I have an 1987 ford F25o 3/4 tn truck , I put a new alternator on it cause I thought it was bad, still th same. When I check the the battery while its running Im getting 13.5 volts ?? Now while its running if I remove both pos and neg battery terminals by pass the battery and hook my tester to the truck cables it read like it should 14.5 volts? I don't under stand it and would like to kno the solution??Help
2007-03-03 10:37:51 · 3 answers · asked by redcrewcab 1 in Cars & Transportation ➔ Maintenance & Repairs
The battery is almost dead and just drawing a lot of charging current. Drive it for a while and the voltage will be back up.
2007-03-03 12:32:38 · answer #1 · answered by Nomadd 7 · 0⤊ 0⤋
battery fully charged, but not connected is about 12 volts,more or less.A good alt. with engine running has an out put of 14.5 volts max.with battery connected properly, showing 14.5 on the battery terminals, will also read 14.5 volts wich is normal, BUT if the diode block is bad inside that altornator, voltage will back off, when electrical items are turned on.
remove the negative clamp from the battery after the engine has been started, start turning on the lights, heater blower, radio, wipers and such. If the alt is good, with that cable off the battery, the altornator ought to support all evectrical items, with out shutting down. by its self
2007-03-03 10:51:40 · answer #2 · answered by duster 6 · 0⤊ 0⤋
sounds like the battery is not taking the full charge.you might have a weak cell in the battery.
2007-03-03 10:45:43 · answer #3 · answered by Anonymous · 0⤊ 0⤋