So I'm on my 2nd battery...but why?

[crazeetxn]

Howdy all -

My son's truck is a '69 with a 327. We bought him an interstate battery when he first got the truck. He didn't drive it much on account the previous owner had antique plates on it (In TX, those are pretty much only good for parades). Battery went out after a few months.

He bought another one from AZ because it's in town and he can take it back if it goes out. Well, now it needs to be jumped to get started.

He changed the ground and starter wire. There's the one wire that goes straight from the postive to the alternator. Then a couple of wires that go from the alternator to a block thing on the front with a bunch of wires going all over the place from there.

I'm sure it's due to lack of driving, but I wanted to see if I was missing something before I let him on the road with it and he gets stranded somewhere.

All the lights and horn and stuff work.

The alternator checked out good so now we're at a loss.

Thanks for the help!

[Shyguy]

It sounds like the alternator or voltage regulator is not working. An alternator can check out ok, but if the regulator is bad or the wiring is wrong no charging will happen.

Have you checked the voltage at the battery when the truck is running, it should read in the 13.5-14.5 range?

[RexDodge]

Originally Posted by Shyguy

It sounds like the alternator or voltage regulator is not working. An alternator can check out ok, but if the regulator is bad or the wiring is wrong no charging will happen.

Have you checked the voltage at the battery when the truck is running, it should read in the 13.5-14.5 range?

Great advice there. These old trucks are notorious for shorts that cause a slow draw on your battery. If driven daily you'd never know. If the alternator and voltage regulator check out try this. Remove the NEGATIVE battery cable and install a test light or meter. It will probably show a voltage draw. Pull fuses one at a time until the draw goes away. Now you have narrowed your search. Start looking for a wire with damaged insulation or a weak connection. Good luck.
Oh, one more. This is one of those head slapper things. Check your cables. Grab the cable at the battery and try to twist it. If it moves it is too loose. Lots of folks just shovem on and think it's good but...

[too much stuff]

Some good advice already, and remember, just because a battery is new doesn't mean it is good. Do a load test on the battery also.

[k_n_browning]

One thing if it has a aftermarket radio in it the radio is not off off it still has power for the the preset and clock is still running.Where I work we sell lots of batterys And the main trouble is that the truck or tractor sets.and that radio is just sucking the power out.Now the failure rate on Battery is less than 1% of 1% but you can get 1 that is bad from the get go.If it sets for long time get a trickle chager that it auto.

[crazeetxn]

Great advice ya'll.

So I'm going out on a limb here and figuring the voltage regulator is the "black box" with wires coming from the alternator then going out all over the place? (and I thought this truck was going to be easier than my '86 )

If that looks good, I'll start tracing wires to see if any of them are shorted out.

Good idea on the radio. It came with an aftermarket detachable face. I'll have to double check and see how it's wired and if it stays on.

I've told him while he's not driving around the neighborhood to disconnect the battery. Thought about the trickle charger, because then I could use it for other things as well.

Thanks again for all ya'll's help. Will diagnose tonight and let you know what we came up with.

[rsavage]

You can't tell by looking if the voltage regulator is good. Put a test meter on dc voltage and check the voltage going to the battery when the truck is running. As indicated in an earlier post, it should be about 14.2 volts. If you took your alternator in to an auto parts store and it tested good, and you are not getting the 14 volts at the battery, your regulator is probably bad. But before changing it, make sure the body of the regulator is well grounded to the core support - you can run a separate little ground wire from one of the cover screws to the core. It is a common problem. Then check the voltage at the battery with engine running again.

[cdowns]

there should not be a wire going from the battery pos to the altenator in the stock wiring of your truck

[1972_K5]

I had a similar problem. Could not get my battery to charge. Pulled my alternator twice to be tested. Finally figured out that I had a bad ground on the voltage regulator. Fixed that and no more battery issues.

[litew8]

Originally Posted by cdowns

there should not be a wire going from the battery pos to the altenator in the stock wiring of your truck

Correct, if he has a external regulator. If it's an internal regulated alternator, the black box (external regulator)
shouldn't be in use and there then would be a charge wire going directly (routed to the wire block, then >) to the battery.

[crazeetxn]

Thanks again for the info so far!

So here's an update:

- Charged the battery back up so I could test.
- Cranked the truck up, pulled the negative cable off and the truck died
- Checked volts at the battery while running: 12.1 - 12.4
- Checked volts at the battery with truck off: .7 with meter set at 2000m DC
- Volts at wire going from alternator to battery (pos side): 12.1 - 12.4

I didn't get a chance to check the volt regulator as my bulb went out on the light so I figured it was time to close up shop.

Originally he had the radio in there, but he said he took it out a while back. Did find out the power wire was still hot even with the key off, but since it was out, don't think it would pull a charge.

I will double check the ground at the voltage regulator this evening. I also told him to get a new plug in for the alternator. The two wires in the back (not the red one on the screw) were just crammed in there and not even connected to the blades. They might have been touching enough to get juice as everything still worked. These two wires go to the voltage regulator.

Looking at this diagram - http://67-72chevytrucks.com/vboard/a...1&d=1287815401 Looks like there's a wire going from the battery to the alternator.

[litew8]

My comments may not have been clear enough. Yes, there's a wire going from the alternator (+ out) to the junction block and then similar gauge going to the battery. That's the charge wire. But there's also another wire that goes to the volt regulator, seen in the diagram also. If wired correctly, w/out an internal regulated alternator - you have a 3 wire setup (hence three wires coming off of alternator).

