Relay module for more than 30 Volt Dc

Hello, I am new here and this is my first post. I have being searching for a Relay module for arduino uno, so I can control a solar pool pump to turn it on/off using the relay module. I have being looking on eBay for different modules, and the ones I have seen are only for 220 volt AC max 30A/ or max 30 volt DC. My pool pump uses 72V 1200 W. The solar panel can get up to 108 Volt DC and about 1870W.

Can I use the 30 Amp module that works with 220 Volt AC? . or will I just fry the module. Are there any module can handle that many dc volts?.

Thank you. -Lui

Ciao Lui. Your pump draws 17 amps (1200W @ 72VDC). You need a relay with contacts rated for at least that DC current (say 30A at 120VDC - I recommend you over-rate relay contacts). It is important to note I am talking DC here. AC ratings are completely different and generally speaking a contact set can handle higher AC voltages and currents than they can DC.

A solution to your issue could be to drive as suitable relay from the contact set of the module relay you are looking at. Arduino drives low rated module relay whose contacts operate a more capable relay. You may find a relay that Arduino can drive (note that Arduino pins can only directly source 40mA) or you have several electronic solutions.

I would consider using a MOSFET as a driver. A logic level FET like FQP30N06L can handle 32A at 60VDC (not enough to directly drive your motor, but plenty to drive a substantial relay).

Have a look around this site and google to see how others have done this. Good luck with your project.

You could use a relay module to control a solar panel relay.

Thank you guys, The Fujitsu relays look very promising.