1990 Volvo 740 • 380,000 miles

Runs good had to boost it. The problem is I turned it off after it had been boosted for about 15 mins then driven for about 20 and then all the electrical died like 2 mins after that. Any theory?
April 25, 2012.

Defective battery, generator, or voltage regulator. Start by measuring the battery voltage after charging it at a slow rate for an hour, first with the engine off, then with it running. Holler back with those numbers. Use an inexpensive digital voltmeter. Harbor Freight Tools has them for well under ten bucks, often on sale for $2.99.

Apr 25, 2012.