My truck would not crank right and the local parts store was testing my batteries and telling me they were good.


The new school testers light duty models seem to have limitations. I was just fixing to pull the starter and then took my batteries to a shop with a old style heavy duty tester that puts a real and proper load on the battery.


It found a problem and the battery would short under their test load. re placed one battery and truck spun like a champ and fired.


Happy New Year.

 

What do you mean "short under their test load"?

Do you mean the voltage dropped significantly?

One thing I learned recently about batteries is the whole deal with "pulsers"/"rejuvinators". After doing some research, I came across a very interesting bit of information that suggested that the lead alloy in modern "maintaince free" batteries tends to build up an oxide layer under some conditions, resulting in a battery that may have all it's cells working, but put a load on it and it won't supply much power, because of the resistance in that layer.
This is why people sometimes have great luck with a "pulser"-type charger, which seems to break down this layer. But it only works to fix that problem; if the battery in question is damaged or shorted, it probably won't work.
I still wonder if this is any different to plain old sulfation, but when the military buys "pulser" type chargers, there's probably a reason.

What this means is you might be able to fix these batteries with a good pulser-charger; but it's probably easier to just replace them.

 

Thanks, I wonder what the problem with the lead is. Can you just sand it ? you would put a load on it and it would not put out right.

 

Parts stores probably just check the voltage, which is almost useless in determining a batteries health. Like you say, you have to actually put a load on it and measure the amps and voltage drop.

 

Working for a large autoparts.chain for 15 years has shown me a few things. The biggest rookie/newbie mistake is to not isolate the batteries. Test both batteries hooked together and you will most likely always get good test results. Always watch them do the test and make sure one battery is unhooked before testing.

 

Thanksdddd

 

Thanksssss

 

^^^ this^^^
most places these days hire idiots that can just barely use a computer.
thy put a volt meter on a battery and say it is good because it reads 12.5 volts.
but that same battery will read bad when a load tester is put on it.

 

they use that gizmo that does a print sheet.

 

i use one of these gizmos at home:
http://www.matcotools.com/catalog/pr...Y-LOAD-TESTER/
and one of these is always in the back seat of the pickup:
http://www.matcotools.com/catalog/pr...Y-LOAD-TESTER/
hook it up, flick the switch on for ten seconds. the gauge will tell you if the battery is good or bad.

 

This - 500 Amp Carbon Pile Load Tester - will put a meaningful test load on an 850 or more CCA battery. And since you can dial up the load, you can use it on even small SLA 12V batteries like those used in UPSes, electric start generators, etc.

 

Yeah, I'd trust that above anything smaller. Our starters draw quite a bit. For a car battery, a smaller one is fine, for the massive batteries we use? Not so much.

 

Carbon piles are the best way to test a battery as such though for accuracy it must be completely charged prior to testing. Then, it will need charging yet again after testing.

Because of the charging time factor and the other, ahem, "issues", for warranty service these days a lot of vendors will use AC conductance method of testing. Midtronics makes a range of several. They work pretty slick, at least in rooting out bad ones.

One advantage is that the battery need not (supposedly) be completely charged for accurate testing. It is quick. I would say, load testing is superior but the conductance testers are useful in that if they indicate a battery is bad, it is definitely bad, it's just that the reverse is not always true.

 

What ive always used, never failed me yet.

 

Basic load tester works as stated but it requires the battery to be charged. We use this or some variation of it.
http://www.midtronics.com/shop/products-1/battery-chargers-and-maintenance-products/diagnostic-chargers/gr-series/midtronics-gr8-series-diagnostic-battery-chargers