Undersized alternator

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Mar 12, 2013 | 10:22 PM

#16

mhoefer

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Joined: Jan 2005

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From: BC Canada

My 140 amp alternator, original stock, charges to 13.1, sometimes hit 13.2 main voltage. The charge curcuit hits 14.4 at cold start, as high as 14.8 volts after a short bit. My batteries have only ever read 12.8 across the terminals or on the outlook monitor, whether charged by the alt or overnight with a a heavy duty trickle charger. They are 100% charged with the trickle charger as it's a smart charger and automatically turns off. I don't have a fluke with clamp that can measure DC amps so I can't verify the above amp flows. In winter I often have short trips, often not warmed up, only on my second set of batteries, the originals ran 7.3 years, before I dropped a single cell. Tried to desulphate but no go, had to replace both with new motor craft 850 CCA. Running all my aftermarket lights, I have about an extra 650 watts I can run, I am burning probably close to 50 amps alone, I don't see any decrease in main voltage. I would say I agree the alternators are barely adequate, but I seem to have a good one. If I have to I will upgrade when replacing anyway. Maybe a 200 amp DC.

Mar 12, 2013 | 11:52 PM

#17

diesel_dan

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Joined: Jul 2004

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From: Foothills, CA

^^^^^ Ditto -- our originals went 6 years or so. Besides an FICM, all of the electrical wizards out there, what's the FIRST thing that goes with a weak alternator??!

I think the 140s are ok unless you got a defect...

Mar 12, 2013 | 11:59 PM

#18

run6.0run

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From: Kansas City MO

I have an Oreillys lifetime alt that was $250 n it sits above 14 all the time. Granted, this video isn't from a cold start, but the "junk" big box alts, have been working for me. I've got lots of lights, a 26" tv in the back with the sat tv on also.

Mar 13, 2013 | 06:19 AM

#19

sammy77

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Joined: Oct 2007

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From: Illinois

The best luck I've had with the stock alternator was 19 months. Yes I did plow with it, and do run a stereo with subs. DC Power is no longer an option it seems either, we ordered one over a month ago and never got it..

Mar 13, 2013 | 07:12 AM

#20

fmtrvt

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Joined: Oct 2001

Posts: 544

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From: Jersey Shore Not Seaside!

I made it 9 years 8 months with the stock 110amp alternator before the voltage output got a little erratic. The original batteries made it for 7 years. Still have original FICM. Fairly good GP usage here in the Garden state, driving it every day.

As with Mark, I would have preferred to see a 140amp unit on these trucks stock. But I think the OE setup is adequate, but as soon as you go to most aftermarket batteries you may not have the reserve to keep voltage up to a minimum needed during GP / FICM use.

Of course I still have original trucks programing with the pilot injection, so my FICM does not to turn the injector's spools in Easy Bake Ovens.

Mar 13, 2013 | 08:24 PM

#21

Kayteg1

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Joined: Mar 2013

Posts: 60

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Here is the truck voltage on c-cold morning in march (52F here)
I measured the voltage with different meter and it was like 12.6V before turning the ignition on.
Looks like the scanner missed tho lowest point during cranking as it was lower than 12.5v, but after the start the alternator put close to 13v with GP surging. Meaning it was already charging on the first second on idle.
On 30 second I turned the headlights and blower on, so the voltage dropped to 12.7v, what is probably close to 0 charge. I turned the load off at 45 sec and the charge shoot to 13.2v. I put the load 2 more time as you can see from voltage fluctuation, but the readouts clearly shows that even at idle my alternator can handle max load my truck can have after about 40 seconds warm up and GP draw.
Starting at about 80 seconds the alternator was clearly charging the batteries load or not. Bottom line - my truck never runs on battery power besides few seconds at start up when I turn the load on and GP click in.
I had motorhome with 300 lb of batteries in them and they run just fine on 60 amp alternators, so per my experience the only times when you need second alternator is ambulance, snow plow that has 2HP electro-hydraulic pump and drives with 6 halogens at night, or somebody welding on alternator power (I tried it on 24V bus and it was fun)

Mar 13, 2013 | 08:33 PM

#22

Kayteg1

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Joined: Mar 2013

Posts: 60

Likes: 0

Quote:

