Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
RV Trip Planning Discussions

Go Back   iRV2 Forums > iRV2.com COMMUNITY FORUMS > Vintage RV's
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
 
Thread Tools Search this Thread Display Modes
 
Old 09-20-2010, 12:04 PM   #1
Senior Member
 
TheDubs's Avatar
 
Join Date: Nov 2009
Posts: 136
Alternator frying batts need help!!!

I just replaced the alt in my rv about a month ago and it wasn't putting out enough volts. I found that the wire from the back of the alt had a bad connection on it so I replaced it. That seem to fix the problem.

Untill yesterday. We got stopped at a red light and the engine died. Looked at the batts and one was boiling and spewing batt acid. finally they got cooled down enough to get to a parking lot. I took the alt out and took it to auto zone and had it tested it was bad. Picked up another new alt hooked it up and it was giving me 18 volts off the back of the alt. and 17.5 at the isolator and 17.5 to the batts. No wonder I fryed the batts. I thought I might have got a bad alt again so I took that one back and had it tested and it was fine.

So i thought it might be the batts that were bad. I took them to auto zone and had them tested, 3 out of the 4 were bad. :( ( they were only 6 months old) I replaced those. And am still having the same problem. I cannot figure this out. all the cables to the batts are nice and tight.

I think im going to start at the wires going to the voltage regulator on the alt and see if they are fryed. and then check the ground going from the batts to the engine. I might also check the ground from the engine to the chassis too. I would think It has to be a grounding issue. Due to not having any place for the extra volts to go.

I am at a loss and can't figure it out any help would be great.
__________________
1982 Winnebago Brave 22' ft
Solar powered and running on waste veggie oil (WVO)
Blogging at Not Too Simple
TheDubs is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 09-20-2010, 01:17 PM   #2
Senior Member
 
powderman's Avatar
 
Join Date: Mar 2010
Location: N. E. Ohio & Lady Lake Fl.
Posts: 1,120
That sounds like the voltage regulator is kaput.
powderman is offline   Reply With Quote
Old 09-20-2010, 04:30 PM   #3
Senior Member
 
Join Date: Nov 2009
Posts: 1,152
l would suspect the voltage regulator also. Some regulators are adjustable, but sounds like yours is bad.

If you have a DVOM you can check for voltage drop between the connections. If you have more than 1/2 volt drop you need to figure out why, bad connection, corrosion, etc.
leadman is offline   Reply With Quote
Old 09-20-2010, 06:56 PM   #4
Junior Member
 
swailes's Avatar
 
Join Date: Sep 2010
Posts: 6
My vote is for the voltage regulator as well.
__________________
LIFE IS A JOURNEY, PACK WELL
swailes is offline   Reply With Quote
Old 09-21-2010, 06:34 AM   #5
Senior Member
 
Join Date: Mar 2005
Location: where its warmmmmm
Posts: 811
I would wager that you have a dodge components from the sound of it. And if so, the volt reg sounds kaput.
mick is offline   Reply With Quote
Old 09-21-2010, 11:09 AM   #6
Senior Member
 
Join Date: Feb 2010
Posts: 4,654
Regulator is toast

The alternator will output voltage a lot higher than the system needs, it does what it is told to do.

The regulator controls the output of the alternator, and given that you have changed it and the replacment was the same type and assumed working then I suspect the regulatorhas a shorted output control.

It has the field wire shorted to the "on" position thus the alternator is running in a "floored" condition.

Locate the regulator and unplug it, then re-test, if the output of the alternator now reads the same as before the engine was running then the alternator is not self-exciting, if the voltage is still too high the alternator may be self exciting or there may be a shorted wire in the harness that needs to be confirmed.

If the alternator tests ok at the parts house and it was reading high with the regulator unplugged then locate the wire shorted to battery.

If the alternator is not running a high voltage then replace the regulator.

Be sure to get a regulator that is adjustable so the voltage can be set to correctly maintain your batteries with the voltage drop across the isolator.
TQ60 is offline   Reply With Quote
Old 09-21-2010, 03:16 PM   #7
Senior Member
 
TheDubs's Avatar
 
Join Date: Nov 2009
Posts: 136
Mic I have a 82 chevy 6.2 diesel.

I took the alt back to auto zone and they tested it and it was fine. but I insisted the give me a new one. They did and I also had them test that one and it was fine. Got it installed and the problem persists.

The alt that I have has the regulator built into it. It has what looks to be like a pos wire and a neg wire going to it in a harness that you plug into the alt. I jammed my volt meter into the pos wire coming out of the regulator harness and it gives me 12.63 volts with the engine running. I would assume its regulating just fine. Now for the pos on the back of the alt I get a reading of 18. and a reading of 17.5 at the isolator and 16 to 16.5 at the batt terminals. I have checked the ground from the batts to the frame and the frame to the engine. and they seem fine.

