3P8S 840 AH build


Solar Enthusiast
Nov 24, 2020
eastern Ontario
I considered he Midnite breaker but used a different one for the reasons you state.
The TAIXI breakers I used have a shunt trip module that has auxiliary contacts that can be wired to de-energize the shunt once it trips.
Works great.
As far as he SOC alarm, I was going o use a NC relay but it isn't necessary.
24V----4700 ohm resistor---------LED---------ground
ETX is connected to the 4700 ohm resistor, and when the SOC is above the setpoint EXT is closed and 5 milliamps drains to ground.
When he SOC drops below the setpoint, EX opens, the drain stops, and enough current flows to light the LED.

Not my idea - this info was provided on the Electrodacus board, as follows:
You will need type 4 to see if SOC has dropped under a set value.
You do not need a relay and you can just have the EXT IOx set as type 4 shorting the LED while the resistor is connected to battery
So say you have a 4s so 12V battery about 12.8V nominal then LED if say is RED will have around 1.8V drop at 5mA thus 12.8V - 1.8V = 11V
Using a 2.2kOhm will get you close to your desired value as 11V / 2200Ohm = 5mA then when EXT IOx shorts the LED current will not be much higher 5.8mA
This way you are warned also if the EXT IOx wires are disconnected

In my case I used a red LED, and I have a 24V system, so the 4700 ohm resistor popped out of the arithmetic.