lerneaen_hydra
100 µW
- Joined
- Apr 8, 2019
- Messages
- 8
So for a few different projects I've been working on I eventually caved in and made yet another homebrew BMS. IMO it turned out pretty well (i.e. works for me and no battery fires to date), and someone else here might also have a use for it.
Unlike most BMSs I've seen so far, this one;
Functionally, the BMS does the following actions:
There's schematics, source code, and documentation available here: https://gitlab.com/lerneaen_hydra/rabidmantis/tree/master/modular_bms
EDIT: in particular, there's pretty extensive documentation available here: https://gitlab.com/lerneaen_hydra/rabidmantis/blob/master/modular_bms/doc/modular-bms_manual_v1.1.1_2019-04-23.pdf This covers how to assemble, configure, program, and wire up the boards to form a complete BMS.
Unlike most BMSs I've seen so far, this one;
- Is not made for any given number of cells, each cell has it's own submodule, which are connected together to form the entire BMS. This allows for however many cells the given project needs.
- By setting some statements in the source code all voltage thresholds can be adjusted in software. This allows the BMS to be used for any cell chemistry (in the range 2.5 - 5.1V).
- It displays the current cell voltage continously (measured around once per second).
- Draws very little standby current, typically on the order of 20-40uA, including the current needed for the display.
- Is not in series with the high-current path of the battery, so the BMS does not limit the maximum allowable current drain. (However, this of course means that the BMS can not disconnect the batteries from the load, which would have been nice when overly discharged).
Functionally, the BMS does the following actions:
- Undervoltage/overvoltage alarm with a piezo buzzer
- Active cell balancing during charge termination using some power resistors
- A common output allows for disconnecting a CC/CV charger from the battery on cell overvoltage
There's schematics, source code, and documentation available here: https://gitlab.com/lerneaen_hydra/rabidmantis/tree/master/modular_bms
EDIT: in particular, there's pretty extensive documentation available here: https://gitlab.com/lerneaen_hydra/rabidmantis/blob/master/modular_bms/doc/modular-bms_manual_v1.1.1_2019-04-23.pdf This covers how to assemble, configure, program, and wire up the boards to form a complete BMS.