I use the power cables that came with the graph and black box, tied them both together inside a connector and use a AMPED 32 14.6 volt battery. I have zero complaints, I like the higher voltage not only does it seem to run longer, but all of my other fishing friends said that my screen has much less noise than all of theirs. A single charge will run mine for about 16ish hours, I honestly have never had it go dead.