warranty purposes, but once the manufacturers had real word data on actual reliability they did less over engineering. ?
But either way my Winston LiFePo4 cells are still delivering like new performance ten years later. ?
On May 23, 2020, at 9:23 AM, Robert McArthur <rjmcarthur@...> wrote:
? Something I have wondered about hybrids and use of regular solar plus gensets... If you are going along and using power from the battery, and each moment there¡¯s some solar going in and you are running a genset so that¡¯s going in to the battery too: a battery has a certain number of cycles that it¡¯s good for (¡°good¡± being relative, but let¡¯s pretend it means that it still retains a useful amount of charge). The manufacturer may say a particular battery may be good for ¡°2000 cycles¡°. But given at every moment you are taking out, say, 100amps, while at the same time putting in 100amps (let¡¯s say), how much does that eat into the ¡°cycles¡± if you do that hour after hour, day after day?
Now what if you¡¯re pulling 100amps from a pack and that after an hour it takes The battery to 50% without anything going in (nice quiet motoring). At the start of the hour you start your oversized genset which, over the next hour, replaces the original 100amps AND the 100amps that the motor is using while the genset was running. So at the end of the second hour the battery is full. Then you run another hour quietly. Rinse and repeat. Under that scenario, are you eating into the cycle lifetime of the battery by 12 times every day? More? Less?
I¡¯m happy to assume LiFePO4 if that helps answer :).
Thanks Rob On 17 May 2020, at 11:36 pm, MATT <msteverson@...> wrote:
?Hello all, I'm a longtime lurker, this is my first post, so please, be gentle.
We have lived on our 39' sloop for about 5 years now and are ready to convert to hybrid...this is the plan I've come up with and am looking for your critical analysis.
The boat is a custom build. It displaces about 18000 lbs all full, has a 3/4 length "scheel" keel, and only draws about 50".? We currently have a very good running yanmar 3gm30f that turns a 17" 2 blade max prop.? We've put in about 20k nm over the past few years and she solidly averages 6kts.? The engine is in the middle of the boat under the galley sink and makes A LOT of noise and stink and we're sick of it.? We've got a little extra time and money so we think this project could go a long way.
The plan
- 48V 12KW Thunderstuck ME1616 kit - currently its on backorder - with a 3:1 gear reduction
- About 15kw lithium battery bank (right now Thunderstruck has Valence 1.6kw batteries used for $350 each, so 8 of these, and the VC1 BMS they sell, I think would be easy to install and work well.)
- A 3.5-4kw diesel generator that is PURELY for recharging batteries using the thunderstruck TSM2500 kit with 2 chargers.? This should get me 70amps at 48volts running from 240VAC.? This is important because we live at anchor in the PNW year round.? We often have a long way to go with no wind, or sun and generally avoid marinas.? I will buy this used or rebuilt to save dollars.
- Run existing loads off of a DC-DC converter
- We have 500W of PV installed with 12V Victron charge controllers?that keeps up with our daily usage.? I would like to get them putting electrons into the 48v bank and?am wondering if there is a work-around with DC to DC converters or something so I don't have to buy all new CCs.??
I will be doing this install myself.? I'm confident with basic stuff like solar installs and alternators but this project will be a little out of my comfort range, I'm very much looking forward to it.? What is most important to me is to keep the system as simple and user friendly as possible mostly for resale purposes.??
Any advice/comments/questions/trashtalk would be appreciated.??
Matt
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A cycle is generally a large draw down of your battery, under 20% to nearly full again. It takes many small draw downs to say 90% and back to nearly full again to equal one ¡°real¡± cycle. ?As for If solar or A generator while under way, Is counting against your cycles. Probably not if no charging and or drawdown is happening, if your batteries are not gaining or losing any charge then the internal resistance is higher then the resistance of your loads, so all the power from solar is going directly to loads. ?The battery really can not tell the difference between that and doing nothing. With the caveat that they would notice some fluctuations or ripples in the voltage. ?