Originally Posted by bismic

Kayteg1 - I have to admit that you are the first person I have seen that gets 14V+ out of a stock alternator. I would love to know the part number and if it is original.<table style="border-collapse: collapse;" x:str="" border="0" cellpadding="0" cellspacing="0" height="126" width="793"><tbody><tr style="HEIGHT: 13.2pt" height="18"><td style="BORDER-BOTTOM: #d4d0c8; BORDER-LEFT: #d4d0c8; BACKGROUND-COLOR: silver; WIDTH: 670pt; HEIGHT: 13.2pt; BORDER-TOP: #d4d0c8; BORDER-RIGHT: #d4d0c8" class="xl24" align="left" height="18" width="894">
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</td></tr><tr style="HEIGHT: 13.2pt" height="18"><td style="BORDER-BOTTOM: #d4d0c8; BORDER-LEFT: #d4d0c8; BACKGROUND-COLOR: silver; WIDTH: 670pt; HEIGHT: 13.2pt; BORDER-TOP: #d4d0c8; BORDER-RIGHT: #d4d0c8" class="xl24" align="left" height="18" width="894">
</td></tr><tr style="HEIGHT: 13.2pt" height="18"><td style="BORDER-BOTTOM: #d4d0c8; BORDER-LEFT: #d4d0c8; BACKGROUND-COLOR: silver; WIDTH: 670pt; HEIGHT: 13.2pt; BORDER-TOP: #d4d0c8; BORDER-RIGHT: #d4d0c8" class="xl24" align="left" height="18" width="894">
</td></tr><tr style="HEIGHT: 13.2pt" height="18"><td style="BORDER-BOTTOM: #d4d0c8; BORDER-LEFT: #d4d0c8; BACKGROUND-COLOR: silver; WIDTH: 670pt; HEIGHT: 13.2pt; BORDER-TOP: #d4d0c8; BORDER-RIGHT: #d4d0c8" class="xl24" align="left" height="18" width="894">
</td></tr><tr style="HEIGHT: 13.2pt" height="18"><td style="BORDER-BOTTOM: #d4d0c8; BORDER-LEFT: #d4d0c8; BACKGROUND-COLOR: silver; WIDTH: 670pt; HEIGHT: 13.2pt; BORDER-TOP: #d4d0c8; BORDER-RIGHT: #d4d0c8" class="xl24" align="left" height="18" width="894">
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</td></tr></tbody></table>

Looks like my alternator was replaced shortly before the sale as it shines comparing to pretty nasty engine. Here is the picture of the labels. I had over 14 v on 7.3l as well, although I remember those truck have like 2 minutes delay on alternator activation.
I think the 14+V charge is battery killer. On other vehicles batteries of last generation last quite often 12 years, when the highest I heard on Ford was 7 years.

Mar 14, 2013 | 05:25 AM

#23

Fulthrotl

Elder User

Joined: Apr 2012

Posts: 904

Likes: 1

Quote:

Originally Posted by diesel_dan

batteries are under duress from the get go with stock alternator.

if you read the specs on oddesy's charger designed for
their batteries, to get full charge, the profile goes up to
14.8 volts. that if for AGM batteries, but most alternators
run an output voltage around 14.5 in most vehicles.

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Mar 14, 2013 | 06:41 AM

#24

sammy77

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Joined: Oct 2007

Posts: 4,202

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From: Illinois

Quote:

Originally Posted by fmtrvt

This is a freakin miracle...lol I've had no luck whatsoever with the Motorcraft batteries.

Mar 14, 2013 | 07:01 AM

#25

fmtrvt

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Joined: Oct 2001

Posts: 544

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From: Jersey Shore Not Seaside!

Thats with the OE batteries. The standard Motorcraft versions are not the same.

Mar 14, 2013 | 07:14 AM

#26

Bullitt390

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Joined: Aug 2001

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The longest I have seen in fleet service is 4 years for OE 6.0 batteries.

Josh

Mar 14, 2013 | 07:18 AM

#27

bismic

Fleet Owner

Joined: Nov 2003

Posts: 27,881

Likes: 3,595

Quote:

Originally Posted by fmtrvt

Thats with the OE batteries. The standard Motorcraft versions are not the same.

That is sure the truth!! For one, the Motorcraft batteries are made in Mexico while the OE batteries are made in the U.S.

I have had Ford diesel trucks for a long time and always had good service from the OE batteries. For my current 06 truck though, my original batteries lasted exactly 36 months (hmmm - how do they do that??). Seven years is quite outstanding for sure. I have always felt that the "marginal" alternators have contributed to the reduced battery life. The weather here is far from extreme - ie practically never freezes and the summers (102 is typical max temp) aren't as bad as places in Arizona (for example), so weather here plays a minimal role in the battery life (at least IMO). Also, my driving routine is FAR from the "short trip" type driving.

Mar 14, 2013 | 08:01 AM

#28

sammy77

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Joined: Oct 2007

Posts: 4,202

Likes: 1

From: Illinois

Quote:

Originally Posted by fmtrvt

Thats with the OE batteries. The standard Motorcraft versions are not the same.

Definitely.

The OE batteries lasted me the longest on my truck at 30 months or so IIRC. Again, I do ask a lot from the batteries/charging system. Strobe lights, stereo subs, amp, heater, wipers, etc, when I plowed with it. The weather here is anywhere from -20 with wind chills to +110 with the heat index. The batteries I purchased after that lasted me in the 2yr range(all Motorcraft).

Finally bit the bullet on some Die Hard Platinums a couple months back. Truck cranks like it's on steriods now

Mar 14, 2013 | 09:23 AM

#29

Kayteg1

Junior User

Joined: Mar 2013

Posts: 60

Likes: 0

In our SUV the Spanish battery made in 1998 made it 12 years and 4 months. Mercedes alternators run at 13.8v and somehow they manage to keep the steady voltage no matter the load. Even those made 30 years ago.