Alternator Not Charging Battery

[Lumpy Grits]

OP/How old and what is the CCA rating of your battery?
Let'n a wet cell starter battery sit 'flat' is not good, and even more so in winter.
LG

 

[MaineMan87]

OP/How old and what is the CCA rating of your battery?
Let'n a wet cell starter battery sit 'flat' is not good, and even more so in winter.
LG

The battery I just replaced was 2 years old. Not sure of the CCA rating. The new battery that I put in yesterday has a CCA rating of 675.

 

[Aaron]

I got the diode from radio shack but they didn't have the 276-1143 or 276-1144 in stock and when the kid behind the desk looked them up he said they don't exist. ( the ones with this part number are on Radio Shacks website so I don't think he knew what he was doing.) I ended up buying a pair of 276 1141 diodes. They come in pairs and I don't foresee my self needing another one. If you want it you can have it. They are cheap but I don't see it doing me any good in my tool box.

 

[MaineMan87]

I got the diode from radio shack but they didn't have the 276-1143 or 276-1144 in stock and when the kid behind the desk looked them up he said they don't exist. ( the ones with this part number are on Radio Shacks website so I don't think he knew what he was doing.) I ended up buying a pair of 276 1141 diodes. They come in pairs and I don't foresee my self needing another one. If you want it you can have it. They are cheap but I don't see it doing me any good in my tool box.

I appreciate the offer, but it'd cost more to ship than it would to buy them at the store. Good to know that I have a couple of options on diodes.

 

[MaineMan87]

I know you guys have been losing sleep, awaiting my update...so here it goes. I ended up buying a new battery and solenoid. I added a diode to the alternator's excite wire, which was previously snipped. The PO had also wired the battery wire, coming out of the alternator's plug, directly to the battery using a very small 18 gauge wire. It's my understanding that it's ok to go directly to the battery, but I still opted to wire it to the post on the back of the alternator and have the second battery wire go from the post to the solenoid.

I tested the voltage on the battery with the Jeep off and it was about 12.6 volts. I then started the Jeep and took the voltage again, and it didn't change, so I'm thinking it's the alternator itself that's bad. I didn't have another set of hands around, so I couldn't have someone rev the jeep up as I took the voltage, so it's possible that I didn't wire up the excite wire properly and the alternator wasn't getting the low rpm signal to charge. What else can I do for tests prior to ripping the alternator out and getting it tested?

If I test the voltage at the battery post on the back of the alternator with the jeep running, should it read 14+ volts if it's working as it should?

Thanks again for all of the help!

 

[Lumpy Grits]

A Popsicle stick works wonders to 'kick-up' RPMs.
YES-14VDC is good.
LG

 

[Aaron]

You can rev you engine from under the hood by moving the throttle linkage. If your creative this will leave you two free hands to work your multimeter. Have you checked all terminals on the alternator? If none of them read more than the battery you need to pull it and get it checked.

 

[MaineMan87]

I will give those methods a shot.

Thanks

 

[Dolf]

Each cell of the battery is around 2.2 volts when fully charged. A 12 volt battery has six cells which equals 13.2 volts at full charge. If you have a fully charged battery and you measure the voltage with the engine off, but both battery posts hooked up and it’s a little less, then you have a small discharge such as a clock, or even capacitive discharge can happen to a small degree. No big deal. To get a charge on the battery, it’s nice to have around 13.8 volts, or a little more, measured across the battery posts when the engine is running.

 

[Lumpy Grits]

Anything under 14 vdc when run'n(1K rpm). I would be worried--
LG

 

[Hedgehog]

Looks like a duck, walks like a duck, quacks like a duck it is best to look for a duck. Right from the beginning this had all the appearance of a faulty alternator, more than likely a bad regulator in the alterantor. Right here you have more options than you might think. You can go to an auto parts store for another alterantor, you can find a local rebuilding shop and have them do it (I'd opt for a single wire regulator) or you can do it yourself with a kit from NAPA. Going to a rebuilding shop was a new option for me. They can do quite a few things with your alternator. Like increase the output, change to a single wire regulator or keep it the same with your stock DElCO plug. Unfortunately increasing the output will cost money.

I have to say this, please don't take it as an insult, it's not meant to be. The selonoid has nothing to do with charging. Sure it gives a nice place to attach wires to, but that's about it. The selonoid is all about the starter, I.E. the starter selonoid. It doesn't hurt to change out an old one, but it isn't necessary when dealing with a charging problem. If it stuck on you'd discharge your battery, that is true, but you's also burn up your starter.

 

[MaineMan87]

Looks like a duck, walks like a duck, quacks like a duck it is best to look for a duck. Right from the beginning this had all the appearance of a faulty alternator, more than likely a bad regulator in the alterantor. Right here you have more options than you might think. You can go to an auto parts store for another alterantor, you can find a local rebuilding shop and have them do it (I'd opt for a single wire regulator) or you can do it yourself with a kit from NAPA. Going to a rebuilding shop was a new option for me. They can do quite a few things with your alternator. Like increase the output, change to a single wire regulator or keep it the same with your stock DElCO plug. Unfortunately increasing the output will cost money.

I have to say this, please don't take it as an insult, it's not meant to be. The selonoid has nothing to do with charging. Sure it gives a nice place to attach wires to, but that's about it. The selonoid is all about the starter, I.E. the starter selonoid. It doesn't hurt to change out an old one, but it isn't necessary when dealing with a charging problem. If it stuck on you'd discharge your battery, that is true, but you's also burn up your starter.

These are certainly viable options and I appreciate it. Now that I have everything wired properly, I'd prefer to stick with my current plug setup, but I'm certainly not opposed to a one wire. The alternator that's in there isn't a great fit, so I'm leaning towards buying he Delco 10si or 12si, which seem to be common on here. What does everyone suggest for amperage? My only accessories are a CD player and fog lights. I have 10 gauge wire going from the alternator to the battery, so it can handle some juice.

No offense taken on the solenoid comment. My decision to replace it had nothing to do with the charging issue. I just figured, what the heck, since it's $13 and every other component of the ignition is new, so might as well replace the 20+ year old solenoid while I'm in there.

 

[Hedgehog]

Sound reasoning ont he selenoid. I recently had to change mine and I wish I'd done it sooner. Early on I was hadn't started the 360 much at all. When the Transmission , Transfer Case and drive shafts were installed, NO clutch Pedal yet, I placed her up on jack stands, put her in gear and fired her up. It sounded HORRIBLE! I looked and looked fussed and fooled around trying to figure out why. After about 5 minutes I shet her down, but the engine continued to turn. The starter was still engaged, still turning. A whack on the selonoid stopped the starter, but it was to late, the starter gearing was fried. It's simply not meant to turn at 2000 rpms for any time. That was another $100 I didn'twant to spend at the time.