Generally speaking it takes 100 of small draw downs and recharges to equal one cycle lost. ?You are a probably losing more capacity to just plan calendar life lose then from cycle life lose is most situations with LiFePo4, when not doing large drawdowns to under 20% back to full, they maintain they Capacity very well. ?
My pack is now 10 years old, I have lived aboard for over eight years of there life using them as a house bank (many small drawdowns to say 90-85% daily, and have Cruised the last 2 years meaning large draw downs a couple of times a month when I switch anchorages/marines as I travel. Generally I only draw them down to a little less then 50% on most travel days. ?But occasionally go down as far as 30%. ?I like to keep plenty of reserve capacity incase things don¡¯t go well. ?After 10 years, I have no measurable difference in there rated capacity.
What follows is ¡°internet theory¡± ?Some of that amazing lack of capacity lose may be do to Winston manufacturing ?there 1000ah cells with some reserve capacity. Meaning they may have Really been 1010 ah Cells originally. ?Most cell manufacturers no longer under rate there cells anymore. ?When large prismatic cells where new, they where a little over engineered for warranty purposes, but once the manufacturers had real word data on actual reliability they did less over engineering. ?
But either way my Winston LiFePo4 cells are still delivering like new performance ten years later. ?
toggle quoted message
Show quoted text
On May 23, 2020, at 9:23 AM, Robert McArthur <rjmcarthur@...> wrote:
? Something I have wondered about hybrids and use of regular solar plus gensets... If you are going along and using power from the battery, and each moment there¡¯s some solar going in and you are running a genset so that¡¯s going in to the battery too: a battery has a certain number of cycles that it¡¯s good for (¡°good¡± being relative, but let¡¯s pretend it means that it still retains a useful amount of charge). The manufacturer may say a particular battery may be good for ¡°2000 cycles¡°. But given at every moment you are taking out, say, 100amps, while at the same time putting in 100amps (let¡¯s say), how much does that eat into the ¡°cycles¡± if you do that hour after hour, day after day?
Now what if you¡¯re pulling 100amps from a pack and that after an hour it takes The battery to 50% without anything going in (nice quiet motoring). At the start of the hour you start your oversized genset which, over the next hour, replaces the original 100amps AND the 100amps that the motor is using while the genset was running. So at the end of the second hour the battery is full. Then you run another hour quietly. Rinse and repeat. Under that scenario, are you eating into the cycle lifetime of the battery by 12 times every day? More? Less?
I¡¯m happy to assume LiFePO4 if that helps answer :).
Thanks Rob On 17 May 2020, at 11:36 pm, MATT <msteverson@...> wrote:
?Hello all, I'm a longtime lurker, this is my first post, so please, be gentle.
We have lived on our 39' sloop for about 5 years now and are ready to convert to hybrid...this is the plan I've come up with and am looking for your critical analysis.
The boat is a custom build. It displaces about 18000 lbs all full, has a 3/4 length "scheel" keel, and only draws about 50".? We currently have a very good running yanmar 3gm30f that turns a 17" 2 blade max prop.? We've put in about 20k nm over the past few years and she solidly averages 6kts.? The engine is in the middle of the boat under the galley sink and makes A LOT of noise and stink and we're sick of it.? We've got a little extra time and money so we think this project could go a long way.
The plan
- 48V 12KW Thunderstuck ME1616 kit - currently its on backorder - with a 3:1 gear reduction
- About 15kw lithium battery bank (right now Thunderstruck has Valence 1.6kw batteries used for $350 each, so 8 of these, and the VC1 BMS they sell, I think would be easy to install and work well.)
- A 3.5-4kw diesel generator that is PURELY for recharging batteries using the thunderstruck TSM2500 kit with 2 chargers.? This should get me 70amps at 48volts running from 240VAC.? This is important because we live at anchor in the PNW year round.? We often have a long way to go with no wind, or sun and generally avoid marinas.? I will buy this used or rebuilt to save dollars.
