Building Electric Moped. Battery Questions

vfr400

Esteemed Pedelecer
Jun 12, 2011
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3,993
Basildon
The idea of the BMS is to protect you and the battery. If you go too high on the allowed current, there's not so much protection. If you want high power, it's better to go higher on the voltage rather than the current. High currents mean massive wires, terminals and connectors, all of which cost more too.
 
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pedbuild

Finding my (electric) wheels
May 15, 2021
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BMS wise there is no harm in going with a higher rated one those cost is more, the main ting is there isn't a minimum current draw. One might even consider a smart BMS so one can monitor each P cell as and when you wish. The speedict Neptunes might be the best there is for this.

Yeah I was going to use a Daly SMART BMS Common Port (For simplicity charge/discharge from same port). I like the Bluetooth app and how you can stop the battery from charging at a certain voltage. So charge basically to 80% to preserve longer cycles and such. I haven't seen that BMS or heard about it but will check it out!
 

pedbuild

Finding my (electric) wheels
May 15, 2021
11
0
The idea of the BMS is to protect you and the battery. If you go too high on the allowed current, there's not so much protection. If you want high power, it's better to go higher on the voltage rather than the current. High currents mean massive wires, terminals and connectors, all of which cost more too.

Ah yes, great point. Yeah seeing online looks like 100A needs a very beefy 2AWG wire which is very expensive. So that's a great point didn't think of that.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
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West Sx RH
10awg is what I have used for the Swizzbee but the wire runs are very short.
10awg is good for 60a optimal and up to 120a max.
The rear battery only needs to supply half the current but for a margin I have used 12awg for the parallel connection so ample to deliver all the power if ever needed to.

Set your aims a bit lower and opt for a max of 40a at 48v for 1900w of power.