To regular check your batteries is important, they are a large, maybe even the largest cost in your solar setup. Now stuff like fluids or frost is just a regular check, but for under-voltage (to far dis-charge) we can rely on electronics, so let’s build a battery guard.
The XH-M601 board.
A dedicated 12-Volt solution. The board by itself can be used un-modified, but we just use it to sound an alarm. The board is designed to automatically switch on a charger. This sounds like a good solution, but with solar energy it’s not like a back-up grid is available. Just a cheap and simple battery guard with audio-able alarm and flashing light will do for most users.
The whole setup consist out of a small enclosure (3.94″ x 2.68″ x 1.97″), the XH-M601 board, a voltmeter, the flash-buzzer-light and a switch to cut the alarm.
During the day while the charge controller charges the battery an alarm shouldn’t sound since the battery-voltage is high enough. If something goes wrong, the alarm will sound.
The XH-M602 board.
This is a universal board that can be used to check different battery voltages (6-60Volts) so it could be suitable for 12, 24, 36 and 48-Volts, named XH-MA602, we did modify it a bit.
On this board we can set the correct voltage and it would switch on a charger in default modus. Same problem as before, a charger has to be plugged in, so a back-up generator is needed.
XH-M603 and XH-M604 boards.
There are 2 more boards available, but we leave them be. The XH-M603 is a modified XH-M602 board to fit both 12 and 24-Volt setups, we went a step further by also adding support for 36 and 48-Volt on our XH-M602 modified version.
The XH-M604 also adapts batteries from 6-60 Volt but als has a 30A relay for heavier chargers.
In our schematics we use a nice flashing-light with buzzer to alarm someone. Sorry if the alarm goes of at night, but that is a time where you might need this protection since the is not (re-)charging done at night.
Auto-starting your back-up generator is not something we are covering on this topic. Most portable generators have to be pulled to start anyway.
Also we make the assumption that you own a correct charger that corresponds to the voltage of your battery (bank).