Re: Two voltage battery banks on one charger
There is a company in the UK that makes a generator starter when the battery voltage drops below 11.8v the gen set turns on and turns off at 12.8v or so. ?All automatic. ?I have one but never installed it. Cost was about $75 with a waterproof enclosure.
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On Sep 3, 2020, at 16:00, sw via groups.io <v1opps@...> wrote:
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Mppt?charger maybe cheaper? On Thursday, September 3, 2020, 14:43, damonalane <dlane@...> wrote: I would go with the DC-DC converter as the simpler option, assuming you can buy one that steps down that far: 72V to 12V or 24V. That's how mine is setup, though my motor only needs 48V. I'm guessing with the proliferation of higher voltage motors that converters are available for those systems.
To use another solar controller, wouldn't you need another solar array? And to figure out how many watts of solar panels to give to each controller? With one controller you can put the solar where it works best. Let the controller control all of it, and let voltage flow "downhill" through the DC-DC converter.
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Re: Two voltage battery banks on one charger
With the solar charge them in series Peter.?
I assume your 48 Volt pack is made up of four 12volt batteries in series. Do you charge them in series i.e at 48 volts+ or do you charge each 12 volt battery separately? ? If separately do you connect them all to the same controller and charge them at the same time ? Rgds? Peter Beckett ? ? FWIW, I have a separate 48 volt propulsion bank & 12 volt house bank. I charge both banks with 260 watts of 24 volt panels wired in series using a midnight kid solar controller.? I wired the controller output to a double pole double throw transfer switch. I can pick which bank I'd like to charge & easily adjust the parameters.?? ? I like the mppt charger because they usually have adjustable voltage and amperage tsp can use for many battery types On Friday, September 4, 2020, 11:55:16 AM PDT, Damon Lane <dlane@...> wrote: DC-DC converters are simple: they produce the lower voltage from the higher voltage, and supply current up to their max rated power throughput.?
On my boat, I have no lower voltage batteries, so if the propulsion bank or DC-DC converter had a problem, I'd have no 12V. That is a problem, and I'm realizing that if I did have batteries at 12V, the DC-DC converter probably wouldn't charge them because the voltage it supplies is too low (13.1V) and it's not a charger.?
So I'll amend my initial comment and say DC-DC converters are simpler if you don't plan to have separate battery banks at different voltages. If you do, I think you do need two chargers. Setting up two chargers and a generator is surely possible, but you may want to consult a book or specialist. I think the generator could be set to trip on at low voltage, but would you want it to if it would come on each morning at dawn, only to charge for a few minutes before the solar would have come on anyway? I would want more complex controls.
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Re: Relationship of voltage to capacity
Can't go by voltage unless the bank has been resting. A battery monitor like a Victron 700 is a better option.?
On Fri, Sep 4, 2020, 4:03 PM Ryan Sweet < ryan@...> wrote: 48v battery bank of 4s 12v AGM. When ¡°full¡± according to the charger the voltage is around 52.8,?
I have a battery capacity monitor that wants to be set to 48v, lead acid, and it wants a voltage level to use for a warning threshold.
So the question is, what voltage should I consider to be ¡°50%¡± and thus the floor of my safe discharge?
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Relationship of voltage to capacity
48v battery bank of 4s 12v AGM. When ¡°full¡± according to the charger the voltage is around 52.8,
I have a battery capacity monitor that wants to be set to 48v, lead acid, and it wants a voltage level to use for a warning threshold.
So the question is, what voltage should I consider to be ¡°50%¡± and thus the floor of my safe discharge?
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Re: Two voltage battery banks on one charger
I assume your 48 Volt pack is made up of four 12volt batteries in series. Do you charge them in series i.e at 48 volts+ or do you charge each 12 volt battery separately? ? If separately do you connect them all to the same controller and charge them at the same time ? Rgds? Peter Beckett ?
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From: [email protected] < [email protected]> On Behalf Of Bob Jennings Sent: Friday, September 4, 2020 3:47 PM To: [email protected]Subject: Re: [electricboats] Two voltage battery banks on one charger ? FWIW, I have a separate 48 volt propulsion bank & 12 volt house bank. I charge both banks with 260 watts of 24 volt panels wired in series using a midnight kid solar controller.? I wired the controller output to a double pole double throw transfer switch. I can pick which bank I'd like to charge & easily adjust the parameters.?? ? I like the mppt charger because they usually have adjustable voltage and amperage tsp can use for many battery types On Friday, September 4, 2020, 11:55:16 AM PDT, Damon Lane <dlane@...> wrote: DC-DC converters are simple: they produce the lower voltage from the higher voltage, and supply current up to their max rated power throughput.?
