Hello.
My alternator has packed up. After starting the engine, the engine battery light comes on after about 30 seconds. The voltage across the engine battery terminals is 12.8 volts only, this is whilst the engine is running!
I have noticed as well that there is a discharge from the hab. battery whist engine is running and engine battery light NOT on. As said, after about 20 - 30 seconds the engine battery light illuminates and then the hab. battery discharge stops.
Any ideas? Many thanks. John
Well, at least you've found this out at home! Our alternator packed in when we were several hours away at the start of a fortnight's trip, and MH wouldn't start at all after the comfort stop. Ended up being towed home. We hadn't had the MH long, and our mechanic found we had a Cortina-type car battery, not the heavy duty battery we needed. As for ideas - sorry, I'm not mechanical but there are some very handy folk on the forum who'll come up trumps for you.
Disconnect the habitation(aka leisure)battery & try again. This will tell you if it is leisure battery related. Voltage reading from engine battery should be around 14volts on fast tickover. If it is much lower then this does suggest alternator is on the way out or just worn brushes. Yrs ago brush replacement was easy & cheap but I don't know if it can be done on modern alternators. Otherwise probably replacement alternator is needed.
With a voltmeter across the starter battery terminals. Note meter reading. Rev the engine, you should see the voltage increase.
If it doesn't, two options;
1. Alternator belt snapped. 2. Alternator faulty.
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Topic: Faulty alternator.
