I have the Hellroaring dual Battery system with two fairly new Sears Platinum AGM Batteries.
I had a problem a few weeks ago where I ran the fridge and couldn't start the vehicle, flipped it over to the backup and got just a click. More like a single clunk.
Thought maybe the backup problem was caused because I took the backup power cable to the primary battery rather than the starter like recommended.
Moved the cable to connect on the starter and it happened again
This time the primary was down to 12.6V, which shouldn't have caused any starting issues to begin with.
So I made sure the cables were tight and took the neutral safety connector of the tranny to make sure it wasn't corroded. It was a little gummy, but in pretty good shape and I cleaned it up and put it back on.
Ran a test over several days in between business trips
Ran the battery down to 12.5V - started fine
Ran the battery down to 11.5V - started fine
Ran the battery down below 10V and it did not start
So I switched to the backup battery and the lights and radio came back on. Tried to start it and the "thunk"
Measured 11.5V at primary battery with both batteries combined
So I know there is a voltage sensing switch and Robbie had suggested watching the voltmeter when trying to start it if this problem re-appears.
Voltage drop when starting shows it is not the cut off or neutral safety switch and the starter is getting voltage.
The voltage dropped with the key engaged
But wait, there is more
Holding the key in the engage position for a few seconds to read the voltage drop, the starter then kicked over.
Shut it off, tried it again and "thunk". Held the key in the on position and the starter would start to kick over after >7 seconds.
When it starts to kick over, it kicks over like normal not the slow pausing grind of a low battery.
I left the batteries connected for a few minutes and tried it again with the same result, so don't think the load of the low battery could be causing the delay
So I have ruled out the Neutral Saftey Switch and the Alarm voltage sense circuit. Pretty much leaves the starter. Course I changed the contacts about 40K miles ago
I had a problem a few weeks ago where I ran the fridge and couldn't start the vehicle, flipped it over to the backup and got just a click. More like a single clunk.
Thought maybe the backup problem was caused because I took the backup power cable to the primary battery rather than the starter like recommended.
Moved the cable to connect on the starter and it happened again
This time the primary was down to 12.6V, which shouldn't have caused any starting issues to begin with.
So I made sure the cables were tight and took the neutral safety connector of the tranny to make sure it wasn't corroded. It was a little gummy, but in pretty good shape and I cleaned it up and put it back on.
Ran a test over several days in between business trips
Ran the battery down to 12.5V - started fine
Ran the battery down to 11.5V - started fine
Ran the battery down below 10V and it did not start
So I switched to the backup battery and the lights and radio came back on. Tried to start it and the "thunk"
Measured 11.5V at primary battery with both batteries combined
So I know there is a voltage sensing switch and Robbie had suggested watching the voltmeter when trying to start it if this problem re-appears.
Voltage drop when starting shows it is not the cut off or neutral safety switch and the starter is getting voltage.
The voltage dropped with the key engaged
But wait, there is more
Holding the key in the engage position for a few seconds to read the voltage drop, the starter then kicked over.
Shut it off, tried it again and "thunk". Held the key in the on position and the starter would start to kick over after >7 seconds.
When it starts to kick over, it kicks over like normal not the slow pausing grind of a low battery.
I left the batteries connected for a few minutes and tried it again with the same result, so don't think the load of the low battery could be causing the delay
So I have ruled out the Neutral Saftey Switch and the Alarm voltage sense circuit. Pretty much leaves the starter. Course I changed the contacts about 40K miles ago