Alternator confusion

[BillyGman]

I have a question for you MM owners who have either hooked a portable voltmeter to the battery of your MM to test the charging system, or have watched your voltmeter inside your car closely.......

I've tested the charging systems of various cars that I've had in the past, but I've never seen results like I'm now seeing with my MM. I hooked up a volt meter to the battery before starting the car. It read 12.5 volts. However, I also noticed that when I start the engine, as long as I turn the A/C on, the volts just stay at 12.5 with he engine idling as long as I leave the A/C turned on. However, as soon as I turn off the A/C, the voltage climbs right up to 14.0 with the engine at idle. Even if I have all the other accessories turned on all at once, including the heater, interior lights, radio, and hi-beam headlights, the voltage will still climb right up to 14.0 volts with the engine at idle. But as soon as the A/C is turned on, the voltage drops down to 12.5, and stays there until I turn it back off again.

Does the voltage do this with your MM's when the A/C is on? I would think that if there's a problem with the alternator on my car, then the voltage wouldn't climb to 14.0 like it does when I have all the other accessories turned on all at the same time. BTW, I never have any problem getting the car started (atleast not yet anyway:rolleyes: ).

[grampaws]

The altenator voltage will drop significantly when the A/C is engaged

due to the high current draw..at idle the alt is not turning fast enough
to maintain full voltage under a high current draw...a fully charged battery
and a reasonable ALT should maintain 13volt or better at idle and the battery
should be 12.8 to 13.2 fully charged no load engine not running..
I would recommend the ALT be replaced hopefully it is still under war..
Another factor is if the idle speed is at or below 600rpm could contribute
to the alt not performing up to par.as well as the installation of underdrive
pulleys...(dealer may blame UD pulleys)...
ALtenator should be replaced

[Marauderjack]

Very big current drain with the electromagnetic clutch on the A/C compressor!! :argue:

You are probably fine!! :)

Marauderjack :pimp:

[Marauderjack]

Very big current drain with the electromagnetic clutch on the A/C compressor!! You may see the volts rise when the clutch disengages :argue:

You are probably fine!! :)

Marauderjack :pimp:

[FordNut]

I have a question for you MM owners who have either hooked a portable voltmeter to the battery of your MM to test the charging system, or have watched your voltmeter inside your car closely.......

I've tested the charging systems of various cars that I've had in the past, but I've never seen results like I'm now seeing with my MM. I hooked up a volt meter to the battery before starting the car. It read 12.5 volts. However, I also noticed that when I start the engine, as long as I turn the A/C on, the volts just stay at 12.5 with he engine idling as long as I leave the A/C turned on. However, as soon as I turn off the A/C, the voltage climbs right up to 14.0 with the engine at idle. Even if I have all the other accessories turned on all at once, including the heater, interior lights, radio, and hi-beam headlights, the voltage will still climb right up to 14.0 volts with the engine at idle. But as soon as the A/C is turned on, the voltage drops down to 12.5, and stays there until I turn it back off again.

Does the voltage do this with your MM's when the A/C is on? I would think that if there's a problem with the alternator on my car, then the voltage wouldn't climb to 14.0 like it does when I have all the other accessories turned on all at the same time. BTW, I never have any problem getting the car started (atleast not yet anyway:rolleyes: ).

I'll check to see if the A/C has that effect with mine. The symptom sounds similar to what mine does, but I already had the alternator replaced and the same problem returned. The alternator (regulator) is controlled by the pcm, so the program can have an effect also. If you have a scantool, there is a way to verify that the alternator is actually putting out what the pcm is telling it to.

[grampaws]

Normally mine charges at 14.3 to 14.4v with AC engaged it

drops to 14.2 and gradually after 5-10 minutes idling on a hot day
will drop to 13.2 or 13.5 and quickly rise with a slight rev of the
throttle if it is below 13 volt it will not maintain a good charge on
the battery and will reduce your battery life.
My f-150 has done this since new also.
The only time I have
had voltages below that are when the lights have been on for extened
period or Radio such as the drive-in without the engine running...
Don't idle to long or replace the Alt...:D
The A/c clutch could be drawing more current than it needs
possibly a short in the coil,or the fan motor..check using an
ammeter I do not have exact numbers or an ammeter available
to check mine but no more than 4-6 amps for each is a reading
I would expect..Hope this helps..

