I hooked them both upto a 40 amp duel channel relay extention module and they worked great at first. One of the units fried a 20 amp fuse and tripped a breaker so I isolated the acuator and ran test on it and determined somewhere inside the acuator it is shorting out and heating up the wires anytime power is applied in reverse polarity or normal . So it's defective. So now I am waiting for the manufacturer to help with it a call back from them. Meanwhile my soalr tracking system is down .no power for me.