I am trying to run small 24v 200w water pump on solar panel.
To prevent pump from damage I would like to cut off power when voltage is insufficient.
I did try multiple solutions with PWM Solar charge controller and set of two 12v batteries conected in series to get 24V .
Solar charge controllers suppose to do exactly that - cut off power when voltage drops - say below 22 V or so .
But all solar charge controllers detect 12/24 v automatically this days.
When I connect fresh battery they do detect properly 24v but then when voltage drops they detect 12V and keep running!
I did damage already few deep cycle batteries because controllers keep discharging 24V bank to 10 volts then cut off.
I wonder if anybody come with solution how to cut off power below 22V ? using relay ? zenner diode or something that will over ride those stupid solar charge controllers? Or advice solar charge controller that works.
I did try many bought on eBay and all comes with same fault - keep discharging battery till complete damage.

I think problem is universal and many camper users also may use 24V system , not 12V.

I will be grateful for advice