What is this board?
This board has 8 fully isolated CC-CV power supplies, adjustable from 1.25-5V and 10-100mA. The 12V input converter to 8 isolated 12V supplies, with a linear CC CV circuit on their outputs. 2 Standard 317 regulators are used on each output, one for current regulation and the other for voltage regulation, both adjustable with potentiometers. The regulators and potentiometers are not precision devices, so the full voltage and current range is not guaranteed on each output (on the ones I’ve tested, some outputs only go up to 4.4V).
PCB dimensions: 100 x 100mm
Mounting stud dimensions: 92 x 92mm
Input voltage: 12V, up to 1A
Output voltage: 1.25-5V, 10-100mA per channel
What can I use it for?
If you’ve ever wanted to test a Battery Management System to see what the voltage trip points are or to see if balancing works properly, this board can help. Generally, the process for BMS testing is to plug all cells except one in and replace that single cell with a power supply. Then adjust the voltage on the power supply to see when the BMS cuts out, repeating the process for each cell. With that approach, you still need to find enough other cells to connect, find the hardware to connect them, or cut a pair of leads out of a balance connector. With this board, you don’t need to use any cells, and you can adjust the voltage of every cell. Just plug the board into the balance port of the BMS and turn the potentiometers to adjust the voltage, watching the BMS output.
Manual charging or rebalancing of individual cells in an 8S battery is also easy using this module. Set all the output voltages to the same level, and turn up the current for cells that measure lower voltages to charge them faster.
You can also use it as 8 independent CC CV chargers for small 1S cells by removing a jumper resistor and connecting to the headers at each channel.
It can work with any number of series cells from 1-8S, and by stacking multiple boards together can work up to hundreds of volts (isolation ratings of the DC-DC converters and Y capacitors are at least 1000V but the PCB has not been designed to properly isolate such high voltages – no cutouts for creepage distance, etc.).
- Fully assembled PCB with M3 standoffs mounted in the 4 corners
- Connector for 12V input side (2-pin 3.81mm pitch pluggable terminal block)
- Connector for 8S output side (9-pin 3.81mm pitch pluggable terminal block)
The full schematic is available here.