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BrianGlenn · 08-12-2017, 04:47 PM

I am on a long road trip and I have noticed my alternator voltage on my 2007 400ISL has increased from its usual 13.5-13.9 VDC to 14.9-15.1V.

It started two days ago on a long day travelling where it peaked (step change) to over 14V on the dash gauge, and dropped back to near 13.5V (that got my attention). I switched my Silverleaf to chassis battery voltage and noticed the trend graph where I saw the step change voltage change to 15V then dropped back to 13.5 (approximate). Only lasted 2-3 minutes. Over the next 100-150 miles it peaked again and dropped back to 13.5-13.9 a couple of times and stayed at 13.7ish for the remainder of the trip.

Today is started out at normal(ish) at 14 and stayed at 13.5-13.7 (on silverleaf) until about 1:00PM when it trended up to about 15.2 and stayed at 14.8-15.0 for 50 or so miles. I stopped to measure voltage at batteries and they were the same as silverleaf and dash gauge.

Here is what I have noted:

Overvoltage from alternator appears to be independent from rpm/speed/engine load,
all other engine parameters are normal,
no other electrical irregularities,
voltages at battery terminals, dash gauge, SeeLevel monitor panel are all reading equal,
grounds are good - have been removed and cleaned and re-tightened (I read twinboat posts as well),

I was able to use my Fluke clamp on amp meter on battery cables when the over voltage was happening (15.1V) while idling at truck stop and the amperage was fluctuating all over the place on the Fluke meter (ranged from +11A to -2A), with very rapid changes.

When I pulled into campground tonight, voltage was constant at 13.7V, and I measure DC amps on the battery cables - constant at 4-5A.

I am suspecting the alternator is on its way out, but I do not know if my medium duty diesel engine alternator is similar to simple engine alternators with voltage regulators built in.

Any other suggestions? Anyone else have similar symptoms?

Thanks,
Brian

twinboat · 08-12-2017, 05:24 PM

Check the wire connections on the alternator.

There may be a battery voltage sense wire. If it's loose and has some resistance, the alt will see low battery voltage and try to increase it.

BrianGlenn · 08-13-2017, 02:16 PM

Quote:

Originally Posted by twinboat

Check the wire connections on the alternator.

There may be a battery voltage sense wire. If it's loose and has some resistance, the alt will see low battery voltage and try to increase it.

All connections are tight and clean.

I cannot see any external voltage regulator so I am suspecting the alternator is starting to fail.

I took a camera and found the model # Leece Neville A0012800LC (Prestolite), 160A.

Difficult thing is cellular and internet connections are painfully slow here in Newfoundland......

Brian

**CountryFit** · 08-13-2017, 05:56 PM

suspecting faulty voltage regulator. part is about $30.

**CountryFit** · 08-13-2017, 11:45 PM

its v regulator pn. 103450.

BrianGlenn · 08-14-2017, 11:47 AM

Thank you. I have not replaced a voltage regulator that has been integral to the alternator. It appears it may be bolted/screwed on to the back of the alternator body? I need to look in more detail at a schematic outline or the back of my alternator to better understand.....

I did not know you could buy the part separately; thanks again.

Is it an easy job to replace?

Brian

palehorse89 · 08-14-2017, 11:56 AM

Mine went south 2 years ago, and I took it to a friend that has a shop and all the parts to completely rebuild it.......even new bearings and all new internal parts........
you might want to think about just getting it refurbished/rebuilt with all new part's as long as it is out and opened up..........then it is good to go and do its job with a fresh rebuild?? Mine had gotten very hot due to a internal shorted out battery and it operated at 100% output for a time that fried it........Now I make sure that all the batteries are up to or close to full charge either with shore power or running the genset before starting the engine and load test them a couple of times a year........so all it has to do is maintain them.

Smitty77 · 08-14-2017, 02:10 PM

Another option is to replace it with a Delco Remy 200A unit. Many have made this switch, and it is the way I went when ours went out about two years ago. My cost for the new Delco Remy was within a few dollars of a rebuilt LN 160A unit.

And timing was a issue for me, and I could get the Delco Remy the next day...

