eig co20b cells

jake202

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Nov 27, 2021
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Hello all,

Wonder if anyone can help I am building a electric bike using a QS138 V3 motor and a Votol Em150 controller the part i am struggling with is batteries I have been offered 20x of the above cells this apparently will be 72v. which sounds ideal for my controller and motor setup does anyone have much experience with these? I didn't plan to build a battery myself however these are at a price which is hard to ignore does anyone have a crash course on how to build one of these?

Cheers!

Jake.
 
jake202 said:
I have been offered 20x of the above cells this apparently will be 72v.
Depends on what series/parallel configuration you use.

At 20s1p, then yes, that would be nominal of 73v (3.65v/cell), HVC of 83v (4.15v/cell), and 66v LVC (3.3v/cell) whcih is close enough for your purposes.

For controller performance and controller current limiting setup, at 1p they'll do 100A continuous when new (I'd say cut that in half for old used cells), with peaks of 200A (again, cut that in half for used).

For range, I'd also assume you don't have the full 20Ah, but call it 15Ah unless you test them and verify they'll do more without overdischarging them.

I'm using a 14s2p pack on the SB Cruiser, so it is only a "52v" pack, but it will do twice the current if needed.


does anyone have much experience with these?
There are a number of threads with info about them, including an ongoing sale thread in the marketplace that has datasheets, and that seller also has busbars to connect the cells together, which makes it very easy to assemble the pack.




I didn't plan to build a battery myself however these are at a price which is hard to ignore does anyone have a crash course on how to build one of these?
Not really.

If you have never built a battery, these are certtainly a lot easier to do so with than any other commonly available cell, assuming they come with all the original hardware.

However, you may want to test the cells when you get them, unless the person providing them can give you all the data they have on them and you can post that here so we can go thru the data to see if they are still useful for your purposes.

THey are easy to bolt together if you have busbars *and* they come in their plastic holders, rather than being bare cells. It's nearly a dream to do so. ;)

If you have to wire them (no busbars) then you need to learn wiring and connector techniques first, and get the right tools for crimping small lugs onto large-enough-gauge wire (or have busbars made for them, like having copper or brass waterjet cut or laser cut).

If they don't come in their original plastic holders that stack them up neatly and secure and protect them, along with the ability to just screw interconnects down to them, then they are not that easy to assemble. If they still have the copper tabs with screwholes in them then you can at least still use those to bolt or solder interconnects to. But you'll still have to come up with a box and moutning solution for the cells, and a way to ensure no interconnects or tabs touch that aren't intended to.

If they don't have those welded-on copper tabs, then you'll have to deal with not only a casing but also an interconnect scheme, and that I can only refer you to the various pouch-cell build threads around the forum, like the stuff by JonesCG, and the various A123 pouch cell threads, etc. I haven't had to deal with that except with RC Lipo pouches, and that pretty well sucked to do. :/
 
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