SBC, 283, Holly Pro-jection (it sucks, don't buy it ever under any circumstances), one wire alternator to Optima Blue-top.

What kind of test do I run to see if my alternator is charging the battery? I know the alternator works, had it tested off of the truck at Napa, but I don't know if it's charging the battery or not.

All the connections look good, but I have had a charging problem in the past and am trying to track it down.

Thanks.

:flipoff2:

Check voltage across battery terminals when motor is running.
You should be somewhere in the 14+ volts range.

Any reading below 12 volts means you're not getting any alternator charging.

Check voltage across battery terminals when motor is running.
You should be somewhere in the 14+ volts range.

Any reading below 12 volts means you're not getting any alternator charging.

10-4. I'll check it in the morning.

Thanks!

Oh, if it's not charging...then what? I think it's internally regulated, but if it's showing good on the bench test, then should that mean that the regulator is good too?

:confused:

Total New-b I know...but I gotta learn it somehow!

:flipoff2:

EDIT: I'm getting 13.5 volts when the engine is running. So, at least I'm getting some kind of a charge I guess?

Heres the easiest way. you drive the truck......and if your battery dies the alternator isnt recharging it :flipoff2:

whatcha getting at the batt. when it ain't runnin'?

whatcha getting at the batt. when it ain't runnin'?

Something like 12.3 or so. I just charged it up so it's not going to be a very good assesment of how well the battery is charging (or not).

Basically, as long as your voltage goes up with the vehicle running, the alternator is likely charging. To me it sounds like everything is fine, but if you had problems in the past, I would keep an eye on it.

Sounds like the voltage to your battery is good when the rig is running, should be charging. You can also disconnect the ground on the battery and turn on the headlights. If the rig is still running, the alternator is putting out some decent current.
Bryan

Sounds like the voltage to your battery is good when the rig is running, should be charging. You can also disconnect the ground on the battery and turn on the headlights. If the rig is still running, the alternator is putting out some decent current.
Bryan

THAT IS THE ANSWER I'VE BEEN LOOKING FOR! :D

I knew there was some very simple real world test for the alt., and you gave me it.

I'll try that today and see how it works.

Thanks for all the help! (everyone!)

:beer:

did you notice problems when you put on the projection?

When I converted my truck to efi the stock alternator was not enough to keep up with the added electronics.

did you notice problems when you put on the projection?

When I converted my truck to efi the stock alternator was not enough to keep up with the added electronics.

Honestly, no. I have had the Holley on the truck since we built it, so I don't know any different. The alternator is a 120amp Powermaster alt. which IMO sucks (I've had one go bad, and another shatter the cooling fan). Dunno why I stick with it. I had two laying around, so I ran with it.

The Holley is VERY finicky, and unless you're willing to devote hour after hour installing it CORRECTLY (which is tricky because the instructions are difficult to understand), then tuning it and dealing with it's little 'issues', you'll be frustrated.

I mentally commited to it when we put it in, and that plus the fact that it's so damn expensive is the only reason I've stuck with it.

IMO factory TBI or a Howell system would have been much better.

Thanks again,

do you have the alternator field wire hooked up to a 12 volt switch?

without it the alt. won't charge until you rev it up to 3k rpm's or so.

I agree with you about the projection. Just finished up helping a buddy replace his projection with a TPI setup. MUCH better :smokin:

do you have the alternator field wire hooked up to a 12 volt switch?

without it the alt. won't charge until you rev it up to 3k rpm's or so.

You know, I'm going to sound stupid (that's why this is newbie tech right?), but I'm not sure.

I am assuming that since I'm seeing a voltage increase with the truck at idle, I do have it hooked up and it is charging under 3K.

I went through the main power leads yesterday and took off all of the old eye terminal ends and replaced them with better ones that are double hex-crimped (mil. spec).

I have all the right tools, but got them after I wired that truck up. I might have been seeing charging problems because at least one of those terminal ends was pretty loose.

I'll check the 12v lead.

Thanks!

I am assuming that since I'm seeing a voltage increase with the truck at idle, I do have it hooked up and it is charging under 3K.


well I said it the wrong way, it won't start to charge until the engine is reved up, then it charges normally. If you start the engine and don't hit the gas but the volt meter is where it should be, then it is hooked up fine.

What the field wire is.... On the delco alternator you have your 1 wire that goes to the battery, then theres a plastic 2 terminal plug. one is a red wire that also goes to the battery (usually jumpered to the 1 wire hookup on the alt) the second is usually white, but could be any color and it is the 12 volt switched wire. It is supposed to be a resistance wire (not sure how many ohms) but not having a resistor in there and using regular 14 gauge wire doesn't seem to hurt them.

Did you find any problems?how about a slipping alt. belt?Could show good charging voltage at idle and on the bench but not when the engine starts to turn quicker.

Deep cycles have a hard time charging on a surge charge like an alternator puts out. It is just going to take a while for the battery to charge with a deep cycle.