How do I test my batteries?

[Mtrdrms]

Hey guys. I am thinking of getting new batteries for my 08 but want to make sure mine are totally shot before I replace them. Peace of mind, ya know? So they are not strong enough to turn over the engine more than a couple of times and they won't accept much charge at all but when I volt check them they both show between 11 and 12 volts - what gives?

 

[dmc-4359]

Voltage (pressure) is only one part of the equation. If they are unable to put out the current (volume), then the voltage will drop too far to be useful enough to turn the starter.

Not sure about your part of the world, but around here we can take batteries to the local Advance or Autozone and they will hook them up to a computerized charger gadget for free. The charger gadget takes various measurements on the electrical characteristics of the battery and if it is deemed worthy, it will recharge it. I've brought in a few batteries that were beyond the capabilities of my home charger to bring back to life and they have restored them for me. If the battery is toast though, then you're at least at a convenient spot to buy one (grin).

 

[hobie237]

Your batteries don't work. They won't accept a charge. They are shot. Replace them. If you'd really like, you can have them tested at Advance Auto, AutoZone, whatever, but I'd say they're shot- they show proper voltage, but won't hold enough charge to start the truck, so when you put a load on them, they crap out.

 

[swbradley1]

You could also buy your own battery tester at Harbor Freight. Just hook it up and it will show you a bad or weak battery in a few seconds.

 

[WillWagner]

High resistanc grounds will do the same thing. I'd buy a load tester, tale the batteries out and slow charege them, then load test. If they check out good, you got an issue on the truck.

 

[hobie237]

Or just check the grounds for resistance.

 

[Mtrdrms]

Well I took the batts to Napa and they tested them underload and told me they are both good! They show good voltage but are only producing about 400 CCA each. I am going to leave them on the trickle charger for a while see what happens. The funny thing is they werent taking a charge in the truck so I am not sure why they will outside the truck. We shall see...

 

[WillWagner]

High resistanc grounds will do the same thing. I'd buy a load tester, tale the batteries out and slow charege them, then load test. If they check out good, you got an issue on the truck.

Where did I go to school? I gotta spell check more often!
Alot of times, cables will get full of corrosion inside the housings. Buy a good DMM and start checking grounds from the batteries back...bat to frame, engine and body. Quick and simple to do. When you say it wasn't charging, were you going by the gauge or a VOM?

 

[Mtrdrms]

I was going by the fact that after a few hours on the charger, the batts could barely turn the engine over. Maybe I wasn't charging them long enough or maybe a fast charge is not the way to go - i'm slow-charging now.

Andy

 

[WillWagner]

Could be a starter issue. If the batteries LT fine, there is an issue with either the power/amp delivery to the load...cables, or the loaded part..the starter, is having issues

 

[LanceRobson]

A fully charged battery, with clean posts, should read 12.6 volts. Anything less indicates a weak battery.

If you have access to a good voltmeter, remove the cell caps and start next to either post, connect one lead to a post and check each cell in sequence. It may take a few tries to figure out which way they are internally connected but a fully charged 12 volt battery should show a 2.1 volt increase in voltage as you progress from one cell to another. Typically, given your description, you will find one (maybe two) weak cell(s). The voltage values you have already noticed would lead me to try this test first. This check does not need any allowance or correction for temperature.

I believe you have one or more tired cells in each battery. If so, even if they are as fully charged as they can get, they will discharge very quickly and will not provide any real power for more than a very short time-exactly as you have described.

A flooded cell (wet cell) lead acid battery designed for cranking (such as the 6TL and U6TL GI batteries) is considered fully discharged at 11.8 volts. Your description of "between 11 and 12 volts" tells the story.

If you wait for daylight and look up in the air over the truck, you will see the buzzards circling your batteries.

BTW, you can't "load test" a battery that is not already fully charged. If a battery shows less than 12.4 volts you cannot accurately load test it because a load test is designed to test a fully charged battery.

Lance

EDIT: A 6TL, U6TL, 6TMF etc, depending on when it was made and who made it should show in the 720-825 CCA range, when fully charged at 0 degrees F.

400CCA is way past servicability.

 

[hobie237]

If the batteries are "fine," yet showing only 400CCA, something is amiss. Try a trickle charge (it's worth a shot, I guess), but I'm wondering if there's just something wrong with the batteries overall- are they the correct size/shape/description/model/etc.?

