Skip to main content ↑ ↓
Topic: Alternator wiring. (Read 945 times) previous topic - next topic

Re: Alternator wiring.

Reply #25 –
Quote from: Moby –
Or, if I can't identify, get a new alternator.
 I mean, if it's a hassle to pull why put back a used part?
I agree that may be the best solution.  It's your money, and your decision.
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: Alternator wiring.

Reply #26 –
Model and vendor suggestions?
In restless dreams I walked alone.
Narrow streets of cobblestone.


'93 U225
Build 4337
'14 CRV Toad

Re: Alternator wiring.

Reply #27 –
Quote from: Moby –
Model and vendor suggestions?
Shop around online - items in stock and prices change often these days with supply chain disruptions.

See link below for a recent thread where we discussed replacement alternators.  Reply #10 has links to what I believe would be a good direct replacement unit for your coach.

UPDATE Engine batteries not charging while engine is on UPDATED
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: Alternator wiring.

Reply #28 –
An alternate setup option would be a 160 amp Delco alternator and a Victron argoFET Zero voltage loss battery isolator.

Delco 28si 160 amp 8600308 ~$233.  J180 long hinge.
https://www.finditparts.com/products/1881560/delco-remy-8600308?ga_list=Related%20Products

Victron argofet isolator, 200 amps, 2 batteries, ~$120.
Victron ArgoFET Battery Isolator

The Delco does not need the excite wire connection. It can use the remote sense wire.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Alternator wiring.

Reply #29 –
Rich,

I am presently running a Delco 28Si on our coach.  I am very happy with it.  Link below to my installation thread.  Ignore the stuff after the first two posts - I was "customizing" my electrical setup just for fun.

Delco Remy 28SI Alternator Installation
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: Alternator wiring.

Reply #30 –
Agreed, a "standard" alternator will not work properly with a DIODE-BASED ISOLATOR.  There is approximately a .7 VDC drop across that type of isolator so batteries will be undercharged. Yes, assuming the excite terminal is jumped to the B+ terminal.

If you are going to stay with the diode-based isolator, you do need a DUVAC alternator, as the sense wire is on the chassis battery side of the isolator.  So, what happens is the sense wire tells the alternator to produce approximately .7 VDC MORE than will reach the batteries so the batteries receive the correct voltage.

Moby,
I ASSUME you have used a  digital voltmeter to verify the problem.  Easiest place is at the diode-based isolator.  With engine at 1,000 RPM or so, you should have mid 13's- low 14's at both the outer lugs and approximately .7 VDC more at the center lug which is direct to the alternator B+ terminal.  I suggest testing before dismantling anything, as symptoms of a bad isolator are difficult to differentiate from a bad alternator.

Post what you get or PM if you want to visit on the phone.

And, the "non-DUVAC"  alternator will work, but not with the diode-based isolator.  Either a $$ battery isolator with low loss or a simple ON-OFF switch will work just fine with a non-DUVAC.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Alternator wiring.

Reply #31 –
I agree that using the OEM alternator is preferred. Mine went out in Kentucky on a busy bridge. So once the tranny didn't have enough voltage to stay in drive there I was. Police had a tow company come out but I was able to get a charger on the engine batteries long enough to get in gear and off the bridge.
  The tow company showed up and said they could put on new alternator and get me back on the road so told them to go ahead. They put on a Delco like semis use and when I started the engine it fried the engine wiring harness for several feet. The man hooked it up wrong. Long story short after they towed it to a truck shop they tried to use a non OEM alternator that they couldn't get to work. Finally called Foretravel and they told them only use the alternator that came on it. Total bill was 8500.00 which the tow company covered. So IMHO use the correct one.
Larry
Larry & Debbie Town
2000 U320 4210 
Previous 88 GV

Re: Alternator wiring.

Reply #32 –
Larry, et al;

If that ever happens again (chassis battery voltage too low to run coach) there is a very easy work around:

Start the generator and turn on the boost switch.  The inverter/charger, powered by the generator will charge the house battery bank.  Through the boost switch it will charge the chassis battery.

You could drive cross country like that.

And, if both banks too low to even start the generator, a jump from your toad battery should be enough to the the generator started.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Alternator wiring.

Reply #33 –
I agree that using the OEM alternator is preferred. Mine went out in Kentucky on a busy bridge. So once the tranny didn't have enough voltage to stay in drive there I was. Police had a tow company come out but I was able to get a charger on the engine batteries long enough to get in gear and off the bridge.
  The tow company showed up and said they could put on new alternator and get me back on the road so told them to go ahead. They put on a Delco like semis use and when I started the engine it fried the engine wiring harness for several feet. The man hooked it up wrong. Long story short after they towed it to a truck shop they tried to use a non OEM alternator that they couldn't get to work. Finally called Foretravel and they told them only use the alternator that came on it. Total bill was 8500.00 which the tow company covered. So IMHO use the correct one.
Larry
Quote from: wolfe10 –
Larry, et al;

If that ever happens again (chassis battery voltage too low to run coach) there is a very easy work around:

Start the generator and turn on the boost switch.  The inverter/charger, powered by the generator will charge the house battery bank.  Through the boost switch it will charge the chassis battery.

You could drive cross country like that.

And, if both banks too low to even start the generator, a jump from your toad battery should be enough to the the generator started.

      Yes that would of worked but we had just bought the coach and was a emergency trip first time out and didn't know the boast switch relay was bad. Have learned a lot since that trip.
Larry & Debbie Town
2000 U320 4210 
Previous 88 GV

Re: Alternator wiring.

Reply #34 –
Quote from: wolfe10 –
Moby,
I ASSUME you have used a  digital voltmeter to verify the  problem.

 TBH I didn't get the VOM out.
I was made aware of the issue by the dash Guage and audit system reporting falling voltage. Then seeing only the two large cables attached and no excite or sense wires I ASSUMED that was the problem.
 Raining and home schooling the grand kids now.
Will attack the VOM measurements and terminal identification (through use of flexible son in law) later and will report back.
In restless dreams I walked alone.
Narrow streets of cobblestone.


'93 U225
Build 4337
'14 CRV Toad
 

Re: Alternator wiring.

Reply #35 –
Have had the same one as Chuck and Jeanne for 3 years,no problems,upgraded isolator at the same time.
96 U270 BUILD 4810
85 380SL
Drummonds TN.