Hi guys,

My battery no longer seems to hold a charge, so I took it in and got a warranty replacement. They tried to test my dead battery, but it was so dead that the machine wanted to charge it for 2h before it would run its test, so they just warrantied it instead of waiting for a charge.

Anyways, I put the new battery in and put my multimeter on the posts with the engine running, the headlights on and the HVAC blower on full.

I got a 13.69 - 13.70v regardless of engine speed.

Does this alternator output sound right? I read the following on Pelican:

"Your battery should read a little more than 12 volts with the engine off. Next check the voltage of your charging system under load. The voltage should be within 13.2: 14.5 volts d/c."

However other sites on the internet are saying that 13.8 is bare minimum to charge a battery and that ideally it should read 14.2-14.5.

Thanks!

 

13.7 at the battery terminals sounds acceptable to me, especially with the headlights and blower running. It's probably a little higher at the alternator and losing a bit via the cables and grounds, etc. too. I'd probably check for parasitic drains next (i.e., how much current is being drawn from the battery when the car is off and just sitting).

 

Yup, good point. I just checked that and I am drawing 90mA with everything off, which I believe is much too high. Crap. Gonna have to start pulling fuses and relays tomorrow.