Daly Smart BMS- Lengthen balance cables and UART cable

[Zwy]

The balance leads are just too dang short for how I want to mount the BMS to pack. I see some have used a busbar but wonder about increased resistance from the connections leading to erroneous cell voltage readings. Lengthening the lead might be a better choice or purchasing a longer lead. Increased length would again have some effect, would it be enough to be concerned about adding a foot of length or should I simply build a new cable with larger wire size? Does someone have a source for parts to build one or source for prebuilt longer balance leads?

Second is the UART cable to the touchscreen, wire must have increased in price a huge amount since Covid started, who builds a touchscreen to mount on a wall but makes the lead about 9 inches long? Can I just lengthen it or find another source for something longer?

 

[Lt.Dan]

Did you ever get any more info on using a divided bus bar for the balance leads? I'm debating on doing it to mine to simplify wiring, and my wires are a little too short also lol

 

[Zwy]

Did you ever get any more info on using a divided bus bar for the balance leads? I'm debating on doing it to mine to simplify wiring, and my wires are a little too short also lol

I just bought some good silicone 24 ga wire and extended the leads. All are the exact same total length too.

You will have to fold over the balance lead wires to get a solid crimp in the barrel.

 

[Lt.Dan]

I just bought some good silicone 24 ga wire and extended the leads. All are the exact same total length too.

You will have to fold over the balance lead wires to get a solid crimp in the barrel.

Do you know if the balance leads all need to be the same length? Or will that cause voltage mismatch issues?

 

[DanBo]

A regular voltmeter is typically a very high impedance circuit. If it were not, the voltage drop in the leads would mean the voltage you were trying to measure would be false. So, typically no or almost no current flows in the leads of a voltage measuring circuit and therefore, the length of the leads should make little difference. On the other hand, I just bought a Smart Daly BMS myself and I am prepared to accept that Ohms Law is maybe up for repeal. I agree the leads are too short. My 16 batteries were in a 2x8 config. Changed to 4x4 and now they all fit without stretching. Mind you, I had to stick the Daly to the side of the batteries. No way to mount it remotely.

 

[Zwy]

Do you know if the balance leads all need to be the same length? Or will that cause voltage mismatch issues?

I'm always of the camp to keep resistance the same on circuits like this. While these are short, the wires are very small gauge. The leads should be longer from Daly.

It may not matter regarding the length but I'm a stickler for details. Less problems this way that won't lead to the "I can't figure out what's wrong".