Battery connection problem

Hello everyone, I have a problem with my battery / BMS.
The battery is a 10s4p Samsung 30Q Bestech HCX-D596.
The problem is when I connect the BMS ignition cables, the BMS doesn’t stay on, it goes up in a V shape then goes down directly to 10V or it’s off position.

When I’m charging no worries the battery is charging but I’m not going to drive with it connected.

Here is the video which will surely be more talking:

At first I thought the problem was with the switch so I removed it but the problem is the same.
Please help me.

Looks like the bms is busted, does it take the full charge?

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Yes, he takes charge.
And I would like to specify that I had the problem with the construction and then it started to work like magic and I did a few kilometres and after that I couldn’t restart the board and the problem came back.

Umm, maybe you have a bad series connection, can you open the battery up?

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I didn’t build the battery but here is the construction post:

I can open it but I’m a bit afraid to open it as I don’t know much about batteries. And I don’t have nothing to close it again.

Strange… I’m not as familiar with that BMS so it took me a while to understand the whole ignition thing. But if it was a bad series connection, I don’t think it would read full voltage. Still a good idea to open her up though as it’s almost almost a connection issue somewhere

Otherwise I can only open the BMS part and I can close it cleanly with electrical tape in the meantime.

Where are you located? I might be able to ship over some heat shrink tubing for you

I live in France

I opened the bms part so it doesn’t look like there’s a bad weld or anything like that on this wire


I was able to find the solution, the problem came from the connector which, with the vibrations, had been slightly removed, enough to make it no longer work.
So all I had to do was put it back on, I’m going to put a bit of hot glue on it to fix it and everything will be fine.


Now I am appealing to your generosity, if someone has some heat-shrinkable material to close it, it would be a pleasure!

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I’m not sure a simple touch is enough to get the bms to stay on. You may need a switch to make solid contact or to solder the wires together for a constant on connection.

The 10V is weird tho. I was under the impression it should be 0V when the bms is off but I dont think I ever confirmed that when I used one.

Don’t worry I put more than a little :joy: I just took care to avoid going over components.

Hi Shelby! sorry for my late response I didn’t saw the post before. Did you solved the problem? I always check battery before send and it was working good. That looks like the BMS cut off the power. First of all please do the mechanical on/off switch (white wire must be connected to turn on the BMS).

No worries as the problem could be solved without too much difficulty it just means that I find heat shrinkable film and everything will be perfect.