DIYBMS V4 for diy powerwall and other application. WI-FI, MQTT, relay rules.

Description

Fully assembled, programmed and tested.
software & hardware opensource. Just search github diybmsv4.
Pcb colour can be different.
A DIY Powerwall is the DIY construction of a pack of battery cells to create an energy store which can be used via inverters to power electrical items in the home. Generally cells are salvaged/second hand, and typically use Lithium 18650 cells.
Lithium batteries need to be kept at the same voltage level across a parallel pack. This is done by balancing each cell in the pack to raise or lower its voltage to match the others.
Existing balancing solutions are available in the market place, but at a relatively high cost compared to the cost of the battery bank, so this project is to design a low-cost, simple featured BMS/balancer.
Controller provides human interface over Wifi/Web and also integrates with other systems like MQTT, emonCMS and Grafana.
Controller should be able to take action on alerts/events to shut down inverters/chargers/fuses.
Each cell in a battery pack has a monitoring module. This uses AVR ATTINY841 linked together by optoisolated serial ports for communication.
ATTINY841 provides:
internal temperature monitoring
external temperature monitoring
Spare input/output for 3rd party use
autonomous cell voltage balancing - it should still work even if controller is down
Don't buy this if you have no idea what your doing, I will not be able to support you. I just sold unnecessary items