On my boat, I have no lower voltage batteries, so if the propulsion bank or DC-DC converter had a problem, I'd have no 12V. That is a problem, and I'm realizing that if I did have batteries at 12V, the DC-DC converter probably wouldn't charge them because the voltage it supplies is too low (13.1V) and it's not a charger.?
So I'll amend my initial comment and say DC-DC converters are simpler if you don't plan to have separate battery banks at different voltages. If you do, I think you do need two chargers. Setting up two chargers and a generator is surely possible, but you may want to consult a book or specialist. I think the generator could be set to trip on at low voltage, but would you want it to if it would come on each morning at dawn, only to charge for a few minutes before the solar would have come on anyway? I would want more complex controls.
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Re: Two voltage battery banks on one charger
FWIW, I have a separate 48 volt propulsion bank & 12 volt house bank. I charge both banks with 260 watts of 24 volt panels wired in series using a midnight kid solar controller.? I wired the controller output to a double pole double throw transfer switch. I can pick which bank I'd like to charge & easily adjust the parameters.??
I like the mppt charger because they usually have adjustable voltage and amperage tsp can use for many battery types
On Friday, September 4, 2020, 11:55:16 AM PDT, Damon Lane < dlane@...> wrote:
DC-DC converters are simple: they produce the lower voltage from the higher voltage, and supply current up to their max rated power throughput.?
On my boat, I have no lower voltage batteries, so if the propulsion bank or DC-DC converter had a problem, I'd have no 12V. That is a problem, and I'm realizing that if I did have batteries at 12V, the DC-DC converter probably wouldn't charge them because the voltage it supplies is too low (13.1V) and it's not a charger.?
So I'll amend my initial comment and say DC-DC converters are simpler if you don't plan to have separate battery banks at different voltages. If you do, I think you do need two chargers. Setting up two chargers and a generator is surely possible, but you may want to consult a book or specialist. I think the generator could be set to trip on at low voltage, but would you want it to if it would come on each morning at dawn, only to charge for a few minutes before the solar would have come on anyway? I would want more complex controls.
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Re: Two voltage battery banks on one charger
I like the mppt charger because they usually have adjustable voltage and amperage tsp can use for many battery types
On Friday, September 4, 2020, 11:55:16 AM PDT, Damon Lane <dlane@...> wrote:
DC-DC converters are simple: they produce the lower voltage from the higher voltage, and supply current up to their max rated power throughput.?
On my boat, I have no lower voltage batteries, so if the propulsion bank or DC-DC converter had a problem, I'd have no 12V. That is a problem, and I'm realizing that if I did have batteries at 12V, the DC-DC converter probably wouldn't charge them because the voltage it supplies is too low (13.1V) and it's not a charger.?
So I'll amend my initial comment and say DC-DC converters are simpler if you don't plan to have separate battery banks at different voltages. If you do, I think you do need two chargers. Setting up two chargers and a generator is surely possible, but you may want to consult a book or specialist. I think the generator could be set to trip on at low voltage, but would you want it to if it would come on each morning at dawn, only to charge for a few minutes before the solar would have come on anyway? I would want more complex controls.
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Re: Two voltage battery banks on one charger
DC-DC converters are simple: they produce the lower voltage from the higher voltage, and supply current up to their max rated power throughput.?
On my boat, I have no lower voltage batteries, so if the propulsion bank or DC-DC converter had a problem, I'd have no 12V. That is a problem, and I'm realizing that if I did have batteries at 12V, the DC-DC converter probably wouldn't charge them because the voltage it supplies is too low (13.1V) and it's not a charger.?
So I'll amend my initial comment and say DC-DC converters are simpler if you don't plan to have separate battery banks at different voltages. If you do, I think you do need two chargers. Setting up two chargers and a generator is surely possible, but you may want to consult a book or specialist. I think the generator could be set to trip on at low voltage, but would you want it to if it would come on each morning at dawn, only to charge for a few minutes before the solar would have come on anyway? I would want more complex controls.
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Re: Supplementary electric power for heavy old sailing boat
I just took a look in my engine room and I do think I could possibly mount the motor directly onto the transmission.? Orest, would you be willing to post a photo of your arrangement?? I'd be most interested to see just where you bolted the mounting bracket.??
Also, I was looking at Goodyear toothed power transmission belts.? There are many different types!? Do you recall just what kind you are using?
