Battery monitor question

[stu]

I built a 100ha Fortune LiFePO4 with a Overkill Solar 12v 4S 120A BMS with bluetooth. I also bought/installed a cheap AiLi battery monitor. I sold that RV and bought another one so I am back to upgrading the new system to a 280ah LiFePO4 battery system. So the question is, since the Overkill 12v 4S 120A BMS with bluetooth app (which I will be installing in the 2nd build) gives me the same info as the battery monitor why even install a separate battery monitor. What am I missing?

Thanks all

 

[Bob B]

Some people want something they can glance at when they walk by .... as long as the BMS accurately measures current draw, you will get the same info and more.
I had to calibrate BMY JBD BMS. Out of the box it didn't track correctly .... but, that is not difficult.

 

[Positronium]

I am not certain the Overkill Solar BMS has an actual coulometer. I have a 50Ah battery that I discharged halfway with battery discharger as soon as I plugged in my 25A Victron charger the BMS went from displaying 50% to 80%. This leads me to believe that the SoC in the app is based on voltage and not on a coulometer. Voltage is pretty much useless for SoC of LiFePO4 as the charging curve is so flat through a majority range and voltage sags under load.

 

[Bob B]

I am not certain the Overkill Solar BMS has an actual coulometer. I have a 50Ah battery that I discharged halfway with battery discharger as soon as I plugged in my 25A Victron charger the BMS went from displaying 50% to 80%. This leads me to believe that the SoC in the app is based on voltage and not on a coulometer. Voltage is pretty much useless for SoC of LiFePO4 as the charging curve is so flat through a majority range and voltage sags under load.

Have you fully charged the battery? The BMS will track based on voltage til you fully charge it the value you have chosen for highest cell voltage ..... after that it will track via amps in amps out.
If you write a new parameter setting, this starts over based an a voltage guestimate til you fully charge again ..... at least that's how mine works.

 

[Freep]

I have the AiLi and the Overkill solar BMS. I don't want to have to find my ipad and open an app to see the state of charge of the battery. It's also nice to be able to look over at it and see the amperage draw when I'm heating something up in the microwave.

 

[Positronium]

Have you fully charged the battery? The BMS will track based on voltage til you fully charge it the value you have chosen for highest cell voltage ..... after that it will track via amps in amps out.
If you write a new parameter setting, this starts over based an a voltage guestimate til you fully charge again ..... at least that's how mine works.

I had fully charged the battery but I had been testing different parameters settings on BMS. Thanks I will fully charge battery again.