Just got my data logger up and running and was checking voltage with everything on. About 12.7 volts with nothing on, with both fuel pumps, fan, water pump, ignition, and solenoids powered voltage is dropped all the way back to 11 volts. How low is too low? Would a second battery or alternator be a better choice. I charge between rounds because I usually run the fan and water pump and use a NOS bottle heater?