Empowering car owners right across the globe in the fight against weapons of mass prosecution, slippery car sales tactics (new & used), extortionate motoring expences, road rage...

Posts & Solutions

Back to Discussion Summary Page
Discussion Title:  alternator output

atrovariousg

2005-04-12 23:51:00

alternator output

I have an alternator that is putting out 14.4 volts when not hooked up to the hot wire.
Yet when hooked up the voltage drops to near 12 even after hours of idling.
Assuming that the batteries are drawn down a bit, is it possible that the above scenario is not a symptom of a problem but is normal?



curtis73

2005-04-13 03:07:00

Re: alternator output

Its possible that your battery is in its twilight months. Test the battery when the car is off. If it gives 12v or less its probably toast.

Sometimes a battery shorts and some of the plates join their voltage. If so it would provide less voltage to the system. The only solution is a new battery.

Most major chain parts stores have little testers and they can test the battery, alternator, and other components in about 4 minutes. Its free



tom3

2005-04-13 07:55:00

Re: alternator output

If you've run the engine with the battery unhooked I'd guess you fried some of the diodes and the output sure would suffer. Autozone and others can bench test the alternator for full output, free, but you need to take it off.



DRW1000

2005-04-13 19:38:00

Re: alternator output

I would measure the battery at no-load, engine off. I tend to think Curtis is right and that two adjacent plates have fused and thus the battery output effectively contains 5 cells instead of 6.



Autoinfozone is an established Trade Mark owned by Internet Unlimited LLC
Autoinfozone.com is owned and operated by Internet Unlimited LLC
Copyright 2003 - All Rights Reserved Internet Unlimited LLC

Website: Terms of Use
Stock Trading Site