In the short time that my RV-7A has been flying I have observed a slow drain on the PC680 battery between flights. For example, when I returned from my flight last a week ago, the battery voltage was reading 12.8V with both Dynon EFIS's running. When I powered up the Master on Saturday morning and both EFIS booted, the voltage was down to 12.1V. (Actual voltage right at the battery is about 0.6V higher than the numbers above when EFIS's are not powered up and the current from the battery is zero.) I thought it was just a bad battery at first so I switched it out with a new one but the same problem persists.
I have looked for a parastic leak on the battery but nothing is connected to it except on the switched side of the master contactor. If the master switch is off the battery should be isolated from all loads. So Saturday I used a handheld voltmeter to measure the voltage from the switched side of the master contactor to ground with everything shut off. It reads 0.07 volts. Small, but I expected zero with the master switch off. Is it possible that my master contactor is leaking a small amount of current through when powered off and that is causing the slow drain? I have the standard Vans master contactor.
I have looked for a parastic leak on the battery but nothing is connected to it except on the switched side of the master contactor. If the master switch is off the battery should be isolated from all loads. So Saturday I used a handheld voltmeter to measure the voltage from the switched side of the master contactor to ground with everything shut off. It reads 0.07 volts. Small, but I expected zero with the master switch off. Is it possible that my master contactor is leaking a small amount of current through when powered off and that is causing the slow drain? I have the standard Vans master contactor.