[FordNut]

I'll check to see if the A/C has that effect with mine. The symptom sounds similar to what mine does, but I already had the alternator replaced and the same problem returned. The alternator (regulator) is controlled by the pcm, so the program can have an effect also. If you have a scantool, there is a way to verify that the alternator is actually putting out what the pcm is telling it to.
Nope, mine is not effected by the A/C. It stays at about 11v just after starting, if you leave it idling a little while it goes up to about 13v. At cruising speed it goes up to 14v. When I stomp it, the voltage drops to about 11v but when I go back to normal cruising it takes a little while for it to go back to 14v.

[DEFYANT]

Was you A/C on MAX?

I noticed my volts was low the other night while stopped at a red light with all the night time accessories on. When the light changed and I gave it the gas, she was up to 14+ volts.

Now I just dont stop for red lights. That seems to have fixed the problem. ;)

Seriously, you car sounds fine.

[Sully008]

I've noticed the same thing. On reg A/C at a stoplight the gauge reads 12v. (I haven't verified with a voltmeter). During cruising or slight acceleration it jumps back to approx. 14v. Using all other accessories (eg. headlights, radio) except the A/C and it's around13.5v.

I read somewhere on here that our car's have the dimming headlight condition inherently from the factory. So right now I'm guessing that everything is "normal" for this car.

[RoyLPita]

Could this be from running that alternator backwards w/ the kit????

[Tallboy]

Could this be from running that alternator backwards w/ the kit????
Negative. My volt guage read the same before and after the kit. Output was also tested before and after. No difference.

[BigCars4Ever]

I have a question for you MM owners who have either hooked a portable voltmeter to the battery of your MM to test the charging system, or have watched your voltmeter inside your car closely.......

I've tested the charging systems of various cars that I've had in the past, but I've never seen results like I'm now seeing with my MM. I hooked up a volt meter to the battery before starting the car. It read 12.5 volts. However, I also noticed that when I start the engine, as long as I turn the A/C on, the volts just stay at 12.5 with he engine idling as long as I leave the A/C turned on. However, as soon as I turn off the A/C, the voltage climbs right up to 14.0 with the engine at idle. Even if I have all the other accessories turned on all at once, including the heater, interior lights, radio, and hi-beam headlights, the voltage will still climb right up to 14.0 volts with the engine at idle. But as soon as the A/C is turned on, the voltage drops down to 12.5, and stays there until I turn it back off again.

Does the voltage do this with your MM's when the A/C is on? I would think that if there's a problem with the alternator on my car, then the voltage wouldn't climb to 14.0 like it does when I have all the other accessories turned on all at the same time. BTW, I never have any problem getting the car started (atleast not yet anyway:rolleyes: ).
This is normal for the civilian panther platform. The police programs have a higher idle speed to compensate for this.

[BillyGman]

Hmmmm, I'm getting a lot of contradicting viewpoints here, but because Fordnut actually went and checked with his voltmeter what his car does, then I'm inclined to believe him (thanks FordNut;) ). However Fordnut, you stated that it was "11v" ??? Was that a typo? Anyway, if anyone else decides to check their cars voltage, then make sure that you have the "A/C MAX" button on, and the temperature set to 60 degrees, so the thing will stay on. That's what I did. But thankyou for everyone's replies.


BTW, I've already replaced the alternator once last year, and it was a brand new alternator that I purchased from the Mercury dealer parts department ($200 !!!). There's an automotive electrical place in the next town over from me that does nothing but rebuild alternators ans starters for cars, and deisel trucks, and they told me that spinning the alternator backwards shouldn't have any negative effects on it. they also told me that they did an airflow test on mine while running it in both directions, and found that the reverse direction only flows about 60% of the air that the forward direction does due to the fan blades inside of the alternator being angled in a certain direction, however, it was their opinion that it isn't anything to worry about, and that it shouldn't be a problem.

BTW, my car idles at 650-700 RPM's, and the voltage stays at 12.5 as long as the "A/C MAX" button is turned on even if I rev it to 2,000 RPM's. So it has nothing to do with engine revs. I didn't think that the A/C would be drawing more current than having all of the other accessories on all at once (ie. Hi-beams, heater fan motor on hi, radio, and interior lights). So I'm wondering if This has something to do with the programing in the chip I have.:confused: However, I'm not even sure if this is really anything to worry about. I don't have a scanner to check to see if the alternator is doing what the PCM is telling it to do, although that sounds like a great idea. Maybe this is one of those things that only time will provide the answer to. If the battery is still fine a cpouple months from now, I guess there's nothing wrong, but if I get stranded somewhere due to the car failing to start.......:rolleyes:

[Tinaree]

I'll check mine at home. If I can get to the autotap and find all the stuff for the laptop I'll check the PCM too. That really is curious.

