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I recently bought a E-board (electric skateboard) which would not charge. I opened up the battery compartment to check the voltage of the batteries. In case of an undervoltage which led to them not charging back up.

I am not great with electronics, but I think I understand the basics.

I measured the voltage of the charger (Plugged in to a EU [Swedish] socket) and the battery with this tool set to VDC 200.

The charger showed 42.2 volt plugged in to a socket

Charging port voltage

And the battery showed 5.0 volts.

Battery open circuit voltage reading

Is the battery "dead" and not possible to be recharged and used again, or is there some way that I can make it functional again?

Battery Info: AHCOF Intelligent Commuting.

Voltage: 36 V

Model: HB-10S1P

Capacity: 2.6 Ah 93.6 Wh

If there is any additional information required, please inform me and I will do my best to describe or give further information.

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  • \$\begingroup\$ No BMS in the battery pack? I would try to charge each cell individually while in the pack with CC/CV. Where in Sweden are you? If close you can borrow mine. \$\endgroup\$ – winny Oct 28 '19 at 15:56
  • \$\begingroup\$ 5V is disabled and quite possibly dead. V of individual cells will tell you more. \$\endgroup\$ – Russell McMahon Oct 28 '19 at 23:33
  • \$\begingroup\$ @winny I am not that experienced with electronics, so you'll have to explain what BMS and CC/CV means. I'm in Helsingborg, Skåne. \$\endgroup\$ – FilipE92 Oct 29 '19 at 8:24
  • \$\begingroup\$ Oh! That's very far away from me. BMS is a PCB with components on it and a wire to each cell used for monitoring and balancing of cells. If the pack does not have it, it was doomed to fail anyway. If it has it and you just recently managed to discharge it deeply somehow, breaking it open and charge each cell individually might revive it. \$\endgroup\$ – winny Oct 29 '19 at 8:55
  • \$\begingroup\$ @winny There is another box which holds the PCB and ESC (Electronic speed controller) and all of those stuff. This box compartment just held the battery. But the battery was drained from the day it arrived. I will probably not be doing that. My plan is just returning it and having a refund. \$\endgroup\$ – FilipE92 Oct 30 '19 at 10:07
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5V across 10 cells gives you half a volt per cell.

Using the pack details, 2.6Ah, 93.6Wh, that gives us a "nominal voltage" of 36V for the ten cells. So 3.6V per cell is nominal, so I think it would be a good guess that these are Li-Ion cells.

Assuming that these are li-ion rechargeable cells they are designed to be operated at voltages between 2.9-4.2V (there are variations on these limits depending on the cells, but this is a good rule of thumb). So we are looking at the cells being massively under voltage.

Under voltage cells should still charge up. But doing so can be dangerous, and so a well designed charging circuit should look at the cell voltage. If the cells are dangerously low (say under 2.5V or so) the charger does not charge them. And so the cells will stay dead.

This is for your safety. Dead cells can explode.

DO NOT ATTEMPT TO CHARGE THE CELLS. Yes, you could put a current source on the cells and try to revive them. I would not do this. Li-Ion cells are cheap compared to the risk.

Buy new cells or, better still, use your foot to power your skateboard.

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  • \$\begingroup\$ Thank you for the information, especially the bit about exploding cells. Of course using my foot would, and still is a possibility, however this is an electric skateboard. It's purpose is mostly to drive through electrical power. Unfortunately this is a broken unit so I will try and return it. That's all I needed to know, I'll mark as answered. \$\endgroup\$ – FilipE92 Oct 28 '19 at 14:05

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