- Run existing loads off of a DC-DC converter
- We have 500W of PV installed with 12V Victron charge controllers?that keeps up with our daily usage.? I would like to get them putting electrons into the 48v bank and?am wondering if there is a work-around with DC to DC converters or something so I don't have to buy all new CCs.??
I will be doing this install myself.? I'm confident with basic stuff like solar installs and alternators but this project will be a little out of my comfort range, I'm very much looking forward to it.? What is most important to me is to keep the system as simple and user friendly as possible mostly for resale purposes.??
Any advice/comments/questions/trashtalk would be appreciated.??
Matt
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Ill try to make this a short read, LOL Impossible.Found this older Sail Craft in St. Pete Florida, discovered its has three phase PM servo motors, 2000 watts of solar, regen, 2 ac units, no genset, and a 240v charger, uses 12 group 31 AGMs, all below floors in each hull, twin systems with cross tie for charging both sides at the same time. 8 more AGMs for two 12v house systems, 3 inverters. older style catamaran @ 44 LOA and 20 Beam.? Apache 40' modified to 44'.So, I added the Fisher Panda mini digital 9 Kw, it contributes 46 amps in 220v configuration, so I can run one reverse cycle AC and the charger or both AC units, plus galley. 50 gal of diesel lasts about week.Inside helm shows voltage of each bank, outside helm displays each motor's amp draw plus or minus, I have no idea what SOC or charger out put is, BTW is a Zivan 144v.I'm going to include my motor plate for all you electrical engineers out there to run the math, I'm looking for feed back.Heat is my main concern, Servo amplifiers do not heat up, the TENV PM motors will get warm after an hour or so. Let me back up.When I bought her, the boat would not accelerate, I splashed her after the big gen install new battery's, (Duracell AGM 105 AH) and a 2.5 hr stress test tied to the dock I fried the starboard amp, so I pulled the motors sent them for inspection, new bearings, new Hall effect sensors, insulation, then contacted Advanced Motion Controls (Nash Dingman) for new amps, after a few months of schooling and no fires or sparks we were moving again. I added huge heat syncs to the amps and pancake fans, I did not have a O scope to tune the drives, I did it by the seat of my pants, its not perfect, nor am I, it works! Its tuned in Duty Cycle mode. Which meant it will quit on low voltage, 36v and high175v. I turn on the rear Ac unit and have box fans blowing into the motor compartment's because I'm worried ill over heat, the highest motor case temp I've reached is 146 degrees, taken with a thermal laser, I don't think that's HOT but I'm not sure either. I've never pushed the amps over 18, and when I engage the motors it shows about 3.2 average amps after a spike to 6 on start up and the boat moves about 3knts in ideal conditions. I want to know how hard I can push with out blowing fuses or melting wires? I want to install a BMS so any brand names please post links if you have them?I want to convert the TENV NEMA 180 cases to TEFC (fan cooled). Cameron @Power Tec will someday answer my emails where to get the fans.Props are 15 inch, I don't know the pitch, I think the boat is 13 tons displacement I could be wrong. I would like to know what my range is, mathematical theoretic calculations will do.
Thanks all, attached are the?
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Thanks, Eric.? I'm looking at the spreadsheet and the photos you generously posted.? I have a follow-on question, but first, appreciation, I would say one thing.? Certainly some folks who'd developed such a knowledge base as you have might have tried to monetize it by publishing a book!? Life gets in the way for many, I'm sure, who attempt such a project on their own, and those who've simply paid someone to do it would have little interest in a group like this one.? But for someone like me who has the desire to do something personally and globally beneficial but lacks the appropriate theoretical or practical background, it's a much slower process!
Now, back to my follow-up question.? Your prop is a 4-blade 13" dia. X 15.5" pitch wheel.? (Being 4-blade, I presume you let it freewheel while under sail so that it does not add drag while getting the "gift" you mentioned earlier of 0.7 amp of regen.)? In your photo of the motor installation, it appears that you've connected it to an old transmission.? What is the reduction ratio, please?? Your spreadsheet shows motor RPM and I'm interested in translating that into prop shaft RPM.
