On May 24, 2020, at 3:06 PM, Eric via groups.io <ewdysar@...> wrote:

?Unfortunately, that isn’t really an option. ?I put this all together 10 years ago, and most of what I bought is no longer available. ?Thundersky stopped making prismatic cells, but there are a number of other reputable manufacturers that still do, like CALB. ?ElCon no longer makes the PFC 2000+ charger, although the still available PFC 2500 will produce almost 90% of the charge of the 2000+ when powered by 115V A/C. ?The EVPower mini-BMS modules are no longer made, there were other manufacturer’s versions, but even those may be gone now. ?There are plenty of other BMS solutions, you pick the features and price that meet your needs. ?But the E-xpert Pro HV monitor is still available, I saw a listing on amazon for about $250. ?

You should also consider very heavy gauge cabling for your battery pack (see my photo album referenced in another post). I bought the cabling and hardware to make my own cables from genuinedealz.com, they’ve got great prices on marine quality wire. ?I used 2/0 cable for all of my main current connections. ?The bigger the wire, the lower the resistance (losses) over distance, and therefore, the greater efficiency of your system as a whole.

Fair winds,
Eric

PS, I didn’t know anything about any of this when I started my project, and the help I got early on was limited. ?But I figured out what my questions were, learned what I could here and from other groups; DIY electric car builders, boat builders, battery manufacturers, electrical engineers, etc. and figured out my own answers. ?My credentials? I’ve got none, no college degree, just a smattering of practical experience in a wide variety of interests. ?This is just a hobby for me.

On Sat, May 23, 2020 at 08:49 PM, fred jelich wrote:

How much to duplicate your setup? I don't know enough about it to try to build it myself.

On Sat, May 23, 2020, 2:31 AM Eric via <ewdysar=[email protected]> wrote:

Hey Fred,

Here's a post that I made a few years ago about my LiFePO4 battery bank:

?Eric

01/26/17???#28070??

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.

On May 25, 2020, at 10:41 AM, Ric Sanders <rsandersemail@...> wrote:

?

I looked up the Elcon line. They want a 230 volt input. I’m trying to not have to rewire my existing generator to that voltage.?

I love the Victron line and use their charge controllers on our solar. I have a 2k inverter charger on our house system which is completely separate from the motor system so do not need another inverter. I’ve not found a Charger only yet to do what I desire and am still looking. I’m just beginning to get to where we can do some more extensive runs to find amp draw versus speed. With the limited ability we have to put power into the system, longer runs have so far been impractical.

Thanks guys

Ric

On Sat, May 23, 2020 at 3:26 PM Ric Sanders <rsandersemail@...> wrote:

Thank “Powermax” 48 volt 20 amp chargers powered from a 6KW 120 volt AC output generator set but I would really like to do is be able to put about 100 amps into the battery/motor circuit.?

Cheers,

Ric

On May 24, 2020, at 1:28 PM, Eric via groups.io <ewdysar@...> wrote:

?Before I get to the calculators that are relevant to an electric boat conversion project, let’s discuss the purpose of the calculators and how they work.

There are all sorts of calculators available, ones to plan retirement, manage our weight, make home improvements, etc. etc. ?All of these calculators are based on known values and assumptions for the values that are not known, put into formulae that calculate the interaction of the data input and produce an answer to whatever question that we asked . ?We use these calculators to predict future performance of a new system or changes to an existing system. This allows us to try different components or actions and see how those changes might influence the outcomes. ?These calculators are limited by both the quality of the data, i.e. accuracy of the known data and validity of the assumed data, and the quality of the formulae in modeling results in the real world.

Simple calculators using only known data work very well, like converting standard measurements to metric, there are single constants and they always work. ?Calculating miles per gallon is done with measured input, but the results are dependent on how accurate the distance (miles) or consumed resource (gallons of gas) are measured. ?Estimating your retirement wealth 20 years in the future is harder, because the assumptions of available income, investment returns, and inflation are guesses at best.

We can validate how well a calculator works by checking the predictions against objective measurements of the system after implementation. ?A 59” board will measure to 150cm every time (149.86cm to be more precise). ?If my car gets 39.6mpg (2014 VW Jetta Sportwagen TDI) and I plan a trip of 500 miles, I should use 12.7 gallons. ?But traffic, terrain, and how the car is loaded, influence the outcome, so the real answer might be +/- up to a gallon (36 to 42 mpg) and I would find that acceptable. ?Alternatively, I could make assumptions about the additional influences and add them into the formulae in an effort to make the prediction more accurate, but at some point there are diminishing returns for the additional effort and complexity.?

