Hi folks. I have a 200ah Lifepo4 battery with a 120a 4 cell BMS from overkill. I've have to battery and been using it regularly for about 2 years now and everything has been perfect until last night. During the night the battery made a long beep and then the power cut off, I'm assuming the battery was drained (a little confused on this too as I was sure there was plenty of juice left in there) anyway I tried to charge up the battery this morning but now the Bluetooth no longer seems to work, I cannot connect to the BMS via the app so I'm not sure how to see what's going on with the battery now. I connected the battery to my home charger and it's now showing as full but still no life from the Bluetooth. Any ideas? Thanks
Overkill BMS not working?
- Thread starter Liv2020
- Start date
MisterSandals
Participation Medalist
Have you tried restarting you phone (or whatever device you connect with)?
With iOS, you can "Forget this Device" in bluetooth settings. Perhaps deleting old devices will allow you to rediscover it.
Does the blue light on the bluetooth dongle light up? Mine does when its connected. Sometimes i have a device already connected (my iPad) and it won't accept a second connection.
Maybe unplug bluetooth dongle and reseat.
Lots of things to try. Do you have reason to believe BMS is alive but not bluetooth?
No the blue light is not illuminated anymore
I'll check this now.
The Blue light is not coming on the the dongle. I'll try plug it out and back in. I don't know how to tell if the BMS is working without the App.
So it's currently 3.3v on each individual cell and 13.2v across the pack.
Whem I measure the voltage on the other side of the BMS its showing, around 12.4v but the voltage is moving around a lot.
MisterSandals
Participation Medalist
What device are you using to connect to the BMS?
Does this change when you unplug the balance wires from the BMS? This "should" cause the BMS to open the circuit so voltage thru BMS should be 0V (but some BMSs still leak a few volts, which is concerning).
Thanks for the response. I have removed the balance wires now and yes it's still showing a voltage of 11.7v.
John Frum
Tell me your problems
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- Nov 30, 2019
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- 15,233
Thanks for that.
John Frum
Tell me your problems
- Joined
- Nov 30, 2019
- Messages
- 15,233
@Liv2020 I think you should walk the BMS balance leads with your multimeter.
Take the connector off the bms.
set your multimeter to dc volts.
put the black test lead on the connector pin that corresponds with the most negative pin on the connector.
Put your red test lead on the pin that corresponds with the next pin.
The voltage should be ~3.3 dc volts.
Now put your red test lead on each subsequent pin.
The voltage should increment by ~3.3 dc volts.
Take the connector off the bms.
set your multimeter to dc volts.
put the black test lead on the connector pin that corresponds with the most negative pin on the connector.
Put your red test lead on the pin that corresponds with the next pin.
The voltage should be ~3.3 dc volts.
Now put your red test lead on each subsequent pin.
The voltage should increment by ~3.3 dc volts.
