Pictured below is a controller designed to automate backup mains charging of a battery bank which is charged by an array of photovoltaic solar panels.
This controller is based around our low voltage disconnect products. It constantly monitors the voltage of the battery bank. When the voltage falls below a user set low voltage (e.g. 12.0V), the on board relay closes which connects a mains powered battery charger to the battery bank.
When the battery voltage then gets up to a user set high voltage (e.g. 13.6V), the on board relay opens which disconnects the battery charger.
This controller is fitted with manual overrides so that the user can ‘override’ the controller and force the mains powered battery charger to come on when off, or turn off when on.
This is very useful for a solar powered system since the battery bank voltage may be getting low and the weather forecast may also be bad for the coming day. In that scenario, it is worth charging up the battery bank fully immediately to prevent the battery bank from hanging around at a low voltage for an extended period of time (which is bad for battery longevity).
Similarly, if the mains charger is on because the battery bank was low on charge, but the weather forecast is for non-stop sunshine, the override enables the charger to be turned off to leave the solar panels to do the rest of the work.
If you need a controller like this, email email@example.com with details of your exact requirements.