40V Greenworks Battery not charging

[Johnrobert999]

5 Groups of 4 batteries in parallel, when charged to 4.2V, 4.2x5 = 21V. How can it be a 40V battery?
When I measure across + and - on the battery, the current state is 38V Cells must be decent
When I measure output terminals 1 and 4 , nothing, 1 and 3 = 28V
Looks like BMS is defective, could I jumper wire directly from battery terminals - and + to pins 1 and 4 not sure what the 2 terminals in the middle are for, maybe something to do with BMS

Thanks in advance

 

[magnie]

5 Groups of 4 batteries in parallel, when charged to 4.2V, 4.2x5 = 21V. How can it be a 40V battery?

It is 10s2p, not 5s4p. Each of those metal plates is 2 in series. So 5 * 2 = 10 * 4.2v = 42v.

 

[docw009]

You cam't assume a bad BMS until you check the cell voltages. You can check at the blue wires on both sides. Start at the most negative end and walk up to the end. There are ten groups and each one will show an increase in level til you get to 38V.

THis schematic shows what would happen if each group is at 4V. The BMS should close its switch if all groups are above 3V. If any are below, that is not normal, and it shuts off, So you will be checking for increasing. volatge and every increase at least 3V higher.