Charging System Q's???

[Anonymous]

OK. I replaced the stock alternator with the $39.00 Checker Auto replacement. The alternator is not charging the battery (alternator light stays on). I know I need to replace the starter relay because it is sticking, and probably the voltage regulator too (along with all the battery/ ground/starter cables). How many amps does a Checker Auto alternator put out and how can I test this? Can I use a standard issue voltage/multi tester? I'm getting tired of jump starting a brand new battery just to work on the car!
OH, oh yeah.....
66 Ranchero, 200 motor with a 250 head, single hole carb, and a Pertronix 2 ignitor system.

 

[mustang6]

Somewhere on the body of the alternator, usually on one of the outer sides near where the pivot bolt goes through the maximum amperage will be stamped on it (something like 38A, meaning 38 amps). You can't really test much current with a typical voltmeter, even the better ones I 've seen will only test up to 20 DC amps, most are 5 amps or less.

Ford offered 4 different alternator amperages from 65-70 in passenger cars, they were 38 (most sixes got these), 42, 50, and 65 amp. Trucks and vans had alternators with higher amperages and they will usually interchange but sometimes that gets you into double pulleys.

You can test voltage coming off the back of the alternator, it should be 14V+ at a fast idle Compare that with the voltage output from your voltage regulator, which should be from 12.5- 13.5 volts. Replacement voltage regulators these days are solid state, much improved over the older style.

 

[Anonymous]

well not that i have done this, cough cough, but the make sure the 2 'small' wires are connected and not reversed

 

[mugsy]

To test the alternator, take it off and go to a parts store that will test it for you. Most have the ability to hook it up and tell you if the darn thing works or not. All the parts stores I have use will test for free. Call around and ask.

tanx,
Mugsy 8)

 

[Anonymous]

Same thing happened to me--new alternator, new battery, no charge. Alternator light would come on at idle. Put in a new voltage regulator from NAPA, about $12. It was solid state, rather than coils like in the original. Started right up and never had a problem since.

 

[rbohm]

8) i also had the same thing happen to me in my old merc. in that car it turned out to be a bad plug on the regulator.

 

[Anonymous]

Thanks guys. Somewhere in between my holiday shopping I 'll stop by the parts store and pickup a new regulator, starter relay, and cables. Hopefully that will cover it. Before I do that I'll check for a amperage stamp on the alternator.

 

[66 Fastback]

Most of your multi testers do not have enough capacity to handle 30+ amps. Most Muulti-meters test only miliamps. I have always just used the voltage to see if the alternator/generator was putting out sufficient voltage.
Doug

 

[66 Fastback]

Most of the multi meters do not have enough capacity to handle 30+ amps. Most Muulti-meters test only miliamps. You can get some that can handle the amperage, but they are not common. I have always just used the voltage to see if the alternator/generator was putting out sufficient voltage.
Doug

 

[jamyers]

Best to pull the alternator and regulator and take them both in and have them checked together, especially given the notice shown below, from PartsAmerica (Checker's sister company):

Vehicle: 1966 FORD RANCHERO
Engine: L6 3.3 Liter Carbureted
Reman Alternator; 65 Amps; CAUTION: Pulley Change may be Required; INSTALLATION ALERT! This application prone to voltage regulator failure. Follow prescribed test procedure to avoid mis-diagnosing the charging system.; See Tech Tip # 595; Test Chart Page # UNIV pg 3

Looks like a 65 amp alt, and AutoZone shows a 61 amp as a replacement.
I'd worry more about the output voltage than the amps, unless you've added a LOT of electrical stuff (rad. fans and a HUGE stereo, etc) 65 amps is quite a bit.

 

[Anonymous]

No huge stereo here. Just the standard issue things such as headlights (stock) turn signals, brake lights, radiator fan, dash lights, etc.
IS the 65 amp (61 amp) alternator the two belt one? All I am running is a single belt pulley alternator. I'll look for the amperage marking this weekend.