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Topic: Need to understand my 454 Chevy FEG alternator (Read 672 times) previous topic - next topic

Need to understand my 454 Chevy FEG alternator

Hello.  More tech help.  Problem solved but want to understand the issues for next time..

Our alternator failed on a Texas Hill Country trip last Thanksgiving.... returned to boulder with a replaced alternator and new battery ( 12 hours on failed alternator will hurt a battery)...

Put away for the winter.. now dewintereized and our local shop went over a few things for us.... but found that the NEW alternator was all good but NO power wire /diode in place to charge battery.... WHAT ?  Are you saying after alternator was replaced that we came back from Texas Hill Country to Boulder on the NEW battery ???

Texas shop tech just used the ONE hot wire from alternator direct to new battery as the new alternator had the regulator built in.  ( old OEM one had a separate regulator mounted in front of fire wall.

What did we miss ?   

1986 Grand Villa, 454 Chevrolet, 33 SBI tag axle
Build # 2658
2nd owner, original owner was Newman/Freeman Racing, racer Bill Freeman and actor/racer Paul Newman

Re: Need to understand my 454 Chevy FEG alternator

Reply #1 –
Quote from: Subsilked –
Texas shop tech just used the ONE hot wire from alternator direct to new battery as the new alternator had the regulator built in. 
Sounds like you have a "one wire alternator".  This is not uncommon with older GM gas engine vehicles.  It will keep your START battery charged, but it will not charge your COACH batteries.  To do that, you need a battery isolator.  Do you have a isolator?  It's the red thing in 2nd photo.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Need to understand my 454 Chevy FEG alternator

Reply #2 –
Quote from: Chuck & Jeannie –
Sounds like you have a "one wire alternator".  This is not uncommon with older GM gas engine vehicles.  It will keep your START battery charged, but it will not charge your COACH batteries.  To do that, you need a battery isolator.  Do you have a isolator?  It's the red thing in 2nd photo.

House batteries are all good with recharging by Generator and Shore Power..    i was asking how we had a new alternator installed on a Texas road trip and found months later that the "Power Wire" and Diode were not in place for alternator to charge the Chassis Battery.... to discover months later that we have been driving hundreds of miles on the BATTERY only with no charging from the alternator....

Today's repair statement:  " Alternator found to be missing remote power wire and diode , Repaired correctly and altenator now working as new...".    The original alternator had a exterior regulator,  the Texas tech installed a new alternator with a built in regulator and wired alternator straight to chassis battery.... did he miss something.. ?
1986 Grand Villa, 454 Chevrolet, 33 SBI tag axle
Build # 2658
2nd owner, original owner was Newman/Freeman Racing, racer Bill Freeman and actor/racer Paul Newman

Re: Need to understand my 454 Chevy FEG alternator

Reply #3 –
Quote from: Subsilked –
House batteries are all good with recharging by Generator and Shore Power..    i was asking how we had a new alternator installed on a Texas road trip and found months later that the "Power Wire" and Diode were not in place for alternator to charge the Chassis Battery.... to discover months later that we have been driving hundreds of miles on the BATTERY only with no charging from the alternator....
Sorry - I will have to pass on this question, because your statement above does not make any sense to me.  I don't know what you mean by "power wire and diode", so I guess I'm not smart enough to answer this question.

In my experience, I would say it's not possible to drive "hundreds of miles" on the power from a single chassis battery.  This is especially true with a gasoline engine that has a distributer and coil ignition system.  You would soon run the chassis battery down, and the engine would quit.  Even quicker if you used the headlights.  So I would say your chassis battery must have been getting charging current from someplace.

In the diagram I posted above, you can see that it is possible to run a single battery cable from alternator to battery, and keep the chassis battery fully charged.  I don't know where the "power wire and diode" you mention would fit into the diagram, or what its purpose would be.

Unless your coach has been modified by a previous owner, it should have some provision for charging both battery banks from the alternator while the engine is running.  Like I said, on older Foretravel coaches this was usually handled by a diode-based battery isolator, but there are other ways to accomplish the same thing.

