What voltage should my auxiliary battery be?
With a 12v fridge running and the compressor kicked it, it’s completely normal to see the voltage drop by as much as 0.5v-0.7v. That means you may see your auxiliary deep cycle battery reading somewhere around 12.0v-12.2v while your fridge’s powering away keeping your tucker cold.
At what voltage is an AGM battery flat?
At what voltage is an AGM battery flat? A completely flat or empty AGM battery at 0% State of Charge typically has an open-circuit (no-load) voltage between 11.4V and 11.6V. If the battery is loaded, the voltage will depend a lot on how much current is being drawn – for the numbers, see above.
Can you still drive with auxiliary battery malfunction?
Is it safe to drive with auxiliary battery malfunction? The answer is yes and no, it is always not good to drive with any kind of malfunction on your vehicle as you don’t know how it will affect car’s performance or other functions.
When to disconnect aux battery from main battery?
My isolator is designed to disconnect the aux battery when the main battery voltage drops below 12.8 V and after a delay of 60 seconds: Switch the engine off and immediately measure both the main and aux battery voltages. Then switch the parking lights on to draw the voltage down quickly.
What’s the voltage drop between the main and aux battery?
As per the design, 0.5 V drops are allowed in the long cables between the main and aux battery. Note that the alternator chassis return voltage drop (0.06 V) was less than half of the voltage drop in the alternator cable (0.15 V).
Where is the ground on an aux start switch?
If only one small wire, it will be the signal wire and the ground is through the body of the relay/solenoid. Remove the signal wire from the terminal on the relay/solenoid. With the switch on, you should have 12 VDC between it and chassis ground. If you don’t you need to check the switch and/or fuse and/or wiring.
How is the resistance of an aux battery measured?
Measure voltage at the aux battery to verify it is isolated from the alternator charging system. It is difficult to measure accurately the resistance of large diameter battery cables. Resistance can be inferred by measuring voltage drops under load (voltage equals current times resistance).
My isolator is designed to disconnect the aux battery when the main battery voltage drops below 12.8 V and after a delay of 60 seconds: Switch the engine off and immediately measure both the main and aux battery voltages. Then switch the parking lights on to draw the voltage down quickly.
How old is the aux battery rocker switch?
Batteries are less than two years old. Nothing happens when I push the Aux battery rocker switch on to assist start when mains are weak (I’ll start another topic later to address the constantly weak main battery situation). Is this a major problem or do I just need to trace out some wiring with a volt meter or tracer…?
As per the design, 0.5 V drops are allowed in the long cables between the main and aux battery. Note that the alternator chassis return voltage drop (0.06 V) was less than half of the voltage drop in the alternator cable (0.15 V).
If only one small wire, it will be the signal wire and the ground is through the body of the relay/solenoid. Remove the signal wire from the terminal on the relay/solenoid. With the switch on, you should have 12 VDC between it and chassis ground. If you don’t you need to check the switch and/or fuse and/or wiring.
