Reply To: Controlling 12-volt heaters with a power relay

That’s not much current, so most relay boards should be able to handle that with no problem.  I think that latching Grove board (https://www.seeedstudio.com/Grove-2-Coil-Latching-Relay.html) would probably work good for your situation so your Mayfly board could activate the relay 15 minutes before you want to sample, and then go back to sleep and it won’t have to hold a pin high to keep the relay closed.  You can connect the relay board to the Mayfly via one of the unused Grove jacks (but make sure you set the voltage selection jumper next to that Grove jack to 5v since the relay board operates at 5v).  I’m sure there are other latching relay boards out there that would work as well, but the Grove jack makes wiring it up convenient.