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Recommendations for a 48 v AGM Battery with decent Amp/hr rating?

Maple Mex

New Member
Joined
Jan 24, 2025
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Canada
Hello all. Looking for recommendations for decent AGM battery for 48v system. Would consider multiple 12v or 24v in series but preferably 1 48v. Off grid and cold here in Yukon. Thanks
 
Yukon! How cool! (see what I did there?)

AFAIK there's no such thing as a single 48V AGM battery. You'll have to build it 12 volts at a time. Since you'll never be able to properly (easily) equalize them I'd suggest you start off on day one with a battery balancer to keep them all... you guessed it... balanced.

Not sure of your budget but there's some industrial 2V options out there.
 
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Id do it with 6v L16 batteries. They are about as big as youd want to handle by yourself and have good capacity.

If they aren't in a living space, honestly id go with the flooded version, they actually have more capacity and are cheaper. Something like the SPRE-06-415.
 
What's your budget? If you don't mind a bit of work, you can try to find some used electric forklift or pallet jack/pallet stacker battery packs for scrap price or less. Most places use them hard all day until they die, plug them in, and repeat. Once performance degrades, they are discarded as useless. But the larger problem is they didn't keep up with maintenance - watering and equalization charges.

Quite often with a little rehabilitation they can be brought back to rated capacity or close to it. Most solar applications aren't going to be as demanding as industrial use in a forklift so they still have quite a bit of life left in them.

You can get an entire machine cheap (<$1000), pull the battery, scavenge some useful electrical bits, and sell the rest for scrap to get back some of the initial cost of the machine. Several months ago I picked up a 24v 500ah pack for $300, and a couple of weeks ago grabbed an almost new 36v 1000ah pack for $1000. Lots of deals out there if you look hard enough...
 
Thanks all for your recommendations!
As far as I can tell victron only has 24v balancers? Would I need two of those to balance a 48v bank using 12v batteries in series?
 
Hi @Maple Mex
I don't know what your budget is, but I can tell you about the GNB industrial backup batteries that I've been using for 15 years, and they are still not quite dead, yet. These are 440 Ah cells, nominal 2V each, for a total of 48V. The fact that I rescued these from a recycler was pretty lucky on my part, although it means that I'm not sure what a similar set would cost now. However, these robust batteries work at every temperature (I have them installed outdoors in a shed). My winters aren't quite as cold as yours (southern Alberta) but even here, for outdoor applications, AGM is the way to go. In your environment I believe you will need to make some special choices when sizing your solar/wind to make sure they will keep a set of AGM's charged properly.

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I’m still not convinced lead-acid needs balancers.
In parallel they don't but in series they might you help squeeze a few more years out of your battery.

For a flooded battery you can correct the inevitable voltage delta between batteries with an equalization charge but that's not an option for AGM's or GEL's. If I had it to over again I'd use one.
 
In parallel they don't but in series they might you help squeeze a few more years out of your battery.

For a flooded battery you can correct the inevitable voltage delta between batteries with an equalization charge but that's not an option for AGM's or GEL's. If I had it to over again I'd use one.
Right, but does that mean you need to use individual 2 V cells and the equalizer is connected to each and every cell?
 
Right, but does that mean you need to use individual 2 V cells and the equalizer is connected to each and every cell?
Ideally, but I still believe keeping 6V batteries in your pack all at the same voltage is better than letting them swing however they see fit.

I've seen sealed 12v batteries in series be at 11.9 and 14.9 in a 24V system.
 
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