Sorry I can't be more helpful.  Good luck with your alternator and charging system. 
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Need to understand my 454 Chevy FEG alternator

Reply #4 –
Sounds like the Texas tech maybe installed the one wire alternator correctly, but not sure if your local tech understood this, or just wanted to fish in your wallet to see what he could reel in. Anyhow there there are smart battery isolators out there that charge your start battery first, and then switch to charge your house battery bank.
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Need to understand my 454 Chevy FEG alternator

Reply #5 –
Quote from: Chuck & Jeannie –
Sorry - I will have to pass on this question, because your statement above does not make any sense to me.  I don't know what you mean by "power wire and diode", so I guess I'm not smart enough to answer this question.

In my experience, I would say it's not possible to drive "hundreds of miles" on the power from a single chassis battery.  This is especially true with a gasoline engine that has a distributer and coil ignition system.  You would soon run the chassis battery down, and the engine would quit.  Even quicker if you used the headlights.  So I would say your chassis battery must have been getting charging current from someplace.

In the diagram I posted above, you can see that it is possible to run a single battery cable from alternator to battery, and keep the chassis battery fully charged.  I don't know where the "power wire and diode" you mention would fit into the diagram, or what its purpose would be.

Unless your coach has been modified by a previous owner, it should have some provision for charging both battery banks from the alternator while the engine is running.  Like I said, on older Foretravel coaches this was usually handled by a diode-based battery isolator, but there are other ways to accomplish the same thing.

Sorry I can't be more helpful.  Good luck with your alternator and charging system.

Testing has shown us that the alternator now is charging the chassis battery... all good now....  now really sure what our local Boulder tech is saying with his invoice statement " power wire"....  but just to add a trivia issue... the failed alternator that was removed from the engine on our Texas road trip was NOT a GM alternator.. it was a FORD .. from late 70's...  we have oonfirmed with FT that a late 70's FORD alternator was sourced for the 85 / 86 FT GV 454 Chevy motor...   
1986 Grand Villa, 454 Chevrolet, 33 SBI tag axle
Build # 2658
2nd owner, original owner was Newman/Freeman Racing, racer Bill Freeman and actor/racer Paul Newman

Re: Need to understand my 454 Chevy FEG alternator

Reply #7 –
Quote from: Travelin' Man –
What did the dash volt meter say on the trip from TX to CO?
The dashboard for this 86 GV is the Chrysler Electronic from the mid 80's...  the voltmeter gauge is NOT graduated.. it simply starts at 8 and ends at 18...  there is a digital marker on the meter.... it was intermittent green to red ( 8 volts) most of sunday evening... after headlights were needed volt metered stayed in RED....  we knew we had an issue but on back roads there was NO way to stop and no cell phone signal...  we continued... lost headlights and all dash lights, we continued driving as there was no towns in the are for another 25 miles.  We used our cell phones spot lights to illuinate roadway ahead.. small two lane back road.    Lost all chassis battery as we entered small town of Winters Tx and rolled into a gas station in the only intersection around...  slept the night... found a truck /auto shop within walking distance ( Bahlmers Auto) and got a tech to remove the alternator and take us to auto part store and discovered alternator was a Ford product... installed by tech and new battery and voltmeter appeared to be 13 ish...  we had trouble free trip , 12 hours on the road for non stop return to Boulder.  Put away for winter and de winterized this past week.  Voltmeter issues again with just 8-9 volts.  We trickle charged up the chassis battery and found voltmeter in same position ( green) 12.5 to 13.. but while running engine never found 14 needed to maintain battery ... we drove it to local heavy truck shop.... testing showed " missing power wire and diode" .. labor fees of $ 300 but no parts were invoiced....    something is amiss here...  called the tech in Texas and he assured us the new ONE wire alternator was installed correctly .... did not know what the Power Wire is or was...    going back to Boulder tech today to discuss this one more time.    We have full charging from alternator now.... but just need to know what happened and what did we do or not do...
1986 Grand Villa, 454 Chevrolet, 33 SBI tag axle
Build # 2658
2nd owner, original owner was Newman/Freeman Racing, racer Bill Freeman and actor/racer Paul Newman

Re: Need to understand my 454 Chevy FEG alternator

Reply #8 –
"And now you know -- the rest of the story."
Paul Harvey

New or reman alternator?  Sounds like maybe you got a bad one the first time, a good one the second time (assuming you had 14v on the remainder of your trip to CO) and for time in storage the shore power, inverter/charger or battery minder was inadequate.  And don't overlook ground wires and gauge accuracy.