With respect to your statement about cost of LiFePO4 batteries, you mentioned paying ~$0.45/Wh, which if my arithmetic is correct, works out to ~$230 per individual 3.2v cell.? But after some trial and error (and non-trivial cost!), I've located a source in China that will deliver genuine 200Ah CALB LiFePO4 cells for ~$125 ea (including freight & customs) which works out to under $0.20/Wh.? Adding a Thunderstruck BMSC and EVCC brings the cost for the pack up to ~$0.26/Wh.? These are the same battery cells that Electric Car Parts Co sells for $253/ea (T'struck price for 180Ah CALBs is ~$250 also.)? Something I've spent quite a bit of additional money on is what I'll call "user interface", convenience, and compliance materials (an EV Display from T'struck, meters, tachometer, wiring, connectors, switches, lights, alarms, etc).? But that's a topic for a different post!
[-tv]
Tom VanderMeulen
Grace O'Malley
Cape Dory 27
Monroe, MI
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Something I have wondered about hybrids and use of regular solar plus gensets... If you are going along and using power from the battery, and each moment there¡¯s some solar going in and you are running a genset so that¡¯s going in to the battery too: a battery has a certain number of cycles that it¡¯s good for (¡°good¡± being relative, but let¡¯s pretend it means that it still retains a useful amount of charge). The manufacturer may say a particular battery may be good for ¡°2000 cycles¡°. But given at every moment you are taking out, say, 100amps, while at the same time putting in 100amps (let¡¯s say), how much does that eat into the ¡°cycles¡± if you do that hour after hour, day after day?
Now what if you¡¯re pulling 100amps from a pack and that after an hour it takes The battery to 50% without anything going in (nice quiet motoring). At the start of the hour you start your oversized genset which, over the next hour, replaces the original 100amps AND the 100amps that the motor is using while the genset was running. So at the end of the second hour the battery is full. Then you run another hour quietly. Rinse and repeat. Under that scenario, are you eating into the cycle lifetime of the battery by 12 times every day? More? Less?
I¡¯m happy to assume LiFePO4 if that helps answer :).
Thanks
toggle quoted message
Show quoted text
On 17 May 2020, at 11:36 pm, MATT <msteverson@...> wrote:
?Hello all, I'm a longtime lurker, this is my first post, so please, be gentle.
We have lived on our 39' sloop for about 5 years now and are ready to convert to hybrid...this is the plan I've come up with and am looking for your critical analysis.
The boat is a custom build. It displaces about 18000 lbs all full, has a 3/4 length "scheel" keel, and only draws about 50".? We currently have a very good running yanmar 3gm30f that turns a 17" 2 blade max prop.? We've put in about 20k nm over the past few years and she solidly averages 6kts.? The engine is in the middle of the boat under the galley sink and makes A LOT of noise and stink and we're sick of it.? We've got a little extra time and money so we think this project could go a long way.
The plan
- 48V 12KW Thunderstuck ME1616 kit - currently its on backorder - with a 3:1 gear reduction
- About 15kw lithium battery bank (right now Thunderstruck has Valence 1.6kw batteries used for $350 each, so 8 of these, and the VC1 BMS they sell, I think would be easy to install and work well.)
- A 3.5-4kw diesel generator that is PURELY for recharging batteries using the thunderstruck TSM2500 kit with 2 chargers.? This should get me 70amps at 48volts running from 240VAC.? This is important because we live at anchor in the PNW year round.? We often have a long way to go with no wind, or sun and generally avoid marinas.? I will buy this used or rebuilt to save dollars.
- Run existing loads off of a DC-DC converter
- We have 500W of PV installed with 12V Victron charge controllers?that keeps up with our daily usage.? I would like to get them putting electrons into the 48v bank and?am wondering if there is a work-around with DC to DC converters or something so I don't have to buy all new CCs.??
I will be doing this install myself.? I'm confident with basic stuff like solar installs and alternators but this project will be a little out of my comfort range, I'm very much looking forward to it.? What is most important to me is to keep the system as simple and user friendly as possible mostly for resale purposes.??