[BillyGman]

I'll check mine at home. If I can get to the autotap and find all the stuff for the laptop I'll check the PCM too. That really is curious.Thanks pal. I appreciate it.That's the kind of feedback I'm looking for. :up:

[Tinaree]

Then you can hook me up with some range time on that 50 :D

[BillyGman]

Then you can hook me up with some range time on that 50 :DI welcome you to pulling the trigger numerous times on that monster. I think you would LUV it, just as I do. The problem is the distance between our places of residence. That would be a lot of driving for either one of us. And let's face it, since 9/11 I don't believe that there's any way that I'd be able to bring that cannon on a flight. :(

I brought it to Kentucky with me, to shoot it at the famous Knob Creek range where they have the semi-annual machine gun shoots. I also brought a manhole cover with me, which Mike and I managed to put a number of holes in.:D (I don't know if you saw the pics of that on here, but there they are below). But that was a long enough drive as it was.(13+ hours each way).


http://www.mercurymarauder.net/forums/attachment.php?attachmentid=62 07&stc=1&thumb=1 (http://www.mercurymarauder.net/forums/attachment.php?attachmentid=62 07)http://www.mercurymarauder.net/forums/attachment.php?attachmentid=62 05&stc=1&thumb=1 (http://www.mercurymarauder.net/forums/attachment.php?attachmentid=62 05)

[looking97233]

BillyGman- My MM is at the doctor right now but, I think that different programs will have different results. i.e. idle speed and what ever other factors are varibile from program to program. Also when you turn the AC on or off doesn't it affect the idle speed? I believe when turning the AC on my idle speed drops 150-200 rpm due to the AC compressor load and additional current load on the alt.

Just a thought.

...yep can still take firearms on the plane. No ammo though. Must be in a case. Declare it at the ticket counter, get a tag to put INSIDE the case, give to counter person to check the case. Case goes in the belly of the plane. I advise a hard case. Expect the case to be xrayed when they open it to examine, they will find the tag from the counter saying the firearm has been declared and is okay.

[Tinaree]

I'm more of a handgun person myself, but I would jump at the chance. I thought it was agreed you were going to fly me up there? LOL! After my close call (explained below) I was cussing you for a good 30 seconds!

Alright, here is what I saw. Started the baby up, let the ac kick in at max auto (its raining here but still 85*). Idles just on the high side of the 13V mark. Just touching. Turned it off, it idles just below the 14v mark (again, just touching). So I got a little creative; lights on highbeam, stereo blasting out Aerosmith (garage band blues fans will LOVE their new albu Honkin' on Bobo) and no difference from what I saw without it. Okay, so what loads this stuff down? The windows, of course. So in both modes I try a window, and it drops to like 11.7 or so. Then I do all 4 at once, the thing drops like a rock to 11v. It catches up after you let off. I'm doing this noting it all, and its raining, but WTH, and all of a sudden the windows stop half open! I'm like "Billy, I'm gonna kick your butt for this!" LOL! So I pop the fuse panel, check out the big honker 20A fuse for the windows, and it is HOT!. I'm ticked at this point, but I figure I can jumper it. So I go and grab the meter, and lay this in front of the fan (all good Texas garages have a monster fan) and I dig through the pile of stuff I call a toolbox and find my meter. Then I check the fuse (its much cooler now) and it is OK. So I go ahead and say a prayer to Marduk and stab it back in, start the car, and it all works. You are off the hook this time my freind, but watch your step... :D

So what I see is probably great tech for the board. The minimum voltage I saw tells me that I was drawing more than the battery could supply and I was working on alternator current alone. Maybe, can't prove that yet, but I'm betting your minimum is where your alt takes over. Your difference could be battery condition, alternator efficiency, or something unknown at this point.

Also, the fact that the fuse reset tells me it works like a varistor or some other dynamic link. Too hot and it opens, then it resets. This might be of use to someone having window problems.

