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