Re: Need to understand my 454 Chevy FEG alternator

Reply #9 –
 I have added a GM  single wire unit in place of the OE AC compressor.  I did not think that any single wire setups were Ford footprint.  Just GM.

 It is likely that if you drove it for more than about 4 hrs, the alternator was charging  .

Re: Need to understand my 454 Chevy FEG alternator

Reply #10 –
Just a couple of follow ups....  the photo attached is the OLD failed alternator ( exterior regulator) that was removed by a truck shop in Winters Texas... and replaced with a rebuilt ( Chinese ) internal regulator...  that might have been installed incomplete causing us to not be charging our chassis battery...
1986 Grand Villa, 454 Chevrolet, 33 SBI tag axle
Build # 2658
2nd owner, original owner was Newman/Freeman Racing, racer Bill Freeman and actor/racer Paul Newman

Re: Need to understand my 454 Chevy FEG alternator

Reply #11 –
 It must have worked for "12 hours on the road for non stop return to Boulder."

Sorry I misunderstood earlier and thought you had the alternator replaced twice on your way home. And I'm still confused about the Ford alternator. The one pictured is the original that crapped out?  What kind is the new one?

You may have only had a voltage regulator failure, but I don't know if a Lestek one is still available or if there's interchangeable ones. Meaning you may not have needed a new alternator,

Re: Need to understand my 454 Chevy FEG alternator

Reply #12 –
Looks like Lestek was a small manufacturer of electrical equipment.  Seems to have been associated with Balmar Marine at one time.  No longer in business, best I can tell.

It was probably a decent alternator at the time it was installed.  Better stuff available now.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Need to understand my 454 Chevy FEG alternator

Reply #13 –
Quote from: Travelin' Man –
It must have worked for "12 hours on the road for non stop return to Boulder."

Sorry I misunderstood earlier and thought you had the alternator replaced twice on your way home. And I'm still confused about the Ford alternator. The one pictured is the original that crapped out?  What kind is the new one?

You may have only had a voltage regulator failure, but I don't know if a Lestek one is still available or if there's interchangeable ones. Meaning you may not have needed a new alternator,
Not sure of this Lestak is the OEM alternator with an external regulator.  The Lestak is the one that failed on the highway near Winter Texas....  slept overnight in the car/truck stop at only 4 way intersection in the town... the nearby tech took us to the Carquest and could not match the Lestak alternator with his instock inventory and they matched up the posts and the mounting brackets to a Chinese Rebuilt alternator for a Ford 460 engine....  it appears that the original alternator had a separate small gauge wire that would " excite" the alternator and send charging to the chassis battery. This is what was missing from the Texas install and was " fixed " here in Boulder... all good now.... hopefully.
1986 Grand Villa, 454 Chevrolet, 33 SBI tag axle
Build # 2658
2nd owner, original owner was Newman/Freeman Racing, racer Bill Freeman and actor/racer Paul Newman

Re: Need to understand my 454 Chevy FEG alternator

Reply #15 –
Quote from: Subsilked –
it appears that the original alternator had a separate small gauge wire that would " excite" the alternator and send charging to the chassis battery. This is what was missing from the Texas install and was " fixed " here in Boulder... all good now.... hopefully.
I know you are tired of hassling with this alternator problem, and just want to move on.  You are not the first Foretravel owner to buy a preowned coach, and later find the alternator/charging system is all screwed up.  If you search the subject on this Forum, you will find many very similar tales of woe.  I had one of those episodes myself, but thanks to help from more senior Forum members, I was able to straighten things out.  If you are motivated to do so, it would pay to do a little study on the subject of "alternators" and how they interface with RV multi-battery charging systems.  Might save you some grief and/or money next time.

I'm still not sure you are getting the straight story from your local mechanic.

