I have twin engines. Each engine has it's own battery. I have a "house" battery that I beleive is basically to provide voltage for my electronic shift. (yamaha dual station controls) I installed a radar last summer. When I turn the radar on and transmit, my voltages goes waaay down to almost 10.5. If I use another electronic device like lights or washdown pump, the radar shuts off due to lack of power. Any ideas on how to upgrade my system? I was thinking of adding another battery to parallel the house battery and hook the house battery into the main system. I have the perko switches and can parallel both engine batteries if needed. Any suggestions would be appreciated.