RasPad - Battery Addition? BMS info?

Accessories for Raspberry Pi and Arduino
1

I’m looking for info on the RasPad 3 daughter board’s battery maintenance system and charging circuits. I’d like to add more battery capacity within the case. Ideally this means another battery of four 18650s. Maybe eight of them for extended travel. Can the Raspad3 daughterboard charger handle charging another battery bank from the wire leads to the battery? Is the 4S BMS ahead or behind the exposed wires? Ideally I would splice in there for another battery bank, if the daughterboard just feeds power to a BMS wrapped up in the OEM battery.

Thanks for any info and ideas on this.

(I am running a 4B inside my heavily modded RasPad3 and generally enjoy it in daily use.)

2

My backup idea is to splice the second battery bank into the power inlet, feed 15v from the second bank to the original bank, then just charge the second bank from the cord.

3

The raspad only supports three 18650 3.7V lithium batteries connected in series. The total voltage must not exceed 12.6V. You may choose three higher-capacity 18650 3.7V lithium batteries for series operation.

Your second battery pack can be configured as a 15V series setup to act as a power bank, charging the raspad’s internal battery.

The 15V series battery pack must be connected via a DC plug.