Is my battery dying?

[Muleears]

At rest, with nothing turned on, ten minutes after a 20 mile drive, the battery puts out 12.01 V at the terminals. Sounds weak to me. But, in its defense I did kill it this morning and have to jump it. It has been driven about 50 miles since the jump. What do you folks think?

I have a 2, 10 or 15 amp charger that I could put it on overnight and see what I have in the morning. Would that be a reasonable route to take? This is not an AGM, its a standard (Interstate) lead acid. Electricity is not my gig, so I need some input!

[dkl]

How old is the battery? If it's more than 4 years old, I would just replace it

[Muleears]

Originally Posted by dkl

How old is the battery? If it's more than 4 years old, I would just replace it

Thanks for the reply. No idea how old, just bought the X around Thanksgiving. The date "dots" on the battery don't show when it was bought either.

[Attacking Mid]

Put the 2 amp charger on it at least overnight. If it was dead enough to need a jump, your alternator did not have time to recharge it properly.

AM.

[Overboost]

Honestly I would just replace the battery if it doesn't look brand new. Since you don't know the history of it, it could be past it's life of service. The cold weather does play a part on our batteries but again, we just don't know how old it is and we are simply guessing. Charge it overnight and see how it reacts tomorrow.

[Muleears]

Originally Posted by Overboost

Honestly I would just replace the battery if it doesn't look brand new. Since you don't know the history of it, it could be past it's life of service. The cold weather does play a part on our batteries but again, we just don't know how old it is and we are simply guessing. Charge it overnight and see how it reacts tomorrow.

I just put it on the charger, but before I did I checked the voltage again: 11.98v was what it had in it. I hooked the charger up to the under hood terminals and turned on the charger at 2 amps. When first turned on, the charger claimed the battery was 12.0v and 45%. Not good. I'll see what the charger can do for it tonight. If it doesn't do well, I just charged another Interstate 960 CCA battery that came out of another car I had. We'll see what that one has in the morning as well. Currently (pun intended), its 14.55v and 100%. I believe they are the same size, I may swap them.

[andrewwynn]

All indications are it's weak. The problem with assuming vs further testing is that often the starter is at fault.

If you have a multimeter that can measure peak voltage, measure the voltage from cig Lighter to the B+ under the hood while starting.

It should read about 0.75 v when first start and abiut 0.65v for a restart (if oil still in the journal bearings).

Many cases of "weak battery" turn out to be dying starter (they will pull up to double the current as they die).

[Muleears]

After 12hrs. on a 2 amp charge, the batt. only put out 12.3v. Approximately .3v more than yesterday. It appears a new battery is in my near future.

Andrewwynn: I will watch the starter, that is a good point. As with the rest of the X, I have no idea of the age of the starter. At my mileage I doubt it's original, but who knows. It seems to start quickly, even with the weak battery.