Battery and charging issues

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lumbee1

lumbee1

Native American
10 Year
Joined
Sep 21, 2011
Threads
80
Messages
4,841
Location
Holly Springs, NC
For about 5 years, I used a cheap Duralast battery that the previous owner installed in the truck. Last year I replaced it with an interstate from Costco. Just a few months ago, I came out to find a dead truck and a battery reading 2V. Costco swapped it out for $8 (price difference between old and new) and we were good again.

Fast forward to today and the truck won't start. I was able to jump it with my jump pack and Shannon drove it around the block. When she brought it back, I hooked up my DMM to check voltage.

After turning off
12.7 dropping quickly to 12.4

Idle no accessories
14.3 to 13.6

Idle with headlights only
12.97

Idle with headlights, both lightbars, and mini-lightbar
12.32

Engine off
12.36

Everything I've read on the interwebs says these numbers are not healthy. Idle with accessories, the battery should be 14.7 to 13.7 volts. A resting battery should be at 12.6 volts. At 12.4 to 12.3 volts there battery is 50% charged and at 12.2 to 12.1 volts, it's 25% charged.

I don't trust the battery again and it doesn't appear my alternator can keep up. I hadn't planned on replacing the alternator just yet but I might need to do that sooner than later.

Any other advice before I purchase the upgraded alternator and bracket?

Update: BTW, the duralast I removed and the Costco interstate were both built by Johnson Controls.
 
Go to the junkyard and get you a tundra / Sequoia alternator, and use the bracket upgrade. Upgrade your wire from the alternator to the battery and never look back.

I got 135 amp alternator, I think it was 75 bucks.
 
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Your idle voltages look ok to me... Anything from 13.5+ should indicate your alternator is charging. I do like the idea of the alternator upgrade and want to do it to my truck. That said, I'd suspect a parasitic draw in this case since you're draining when the truck isn't in use. Take your truck to the nearest box style parts house and they can check the alternator and battery on the truck before you go to a ton of trouble.

If you've got access to a clamp style multimeter (here's a cheapo https://www.amazon.com/3266TA-Auto-Ranging-Multimeter-Resistor-Continuity/dp/B01C0IYLMM/?tag=ihco-20), turn everything off and see what the load is. I'd bet you've got some significant drain happening somewhere in the system and that's what's killing your battery. It's a known issue on the 80 series I've seen discussed here.

Do you have tons of accessories or the standard stuff? Are those lightbars LED or conventional / HIDs?

Good luck
 
Jon, is your ignition ring light staying on?

I agree with Jeff that your numbers don’t look bad.

I wanna say to test for parasitic to unclamp the battery negative and put your meter between he post and clamp. Engine off, of course. But I’m wrong on a lot of this stuff lately! It won’t tell you what might be draining, but you’ll get a number that you can plug into some fancy math that might guide you to determining if drain is the issue.
 
JohnVee said:
Jon, is your ignition ring light staying on?

I agree with Jeff that your numbers don’t look bad.

I wanna say to test for parasitic to unclamp the battery negative and put your meter between he post and clamp. Engine off, of course. But I’m wrong on a lot of this stuff lately! It won’t tell you what might be draining, but you’ll get a number that you can plug into some fancy math that might guide you to determining if drain is the issue.
Click to expand...

This is correct John. Make sure your DMM is set to current, and the leads are in the correct ports. What I have done in the past to further narrow this down, is to use the DMM jumped across a fuse socket with the fuse pulled. That way you can really hone in on what is pulling the current. In my case, I found a stereo that had crapped out and was pulling several mA when it should have been close to zero.
 
You may want to test for parasitic draw. In the past I found parasitic draw from the winch, another time the starter motor, and yet another it was the driver door switch.

Addition, also had 2 bad alternators, a good place like O’Reillys can test the alternator load
 
Your idle under load numbers seem weak to me - shouldn't dip that low on a normal battery/alternator should it? Would think this is possibly a weak alternator and your battery is just taking a beating all the time because of it and thus the quick battery failures.
 
I need to stay this: You ever notice that when it is someone else's truck, it seems pretty easy to figure out the problem. When it is your truck, the problem seems to make you question everything? :)
 
If you find the issue is the alternator, then SeanLX's suggestion appears to be a very solid upgrade / replacement for not a whole lot of dough. Now has me thinking about upgrading mine!
 
Check your belts, too. The last (97) ( @Beau Diddly ) 80 I was working on the battery kept going dead . We replaced the battery Halloween night. Died again a few days later. The belts were worn really bad. Looked ok while the engine wasn't running, but slapped around running. Changed the belts and afik, its ok now.
Just my .02
 
dbenke said:
Check your belts, too. The last (97) ( @Beau Diddly ) 80 I was working on the battery kept going dead . We replaced the battery Halloween night. Died again a few days later. The belts were worn really bad. Looked ok while the engine wasn't running, but slapped around running. Changed the belts and afik, its ok now.
Just my .02
Click to expand...
The belts were changed when I bought the truck 6 years ago. I've put 50,000 miles on it since then. Probably due for belt replacement.
 
Funny that you mention this, as I drove mine in this morning with the red light on also. Went ahead and bought a new one, but didn't do my due diligence for the upgraded model search, and am getting a original amperage one.

I hadn't checked my belt tensions, but belts are relatively new. I've driven the truck for 130k with the same alternator, and who knows if the PO replaced it. I figured it was time for a new one regardless...
 
My drive belts hold tension fine after stretching once installed. My AC belt is a different story. 3 belts in 2 years. I guess it’s time to replace the adjuster mechanism come spring. The green ‘94. You’d think the rust would allow it to hold, and increase, the required loosening torque... The other trucks are fine.
 
I have a sequoia alternator on my sequoia, still working well at 223k...knock on wood. but I always thought that alternators don't put out much charge at idle...FWIW
 
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