Finally getting around to using cells... a few questions?

beckkl said:

I purchased these 304AH Eve cells from Amy Zheng in 2021, but never got around to building a battery. Now that I am close to having a shed build to store them at my camp, I had a few questions I anyone had a moment.

My plan is seat the cells on a piece of plywood, separate them with a strip of VHB tape the top and bottom edges, then wrap them in Kapton tape. Last I checked the compression made a marginal difference on charge cycles (which is not really a concern for me).

1.) Are the stock/included bus bars ok? I see a lot of folks use the flexible copper.
2.) I currently have an Overkill Solar 48V BMS. I was hoping that by now there might be a BMS that has maybe a relay or something for heating elements? Any other BMS that are worth looking at? If I remember many had decent active balancers now?
3.) Any ideas on an enclosure? I would build something but time is at a premium these days.
4.) I need to heat the battery. Is putting those orange heat elements on the bottom ok, or is it better to adhere them to the sides (short side)?
4.) What else should I be thinking about?

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sunshine_eggo said:

New EVE cell specs only give a compressed cycle life. Check your cell datasheet. If compressed cycle life is given, and you don't compress, you will see reduced cycle life.

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beckkl said:

I figured. I think this battery will be replaced far before I care about losing the small amount due to not compressing.

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Browneye said:

Jigging up a couple of plywood ends with 4 sticks of threaded rod is a super easy 'compression' housing - just cinch up the bolts so the cells are snug - you don't have to crank them down. Primarily this prevents any bulging over time and pulling at the connector bus bars. The stock ones are fine for a 120A bms. If you're going to run a lot of amps through them then an upgrade might make some sense.

I used Starboard with a couple of pieces of aluminum angle - worked out nicely.

If you're going to included heating pads for extreme cold, then a way to insulate them might prove beneficial as well. So some kind of housing box. A storage container and spray foam might do the trick. The pads can go on the bottom or either open side if you use a compression jig.

Can't help you on the Overkill, but I thought it did have a relay port you could use for a switch for temp control. I would have to go thru the manual on that one.

You'll want to charge up all your cells before connecting them together, do a 'top balance'. Good instructions in the Overkill manual on this.

Here's what I did for a jig, these are 230Ah cells from the same source, house bank for a motorhome:

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