After taking advice from members of this forum I bit the bullet and ordered a 35v battery with in built controller , lcd brakes and PAS. I tested before fitting and everything worked. After fitting the battery on/off switch doesn't light up and there is no power. I say no power but when I tested out put I get 2.7v whether battery switch is on or off. Any ideas?
BMS battery
- Thread starter dbar
- Start date
D
Deleted member 4366
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D
Deleted member 4366
Guest
I think you'll have to look inside to see what's wrong. Maybe the switch connector not in the BMS properly.
D
Deleted member 4366
Guest
Follow the wires from the switch to the BMS. There should be a connector. Unplug it and short out the two pins. Does the full voltage appear on the output pins?
D
Deleted member 4366
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There's an explanation of the BMS connections in a photo in this link:
https://bmsbattery.com/bmspcm/714-10s-13s-20a-lithium-bms-for-bottle-battery-09-bms-pcm.html
The cell pack positive (B+) goes directly to the output terminal. Both the charger (C-) and output (P-) negatives are interrupted by the B.MS. The BMS opens the connection between the B- and P- when the switch is on and all the cells (B1 to B10) are in the range 3.0 v to 4.2v).
The LED in the switch must conduct the current for the switch. If it doesn't come on, either the switch doesn't switch on or there is no power on the positive pin of the connector.
Things to check:
Voltage between battery positive terminal (B+) and B-, which is pack voltage.
Connection of the B- and P- to the BMS.
Connection between P- and output terminal.
Individual cell voltages - black probe on B- and red probe on each B1 to B10.
Voltage between B- and each of the two pins on the switch connector.
One of the above results will indicate what is wrong. Try and stick to a logical approach rather than trying random things.
https://bmsbattery.com/bmspcm/714-10s-13s-20a-lithium-bms-for-bottle-battery-09-bms-pcm.html
The cell pack positive (B+) goes directly to the output terminal. Both the charger (C-) and output (P-) negatives are interrupted by the B.MS. The BMS opens the connection between the B- and P- when the switch is on and all the cells (B1 to B10) are in the range 3.0 v to 4.2v).
The LED in the switch must conduct the current for the switch. If it doesn't come on, either the switch doesn't switch on or there is no power on the positive pin of the connector.
Things to check:
Voltage between battery positive terminal (B+) and B-, which is pack voltage.
Connection of the B- and P- to the BMS.
Connection between P- and output terminal.
Individual cell voltages - black probe on B- and red probe on each B1 to B10.
Voltage between B- and each of the two pins on the switch connector.
One of the above results will indicate what is wrong. Try and stick to a logical approach rather than trying random things.
D
Deleted member 4366
Guest
Check again B9 to B10. The difference is only 1.5v, which would switch off the BMS. Put one probe on B9 and the other on B10 to get a direct reading.
D
Deleted member 4366
Guest
There's your problem. The only question is why? It could be a broken weld on one of the strips that join the cells in that string or a faulty cell. Have a good look at those strips first. If all looks OK, you need to charge up that group to 4.2v. You'll need a 5v USB charger or an old 3.7v/4.2v phone charger of anything that charges a single lithium charger. Have a look at what you've got, then report back.
D
Deleted member 4366
Guest
If your imax can do single cells, you have to start off with nicad, then lead, then LiFePO4, working your way up li-ion. You might be able to start with Pb.
D