wlee69

I have a 2001 C2 Cab that has a 2 yr old Optima battery in it that I replaced myself. I've had an issue where my car can stay without a battery tender (I use a CTEK) for about 5 days, then the battery dies. Been like this since I've put in the Optima...not sure if it was a different sympton prior to replacing, but it was the stock battery, so I figured I should change it.

So today I finally decided that it was a big enough pain in the *** of having to have it on a trickle charger all the time, that I tested some thing out. And it seems from the posts I've read, things check out, but I wanted to ask the group if I've read things correctly...

First I check out the current that the battery was drawing...its .31ma which seems normal from the posts I've research...then I also check out how many volts the battery was giving out...also around 12.3V - after about a day without a trickle charger. Am I doing something wrong in the diagnostic? or does this point the the Optima battery not being OK?

I've posted a couple pics with how I'm wiring up the multimeter to test each of the items...any ideas on where to go from here would be appreciated...

jumper5836

I had a battery drain problem to. Found out it was a 2 different tracking devices. I bought it used and didn't even know a boomerang and some other device was installed. It actually damaged my batteries I've went through 3 plus the original in 5 years

C4CRNA

You should try a load test on the battery to see if it is good.

tooloud10

You don't keep the key in the ignition when it's parked in the garage, do you?

StephenB

Check the voltage after first turning on the headlights for 30 seconds. This will burn of the surface charge of the battery.

Voltage Charge Specific Gravity
12.6 100% 1.28-1.26
12.45 75% 1.25-1.23
12.30 50% 1.22-1.20
12.15 25% 1.19-1.17

Your battery is only about 50% charged

smackboy1

There are a couple of things I found that cause the battery to drain:

1) Leaving the key in the ignition while the car is parked (as pointed out ^);
2) Closing the door and then reaching in through the window to pull out the key.

If you think you have a bad battery, you can go to an Optima retailer e.g. Pep Boys, and ask them to confirm it with a load test.

PasPar2

This might be totally obvious to all but my car's po owned it for 4 years and didnt know this: after 5 days the remote unlock will no longer function. you need to unlock manually and start the car to stop the alarm. The PO told of ongoing issues with the car if its parked for too long and gave me his battery tender which I have yet to use since reading about this feature in the owners manual.

wlee69

I should have been more specific on details on how I leave the car....no key in the ignition, no alarm on - it just sits in my garage....When the battery is fully charged from the trickle charger, I get around 12.64 on the battery. I've actually left the multimeter connected for a day and randomly checked the current draw - it sometimes even goes as low as .17....

Sounds like the next step is to go get a load test on the battery!

wlee69

Stephen B - when you are saying to turn on the lights, I'm assuming you mean leaving the car off, turn on the lights for awhile, and after that check the volts....if its somewhere around the 50%ish mark like when I measured it on the pic, then thats kinda like doing a load test to see if the battery actually charges fully??

C4CRNA

If you put lights on and heater fans with ingnition on. It's a load test.
Watch your voltage drop on the dash voltmeter or your tester.

StephenB

Turn the lights on after charging. The surface charge can give a false indication of full voltage. You need to burn off this surface charge to get a decent indication of voltage.

You can only due a true load test with a carbon pile. You can do quite a bit of diagnostics with your VOM and a decent ammeter.

A sulphated battery will often indicate a good voltage but will not start a car due to high resistance caused by sulphation and the high current draw required to start a car. Your starter will draw 200+ amps to start. If you have an ammeter, check to see the draw to the starter. I have a Craftsman 73756 that works great and is more accurate than the old Snap-on inductive ammeter set I had.

Check your alternator with the ammeter.

Ahsai

Looks like the current reads 0.34A and not 0.34mA since your red probe is in the 10A jack and not the "mA" jack. Is that right?

wlee69

Ahsai - thats a great question...I assumed that the different slots for the red probe only mattered if you weren't sure about the current going through and didn't want to blow the multimeter's fuse. I put it on the higher one just in case...and thought that it was the settings on the dial that would be independent. But now that you pointed that out, I wonder if you are correct? And in that case would say I have a drain issue....I guess I'll have to dig out the manual and see what it says!!!

Ahsai

Yes, that's how these multimeters work. The 10A slot is fuse-protected and the reading shown is in Amperes, not mA. However, that 0.3A could be your trunk lamp or other devices that are still active after you turn off the car initially. So you need to wait for the lamp and those devices to time out (or pull the bulb to elimniate it) before you can get a steady and accurate reading. I think normal steady current draw should be in tens of mA. Also, if you do have a 0.3A draw, then 5 days x 24hrs x 0.3A ~ 36Ah, which is quite close to draining a good portion of the battery.

wlee69

The bulb in the trunk is already pulled, so thats not an issue....after about an hr things drop to something more stable at .17A. I heard some noise coming out of the alarm horn so I unplugged that and will see if that helps any.....but at .17A draining, the battery should still last way more than 5 days - maybe it still is an issue with the battery also!