wrote:

On Sep 13, 9:36 pm, GeoLane at PTD dot NET GeoLane at PTD dot NET
wrote:

At Harbor Freight, they have three different auto battery testers.

The one currently on sale is a 50 Amp tester for $10,http://www.harborfreight.com/cpi/cta...emnumber=93784

the 100 Amp tester is about $25,http://www.harborfreight.com/cpi/cta...emnumber=90636

and the 500 Amp carbon pile tester sells for $50.http://www.harborfreight.com/cpi/cta...emnumber=91129

What's the advantage of the higher amp models? Are there any other
conveniences with the more expensive models?

I've always just checked the battery and charging system with a VOM.
If it read less than 12 V at rest, the battery was discharged or bad.
When running, if the system didn't read 13-14 V, it wasn't charging.
Will those battery testers tell me something else?

Thanks.

RWL


They give you a better idea of how the battery performs under load.
The higher amperage ones just have a better load resistance. I've had
one of the cheapies for years, works well for separating sheep from
goats. I've had batteries that will take a charge, look good on a
voltmeter statically and still won't spin the starter. Probably
cracked links or something like that internally, too much internal
resistance. You can also use them for determining if it's a bad
battery you have or a bad charging system, or both. A voltmeter will
just tell you if your voltage is below par, doesn't tell you if you've
got a shorted battery, duff regulator or a failed alternator/
generator. Sometimes a bad charging system will take out the battery,
replacing the battery just leads to another dead battery.

Stan



I wouldn't waste my money on a load meter.. you have one built into the
car, the headlights, heater fans and the starter itself. With the
engine running and the accessories turned on you should be able to see
14 + volts at the battery terminals. If you don't you have a bad
charging system. If your engine starter cranks slow, crank it for 10
seconds and feel the power cables to the starter.. If they are hot you
have a bad starter or engine that is tight. If they are cool you either
have a bad battery or a bad connection in the power wiring. If you have
a bad connection you can feel the hot spot at the terminal but watch out
you might get a burn. You could also put the volt meter on the battery
and turn on the accessories with the engine off. The voltage should not
go below 12 volts with a good charged battery.


John