 

[SCSG-G4]

This is what the Solargizers are supposed to do, fix cells that have sulfated and will not hold. But, be aware that it might take a couple of months according to previous posts on this and similar topics.

 

[Mtrdrms]

If the batteries are "fine," yet showing only 400CCA, something is amiss. Try a trickle charge (it's worth a shot, I guess), but I'm wondering if there's just something wrong with the batteries overall- are they the correct size/shape/description/model/etc.?

I am gonna give it a shot. I have to wait for my new glow plugs to come in anyway. They are the stock-type batteries (6mtl ?) and they were replaced in the truck in 12/07

Andy

 

[ida34]

My newer model battery charger has a desulfate function. It calls it reconditioning. It takes about 24 hours for it to do the job. You might look into getting a new charger and desulfate them with the new charger.

 

[Jersey 93 Ty]

My newer model battery charger has a desulfate function. It calls it reconditioning. It takes about 24 hours for it to do the job. You might look into getting a new charger and desulfate them with the new charger.

I just used that same feature on my new charger to save the single 6tmf that I own (it was one of the batteries in one of my M1009's from GL). After 48 hours of standard charging, the readout told me that the battery had some kind of failure. After using the desulfate feature (called "Equalizing" on my new $50 Pep Boys charger), the battery was full the next morning, and started the truck a couple of hours later. That charger was easily the best $50 I've spent in 2009.

 

[corelokt]

A lot of factors can come into play that cause weak starting. If any of the cables are corroded, wires broken inside the insulation, poorly clamped, or poorly bolted to a bus bar or the starter or a ground point, that will make a good battery seem weak. Also check the ground points from each alternator and each of the charging leads from each of the alternators. You really need some sort of electrical test meter, the $5.00 ones from harbor freight work fine. Another gizmo I find useful is an inductive pick-up. I got mine from JC Whitney. You just hold it against a starter power wire or an alternator power output and it tells you if the part is right. It comes with directions, and works. My daughters 98 escort wagon won't start. I put new battery clamps on it and no help, (it needed them anyhow), so now I will use the inductive pickup to see if it's a starter that needs to much juice, or if the alternator isn't putting out. If both are good, it's test the battery time. Harbor freight has a carbon pile load tester they sell that will test that also, but the one I bought had a defect, I took it back, no problem, and used the refund to buy some other want / need.
Oh, die-electric grease, and a star washer on each bolt or under each nut is always a good idea. I also replaced all my battery clamps with the Humvee type, and installed lug ends in place of the old clamps. Much more solid, and you don't need to remove the clamp each time to disconnect from the battery, which saves the battery clamps from cracking. They are also very heave and really clamp onto the battery very solid.
Lastly, check to see that you have good ground from your cab / firewall to your first battery negative. I ran a lawn tractor battery cable from the negative bus bar to a bolt holding the fuel filter to the firewall. I also ran one from the firewall to the front radiator support where the negative cables that ground to it connect. It may not help your starter issue, but it will help other issues.

 

[rlwm211]

I did not find these specs on the site, or at least I could not find them if they are here. The batteries for a deuce are the U6TL type I am sure most all of you are well aware of. I thought it would be helpful to know the ratings of these batteries when considering a replacement so you buy a type capable of starting the truck as designed by the military. Here is the information:
U6TL 12 volts
CCA 825
RC 215
dimensions (inches) 11.88 X 10.50 X 11.88
weight wet 69 #
weight dry 56 #
number of plates: 138

 

[HardCorps79]

only slightly related::stir pot:

Every time I go to O'Reilly I stand at the Optima display and lust over the $160 red tops. Then I come home and click on the OD Iron link and lust after the adapter trays.

I'm trying to convince the wife I need to spend $300/month on the M1009 since I no longer have a car payment.

I will you to buy the Optima red tops so I can vicariously live through your victory over sub-par batteries.

 

[hobie237]

You don't actually *need* the adapter trays, you can just drop the Optimas in. In fact, my buddy has two smaller Optimas squeezed into the rear tray with minor fabrication work, leaving the area of the front tray open for other stuff as needed/desired (forget what he has there).

That said, there's no way in hell I'd replace good batteries for the sake of replacing batteries.