Hoverboard battery, can I rewire this?

[gr1340]

Hello all.

I have an old hoverboard which longer charges or turns on.
When I test the voltage on the battery plug, I get 0.
If I test it on the positive plug and the what I think is the last battery, I get nearly 20v.
If I relocate the negative to the battery that gives me 20v, is that likely to work or will I have created a potential fire risk as it bypasses all the safety cut offs built in?

[Half Finished]

They are typically 36V. The cheap cells will have self discharged already. The reason you can't measure a voltage is because the battery management PCB has cutoff to prevent further discharge or charging.

They are cheap enough to buy replacements from ebay

[.:ian:.]

Measure each cell individually, if one or more are around 2v or lower they are probably irreparably damaged.

[ARHarh]

I do not recommend this unless you understand all the potential hazards. But it will be easy enough to bring the "dead" cells back to life and then charge it up.

I am not going to tell any one how, but youtube will if you care to look. There is a very real chance of fire if you have not fully understood the issues involved.

[gr1340]

Thank you for the suggestions, just a quick update though:
I tried to ‘jump start’ the battery but that did not work. Completely disassembled the battery back and charged the 18650 cells in my charger so they were all about 70% charge. Spot welded them all back together again and then I got a voltage of around 26v from the red and black wires.
Put it all back together and the hoverboard worked for about 40 minutes then died but unfortunately still won’t charge so will probably abandon any further attempts as not worth it.
Charger is fine as we have another board that charges fine with it and is the same battery/voltage.