The original alternator that needed the small gauge wire was what is called a "externally excited" alternator.  This type alternator was very common on early Foretravel coaches.  The small gauge wire was connected to a contact point which was "hot" with ignition switch in the ON position.

The "single wire" alternator you had installed in Texas may or may not require a "excite" wire.  Some single wire alternators are "self exciting" which means they would not require the small gauge "excite" wire.  The only way to know for sure is to look up the specs on the particular model you ended up with.  This info is easy to find online - just Google the model number.

Anyway, if everything is working and you are happy, then I guess that is all that matters, so time to let this thread die a quiet death.

Quick and dirty alternator types:

One-wire Alternator:
Is another name for the Self-Exciting Alternator.  You only need to connect the big battery cable (one-wire).  The alternator turns on (activates) the voltage regulator when the engine starts turning the alternator.  May require revving the engine to get alternator started charging.

Two-wire Alternator:
Most standard and all self-exciting regulator alternators will work using the two wire setup.  Two wire means that you use the main battery cable to the back of the alternator and also a "hot with ignition" wire to the #1 terminal to activate the alternator.  With this setup the alternator will start charging as soon as the engine is running.
Note: On a 2-wire alternator, the small gauge wire may be a "sense" wire rather than a "excite" wire.  See 3-wire alternator (below)

Three-wire Alternator:
This setup uses a battery cable, hot-with-ignition/warning light wire and voltage sensing (sense) wire.  Three wires.  Voltage sensing is used when you want to be sure the alternator is reading the actual main (start) battery voltage.  Or, the battery installation is such that the main battery is a long distance (long cable run) from the alternator.

1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"
 

Re: Need to understand my 454 Chevy FEG alternator

Reply #16 –
Quote from: Chuck & Jeannie –
I know you are tired of hassling with this alternator problem, and just want to move on.  You are not the first Foretravel owner to buy a preowned coach, and later find the alternator/charging system is all screwed up.  If you search the subject on this Forum, you will find many very similar tales of woe.  I had one of those episodes myself, but thanks to help from more senior Forum members, I was able to straighten things out.  If you are motivated to do so, it would pay to do a little study on the subject of "alternators" and how they interface with RV multi-battery charging systems.  Might save you some grief and/or money next time.

I'm still not sure you are getting the straight story from your local mechanic.

The original alternator that needed the small gauge wire was what is called a "externally excited" alternator.  This type alternator was very common on early Foretravel coaches.  The small gauge wire was connected to a contact point which was "hot" with ignition switch in the ON position.

The "single wire" alternator you had installed in Texas may or may not require a "excite" wire.  Some single wire alternators are "self exciting" which means they would not require the small gauge "excite" wire.  The only way to know for sure is to look up the specs on the particular model you ended up with.  This info is easy to find online - just Google the model number.

Anyway, if everything is working and you are happy, then I guess that is all that matters, so time to let this thread die a quiet death.

Quick and dirty alternator types:

One-wire Alternator:
Is another name for the Self-Exciting Alternator.  You only need to connect the battery cable (one-wire).  The alternator turns on the voltage regulator when the engine starts turning the alternator.  May require revving the engine to get alternator started charging.

Two-wire Alternator:
Most standard and all self-exciting regulator alternators will work using the two wire setup.  Two wire means that you use the main battery cable to the back of the alternator and also "hot with ignition" wire to the #1 terminal to activate the alternator.  With this setup the alternator will start charging as soon as the engine is running.

Three-wire Alternator:
This setup uses a battery cable, hot-with-ignition/warning light wire and voltage sensing wire.  Three wires.  Voltage sensing is used when you want to be sure the alternator is reading actual main (start) battery voltage.  Or, the battery wiring is such that the main battery is a long distance from the alternator.

Amazing and thorough explanations.... i now understand the entire issue.    I believe the Boulder tech uses the term Power Wire to define the Exite Wire....... thanks so much for this great summary.... we have all green indicators now... 
1986 Grand Villa, 454 Chevrolet, 33 SBI tag axle
Build # 2658
2nd owner, original owner was Newman/Freeman Racing, racer Bill Freeman and actor/racer Paul Newman