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Battery Load Test

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ireburb

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I am a little weak(OK very weak) on the electrical side of things.

Do I need to have the batteries disconnected for Advance to do a load test on each battery since there are two batteries?

I need to get the batteries load tested today at Advance Auto (where I purchased them not long ago). I am having intermittent slow cranks or almost no starts and have check the usual suspects (battery connections, grounds, etc).

Hopefully not time for a new starter.
 
I like to charge the batteries individually and then load test them unhooked. Usually the auo parts places will go that route before they will warranty a battery,
The load testers that you use while the batteries are in the truck hooked up do seem to work just fine, though I can't understand how.
I have bought 3 new bad batteries in the past 2 years. And it was strange to me as they would hold and not drop voltage but they had no cranking amps. Prior to the first one all of my previous bad batteries would not hold voltage so I didn't have to load test them to know they were bad.

Also make them leave the battery sit for 1/2 hour after charging as some batteries will pass a load test immediately after being charged but not later.
 
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proper voltage but not pass load test is bad internal connection to post. that is why it is important to load test the terminals that are used. I have had side post go bad but top post ok. have you done the battery post modification? http://www.thetruckstop.us/forum/showthread.php?t=540 , load test each one unhooked, individually. 2 good batteries make an awesome difference in starter rpm.
 
The parts stores can test with both bats hooked up. They said they could not get a reading off one of mine with the other one hooked up and tested fine. That one turned out to be bad.

But to be sure test separately and disconnected. You want 12.8v or higher 30 min after charging. If you have less like 12.6v you need a charge or have a weak/bad battery. Amps are the other failure point. The battery could be low on water or frozen. Bad connections as pointed out above... Have you checked the engine ground connection on the engine intake?
 
Just a quick update:
Batteries tested fine so I purchased a starter and installed it. Problem solved.

Thanks to the forum it only took me 1.5 hrs to remove and replace the starter. I also didn't need to take the fender well off but taking the tire off is what did the trick along with removing the rubber skirt piece.
 
ireburb said:
Just a quick update:
Batteries tested fine so I purchased a starter and installed it. Problem solved.

Thanks to the forum it only took me 1.5 hrs to remove and replace the starter. I also didn't need to take the fender well off but taking the tire off is what did the trick along with removing the rubber skirt piece.
Click to expand...

That's the way I do it.
I also have a Craftsman 1/4" drive battery powered ratchet that is a geat help for this project. It doesn't have much power but once you get things loose it makes taking things apart far easier. It can be a pain especially when you have fat hands.
I also have a several sets of wobble extensions from Harbor Freight that I have been using for what seems like & could be 25 years.
That was the first place I ever saw wobble extensions. The extensions have held up remarkably well. Over the years I've only broken a couple and those were with a pipe or air ratchet or impact. They gotten me in a lot of places I couldn't get with a straight extension, swivel or swivel socket. Plus the socket isn't all floppy on them. At least not near so bad as a swivel
 
just curious - and this may be a dumb question - but is it better to test the batteries cold? I ran over to NAPA, turned the truck off, and had them test the batteries separately. The batteries are Walmart 770 CCA, and he tested 1 at 770 and the other at 710 . Could the 710 be a bad battery, on its way out? Or would it even show that much if it were dying/dead?
 
Batteries can test good when bad if freshly charged. They should be retested in about 1/2 hour if they test good but are still suspect. The same with testing batteries still hooked up.
 
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