48 v adjustable relay for over system hot water heater

[Smilemaker]

How to have a hot water heater turn off below 50 v and on at 52 v. I have a 48v off grid pv system running our cabin. It has a 5000w inverter. I have been heating our domestic hot water during the day with 120vac and manually turning it off at night in order to preserve the battery capacity. But I wonder if there is an adjustable relay with which I could automatically sense the battery voltage and switch the water heater on at say 52vdc and off at say 50vdc. Preferably those voltages would be adjustable so I can experiment to find the best on off voltages.

 

[ChipFanDave]

DC Voltage Monitoring Relay, Under/Over Voltage, 12V/24V/48V DC

DC voltage monitoring relay with 2 C/O contacts (2 Form C or DPDT) provide protection for the equipment from undervoltage and overvoltage in DC circuit 12V, 24V, 36V or 48V, adjustable trip delay time, LED indicator for working state, DIN rail mounting, compact design, good quality and low price.

www.ato.com

Try something like this to monitor the voltage but I would use it to operate a contactor not try to power the water heater through it.

 

[Smilemaker]

DC Voltage Monitoring Relay, Under/Over Voltage, 12V/24V/48V DC

DC voltage monitoring relay with 2 C/O contacts (2 Form C or DPDT) provide protection for the equipment from undervoltage and overvoltage in DC circuit 12V, 24V, 36V or 48V, adjustable trip delay time, LED indicator for working state, DIN rail mounting, compact design, good quality and low price.

www.ato.com

Try something like this to monitor the voltage but I would use it to operate a contactor not try to power the water heater through it.

I had seen these for sale but wondered if they can be wired to close the ac circuit when the dc voltage hits 52 and open the ac circuit when dc voltage gets below 50? I think this is opposite of what they are intended to do.