Wiring question
- Thread starter 1stford
- Start date
Flathead Fever
Well-known member
Did you do the headlight test like Eddie recommended? If you have charged the battery and it started once it should start again but without a voltmeter you don't know if your first start drain the battery. It may be sulfated and it only has enough capacity left in it for one start, even after a full charge. If on the second attempt it will not crank, do the headlight test! Make sure your generator is charging. If it is charging and it fails the headlight test go buy a new battery. If the battery is close to four year's old go buy a new battery anyway. I get rid of them at four year's on my daily drivers. What do you save if you squeeze another year out of the battery but then it leaves you stranded. Not worth it.
You need to buy a voltmeter! All of you out in flathead land, need to go buy a voltmeter!!!!!!!!! Anybody that works on cars for a hobby needs to have a volt meter. Go buy a cheap digital voltmeter that reads AC and DC voltage. If your working on computerized vehicles you need a meter with a lot of impedance to prevent damaging the computer. Those meters cost more. But for you guys need you should be able to get one pretty cheap. If you fix one thing with the meter, it paid for itself.
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Flathead Fever
Well-known member
Lowes AC DC digital voltmeter, $25.00. I'm sure its some foreign made piece of junk but it will work for what you need it for. I have a cheap Radio Shack one I've used for 30-year's. Its accurate to a 1/10th of a volt. I take the AA batteries out every time after I use it. I bet I use that meter twenty-five times a year, just here at home working on car and house projects. If you want the very best you buy a Fluke meter. Those are usually only bought by professional mechanics that do a lot of computer circuit trouble shooting or maybe the guy is building his own communication satellite in his garage. If you can snag one at a garage or estate sale get it.
https://www.lowes.com/pd/southwire-...MI7aa1iYvn4AIVLCCtBh1F8g2yEAQYAiABEgKRF_D_BwE
https://www.lowes.com/pd/southwire-...MI7aa1iYvn4AIVLCCtBh1F8g2yEAQYAiABEgKRF_D_BwE
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Flathead Fever
Well-known member
Battery Load testing. If you are really interested in learning this stuff read this manual that belongs to a battery load tester.
https://www.autometer.com/media/manual/2650-791X.pdf
Look at page 9. On the 6V meter scale it shows that when applying the load the voltage for a 6V battery should hold at above 4.5V or its bad. But you don't need one of these expensive machines. You hook up your Lowes $25.00 meter and watch the voltage as you crank the engine for 15-seconds. If it drops below 4.5V the battery is junk. This test is technically not correct because you don't know what the starter amperage draw is? You want the load to be 1/2 of the Cold Cranking Amperage rating of the battery. But at home the only thing you have to put a large amperage demand on the battery is the starter.
The sun machine I have instructs you on a 12V battyery to apply 1/2 the CCA of the battery for 15-second's. Let the battery and the machine cool for 15-second's. Apply the Load to battery again for 15-seconds and the voltage should never drop below 9.6V. Sometimes they don't drop below the 9.6V load until the second load is applied.
There is no way that these auto parts stores can hook up their hand held battery testers and test your battery. When you load a battery with a real carbon pile tester with a 300A draw for 15-seconds things can start to smoke. I had a battery not holding a charge for more than two-days. The 16 year old kid at Autozone hooked up his handheld tester. Pushed a button, saw a green light and declared the battery good. They refused to warranty it. 30-year-old ASE Master Mechanic versus zit faced millennial kid looking at a green light. Nothing I could say could convince him there was no way his handheld tool could properly test a battery. I went to another parts store. Bought a new battery and the problem was solved.
Never crank any starter for more than 15-seconds, The armature will get so hot the solder will melt. 15-second's cranking, 15-second's cooling off period is the rule.
https://www.autometer.com/media/manual/2650-791X.pdf
Look at page 9. On the 6V meter scale it shows that when applying the load the voltage for a 6V battery should hold at above 4.5V or its bad. But you don't need one of these expensive machines. You hook up your Lowes $25.00 meter and watch the voltage as you crank the engine for 15-seconds. If it drops below 4.5V the battery is junk. This test is technically not correct because you don't know what the starter amperage draw is? You want the load to be 1/2 of the Cold Cranking Amperage rating of the battery. But at home the only thing you have to put a large amperage demand on the battery is the starter.
The sun machine I have instructs you on a 12V battyery to apply 1/2 the CCA of the battery for 15-second's. Let the battery and the machine cool for 15-second's. Apply the Load to battery again for 15-seconds and the voltage should never drop below 9.6V. Sometimes they don't drop below the 9.6V load until the second load is applied.
There is no way that these auto parts stores can hook up their hand held battery testers and test your battery. When you load a battery with a real carbon pile tester with a 300A draw for 15-seconds things can start to smoke. I had a battery not holding a charge for more than two-days. The 16 year old kid at Autozone hooked up his handheld tester. Pushed a button, saw a green light and declared the battery good. They refused to warranty it. 30-year-old ASE Master Mechanic versus zit faced millennial kid looking at a green light. Nothing I could say could convince him there was no way his handheld tool could properly test a battery. I went to another parts store. Bought a new battery and the problem was solved.
Never crank any starter for more than 15-seconds, The armature will get so hot the solder will melt. 15-second's cranking, 15-second's cooling off period is the rule.