Yo,
I’m working on battery for electric mountain skis and want to make sure everything looks good so far.
I’v modeled a basic draft in fusion 360 based on what Iv researched online and attached images of the wiring.
I did not include the balance leads, insulation paper, or tape but, they will be used in the final build.
There will be two of these batteries, one for each foot.
Parts being used include:
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24 x Molicel P28A 18650 2800mAh 35A Battery (per ski)
-
0.2x8mm Pure Nickel Strips (for parallel groups)
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12AWG Silicon Wire (for series connections)
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10AWG Silicon Wire (for main power)
-
DALY 12s BMS (for charging only)
Is there anything I need to consider or would need to change?
Will one layer of nickel strips be enough for the amps or should I double up ?
Any input will be appreciated.
(For reference the DALY BMS is the top of the battery, series connections are at the bottom)
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Do you need the batteries to flex at all? If they are packed into rigid container you can save some effort by using 25mm x 25mm squares of nickel for the series connections instead of 2x 8mm x 50mm with 2x 12awg
Just make sure you layer several layers of nickel on the series connections. Unless you’re only going to use a very small amount of its 70 amp capabilities, you’ll need more.
25mm wide nickel would be plenty
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No it doesn’t need to flex, so that’s a good idea. Do you have a vender you recommend for the 25X25 nickel.
Ask in the battery builder thread if you want to buy a little off someone, or look for the Steel City store on AliExpress if you wanna get a lot of it
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I can sell you some 0.15x30mm if you are interested
I was referencing the fact that he was going to use 8 millimeter nickel that of that 25 mm
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Not sure I’m clear on how you are making the series connections…
Or
12 awg is overkill for the series connections as is 10awg for the main terminals imo. 14 and 12 respectively should be more than adequate for this application.
Also, pulling 70 amps continuous from p28 cells is possible in 2p but not advisable as it will drastically dimish their life cycle. If memory serves, Mooch recommended these be run at 15-20 amps.
Interesting. Yea I won’t run it at 70 amps continuous but I would like to have the ability to for steep hills.
Do you have space to run 21700s in 2p config? If so, you would be in much better shape for getting the current you want. Molicel P42a’s can pull 60 amps continuous in 2p although you will get some sag.
Also, is this going to be a brick pack or a double stacked flat pack?
No, I don’t think I have room for 21700s.
double stack flat pack.
and I don’t “think” I need 60 amps continuous especially since there will be two batteries.
With the 0.15x 30 would you do something like this
to connect both series and parallel?
is that what you had in mind?
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Ya that’s what he’s getting at but I’d do 0.2mm x 30mm for some amperage headroom. That will run 60 amps continuous without trouble.
Imo the 0.15 is plenty, for a 2p pack, it’s even overkill lol
But yes @t3chm0nkey like that, but only if it’s in a hard case
I did something like it in this pack, but it’s got a super rigid backbone so it can’t bend
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Ok cool yea it’s going to be in between the frame with a shell so it should be good. So I’ll take you up on that offer to buy 0.15m x 30m
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What would the safe limit of the 0.15 for continuous be about?
Also I’m going take your advice and use the 12AWG thanks for that.
