DTMR

but it staying over 14 when i drive and at 12 when its off

Nuke

Get a decent voltmeter and check the terminal voltage AFTER the car has sat overnight; preferrably for at least 12 hours. Anything between 12.4 and 12.6 volts is good. 12.3 volts or less after the car has sat is indicative of a problem.

About 14 volts (13.6 is preferred) when running SEEMS to indicate that the alternator is charging but don't depend on voltage readings alone to confirm that it's charging. You need to have both the battery and alternator load tested seperately.

moosestang

Datalog the voltage while cranking. It can charge at 14 and still let alternating current get to the battery. AC and DC don't mix well.

DTMR

Whats the difference between AC and DC?? Do I check the diodes at the alternator itself?

ski

FWIW
My GT(not a daily driver) had a battery problem that started almost 3 years ago. The charging system tested ok, and my $2 tester showed the specific gravity was also up to snuff. So I just kept recharging it with an automatic battery tender, and it would be good for 3-4 months before the next no-start problem occurred. After about a year of doing this I finally got fed up, and had my mechanic check it. He found the battery fluid's specific gravity was low, and gave it a "healthy" charge with his professional manual charger. I haven't had a starting problem since then.
That's what can happen when one depends on a cheap specific gravity tester.

DTMR

i just wanna stress that it hasnt totally died yet since i got the new one, but I feel like its going to because its struggling more to start

DTMR

so i hooked it up at a shop to an accu plus scanner that checked everything, it said diodes were good but battery was bad. Maybe I need to get a maintainer cuz i dont drive it enough in the winter :/ Its an AGM battery not the acid kind. I cant believe I went through two redtops already.

gearhed289

Similar problem. After 5 years, my stock battery finally went. I installed an Optima red top a little under 2 months ago. Everything seemed fine. The car sat for the past 3 weeks due to weather, and when I got in it this morning, it was completely dead. Jumped it with my T-bird and headed to work. Four miles in, I went to set the clock and immediately got a "battery low" message, and the dash went crazy. Pulled onto the median and the car died completely. Hazards wouldn't even work. Had it towed to my mechanic. Waiting for a call...

DTMR

is it true the when u let your car sit for a long time then turn it on again and drive then lt it sit again its called deep cycling??

Ford_Dude

Deep cycling is when you fully (or near fully) drain the battery and then charge it back to full.