This is a great little tester everyone should have. It is a fast charging system tester that can be used on any 12 volt vehicle. it can check a alternator on a car,motorcycle, boat, ATV, lawn tractor, truck, any 12 volt battery system. Just connect across the battery posts.
The best test though is the charging test with the vehicle running. A battery needs 2 volts higher to correctly charge. This shows the charging voltage across the battery from the alternator. Green means its enough to charge the battery, yellow means its not charging enough, & red means the charging system is broke & it's overcharging at 15 volts & will damage the battery. If your a mechanic, Get this for sure. You will use it.
1) Get an instant reading on your car's battery & alternator condition
2) Tests alternator performance for over & under charging
3) Plus measures battery condition; great electrical diagnostic tool to help prevent stalled vehicle
4)Easy to use with clear LED indicators to eliminate guesswork
5) No batteries or wiring needed - runs off car's electrical system; compact 4" size fits in glove box
A.Engine off (no ACC on), connect the positive battery pole with the red probe and the negative battery pole with the black clips;
B.Lights 1 to 3 (or 4) will glow to indicate battery condition.
Some testing may show a reading above number 3, and cause the number 4 light in the alternator section to glow; this does not indicate a problem, some heavy duty high output batteries will glow in that way.
A. Engine running, connect the positive battery pole with the red probe and the negative battery pole with the black clips;
B.Lights 1 to 5 (or 6) will glow to show the charging system status (alternator output).
Remarks: Led lights 1-6 are for 5V (Led#1), 12V (Led#2), 12.5V (Led#3), 13V (Led#4), 13.5V (Led#5), 14V (Led#6)