Bms wires too short

What are people doing if their bms wires are too short for their build. Mine look like thay are about 30cm long

Extend them. I build balance wires out of 20-22 guage silicone wires into my pack, all coming out of one spot, and solder those to the BMS wires. Headshrink, isolate each wire with tape, etc… Don’t want any shorts.

1 Like

You could try a wire stecher


Usually we all go mental and throw out everything related to the board and start all over again… This is why you so often hear that eskate hobby is a wallet killer!! If you don’t want to start all over again I suggest you could try thouse wire stretchers as @skunk mentioned. There’s also a bms press that could press you bms even flatter than it already is, so you would get a few extra cm in XY direction… But that thing is still in RND…


I was thinking about this but was wandering hpw safe it really is. I plan on using an 8amp charger so dont want things to go bad

I can guarantee you if you’re asking this question you don’t need an 8A charger. You really, really don’t.

I was more or less asking if people rebuild the cables for the bms or solder them together to extend.

8amp is well within the charging limits of a 12s7p pack

The balance wires aren’t the issue for charging at higher amps, it’s the charge wires you need to go lower guage on.

You can do either. But if you’re asking this question, I don’t think you should be fucking around with high amo charging.

The balance wires are just for balancing and will never see these high charging amps. Feel free to solder extension wires of the same gauge to them.

For your 8 amp charger please be sure your charge wires are of great enough thickness to handle the current and also check that your bms can handle 8 amps. I just use 12awg for the charge wires same as the power wires but you can go thinner if you know what you’re doing.

Give him/her a break guys. We’ve all been noobs.

Thanks I guess I wasn’t exactly clear about the question. What I was really asking is. Have people soldered extension wires. And if they have how have they held up due to vibrations etc this is the quickest method and dirtiest yes. The alternative is re crimping the wires with appropriate length. Time consuming and requires the right tools. Then there is buying a replacement kit for the bms balance leads with enough length to cut down, this is my preferred method and am wondering if anyone has taken this approach and where they got the cable from. I purchased my bms from

It can handle 15 amps charging.

Also using Turnigy High Quality 10AWG Silicone Wire which is rated for 30 amps so I’m in the clear for these, I also took the charging pin into consideration since the standard laptop charger style can only handle up to 4 amps

Also 12s7p from 30Q cells which are rated at 15c so I’m clear here no fire hazard visible through calculation as the theory is well in the clear

You might struggle to see balancing at all in a 12s7p configuration. Those BMS don’t exactly move a lot of current…

don´t use 10Awg for the charge wires. that´s way too much. 10AWG is good for the main power leads, no need to go that crazy about the charge wires. look up a wire guide and choose the right wire for your application. if you charge with 8A I wouldn´t take more than 18AWG (rated to 16A).

Splicing in extensions via soldering is perfectly fine. Using marine grade heatshrink, the stuff with glue on the inside that melts and seals it is always a great idea, but not necessary.

I suggest 14/16awg wires for a 8A charger. If you go to 18AWG you can feel a bit off heat