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[nowty]

My rule of thumb is if its too hot to touch or hold, its too hot.

[Swwils]

It's for fault tolerance not regular operation.

By 2 units I mean compared to the regular A spec of 4 AWG @70A 60C.

Pylontech recommend banks of 4 to busbar, practically doesn't matter as the BMS is captain of the charge current.

Amazing how good these cells are!

[Caesium]

Spot on Nowty. I don't think there is any concern about temperature rise due to high rate discharge or charging. The issue is low temperature charging. I am in the soft south "desert" where temps usually only dip below zero over night when the batteries are usually charging so not an issue for me. BUT up t'north it may become an issue if the batteries are in an uninsulated outbuilding.

9 degs is as low as I have seen displayed on my bms software and that's with minus 12 outside

Just seen this on another forum that I thought was worth reposting here.

This is from the EVE datasheet and specifies charging rates for various temperatures:



Its actually a bit lower than I would have expected. So for a single set of cells in series (280Ah) at 10c you need to be careful that you don't exceed 56A charging at the top end of SOC, which is actually pretty close to what a lot of us are doing with 70A chargers or so.

Just worth noting I think that its not as simple as being able to stuff 1C into these if you're above freezing; it tapers off quite significantly.

[Joeboy]

Spot on Nowty. I don't think there is any concern about temperature rise due to high rate discharge or charging. The issue is low temperature charging. I am in the soft south "desert" where temps usually only dip below zero over night when the batteries are usually charging so not an issue for me. BUT up t'north it may become an issue if the batteries are in an uninsulated outbuilding.

9 degs is as low as I have seen displayed on my bms software and that's with minus 12 outside

Just seen this on another forum that I thought was worth reposting here.

This is from the EVE datasheet and specifies charging rates for various temperatures:



Its actually a bit lower than I would have expected. So for a single set of cells in series (280Ah) at 10c you need to be careful that you don't exceed 56A charging at the top end of SOC, which is actually pretty close to what a lot of us are doing with 70A chargers or so.

Just worth noting I think that its not as simple as being able to stuff 1C into these if you're above freezing; it tapers off quite significantly.

That's definitely worth noting for those that have went full EVE and removed the Pylontech to hybrid inverter connection. Do the 3rd party bms's provide the capacity to have that thermal feedback control of the charge rate?

[Caesium]

Do the 3rd party bms's provide the capacity to have that thermal feedback control of the charge rate?

Sort of. My JK BMS has a low temperature cutoff, so you can set a temperature at which it stops charging entirely. But you can't set a sliding scale of decreasing charge rates, it doesn't have anything that fancy.

Probably the best I could do is set a low temp cutoff of 10c or something. But on the other hand, my batteries are indoors under my stairs and its generally 15c+ there, even now in the depths of winter, so I'm not too worried.

But for others here with batteries in outbuildings and attics, definitely be aware.

[marshman]

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[Caesium]

When I get the other lot installed I will have 1120AH so won't be able to hit the low temp charge current limit anyway.

So jealous of your stack size

I'm tempted to get a third set mostly for redundancy; I could have any one pack out of action for maintenance/balancing/checking connections etc and still have plenty of capacity to see me by, but I think it can wait for now. No space for it anyway!

[marshman]

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[MrPablo]

Absolutely epic storage, you'll be well sorted for winter days there!
Are you on eco7 or Intelligent Octopus for winter charging?

[Stinsy]

Really nice build! The luxury of some serious storage!