Battery

[new-be]

Hello to all, my 81 has 26000 miles on it and I just assume the alternator is working. The reason I assume this is when Im driving it the the battery indicator on the console registers 13+. The car battery is about two years old and if I don't put a trickle charge on at night, the battery dies the next morning. Could the clock on the radios draw that much? or is there something else I am not aware of that need to be turn off. I know with the ignition off the radio can still play but I do turn it off.

Thanks

[6880 Mike]

The 13+ reading on the voltmeter indicates the alternator is charging the battery. 13 is a normal rate of charge.

The clock has power at all times but should not be running down the battery overnight. If the electric antenna is sticking, this could discharge the battery. Check to see if the storage compartment light or the vanity mirror light are staying on.

Many of the generic auto parts places (Autozone, NAPA, CarQuest, etc.) will check alternators for free.

[Vettehead Mikey]

Disconnect the battery at night. See if it's still charged the next morning. If so, you've got a parasitic load somewhere.

[Tom Bryant]

How old is the battery? The clock or radio memory and the ECM memory are drawing all the time but it should take several months for that to discharge a good battery. You can also have most chain auto parts stores do a load test on the battery to see if it's up to the task. As was said above, eliminate the possibility of any switched light like a pressure switch on the glove box or rear compartment light or a mercury switch like the hood light staying on. It's sort of like wondering if the light in the refrigerator goes out when you close the door. It sounds to me like your alternator is OK.

Tom

[Wajulia]

Don't assume that a two year old battery is not dead. Batteries that sit a lot without being used act exactly like you explain. I personally would change the battery, if it does the same thing, put a test light between the ground lead and the battery and then start pulling fuzes until you find the circuit that is drawing down the battery.

I am a big believer of battery tenders for little used batteries like motorcycles and corvettes. I have lost batteries in one winter without them and they last for 10 years with them. Good luck

[Wayne robson]

Hi just thought i would let you know,that the best battery tester is still the age old and
proven Hydrometer,parts store still sell them and i think still only approx $5.00 $6.00,
in case you dont know what that is , its a small glass tube like with 7 to 8 inches long with
red white green marker,and floating test meter inside,very easy to use ,the object is to test each
cell,to see if there is any inconsistency between the cells,if one cell tests below in the red
then you know that that cell is going bad,it happens alot with the end positive post.
and at the same time you can check battery acid level approx one eight inch above plates while doing the tests.

[Hib Halverson]

I'm sorry but I disagree.

A hydrometer is just one tool for battery troubleshooting. It only tests specific gravity. Also, many of the cheap DIY hydrometers are not very accurate. Lastly, you can't use a hydrometer to test many modern batteries because the batteries are sealed.

A hydrometer may not detect a sulfated battery, nor will it test the battery for an internal short, nor will it test the battery for intermittent problems with its plates.

The "best" test for a battery is a dedicated battery tester which puts a load on the battery and determines its condition by how the battery reacts to the test.

[Wayne robson]

Thankyou Hib, i take your advise,i have had two Hydrometers for years and they
never let me down,and i have older stile batterys, years ago when i lived in CA US
friends use to get ripped of by auto testing and were sold new batterys that were either
low on acid or not faulty and were talked into buying a new batterys,i seen this time and time again
as i managed a big apartment complex so would help tenants with there batterys,.thyankyou.