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Add more battery later?

stvm

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Apr 29, 2024
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Working on a van conversion and want one of the Epoch 460Ah batteries. They each have an internal BMS.

System is 12V and would be 1 battery, moving up to 2 batteries in parallel.

My question is, if I want to add more battery capacity later (such as a second epoch 460Ah), are there any problems with that? Or is it better to buy a pair both at the same time for matching considerations?

I suspect the vehicle will wear out long before the batteries, so I wouldn't expect that having slightly mismatched lifetime cycles is a problem, unless there is some degradation which causes them to mismatch over time, but then the internal BMS in each battery should protect and manage that situation, right?

There is a risk that the product changes or becomes unavailable by the time I want to add a second - so is it advisable to have two mismatched batteries from different suppliers, assuming they are both 12V and have an internal BMS per battery?

TLDR 460Ah is enough for my planned usage initially, but I might want to extend my reserve for winter trips and/or add some higher power draw items later on down the line and it would be nice to be able to add a battery later, but I don't want to over-commit on the battery before I have a chance to try it out. Not so much a price thing (although $2k is certainly a lot for something that won't get used much). But also it's a space thing - every cubic inch kinda matters in a compact build.
 
Working on a van conversion and want one of the Epoch 460Ah batteries. They each have an internal BMS.

System is 12V and would be 1 battery, moving up to 2 batteries in parallel.

My question is, if I want to add more battery capacity later (such as a second epoch 460Ah), are there any problems with that? Or is it better to buy a pair both at the same time for matching considerations?

I suspect the vehicle will wear out long before the batteries, so I wouldn't expect that having slightly mismatched lifetime cycles is a problem, unless there is some degradation which causes them to mismatch over time, but then the internal BMS in each battery should protect and manage that situation, right?

TLDR 460Ah is enough for my planned usage, but I might want to extend my reserve for winter trips and/or add some higher power draw items later on down the line and it would be nice to be able to add a battery later, but I don't want to over-commit on the battery before I have a chance to try it out. Not so much a price thing (although $2k is certainly a lot for something that won't get used much). But also it's a space thing - every cubic inch kinda matters.
From what I've read, the battery manufacturers prefer that you buy the second battery within 6 months of the first so that they perform the same. My opinion? If you're pretty sure you are going to expand the battery bank in the near future and you can afford the second battery, buy a pair of them now.
I nave four different age and capacity lifepo4 batteries; two 100ah purchased in January 2021, a 300ah bought in January 2023 and a different 300ah bought in November 2023. All four are connected in parallel and all four function quite well.
 
How does expanding the bank work if you have closed-loop RS485?

My inverter has only one RS485 ports. Is it possible to add a completely separate additional bank, and somehow have it be closed-loop as well?

My guess is that once I pick a battery manufacturer, I'm essentially stuck with that vendor, or at least - stuck with that BMS protocol. Is that correct?
 
How does expanding the bank work if you have closed-loop RS485?

My inverter has only one RS485 ports. Is it possible to add a completely separate additional bank, and somehow have it be closed-loop as well?

My guess is that once I pick a battery manufacturer, I'm essentially stuck with that vendor, or at least - stuck with that BMS protocol. Is that correct?
At least the Epochs have daisy-chain support for victron VE CAN bus. Supposedly. I just saw a thread vaguely mention that maybe daisy chain support isn’t there yet - need to look into that more. EDIT: the 460ah batteries support daisy chain; the 300ah ones do not apparently.

I suspect mix and match from vendors would be tough to integrate. Or expensive and complex (multiple shunts for independent monitoring? Dunno if the inverter would even support multiple monitors) to the point it’s probably not worth it.
 
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I have 460ah of lifepo4 in my rv, in the ugliest hodgepodge of mixed age and quality (but all cheap!) batteries on ugly mismatched wiring, and it still works fine. With lifepo4 there is no issue adding more in parallel, even if they don't match in brand/capacity/age.

The epoch 460ah sure looks nice!!
 
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