Maybe worth checking into, as for sure you have options here.
Best,
Smitty

**CountryFit** · 08-14-2017, 03:33 PM

Quote:

Originally Posted by BrianGlenn

Thank you. I have not replaced a voltage regulator that has been integral to the alternator. It appears it may be bolted/screwed on to the back of the alternator body? I need to look in more detail at a schematic outline or the back of my alternator to better understand.....

I did not know you could buy the part separately; thanks again.

Is it an easy job to replace?

Brian

only 4 bolts hold it down. don't know how the layout is in your engine bay. on my 2000 intrigue, it's an easy r/r, no need to remove the whole assembly.

(i was under an assumption that you are gonna fix it yourself. if you have to find a shop to do it, you might be better off getting a new or rebuilt unit, or as smitty suggested getting an upgraded one with higher output. i am afraid no mechnic would like to replace just the regulator as no money could be made out of it

). good luck!

BrianGlenn · 08-15-2017, 06:12 AM

Quote:

Originally Posted by CountryFit

only 4 bolts hold it down. don't know how the layout is in your engine bay. on my 2000 intrigue, it's an easy r/r, no need to remove the whole assembly.

(i was under an assumption that you are gonna fix it yourself. if you have to find a shop to do it, you might be better off getting a new or rebuilt unit, or as smitty suggested getting an upgraded one with higher output. i am afraid no mechnic would like to replace just the regulator as no money could be made out of it

). good luck!

I will be replacing it myself; layout in my engine bay is good, alternator is on left side of engine, with voltage regulator on the back underside. R/R would be easy. I was unsure if the alternator case needed to be broken apart to replace regulator or connections to rest of alternator circuits.

Thanks again.

Brian

**CountryFit** · 08-15-2017, 10:09 AM

Quote:

Originally Posted by BrianGlenn

I will be replacing it myself; layout in my engine bay is good, alternator is on left side of engine, with voltage regulator on the back underside. R/R would be easy. I was unsure if the alternator case needed to be broken apart to replace regulator or connections to rest of alternator circuits.

Thanks again.

Brian

alternator housing will not come apart, actually nothing will. after removing 4 corner bolts, the regulator will come off, exposing 2 yellow wires being connected to 2 terminals on the side. watch the polarities when install new.

smlranger · 08-15-2017, 10:48 AM

Quote:

Originally Posted by Smitty77

Another option is to replace it with a Delco Remy 200A unit. Many have made this switch, and it is the way I went when ours went out about two years ago. My cost for the new Delco Remy was within a few dollars of a rebuilt LN 160A unit.

And timing was a issue for me, and I could get the Delco Remy the next day...

Maybe worth checking into, as for sure you have options here.
Best,
Smitty

Did you have to modify the bracket to switch to the Delco? My LN attached to the engine in such a way as to appear only an exact replacement LN would fit without some mods.

BrianGlenn · 08-16-2017, 06:08 AM

Quote:

Originally Posted by smlranger

Did you have to modify the bracket to switch to the Delco? My LN attached to the engine in such a way as to appear only an exact replacement LN would fit without some mods.

From my past alternator change outs the mount style has to be the same, and there are large number of different alternators with similar mount styles. My Leece-Neville is a J-180 mount style. J-180 has both a long mount or short mount - reference link here.

I have removed my alternator this AM and am having it rebuilt for about $180CDN here in St John's Newfoundland. Just waiting for the shop to call and go pick it up and reinstall. Sitting the in the campground drinking coffee (better WIFI this AM!)

Brian

Smitty77 · 08-16-2017, 05:58 PM

Quote:

Originally Posted by BrianGlenn

From my past alternator change outs the mount style has to be the same, and there are large number of different alternators with similar mount styles. My Leece-Neville is a J-180 mount style. J-180 has both a long mount or short mount - reference link here.

I have removed my alternator this AM and am having it rebuilt for about $180CDN here in St John's Newfoundland. Just waiting for the shop to call and go pick it up and reinstall. Sitting the in the campground drinking coffee (better WIFI this AM!)

Brian

Yes to it also being a direct drop in for our CAPS era ISL, a 2003 built engine. No fuss, no muss

!

Brian - Glad you found a shop to do the rebuild for you. Are you having the AM bumped up any? (Not important if the coach is stock battery wise. But if you've upgraded Chassis and or House batteries sizing, going up a bit on alternator output would not hurt.) That is why we bumped up our's from 160A to 200A.

Best to you, and all,
Smitty