I have a Stacer 399 Proangler with crank battery (rear and charged by my outboard) and a 100amp hour deep-cycle forward for my electric, that I recharge after every trip. I purchased a simple 2 battery condition gauge from BCF, which has three wires coming from the backside. It came with no instructions and I have searched the Net to try and find out how to wire it up, but to no avail... can anyone help?