Hi All, I'm changing the motors in my boat and trying to figure out if I can use my existing batteries. I was using 2 x 24v 2.2kw motors with a 24v 100ah LiFePO4 bank on one and a 24v 150ah bank on the other. The new motors I'm putting in are 48v 3kw. So my question is can I utilize these banks maybe through a bump converter or something?
24v batteries to run 48v motor
- Thread starter James Mc
- Start date
jdege
New Member
- Joined
- Dec 16, 2020
- Messages
- 138
Putting unmatched batteries into series doesn't work well. They won't charge and discharge together, so the combination won't allow you to access the full capacity of the two batteries.
That said, they'll have the same problem in parallel.
In both cases, you might get something less that 100Ah out of the combination.
As for bump converters, 24V->48V converters exist, but you'll need one that can handle 60+ amps. If there are any on the market, they will be large, heavy, and expensive.
That said, they'll have the same problem in parallel.
In both cases, you might get something less that 100Ah out of the combination.
As for bump converters, 24V->48V converters exist, but you'll need one that can handle 60+ amps. If there are any on the market, they will be large, heavy, and expensive.
OffGridForGood
Catch, make or grow everything you can.
buy one more of the 100Ah and one more 150Ah,
Pair the 100's together, pair the 150's together. - they will not charge and discharge evenly, maybe close enough for your set up?
Sell the 24v batteries and motors together? - {or repurpose the 24v batteries for a mobile unit with a MPP 2724}
Buy matched 48v 100A batteries and easier to keep them all balanced.
Pair the 100's together, pair the 150's together. - they will not charge and discharge evenly, maybe close enough for your set up?
Sell the 24v batteries and motors together? - {or repurpose the 24v batteries for a mobile unit with a MPP 2724}
Buy matched 48v 100A batteries and easier to keep them all balanced.
Yep jdege.. just had a look at converters cheap as chips up to 30 amps but nothing much over that and 30amps would be fine to run the motor at 80 or 90 percent which would be fine but they wouldn't handle the surge to start them.
Thanks for your thoughts OffGrid. Looks like there are no good budget options. I'll have to just spend the cash on a new bank and looking at what is available in Australia it will have to be 16 x 280ah cells (cheap at $160AU each). Up side is I can rip the top off my tenders outboard and utilize the 24v stuff to convert it to electric.
pollenface
Solar Addict
Absoluetly, but select a converter that is 2-3x bigger than the continuous load. That would be standard practice with a motor controller. You can put a few smaller ones in parallel if you can't find a single one large enough.
Aussie
New Member
Where would you get the 280 ah cells from?
Alibaba, the company is Shenzhen Blackcell Technology they have an Australian warehouse. I chatted with a guy who got some from them and he was very happy with them and it only took a week to get them. https://www.alibaba.com/product-det...678.html?spm=a2700.details.0.0.6db8303f34dfzb
Aussie
New Member
Please let me know how the transaction goes if you buy some. I am interested in buying 16 more cells.
HarryN
Solar Enthusiast
Just add another similar battery to each bank and you are done.
Unlikely.
Used batteries when put into series with new batteries RARELY charge and discharge evenly, especially when under motor loads...
