charging issues

dzjammer · #1 (**permalink**) 01-31-2007, 08:50 AM

HI guys, I have a problem with my charging system and want to see what you think. My battery is 5 years old, alternator is unknown age and regulator is probably original in my restored 79. I have always noticed at idle that my headlights were dim and then would brighten with a little rpm increase. This winter its gotten worse. Slow cranking, etc. I thought my battery needed replacing. After it would start, I could watch my amp gauge (add-on) charge about 20-30 amps and then drop back to just above 0 after a minute. This week, it starts jumping around, really high then drops to nothing as I'm going down the road. Now I'm thinking regulator needs replaced. I checked battery this morning, 12.8 volts cold and 14.3 with engine running. With a little rpm boost it would go up to 15.5. Short of just changing parts out, any suggestions on what I should focus on?
Thanks, Dave

teds74ford · #2 (**permalink**) 01-31-2007, 09:28 AM

Ohm your wiring harness that goes from the alt to the reg. It can do similar screwy things when it gets hot. That being said, I think you are right. I swapped in a gm 12SI because my system was doing weird things and the wiring was bad.

Also, search the electrical for a post by user scottfreeman titles something like "69 charging issues" In it, there is discussion about how the wiring can be shortcutted to make it work.

NumberDummy · #3 (**permalink**) 01-31-2007, 09:32 AM

One source of dimming lights is a battery that is inadequate for the job. Many people put the wrong battery in. There were 3 batteries originally for 70's trucks. The R 24F, used on 300 and 302 without air conditioning, and two different R 27's.

R 27F has 70 amps of cranking power, while R 27FA has 80.

The R 24F was a smaller battery, while the R27's are the same size.

Your battery is 5 years old...that's just about the age limit. You can use a hydrometer to test the cells.

I would recommend the R 27FA for your application.

Mil1ion · #4 (**permalink**) 01-31-2007, 02:53 PM

IMO, everything you mentioned is NORMAL.

VR's tell the alternator to Kick-in at 850-900 RPM.

The ammeter is supposed to go to ZERO if the battery is charged "up to snuff"

IMO> The only thing you need to do is clean all the connections of corrosion

VR connections
VR mounting area
Starter relay connections

Quote:

R 27F has 70 amps of cranking power, while R 27FA has 80.

They better have more than that.

My 24 has 1000 CCA

Back in 78 the best batteries were about 600 CCA

With less quality batteries with 450 CCA.

dzjammer · #5 (**permalink**) 01-31-2007, 03:35 PM

For an update, my battery is an Interstate 1000 cca. The truck hasn't had much use for the last 4 years so it wouldn't surprise me if anything is worn out or corroded. The only concern I've had is that when I turn my lights on, it pulls the engine down 100-200 rpms. At idle (800) the lights are really dim. Is there any way to turn the alternator faster or somehow get more juice for less rpm?

Mil1ion · #6 (**permalink**) 01-31-2007, 04:07 PM

I still think your problem is corrosion.

Clean ALL your charging system electrical connections then see what it's like.

NumberDummy · #7 (**permalink**) 01-31-2007, 06:51 PM

R27F 70 AMPS 540 Cranking amps (prolly more today, this is from the 70's book)

Yes they do have more cranking amps, I went with the older info..where the book calls it "cold" amps. The later book says just amps. I don't print these books, just type the info from them.

Franklin2 · #8 (**permalink**) 01-31-2007, 07:55 PM

15.5 volts is a little bit high.

dzjammer · #9 (**permalink**) 02-01-2007, 08:37 AM

wow, this moved forums, finally found it. Sorry the battery is a 700cca. cleaned the battery posts last weekend. cleaned other connections last night except for ground to block. I swapped out the regulator with another one I had and all hell broke loose now. Took it for a test run and it jumped up to a 50A charge and stayed there unless I was at idle. So I put the old one back on. Then swapped the alternator, I noticed then that one of the wires (F maybe, orange terminal?) was hot and was kicking in the alternator all the time. Since the old one still smelled smoked, I put the other one in. Now this morning, it charges about 30A down the highway and drops to -20A at idle. I'm taking the alternator in to get checked today and see if they can check the battery too. I'm ready to start replacing parts until I find the problem.

teds74ford · #10 (**permalink**) 02-01-2007, 10:01 AM

For the $$ replace your alternator with a gm. Don't think I am trying to sell you on it, but I got a 94 amp for $60, and IIRC, the voltage regulator alone was $30.

Franklin2 · #11 (**permalink**) 02-01-2007, 08:16 PM

Check the voltage at the battery with a voltmeter. I would not trust the dash gauge.

Sounds like the alternator is good, you just don't have any control over it.

dzjammer · #12 (**permalink**) 02-02-2007, 10:33 AM

I went to the o'reilly's yesterday and had the alternator checked. It was a little weak on voltage and amp output so I bought a new one. Replaced it after work and after a little test run my amp gauge was sitting at 50. So I dropped in and bought a regulator to replace it. Everything works fine now. So I had a weak alternator and flakey regulator. Kind of a double whammy.
BTW, the regulator needs screwed down and grounded or it makes your headlights flash like a disco going down the road.

teds74ford · #13 (**permalink**) 02-03-2007, 12:14 PM

Quote:

Originally Posted by dzjammer

BTW, the regulator needs screwed down and grounded or it makes your headlights flash like a disco going down the road.

Yup

It's case grounded, but you could run an external ground and let it flop around in your engine compartment if you wanted

dzjammer · #14 (**permalink**) 02-08-2007, 10:04 AM

still have a problem, I'm starting to think I have a loose connection somewhere but not sure where. I cutout the added on amp gauge so my charge wire goes right back to the solenoid. But, my lights still flicker and get dim/bright flashes. Also, when I let off the gas and hit the brakes at a stop light, my stereo amp cuts out like it loses power. Also will do this when driving on rough road. I tried to shake some wires around last night under hood and under the dash, but it won't do it in the garage. Any suggestions?

Franklin2 · #15 (**permalink**) 02-08-2007, 11:24 AM

Is the engine running correctly? If the idle is too slow, the voltage may drop too much and make the amp cut out, especially if you have a lot of elec loads on.

With the flickering problem, you noticed that grounding the regulator was very important. But it's possible that what you grounded the regulator to may be rusty or intermittent. You might want to try like the other poster said, and run another ground from the engine block or the bat - to the regulator case. This also may improve the grounding to the front sheetmetal were the headlights are grounded also.