It's interesting that you are experiencing heat problems.? Is it when you're running or is it when regenerating that you're developing heat?? Do you think a liquid cooled motor might be in order for this application perhaps?? Do you often run in the 10kw range or are you getting hot at lower power also?
Thanks,
Matthew
Dexter, Michigan
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Re: Supplementary electric power for heavy old sailing boat
I was intending not to have to install any kind of clutch.? My thinking is that I could allow the diesel to drive the motor as a generator until the batteries were charged and then the motor would effectively go offload and freewheel and provide very little parasitic load (Im thinking of using a?48V Sevcon Gen-4 which supports regeneration).?
The Perkins 236 has ample power to drive the boat and the generator.? As it is, the diesel is driving a 170 amp Baldor alternator which I could probably remove and sell and replace with a standard 35amp alternator as it would be relegated to only charging the diesel starter batteries.
Orest, I was thinking of using something like the cogged belt that you suggest.? I'll look into the Goodyear option. Thanks.? I can see that by using a cogged belt the required tension is much less critical and so the side load on the bearings should be less.? I like the idea of mounting directly to the transmission.? I don't know if I have enough room for that.? I'll need to check.? I was thinking of glassing in a mounting pad directly to the hull and mounting the motor onto that via a hinge, similar to an alternator on an engine.
If you get a taker for the transmission?case idea, I could be interested but my budget for the whole project is under US$5k so I imagine that would be out of my reach.
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Re: Supplementary electric power for heavy old sailing boat
That's an interesting idea Darryl but I don't think I'd be able to fit something like that in my case.
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Re: Two voltage battery banks on one charger
I found a 72v to 24v converter on an ev automotive sight. It charges at 50 amps. I don't know much more than that about it. Is there anything else I should be aware of?
On Thu, Sep 3, 2020, 6:12 PM Tommy rochester via <troche289= [email protected]> wrote: Well as far as another mppt controller, I was thinking they take higher voltage in and put out the voltage you need for the battery bank. I was going to feed it with the 72v bank so I would only need one array. My thinking was to have better control of charging the house bank. You are right,? the converter will be easier.? Overall you think I'm on the right track??
My next question is how do I integrate my genset into the system. Ideally I would like to have our turn on automatically at a low voltage set point. I've seen something similar on big semis. Mainly with refrigeration to maintain temperature.?
I know I could rig it through a couple of relays once the voltage would drop to a certain point the relay would open and the normally open contacts would then close to start the genset.?
What I haven't figured out is how to switch between the genset and the charge controller. I may be overthinking it a bit, but automation is my goal if possible.?
On Thu, Sep 3, 2020, 5:43 PM damonalane < dlane@...> wrote: I would go with the DC-DC converter as the simpler option, assuming you can buy one that steps down that far: 72V to 12V or 24V. That's how mine is setup, though my motor only needs 48V. I'm guessing with the proliferation of higher voltage motors that converters are available for those systems.
To use another solar controller, wouldn't you need another solar array? And to figure out how many watts of solar panels to give to each controller? With one controller you can put the solar where it works best. Let the controller control all of it, and let voltage flow "downhill" through the DC-DC converter.
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Re: Two voltage battery banks on one charger
Just use the battery pack as the solar array
On Thursday, September 3, 2020, 15:12, Tommy rochester <troche289@...> wrote: Well as far as another mppt controller, I was thinking they take higher voltage in and put out the voltage you need for the battery bank. I was going to feed it with the 72v bank so I would only need one array. My thinking was to have better control of charging the house bank. You are right,? the converter will be easier.? Overall you think I'm on the right track??
My next question is how do I integrate my genset into the system. Ideally I would like to have our turn on automatically at a low voltage set point. I've seen something similar on big semis. Mainly with refrigeration to maintain temperature.?
I know I could rig it through a couple of relays once the voltage would drop to a certain point the relay would open and the normally open contacts would then close to start the genset.?
What I haven't figured out is how to switch between the genset and the charge controller. I may be overthinking it a bit, but automation is my goal if possible.? On Thu, Sep 3, 2020, 5:43 PM damonalane < dlane@...> wrote: I would go with the DC-DC converter as the simpler option, assuming you can buy one that steps down that far: 72V to 12V or 24V. That's how mine is setup, though my motor only needs 48V. I'm guessing with the proliferation of higher voltage motors that converters are available for those systems.
To use another solar controller, wouldn't you need another solar array? And to figure out how many watts of solar panels to give to each controller? With one controller you can put the solar where it works best. Let the controller control all of it, and let voltage flow "downhill" through the DC-DC converter.