Ok, so what about the calculators for our boat conversions? ?They predict power needed, suggest components (like props) and predict performance of your completed project. ?Some of these calculators are based on very complex models of hydrodynamics and some assumptions of how power is translated into movement. ?These calculators work fairly well for their intended audience, boats being powered by internal combustion engines operation near 90% throttle (look, we’ve already made some specific assumptions). ?And we know that they work fairly well by checking the predictions against the thousands of boats than meet that criteria. ?We can tell if a boat is under-powered, and nobody is particularly concerned about an overpowered installation. ?But even then, picking a propeller is still more of a fuzzy art, than a science, and dialing in a propeller selection when you don’t have an identical example installation is still often trial and error. ?Still, thousands of boats are re-powered with diesel or gasoline inboards and outboards every year and the owners are usually satisfied with the outcome, i.e. the resulting performance is close enough to the calculated predictions.

Unfortunately, these calculators don’t work very well for our projects. ?Most of these calculators today are based on the work of Dave Gerr who published “The Propeller Handbook” almost 20 years ago. ?It is an excellent reference and many of the guidelines and suggestions are as true for us as other boats. ?But, in my experience, the “power needed” predictions are not even close for our use case. ?In the case of the Vicprop calculator, it predicts that my boat needs 15hp at the propeller to motor at 6kts, and that 7hp will only push the boat to 4.5kts. ?You can see my measured performance results in other posts. ?The energy used is measured as it comes out of the batteries, before any losses in the cabling, controller, motor, gearbox, or bearings, therefore, the power available at the propeller must be less than the power coming out of the batteries. ?Let’s check the predictions against my measurements. ?I’ll be using the simple conversion of 1hp = 746W to translate between the two values.

my boat at 6 kts:
prediction: 15hp (11,190W) at the prop
measured: 7hp (5200W) at the batteries
result: calculator predicted 115% more power needed and any losses between my batteries and propeller makes that worse.

My boat at 4.5 kts:
prediction: 7hp (5200W) at the prop
measured: 2.1hp (1600W) at the batteries
result: calculator predicted 225% more power needed and again, my system losses would make the error greater.

We can see that as we slow down, the calculators get more inaccurate. ?I did have a conversation with Dave Gerr about these discrepancies, and he and I agreed that his formulae work for what they are intended for, and that they appear to not work for for our specific use case. ?We did not come to any conclusions about the cause of these discrepancies or adjustments to make for our use case. ?

I know that in this age of information, we want straightforward answers to what seem like straightforward questions. ?But,?recognize that we are outliers in the world of naval architecture and marine engineering. ?For some of it, we’re on our own. ?Which is why we’re in this group, right? ?We’re breaking new ground together. ?Which is why I believe it is so important to go beyond “it works!” or “I’m happy” and really measure our results, share those findings and work together to figure this all out.

Whew! that was more than I had intended...

Fair winds,
Eric

How much to duplicate your setup? I don't know enough about it to try to build it myself.

On Sat, May 23, 2020, 2:31 AM Eric via <ewdysar=[email protected]> wrote:

Hey Fred,

Here's a post that I made a few years ago about my LiFePO4 battery bank:

?Eric

01/26/17???#28070??

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.

I knew this was the right place to ask.

Thanks,

Ric

On Sat, May 23, 2020 at 6:12 PM Eric via <ewdysar=[email protected]> wrote:

hey Ric,
Try looking for ev onboard chargers.? This one is the big brother to my boat’s shore charger.



Not the full 100A that you requested, but it will hit 80A at charging voltages for a 48V pack (56-60V) when driven by a 230V AC source.? Finding this took about 90 sec. online.? With a little more searching, you can probably find a better fit.

Fair winds,
Eric

On May 23, 2020, at 5:53 PM, Ric Sanders <rsandersemail@...> wrote:

?

Thank “Powermax” 48 volt 20 amp chargers powered from a 6KW 120 volt AC output generator set but I would really like to do is be able to put about 100 amps into the battery/motor circuit.?

Cheers,

Ric

?

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)

To: [email protected]

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

From: [email protected] [mailto:[email protected]] On Behalf Of Eric via groups.io
Sent: Friday, May 22, 2020 1:56 PM
To: [email protected]
Subject: Re: [electricboats] Time to re-power

?

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? ?

On May 23, 2020, at 2:37 PM, john winterrowd via groups.io <sailorboy55577@...> wrote:

?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?