Wow, I hate to post something this long, hope you got something out of it. I can't get to my diagnostic bag right now, but I doubt I could see anything extra; current is drawn where voltage is pushed, or that is how I envision it. And I don't have a heavy duty ammeter.

Edit: Smelling errors

[Tinaree]

I forgot to add; the next step I would perform is to put a charger on that battery overnight. Check it before and after. If that low voltage moves up the scale, it is your battery. In the powerstroke I did a lot of short commuting and it wouldn't hold a charge, and the fix was innovative; one of those little solar panel chargers on the dash did wonders. Of course your battery may simply be going south. But from your numbers and mine, I don't suspect the alternator; I'd look for a faulty ground or something and the alt would be my last suspect. Battery first. And maybe this is just normal?

[FordNut]

Nope, mine is not effected by the A/C. It stays at about 11v just after starting, if you leave it idling a little while it goes up to about 13v. At cruising speed it goes up to 14v. When I stomp it, the voltage drops to about 11v but when I go back to normal cruising it takes a little while for it to go back to 14v.
11v if lights are on, 12v if off

[BillyGman]

BillyGman- My MM is at the doctor right now but, I think that different programs will have different results. i.e. idle speed and what ever other factors are varibile from program to program. Also when you turn the AC on or off doesn't it affect the idle speed? I believe when turning the AC on my idle speed drops 150-200 rpm due to the AC compressor load and additional current load on the alt.Nope, not on mine. The idle speed stays the same when the A/C is turned on.

Just a thought.

...yep can still take firearms on the plane. No ammo though. Must be in a case. Declare it at the ticket counter, get a tag to put INSIDE the case, give to counter person to check the case. Case goes in the belly of the plane. I advise a hard case. Expect the case to be xrayed when they open it to examine, they will find the tag from the counter saying the firearm has been declared and is okay.Okay, cool. Thanks for that info. :gunfire:

[BillyGman]

11v if lights are on, 12v if offOkay, got it. thanks fr the clarification FN. :up:

[BillyGman]

I'm more of a handgun person myself, but I would jump at the chance. I thought it was agreed you were going to fly me up there? LOL! After my close call (explained below) I was cussing you for a good 30 seconds!

LOL......that's quite a battle you had with the weather, and your car.:baaa: ...I do appreciate your efforts to help me out though. :)

I think I'll try that battery charger experiment that you mentioned. The battery is only a year old, and is a heavy duty after market one (850 CCA's @ 32 degrees). But I want to make sure there isn't an alternator problem. I might be okay with this. BTW, my battery light on the dash never goes on, so I guess that's a good sign. :) Thankyou for your help, and you might not want to hold your breath real long waiting for that free air fare from me. (notice how I waited until after you've helped me out to break that news to you?:rofl: ).....

[hbarrett]

Mine seems to do the same, and I've noticed a similar effect on other cars I've owned. I think you are OK, but maybe you should get an opinion from a service tech. Please keep us informed.
Howard
I have a question for you MM owners who have either hooked a portable voltmeter to the battery of your MM to test the charging system, or have watched your voltmeter inside your car closely.......

I've tested the charging systems of various cars that I've had in the past, but I've never seen results like I'm now seeing with my MM. I hooked up a volt meter to the battery before starting the car. It read 12.5 volts. However, I also noticed that when I start the engine, as long as I turn the A/C on, the volts just stay at 12.5 with he engine idling as long as I leave the A/C turned on. However, as soon as I turn off the A/C, the voltage climbs right up to 14.0 with the engine at idle. Even if I have all the other accessories turned on all at once, including the heater, interior lights, radio, and hi-beam headlights, the voltage will still climb right up to 14.0 volts with the engine at idle. But as soon as the A/C is turned on, the voltage drops down to 12.5, and stays there until I turn it back off again.

Does the voltage do this with your MM's when the A/C is on? I would think that if there's a problem with the alternator on my car, then the voltage wouldn't climb to 14.0 like it does when I have all the other accessories turned on all at the same time. BTW, I never have any problem getting the car started (atleast not yet anyway:rolleyes: ).

[BillyGman]

I don't bring my car to any garage, nor to the dealer unless I know for sure that it needs to be done, even just for a diagnosis. I've had as many bad experiences with mechanics and the garages and dealers they work for as I have with physicians. Thankyou for your reply. So far, I don't believe that I have any reason to be concerned about this, but I just wanted to check with you guys who also own Marauders about this. And again, I really appreciate everyone's response.