Any advice/comments/questions/trashtalk would be appreciated.??
Matt
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Re: Measured Performance data sheet
Hi All
Incredibly useful information from Eric, just what is needed to clear some of the murk surrounding real time use.
Thank you.
Patrick Kenlock
23ft Westerly Pageant
Thinking of conversion.
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I think the answer is yes about the 2200 watt generator moving you 2.5 to 3 kts.? But that is in a calm wind and sea state and it doesn't account for tidal flow/current.? Prop makes a big difference too.? I'm about to buy a new prop for mine but with an 18" two blade prop it takes 20 amps to move me at 3kts and that's what I would get out of the honda eu2000 generator (25amps).? I have a second generator so with a better prop and both generators I should?be around 5kts with 50amps which is what Eric was showing in his results.? To me that's a minimum for dealing with tidal flow/current and wind and chop.? Between those things I would probably be looking at 2 or 3 kts headway in some situations or maybe a single kt but with the generators running I can keep up that 1 kt till circumstances change or I decide to throw out a sea anchor and wait until things subside.? As Eric mentions a lot of people new to things talk in generalities and I'm afraid I'm one of them until I get my new prop and can report better findings.
Personally I'd say get two chargers and two 2200 generators for a trip around Vancouver Island etc.? They aren't that expensive and at worst having a spare could save you.? Also, someone mentioned the generators possibly shutting off in a rough sea due to the oil sensor thinking the oil is low.? I have a trimaran so my boat doesn't heel.? I'm expecting it won't be a problem for me but you might find otherwise?? Maybe someone on the list who runs one as a backup can confirm it's a problem or that it's not?
Good luck,
Larry
On Fri, May 22, 2020 at 6:02 PM Lee Chrystal < lee@...> wrote: Thank you Eric! So for small displacement boats like my Balboa 27 ft swing keel,4900 lbs disp, 23 ft on waterline 8 ft beam, 13RH11 prop i guess regen is not going to happen except in some marketing ploy. Shattering news but now accepted! ? This brings me to my new issue, What size, brand of small generator will keep me moving at 3 kts, or is that also unlikely/impossible. Seems as I have the space now without the Yanmar. ? I will supplement with solar but space is quite limited and when I am not sailing in the gulf of Thailand it sometimes just wont shine! I was all gung ho, I ripped out the Yanmar package and now cannot seem to get this moving forward with any confidence. ? I believe the gent at Thunderstruck said I should get about 60 miles, with their 5KW-48 V system at about 3 kts. Hopefully that¡¯s accurate, Let me know your opinions on that statement please. ? Normally 60 miles is surely enough, It¡¯s a sailboat but I want to go around Vancouver Island next summer and feel 60 might not be sufficient in a dilemma. Dismasted or other distress situations for example. ? How many watts to generate enough power to just keep moving forward using the Thunderstruck 5KW in a o-crap situation albeit slowly? In reasonable sea states at least. Should a 2200 watt gen keep me moving at about 2.5-3 Kts? ? I don¡¯t mention an outboard and I will have a small one also but I have been on many small sailboats when its prop was just not underwater ? the time. Any advice is appreciated. Thanks. Lee Chrystal Marsh Specialty HVAC LTD Box 5061 STN Main Leduc Alberta T9E-6L5 Cell: (780) 975-6801 ?
? ? ? ? And you asked about regen.? Here's something that I wrote back in 2011:
"Regen is a funny thing.? I have yet to hear any substantiated report of anyone hydro-generating more than 100W at 6 knots.? That's including regular cruising sailors with towed systems.?? It's really a limitation of physics.? If you can sail consistantly at speeds greater than about 8kts (large racing monohulls, big catamarans, etc.) then regen becomes a reasonable power source.? But for boats like mine, under the best of conditions, regen might suffice to replenish house loads, or maybe not.? Regen will not put any significant charge into a traction battery bank on passages of less than a week.? It just that at 6kts, we're at the really flat part of the logorithmic power curve.?? As it is, I have seen peak regen of around 1.4A (70W) while sailing around 6kts but the 5 minute average was probably closer to .7A (35W).?? So any regen power that I get is just a gift, certainly nothing that I would count on.? If I wanted to optimize my regen, I believe that a towed log is most effective, but that would still not generate any significant power at the limited speed of my 30' ketch."??
