If you can run a cord that's the way to go, the pumps aren't much draw and you can use a cheap 12 power supply (brick type) or use an old PC power supply (what I use). Mine, with manifold, is mounted all in a plastic tote and has a light bulb on another one of those cheap 12v thermostats to keep it from getting below freezing inside the tote.

Also be sure to add a strainer before the pump. With a recirc line on a needle valve you should be able to pull plenty of sap. Mine will pull 27" no problem (4008) and it really woke up my silver maples.

There are a few pics of mine in my gallery (2017 season) if you would like any visual references on how it's setup.