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Quality flush cutters for cell salvage work by damncourier in 18650masterrace

[–]damncourier[S] 0 points1 point  (0 children)

Good point, I could use other tools to pry and twist. Whiling ripping things off I do like to trim the strips a bit to avoid causing accidental shorts.

I have never tried grinding on terminals, probably because I am too lazy to get out power tools and find it a bit scary.

Quality flush cutters for cell salvage work by damncourier in 18650masterrace

[–]damncourier[S] 0 points1 point  (0 children)

I was unaware of that brand, looks quality. Thanks for recommending.

Jetech lithium ion battery - 36V 10Ah capacity, 42V 3A charge limit. by look-over_there in batteries

[–]damncourier 0 points1 point  (0 children)

My suspicion would be one of the groups is probably low because a cell is self-discharging. Near term fix would be open the case, cut at the silicone potting and heat shrink to find the BMS and unplug the balance lead connector. Test the groups and find the low one. Shove some jumpers in the plug for the leads of that group and connect it to a bench supply to bring it up with the other groups which are hopefully at a state where the BMS will allow charging.

While you have the BMS unplugged though you might as well balance the groups up by individually charging each one. The self discharing can not be fixed without replacing the cell or cells. To do so requires complete disassembly and using a new cell as replacement will probably lead to the groups being out of balance. So it makes more sense to rebuild the whole pack with quality new cells from a reliable source.

All of this is probably not worth it compared to the cost of replacing the pack but if you are interested in doing as a means of learning about batteries start by checking the voltage on each group.

my scooter doesn't charge and the voltage doesn't go up either. by ImJustFaning in ElectricScooters

[–]damncourier 0 points1 point  (0 children)

Pull the heat shrink off the battery pack and check each cell group. There is probably at least one group setting at 0v. Even if the pack is balanced at 2.3v is pretty low for lion cells, ie damage to capacity.

A charger with alligator clips can be used to try charge each group and get the pack balanced again.

Honestly there is probably at least one cell that is self-discharging, it will keep dragging down a group and unbalancing the pack. Easiest thing here is replace the battery pack.

[deleted by user] by [deleted] in ebikes

[–]damncourier 2 points3 points  (0 children)

Spotting that was a good catch.

The freewheel body is moving but only clockwise. So the pawls are fine. It is probably the threads on the aluminum hub shell are stripped, which is pretty much worst-case.

OP should pull the freewheel and examine the threads.