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