These limitations still appear to be true, even with the dedicated, $10k, technologically advanced, Watt & Sea hydrogenerators.? If they can't generate 100W at 6kts with a specialized and optimized hydrogenration system, the power collected by for your re-purposed drive system will be less.
Fair winds and following seas,
Eric
1964 Cheoy Lee Bermuda 30, 5.5kW drive, 8kWh LiFePO4 battery bank
Marina del Rey, Ca? ?
-- Larry Brown S/V Trident Palm Harbor, FL ~~~~~~~~~~~~~~~~~_/)~~~~~~~~ ? ? ~ ? ? ~ ? ? ? ? ?~~ ? ? ? ? ? ~ ~ ? ? ? ? ? ~~_/) ? ?~ ? ? ?~ ~ ? ? ? ?~ ? ? ?~ ? ? ? ? ? ? ? ? ?_/) ? ? ? ? ?~
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Hey Fred, Here's a post that I made a few years ago about my LiFePO4 battery bank:
My battery pack is 16 Thundersky 160Ah cells in series with Mini-BMS modules from EV Works on each cell. My experience lines up with Jason's. Minimal draw over long storage periods. I have measured cell performance through annual controlled deep discharge and recharge cycles since the pack's installation in 2010. There has been minimal capacity degradation over the last six years, however, the cells are still outperforming their manufacturer's specs. I have adjusted my E-Xpert Pro battery monitor to account for my overall self-discharge rate, I believe that my present setting of 2.6%/month is very close. That rate includes the effects of the BMS cells.
I have stored my batteries starting at states from 100% down to 60%. As I stated earlier, the cells are still outperforming their stated specs. It does not appear that leaving them at 100% for months at a time has had any measurable effect. That said, maybe it has cost me something in cycle life. Since I am still under 100 cycles after six years, I doubt that I will get the chance to observe a small percentage reduction in the stated 2000+ cycle lifespan.
After owning this battery pack for 6 years, I am a solid proponent of the technology. Previously, the average lifespan of a lead acid battery in any intermittent duty has been something less than 3 years for me, in spite of my well intentioned, but apparently inadequate, attention to battery maintenance. This includes classic cars, utility vehicles and my boats.
I have found LiFePO4 cells to be lighter, smaller, take less attention, and safer than the various types of lead acid batteries (wet, AGM, gel). I have blown up a wet cell L/A battery with a trickle charger. This lead to extensive corrosive damage, luckily, the car and my garage did not catch fire. For me, the lithium cells have already proven to be cheaper, based on my personal history, I would be getting ready to buy my third set of lead acid batteries for my boat. That would offset any cost savings that I would have gotten during my initial install.
I purchased my cells and BMS in 2009 for just under $0.45/Wh, including shipping and taxes, which is still an excellent deal today for new, not used or reclaimed, product. So for those of you that are waiting for the prices to drop 20% in the year or so as promised by "experts", I can tell you that they were saying the same thing seven years ago. Maybe Tesla and cordless drill manufacturers are saving money, but those savings have never materialized for small volume, end user customers like us. That said, the prices have been stable while most things have been affected by inflation, so that is a net effect of getting relatively cheaper. Bottom line, other than your ability to afford the initial purchase, it is my belief that every other concern with LiFePO4 batteries that has been listed here recently, is really not an issue in the real world.
This is all based on my first hand experiences. Good luck with your decisions.
Eric
Marina del Rey, CA
1964 Cheoy Lee Bermuda 30, 5KW Propulsion Marine drive, 8KWh LiFePo4 battery pack.
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THOMAS VANDERMEULEN