[webfoot]

Should be reading between 13 and 14 volts running. You are running off the battery only.

[litew8]

Ignore the captioning on the bottom pic. Just showing the plug that goes to the external regulator.
Don't think the external regulator's job is related to charging your battery, the charge wire going direct to the battery is.
Someone correct me if my memory is off. Thus, implying your not charging your battery. Like webfoot suggests, check your alternator.

[litew8]

Sorry, memory is back.
The external regulator is inline to charging the battery.
I get confused since I've never messed with it and have since removed mine and rewired.

"The voltage regulator is basically a gatekeeper that will shut off the flow of juice to your battery if the voltage
goes above a certain level, usually 14.5 volts. This keeps your battery from getting overcharged and cooked."

[Kidd-7]

FYI: to load test your battery use a DC voltmeter attached to the battery, it should read about 12.5 with the truck off, then start it, while its cranking it should not drop more than a volt. If the drop is more then you have a dead cell. Once the truck fires up you should have 14.4v. NAPA carries the regulators for about $15 if I remember correctly.

[crazeetxn]

I'm leaning more towards the alternator now.

- Jumped it off to get it going
- Checked voltage at battery: 12.4
- Checked voltage at the alternator: 12.4
- Voltage regulator has misc volts at each connector and one of those was, yup, 12.4 (ground it also good at regulator)

Just for gee whiz, I pulled the wire from the alternator to the battery, guess what, wouldn't start.

Also tried the ol' screwdriver against the back of the alternator test. Am I missing something or aren't these things supposed to create a magnetic field and pull the screwdriver in? Well, mine didn't. Screwdriver just flopped around in my hand.

Gonna pull it tomorrow and take it to another place and have it checked out again.

Here's a pic of the 1 wire and the back of the alternator. There's isn't a wire going from the post on the left..just the two in the middle and one on the right.

[crazeetxn]

Originally Posted by litew8

Sorry, memory is back.
The external regulator is inline to charging the battery.
I get confused since I've never messed with it and have since removed mine and rewired.

Only wire I have going anywhere near the battery is the infamous red one.

[litew8]

If there is only one red wire going DIRECTLY to the battery from the Alternator Output post, and bypassing the external regulator on the radiator support, - sounds like you have an internal regulated Alternator. That'd mean your internal regulator inside the Alternator has gone bad. Right? A one wire setup. Do you have an ameter in the truck, does it register?

[old Chevy guy]

The alt in that picture is an externally regulated one,it has the square plug. The big red charging wire on the alternater does not go to the regulater at all the regulater sends power through one of the small wires to the square plug and excites the alternater in effect turning it on and making it charge. The left post in your picture is a ground if I remember right and dosent always have a wire on it.Theres 4 wires on the regulater brown blue yellow red,(but not the one that bolts to the alternater). If you jump the regulater with a paper clip between the red and I think the blue it bypasses the regulater and if the alt is good it will charge. But if you are willing to take it off and the part store can test it just do that and if its good then change the regulater

[fixit-p]

Originally Posted by old Chevy guy

The alt in that picture is an externally regulated one,it has the square plug. The big red charging wire on the alternater does not go to the regulater at all the regulater sends power through one of the small wires to the square plug and excites the alternater in effect turning it on and making it charge. The left post in your picture is a ground if I remember right and dosent always have a wire on it.Theres 4 wires on the regulater brown blue yellow red,(but not the one that bolts to the alternater). If you jump the regulater with a paper clip between the red and I think the blue it bypasses the regulater and if the alt is good it will charge. But if you are willing to take it off and the part store can test it just do that and if its good then change the regulater

Yup red and blue wire connected together puts the alternator in full field so if you do it don't keep it that way for too long because the alt will give you all it has

[litew8]

Sorry if my posts are off then. I had a heck of a time learning it myself for the first time Brown would be the field sensing wire then. Blue excites. But if the Output + (red wire) from the alternator goes to the junction block, and the red wire that goes to the regulator taps into the same block, isn't that essentially the same? If it has a ground terminal, you may want to see about using it. Mine doesn't have a ground terminal, but it's self grounding to the bracket.

[fixit-p]

Originally Posted by litew8

Sorry if my posts are off then. I had a heck of a time learning it myself for the first time Brown would be the field sensing wire then. Blue excites. But if the Output + (red wire) from the alternator goes to the junction block, and the red wire that goes to the regulator taps into the same block, isn't that essentially the same? If it has a ground terminal, you may want to see about using it. Mine doesn't have a ground terminal, but it's self grounding to the bracket.

Brown connects to an ignition source blue is the field wire (its voltage is controlled by the regulator which affects alternator output) the white wire connects to the stator and the red wire is the voltage sense wire. Below is a system diagram.

[Jacfourteen]

To me it sounds like a bad regulator. My truck had the same symptoms with a new battery and alt so the only thing that was left to change was the reg. then it worked great. Like others have said they are cheap, so I would swap it and see if it fixes it.

[litew8]

damn I'll stop posting then. Thanks for schooling me again.
Whatever I did for a first time worked for me. I must not remember it all right.
Hope you get it all sorted. It shouldn't be difficult to isolate.

Originally Posted by fixit-p

Brown connects to an ignition source blue is the field wire (its voltage is controlled by the regulator which affects alternator output) the white wire connects to the stator and the red wire is the voltage sense wire. Below is a system diagram.