Reply To: Electrical assistance

Andrew Spruell

    Hi Nick

    Before you replace the isolator which is a splitting diode device it may be worth checking a few other things.
    1. How old is the starter battery. Could it have reached the end of its life. They can suddenly just fail.
    2. No disrespect but is it possible after you turned the engine off that the engine electrics remained powered up. You can do this on the Volvo 2030 as it has a mechanical stop switch. As the engine blower fan takes at least 5 amps it would not take too long to run the battery flat
    3. Is the alternator working properly and if so is it charging the stater battery. Running the engine at 1500-2000 rpm should show a voltage of about 15v at the alternator and 14.2-4 at the battery terminals allowing for a voltage drop across the isolator. Both the starter and service battery should show the same voltage whilst being charged. If the starter battery is showing only 12v when the service battery is showing 14+v then the problem may be the isolator.
    Hope this is helpful.