Mark K Posted February 21, 2012 Share Posted February 21, 2012 Car Battery Charger. Had it hooked up to my son's car - he was late for school, and forgot, hopped in the car and started to back out, and pulled both the alligator clips off the end. I have another charger, so no hurry, but without tearing the whole charger apart, I would like to know if you can tell the difference (pos/neg) between the output wires with a Ohm meter? Normally today, I notice that one wire is marked on the insulation with a stripe, or one wire is silver and the other is gold colored. Neither of these is true with this charger. Just looking to learn a new skill while fixing a charger I have owned for 25 years. Mark K Link to comment Share on other sites More sharing options...
Outsydlooknin75 Posted February 21, 2012 Share Posted February 21, 2012 Mark, crank it up but keep the wires separated. Put your meter to the wires on DC current, if it shows a positive current you have them properly. If it shows negative current you have them reversed. It's really easy, if it shows positive then you have the red side of the meter on the positive side. Sent from my PG06100 using Tapatalk Link to comment Share on other sites More sharing options...
GrumpyOne Posted February 21, 2012 Share Posted February 21, 2012 (edited) Mark, crank it up but keep the wires separated. Put your meter to the wires on DC current, if it shows a positive current you have them properly. If it shows negative current you have them reversed. It's really easy, if it shows positive then you have the red side of the meter on the positive side. Sent from my PG06100 using Tapatalk Positive VOLTAGE, not current. The only way to measure current is a clamp around transducer type meter, commonly referred to as a clamp on amp meter. Also, depending on the meter, putting it on a dc amp setting and sending voltage to it will sometimes make your meter probes shorter, by way of a large flash. Edit to add...the clamp on is not the only way to measure current, but the other ways are much more complex. Edited February 21, 2012 by GrumpyOne Link to comment Share on other sites More sharing options...
ChuckS Posted February 21, 2012 Share Posted February 21, 2012 Mark, crank it up but keep the wires separated. Put your meter to the wires on DC current VOLTAGE, if it shows a positive current you have them properly. If it shows negative current you have them reversed. It's really easy, if it shows positive then you have the red side of the meter on the positive side. Sent from my PG06100 using Tapatalk If you are using some sort of multimeter, use the voltage scale, not current! The current function will provide what amounts to a short circuit to the battery charger and will either blow an internal fuse in the meter or will fry it depending on the capability of the charger. Link to comment Share on other sites More sharing options...
Outsydlooknin75 Posted February 21, 2012 Share Posted February 21, 2012 I'm sorry I'm sorry I'm sorry. They are right, voltage is what you want to check for. Sent from my PG06100 using Tapatalk Link to comment Share on other sites More sharing options...
Mark K Posted February 21, 2012 Author Share Posted February 21, 2012 Thanks all. I was able to do it. Mark Link to comment Share on other sites More sharing options...
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