Battery fuel gauge

Hi! Looking for tips on how to remotely measure battery level/voltage.

We are using BlueRobotics Lithium-ion batteries in a custom setup with 6 of those batteries in parallel. We are looking for a simple fuel gauge to remotely measure battery voltage, that can feed battery data into a Raspberry Pi. Something like the battery cell checker would be perfect, that is, if it’s able to communicate by I2C or some other sort of serial. As far as I know, most off-the-shelf fuel gauges are for single cells, and won’t work for the 4S6P BR batteries.

An resistor and ADC setup could be possible, but if there are any quicker/simpler solutions that would be much preferred.

Hi @UltraFred,

This isn’t something I’ve looked into in depth, but from a brief search the closest potentially relevant thing I found was some automotive battery monitors from Texas Instruments.

If that’s not a fruitful path then likely your best bet is setting up an ADC + resistor combo and multiplexing between the packs (or even between the cells). The voltage generally shouldn’t change super quickly, so it should be sufficient to just repeatedly cycle through the measurements instead of needing several ADCs to measure all the packs (or cells) at the same time.

Have you looked at INA260 boards? We’ve used these ones which connect via i2C. Rated for 36V, but only 15A, so no good if you’re using it for an ROV

Adafruit INA260 High or Low Side Voltage, Current, Power Sensor : ID 4226 : $9.95 : Adafruit Industries, Unique & fun DIY electronics and kits](Adafruit INA260 High or Low Side Voltage, Current, Power Sensor : ID 4226 : $9.95 : Adafruit Industries, Unique & fun DIY electronics and kits

We’ve also connected them to a custom RS485 board for a simple topside battery alarm (LED and piezo) separate to the ethernet connection