When my truck is running, my gauge is on the high side of the gauge...probably around 3/4. When the truck is off, the gauge is slighty above 1/2. So there is an increase in voltage when the truck is turned on, which is expected.

Does the gauge change when the engine is off/on? If not, sounds like you have an alternator problem. Get yourself a voltmeter and take some readings with the engine off and again with the engine running.

 

My volt gauge is almost pegged. I checked my ele system and its around 14-15 volts @ idle.

 

With a charged battery (and engine running), you should get about 14.1v. A charged battery alone is around 12.6-12.9 volts (it depends on temperature), so if you're getting anything between 11 and 12 you're running the battery down. Quickly.

That calculation sounds correct to me. 25ma (0.025A) draw should not be an issue for months.

But you bought a "refurb" battery. What on earth is that? Why do you think the battery is worth diddley? (I note that you had it tested when it was fully charged and got good output, but that doesn't tell you anything about internal leakage.)

You've put a lot of work into this already. You could charge the battery up, disconnect it, and then reconnect it next weekend. If it won't start, your battery is junk, and it is not a parasitic current draw issue.

Good luck!

 

I had a 40-50mA drain on my '85 and found the battery was pulled low enough in about 2 weeks to not be able to start. This was with a slightly smaller capacity battery (about 26AH). My problem was due to a radio that I had wired to constant power and even off, it pulled that much current. Swapped out the radio and all was fine.

25mA should be fine for a few weeks, might try experimenting by disconnecting one of your small loads for a while to see if it makes any difference. A guy in my 4WD club has a Jeep Cherokee with a weird battery drain issue. If he shuts it off and parks it, the battery is dead in a week or two. But when he shuts it off, pulls the battery cable and hooks in a meter, he can find no unusual current drain. Figures it must be some relay or something that is sticking on and powering something. But if he disconnects the cable to plug in an ammeter, that relay/device turns off and stays off.

To test this, might try a clamp-on DC ammeter and see if there is a higher current present w/o disconnecting the cable. Only issue might be the current resolution. My clamp-on meter only reads to 0.1 amps on DC current. So might not pick up currents smaller than this very well.

 

Thanks for the input!

I bought the battery from a guy on craigslist. He gets shipments of Optima Batteries (Red, Yellow, Blue tops) every week...not sure the source but I have a 1 year warranty. He has sold a lot (it took me a couple weeks to get one because people snatched them up quickly), but I didn't ask how often he had people turn in their warranty. He claims that the reman batteries are old cases with new guts. I researched online a little bit before I bought it and this is generally what I read regarding the refurbished Optimas. For $70, I thought it would be worth the risk...if there wasn't a warranty I probably would have past on the deal.

That would be my next move: charge the battery and let it sit on the bench for a week or more to check for internal leakage.

So I have two scenarios here: One is that my original battery is fine and I do in fact have a parasitic current draw in my truck (meaning the Optima is fine)...OR the original battery is junk and it is just a coincident that I picked up a dud Optima battery. Frustrating.

I thought if this too...possibly something isn't acting the way it normally would when I wire in the DMM. I will keep this in mind.


Thanks everyone!

 

Update:

I got home after 6 days to check the truck. Dead again. I leaning toward the battery.

One more test. I charged up the battery on the bench, then wired up an LED that I had laying around. Current draw is 17 mA, close to what my truck's circuits are pulling.

Now that I know for sure what the current draw is, I can leave the battery on the bench for the week and check its condition. Hopefully the battery will be dead, indicating that the battery is toast and my truck is fine. Otherwise, I'll have the task of figuring out what is wrong with my truck. After all the time I spent last week troubleshooting the circuits in the truck, I'd be surprised if the battery is not the problem.

 

you might also check the battery voltage under load. a "bad" battery (one that can't hold a charge well anymore) can be charged up to show 12+ volts on a meter, but that can be due to "surface charge", which will burn off quickly if you put a load on the battery.

hook it up to something with a big current draw (like your headlights) for a while with the engine off. turn off the load and check the voltage across the terminals later and see if it's dropped dramatically or not. if it has, the battery is probably toast. glass mat batteries like the optima might be more resistant to this though, I'm not sure.

oh and if your battery is getting down to 10v, its probably been permanently damaged. even deep cycles are not supposed to get that low.

 

Hate to be a new guy to reply a few days too late, but does the battery drain if you disconnect it for the week at school? When you get home and reconnect, does it start? Saw something very weird with a battery last week that stumped everybody. Just curious.

Edit*** What is your battery sitting in? Original mount?

 

I used to have the same sort of problems.

I upgraded the ground cables no more battery drain and it starts much better of course if it sits to long a few months it still goes dead.

For long term storage I just pull the negative cable.

just curious what are the outside temps or are you in a heated garage.

 

If the OP would either buy a $20 battery tester, or go to the auto parts store and get it tested there. the "bad battery" theory could be proven or eliminated. No need to let it sit for a week, just test it.

 

He DID test it (4/10 1:34 posting), and it passed with flying colors. But a bench test of a battery tells you nothing about internal leakage, which is the most likely cause of the the battery draining itself. Which is very easy to test with the method he is trying now.

 

Thanks guys for all the responses

I will be glad to get this problem sorted out, but I think my current test has already told me what is wrong.

For my 17mA load, the battery started at 12.5 volts.
Checked the voltage today and it is at 12.12 volts...that's about 48 hours. I should not loose that much over 48 hours.

Being an engineer, I got my calculator out If we assume a linear discharge rate (which its not, but we'll do it just for fun), my rate is 0.38V/48hr. Optima states their Ah rating is when it is discharged from 12.8V to 10.5V.

So some quick math and from this calculation my battery is a about a 5 Ah battery! Not even close to the 50 Ah the battery is rated for!

Looks like the battery is toast. The discharge rate when it was hooked up to my truck would be even faster, since my truck is pulling 20-25 mA.

I'm just glad it isn't my truck!!!


Other info: All my cables are in great shape (replaced not too long ago). Also, the truck is outside, and the past couple weeks when i've been messing with this battery the temps have been normal...mid 40s I guess. The battery is in the original mount...the plastic tray thingy with the clamp across the top. I did have to make a plastic spacer for the clamp, since the battery is smaller...a bit of an upgrade from the small block of wood I had for the other battery

 

I have a similar problem with parasite draw on my batt. I discovered one problem was dampness on the top of the batt. causing current to leak between the posts some of those felt washers solved that issue somewhat... need to get myself a new DMM with DCA capability to begin the individual circuit check the OP started...

fwiw the volt meter in the truck will sit in the middle (12V) with the key on/engine off and about 3/4 to the right @14-14.5V with the engine running... 15V-18V is an overcharge condition which may damage the battery/electrical sys. and may indicate a failed voltage regulator.

 

So I was right from the beginning then?

Those optimas are great batterys until you kill them once. find someone who has bought one from advance or something. Return it under their name and all. And get one from a more reliable source this time.

 

Well, sort of. The battery was bad from the beginning. If it was good, it would have never been drained in the first place.

This battery cannot be passed off as a regular optima. When they reman them a mark is melted into the case to indicate it is a reman battery. Also, there are no stickers or anything on the used case.

I have to call the guy to turn in my warranty. Hopefully I got a dud and the next one will be okay. If not, I'll return it again and just ask for my money back.

 

Just an update. We are back in business!

I was able to get a replacement Red Top with no problems. Before I installed it I had it tested at the autoparts store. CCA/CA ratings were great, better than the previous battery.

Installed the battery and checked it 6 days later. Full power! Well, there was some discharge but it was normal.

I'm glad that problem is taken care of. Thanks for all the help!