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Re: Two voltage battery banks on one charger
Well as far as another mppt controller, I was thinking they take higher voltage in and put out the voltage you need for the battery bank. I was going to feed it with the 72v bank so I would only need one array. My thinking was to have better control of charging the house bank. You are right,? the converter will be easier.? Overall you think I'm on the right track??
My next question is how do I integrate my genset into the system. Ideally I would like to have our turn on automatically at a low voltage set point. I've seen something similar on big semis. Mainly with refrigeration to maintain temperature.?
I know I could rig it through a couple of relays once the voltage would drop to a certain point the relay would open and the normally open contacts would then close to start the genset.?
What I haven't figured out is how to switch between the genset and the charge controller. I may be overthinking it a bit, but automation is my goal if possible.?
On Thu, Sep 3, 2020, 5:43 PM damonalane < dlane@...> wrote: I would go with the DC-DC converter as the simpler option, assuming you can buy one that steps down that far: 72V to 12V or 24V. That's how mine is setup, though my motor only needs 48V. I'm guessing with the proliferation of higher voltage motors that converters are available for those systems.
To use another solar controller, wouldn't you need another solar array? And to figure out how many watts of solar panels to give to each controller? With one controller you can put the solar where it works best. Let the controller control all of it, and let voltage flow "downhill" through the DC-DC converter.
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Re: Two voltage battery banks on one charger
Mppt?charger maybe cheaper?
On Thursday, September 3, 2020, 14:43, damonalane <dlane@...> wrote: I would go with the DC-DC converter as the simpler option, assuming you can buy one that steps down that far: 72V to 12V or 24V. That's how mine is setup, though my motor only needs 48V. I'm guessing with the proliferation of higher voltage motors that converters are available for those systems.
To use another solar controller, wouldn't you need another solar array? And to figure out how many watts of solar panels to give to each controller? With one controller you can put the solar where it works best. Let the controller control all of it, and let voltage flow "downhill" through the DC-DC converter.
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Re: Two voltage battery banks on one charger
I would go with the DC-DC converter as the simpler option, assuming you can buy one that steps down that far: 72V to 12V or 24V. That's how mine is setup, though my motor only needs 48V. I'm guessing with the proliferation of higher voltage motors that converters are available for those systems.
To use another solar controller, wouldn't you need another solar array? And to figure out how many watts of solar panels to give to each controller? With one controller you can put the solar where it works best. Let the controller control all of it, and let voltage flow "downhill" through the DC-DC converter.
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Re: Supplementary electric power for heavy old sailing boat
I have gone the double belt route after the one belt experiment ?kept slipping and burned out bearings?from the tension.? ? ? ? Now I use a goodyear synchronous (like in a supercharger) ?and have not?burned out any bearings.?
My electric motor is mounted on a home made?frame to my BorgWarner. Pulled out 4 main cover bolts and used larger ones to mount the frame to the transmission. ?Goodyear supplies gears for the top 10 kw (3 phase) ?and my ?large gear between the transmission and shaft (which had to be machined to fit ). ? ? ? ? ? ? ? ? ?My biggest problem is heat ?... ?and Im thinking?to convert up to 96 volts.? Any ?concurrence?on?96 volts works running?cooler?
There are probably?better ways and head scratching has cost me lot of hair.? ? ? ? ?HAS ANYONE UTILIZED A TRANSFER CASE??
There is a shop in Whisky Creek that has made parts for Borg Warner that is willing and has designed a transfer case for our purpose. ? ? ? ? ? ? 10 k Canadian for the first one ... ?less if there are more ? any interest ? ?Sincerely, Orest? ?Alberni Charters ?250-735-6503.
On Thu, Sep 3, 2020 at 9:54 AM William Shannahan via <shannahanwilliam= [email protected]> wrote:
Wonder if you could install a tensioner pulley of some sort if you wanted to disengage the electric. But don't see why you would want to the seems the electric would work well as an alternator to charge batteries.
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?
You¡¯d have to be able to swap between the diesel and the electric motor on the drive shaft, otherwise the electric motor would act as a giant alternator when running the diesel and that would greatly decrease the efficiency of the diesel.
If you have regen set up, it would however charge your batteries rather quickly.
?
Would you plan to somehow disengage the belt to the pulleys when using your diesel motor?