I have no clue whats going on and hope someone can help me figure it out.
__________________
1982 Winnebago Brave 22' ft
Solar powered and running on waste veggie oil (WVO)
Blogging at Not Too Simple
TheDubs is offline   Reply With Quote
Old 09-21-2010, 06:45 PM   #8
Senior Member
 
bigskymt's Avatar
 
Newmar Owners Club
Join Date: Apr 2010
Posts: 460
The plug you speak of does two things: viewing from the rear forward the wire to the right (from ignition) provides the excitement to start the alternator working(an input) The wire to the left is a feedback (an output)for the idiot light you probably don't have.
You can try unplugging that plug from the alt. and restarting the engine.....you should have no output on the rear terminal (it will read batt. voltage).
I'm curious what output voltage Auto Zone read on the bench...or did their test station only say "good"?
To try and narrow things down you may run only a dedicated wire from the alternator output direct to the engine battery and check voltage.
Whats the output between the single post at the rear of the alt. and chassis ground? And battery ground?
bigskymt is offline   Reply With Quote
Old 09-22-2010, 10:47 AM   #9
Senior Member
 
Join Date: Nov 2009
Posts: 1,152
I would hook the battery wire from the alternator directly to the chassis batteries at the isolator. Isolators can give the alternator a false reading and it will continue to charge. This is very common.

You do not need the chassis batteries hooked to the isolator, just the coach batteries.
There should be 3 terminals on the isolator. Center is usually alt. output, move the chassis battery wire to this terminal, leave the coach batteries on one of the other terminals. If all else is good this might fix your problem.

The diodes in the isolator are a one way device, will let current go thru to the batteries, but not from the batteries to the alternator. There is a hefty voltage drop going thru the isolator also. You can hook the chassis batteries direct to the alternator and use a constant duty solenoid to charge the coach batteries. solenoids have almost no voltage drop. You can either wire this so it is on when the ignition is in the run position, or I recomment turning it on with a toggle swithc. My Itasca has the switch and it works great this way.
leadman is offline   Reply With Quote
Old 09-22-2010, 11:12 AM   #10
Senior Member
 
RedneckExpress's Avatar
 
Vintage RV Owners Club
Join Date: Jul 2006
Location: Sauvie Island, OR
Posts: 2,596
Quote:
Originally Posted by TheDubs View Post
Mic I have a 82 chevy 6.2 diesel.

I took the alt back to auto zone and they tested it and it was fine. but I insisted the give me a new one. They did and I also had them test that one and it was fine. Got it installed and the problem persists.

The alt that I have has the regulator built into it. It has what looks to be like a pos wire and a neg wire going to it in a harness that you plug into the alt. I jammed my volt meter into the pos wire coming out of the regulator harness and it gives me 12.63 volts with the engine running. I would assume its regulating just fine. Now for the pos on the back of the alt I get a reading of 18. and a reading of 17.5 at the isolator and 16 to 16.5 at the batt terminals. I have checked the ground from the batts to the frame and the frame to the engine. and they seem fine.

I have no clue whats going on and hope someone can help me figure it out.
Yup, you still have that damned Diode Isolator that I told you to get rid of when you brought up your charging dilemma the first time. Diode = 1 way current, Alternator can't sense the voltage of the batteries, and thus is running at full tilt.

Get
Rid
Of
The
Diode
Isolator

Get
A
Constant-Duty
Solenoid.
__________________
'92 Dodge W250 "Dually" Power Wagon
'74
KIT 1106 Kamper Slide-in Truck Camper
'06 Heartland Bighorn 3400RL Fifth wheel
Follow along with me in the The Journey of
RedneckExpress is offline   Reply With Quote
Old 09-23-2010, 08:57 PM   #11
Senior Member
 
Dave78Chief's Avatar
 
Join Date: Jun 2009
Posts: 1,528
Given you have a 82 Winnebago, you should have a SI series alternator (most likely rated at 63 Amps). The B+ lead is red. There should be 2 more wires connected via plug to the back of the alternator. 1 of those wires is brown (field exitation from from ignition switch via either a idiot light or resistive wire). The other one is red (sensing wire). I am going to make a guess that the 12.63VDC reading (engine running) was on the red wire in the plug. The red wire is the sense signal that this version of alternator uses to determine system output. Automotive regulators are designed to maintain approx 14.1 VDC on the sense line. The 12.63 VDC reading indicates you have a bad connection (high resistance) in that wire and resulting in the alternator putting out the high voltage. It's trying to raise the 12.63 VDC reading up to 14.1VDC. I recently fixed the same type problem in a friends Ford based system. BTW, the 17.5VDC indication at the isolator indicates that the circuit (wiring) from alternator to isolator is ok. It's the red sense wire that is causing the problem

Good Luck,
Dave

Dave78Chief is offline   Reply With Quote
Old 10-09-2010, 07:15 AM   #12
Senior Member
 
Vintage RV Owners Club
Join Date: Aug 2009
Location: Central Florida
Posts: 671
Dubs, how about an update on the problem ? Did you get it figured out ?
blackf3504dr is offline   Reply With Quote
Reply



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
new batts Bill Overall Workhorse and Chevrolet Chassis Motorhome Forum 6 06-15-2010 07:59 AM
HWH jack levelers...: Run off Chassis or Coach batts? fkloster MH-General Discussions & Problems 16 05-31-2010 07:57 AM
agm house batt's beaverjim iRV2.com General Discussion 9 03-09-2008 05:00 AM
any 29r folks upgrade to golf cart house batts Indy Itasca Winnebago Industries Owner's Forum 12 01-16-2007 07:00 PM
Engine Batts repeatedly dying RanchoVectra Winnebago Industries Owner's Forum 19 01-07-2007 07:57 AM

» Featured Campgrounds

Reviews provided by


All times are GMT -6. The time now is 11:22 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.