81bird

Hey guys so i took my car for a short drive today and something started to smell like rotten eggs. Noone passed gas either. I pop the hood and i hear the battery boiling. So i get home asap and shut the car off. I put my battery volt tester on and its reading 14volts while the car is off. I turn the headlights on and it slowly drops to 12 volts. I go to start it and got nothing. just a click then a buzzing sound. For now i got the battery unhooked and so maybe it can cool down. What do i need to do so it dont draw anything while the car is off?BTW nothing in my setup has changed in months so i see no wrong wiring or anything.

mjr46

sounds like the voltage regulator in the alt may be snafu!!! have the alt tested to see if it's overcharging, such will boil a battery and kill it quick

81bird

Alright. Well with the battery unhooked it reads 14 volts still. I put the tester on the +stud on the alt and it read like 1 volt with the batt still unhooked. idk if that means anything or not..

mjr46

a fully charged battery shouldn't read more than 12.6 volts, with a damage/overcharging alt you could of toasted a battery by now...let the battery electrolyte cool down then go back and retest it, but in the meantime install another battery if you have one and perform an alternator output test with a dvom on the charge wire to the alt and turn on lights and as many accessories as you can to simulate a load and see what voltage output is and if you want after that switch dvom to amp mode and see how much current output there is...this is the quick Harry homeowner way to test for such, expecially if you have an internal voltage reg in the alt, my 85 used to have an external fender mount one, so if yours is the 81 t-bird it may have such too

81bird

it has a internal regulater in the alt. i hooked up a battery charger and it read the battery was at 2 amps..so im lettin it charge for now to see what happens..

mjr46

before attempting to charge the battery if it is not a maintenence free battery and you have access to the cells, I 'd check the specific gravity of each cell to see if it is charged, 1250 usually indicates a fully charged battery on a hydrometer