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Two voltage battery banks on one charger
I purchased a sailboat that wad in the middle of a refit. The previous owner already removed the diesel and had purchased a the components to go electric. The motor is 72v and I've found that the midnight classic chargers charge up to 72v. The issue I'm looking at is I also need either 12 or 24v house batteries.? My thought is to have solar charging the 72v (which is the drive bank) bank with the midnight classic and then charge the house bank of the 72v through either a dc to dc converter or another mppt charge.? The drive bank in theory won't get much ures except to motor in light wind or into a slip.? I have a little over 14kwh on the drive bank and somewhere around 600ah on the house. I also purchased a genset as a backup if needed.? So this is my plan to this point unless someone has a better way or can explain if this will even work.?
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Re: Supplementary electric power for heavy old sailing boat
Hi Matthew,
I don't know if you have the space for this sort of arrangement, but back in the 1980s Briggs&Stratton had an interesting set-up in a hybrid electric car prototype.
Here's an image from my website.
The electric motor was physically in-line between the gasoline engine and the gearbox. There were clutches at each end of the electric motor.
The arrangement could run in a number of modes.
1) Electric motor connected to gearbox via clutch, disconnected from gas engine, runs as 100% electric vehicle.
2) Electric motor disengaged electrically, connected physically at both ends to gearbox and gas engine, runs as 100% gasoline vehicle.
3) Electric motor engaged electrically and to both ends physically, allowing both the gas engine and electric motor to drive the gear box.
4) Electric motor engaged to gas engine, disconnected from gearbox, electrically connected as a generator to charge the batteries while parked (EV charging stations were not common in the early 1980s).
The write-up on the vehicle can be viewed at:
view-source:
I suppose you could set up a clutch arrangement using pulleys to achieve much the same results.
Darryl McMahon
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On 9/3/2020 10:19 AM, Matthew Cook wrote: Hi folks,
I'm new to the group and enjoying reading old posts and learning a lot about electrifying boats.? This may have been covered in older posts so please excuse me if I'm bringing up something that has already been discussed but I would like to run some ideas and questions by ya'll:
* One of the differences between a 1984 38,000lb heavy cruising
sailboat like my Liberty 458 and a modern cruiser/racer is that the
cruiser/racer will point into the wind on a beat about 20-30 deg
higher than I can.
* Another difference is that unlike many "plastic fantastics" my old
boat is very comfortable, seaworthy and affordable.? In all but
sailing performance, I prefer her to something newer and with better
performance.
* I love to sail when possible but I'm no purist and if I can cheat
without compromise, I will.? I'd like to add a 10Kw electric motor
to my existing drive train so that when I'm beating, I can turn my
fixed 3-blade 20" x 15" propellor enough to help my sailing
performance (my transmission is a Borg Warner Velvet Drive and can
freewheel without any problem).? I estimate 2-3kw into the drive
shaft would?be sufficient in most conditions to bring my sailing
angle up to around 30-40deg off the wind which would keep
my?impatience in check.? When there is no wind, I may also use the
"2nd auxiliary" to keep me moving rather than start the noisy 84Hp
Perkins 236 engine.? It would also be very nice coming into harbor
when crew are line handling and we can hear each other without
having to yell over the engine.
Some questions that I have:
* ? Has anybody done something similar to this?? Can they report on
their results?
* ?If I placed a BLDC motor with a 2:1 dual belt drive to two?pulleys
over my propshaft, it would apply some side load to the shaft which
would, in turn, be applied to the bearings of the transmission and
the Cutless?bearing.? I'm confident that the load on the
transmission would not be a problem but I'm not so sure about the
Cutless bearing.? Does anybody have any experience with this?
* Would I need to include pillow blocks on the output shaft of the
motor or can the?motors generally handle the side load of placing a
pulley directly on the output shaft?
* I'd love to use the system to regenerate also.? I've read how
regeneration is not very efficient in smaller boats but, with
sufficient wind, I can consistently?hold 7knts throwing a pretty big
wheel.? I know from experience trying to stall my prop shaft when
I'm running along that there is a lot of power there!? Other than an
old-school brushed DC motor, is there any motor that will do a
better job of regenerating than another?
Thanks in advance for any thoughts.
Matthew
--
Curtains for COVID
Darryl McMahon
COVID-19 blog:
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Re: Supplementary electric power for heavy old sailing boat
Wonder if you could install a tensioner pulley of some sort if you wanted to disengage the electric. But don't see why you would want to the seems the electric would work well as an alternator to charge batteries.
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?
You¡¯d have to be able to swap between the diesel and the electric motor on the drive shaft, otherwise the electric motor would act as a giant alternator when running the diesel and that would greatly decrease the efficiency of the diesel.
If you have regen set up, it would however charge your batteries rather quickly.
?
Would you plan to somehow disengage the belt to the pulleys when using your diesel motor?
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CaptainJohn49
Darryl McMahon