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Battery building: Using thinner wire for shorter lengths?


#1

I’m in the process of building a modular 10S4P pack that can easily be split up into 6 smaller packs so I can take my board on a plane. I’ve got a bunch of this wire already which I’m considering using to solder between the connectors I’m using and the ends of each smaller pack.

http://www.jaycar.co.nz/25-amp-dc-auto-power-cable-black/p/WH3082

I understand that generally you’d want to use thicker wire than this in most areas but considering that the length of wire between the actual battery packs and the connectors are only at most a few cm long, should I be able to get away with thinner wire like this for such short lengths?


#2

These are the sections where I’d be looking to use this wire


#3

what awg you talking? You’ll probably burn up the wire if you use anything thinner than 14-16awg. Keep in mind the faa allows you to bring 2 spare packs with one pack in the “device”, so you probably can’t bring all 6.


#4

I’d try to leave space for some 12 awg and bullets for quick connections and then use longer brass plates to get each pack under 100wh


#5

You can bring any amount of packs under 100wh.


#6

I’m unsure of the AWG but the wire itself is about 2.5mm thick from memory.


#7

Ah you’re right, I’m thinking of 101-160wh

@michaelcpg yea that sounds way too thin. You need wire capable of supporting 80a continuous load without melting.


#8

See here for rough current limits of various wire

http://www.powerstream.com/wire-fusing-currents.htm


#9

80A seems a bit much I would’ve thought? I’ve always had a 40A fuse on my board which has never blown. Thanks for the link, the main thing I’m thinking about when looking at those sort of tables though is that I expect the ratings would be based on wire that’s significantly longer than a few cm’s?


#10

Thickness plays more of a role than length. 80a is what your pack is rated for, so I’d follow that guideline. The 40A fuse made me street my face once from it blowing, so I’d replace that if i were you. However, you shouldn’t blow it if you don’t do anything extreme.


#11

Hmm yea I remember reading your post about that a while ago actually, what was your battery max set to on your VESC/s at the time?


#12

40 per VESC so 80 total.