No Charge to Battery

[The_Handier_Man1]

From: HeavyHaulTrucker  (Original Message)
Sent: 9/23/2004 10:40 PM

I have a non-charging situation that has got me totally stumped, and I need to ask everyone for a bit of "new perspective" on the situation and possible causes.

On Tuesday, the field wire from the alternator blew back against the end of the exhaust manifold and melted to it, shorting the wire.  As a result, some wires fried -- this wire leads back through the loom on the right side of the engine to a 6-wire splice (factory); from there, these wires go varying places.  1 goes to each side of the ballast resistor, 1 goes to the ignition control module, 1 dead-ends in a bullet connector, and 2 go into the coach.  Of these 2, 1 winds its way to the ignition switch with a offshoot into the dash.  This long run of wire was the casualty here -- burned up from 6-wire splice to ignition switch.  I lost all charging, and voltage dropped to 10.6 volts on the chassis wiring.

Yesterday, after replacing alternator & voltage regulator, I re-wired this wire from alternator to splice (re-created splice), and from ignition switch to floorboard pass through, duplicating the path of the wire complete with offshoots and splices.  I clipped the section from floorboard pass through to 6-wire splice, and ran a new wire here; I left the old burned wire in place, rather than tear apart the loom next to the heat shield on the left side of the frame.  No luck... I could not get voltage above 10.6 volts even though amperage was excellent (75 amps peak, 6.5 amps at idle) according to an Advanced Auto Parts test machine.

Today, I completely rebuilt this wire from 6-wire splice to ignition switch, and double checked all of my wiring.  Upon first start (with a jump), I got 10.6 volts (amperage unknown).  When I ran the engine at 2000 rpm, voltage dropped slowly; while the engine was running at idle (700 rpm), voltage increased extremely slowly (1 volt an hour).  I let the engine idle until my multimeter showed 13.1 volts system voltage, then I shut it off and tried to do a re-start.  Nada -- nothing, zilch -- not even a starter relay click!  My CB radio would work, but that only lasted 15 minutes.

Here is a list of all things in the circuit that I have tested:
Ballast Resistor -- Good; tested 1.3 Ohms on one side and 5 Ohms on the other.
Coil -- Good; tested 2 ohms on the primary, and 13.2 k on the secondary.
Alternator -- Good; tested 12.4 volts with 75 amps peak, 6.5 amps at idle.
Voltage Regulator -- Good, both on the bench and in the vehicle.
Ignition Control Module -- Tested good on tester.

I have not been able to test the battery, and that is my prime suspect.  I just question whether this sort of a short would be enough to completely kill a battery.  Would a bad battery kill voltage instead of amps?  It is obvious to me that the battery is not taking a charge, but my question is whether this is caused by lack of proper voltage -- or if the bad battery is not letting the alternator put out the proper voltage, thus not charging?

Any help on this would be greatly appreciated, as I have only a few hairs left -- I can't afford to pull out any more!

John



From: cooneytunes
Sent: 9/23/2004 11:05 PM

John,
wouldn't think it could have daaged the battery.....Could it possably have damaged the fuseable link from the battery. After reading the sevice manual, it may be the main fusable link, that got burned out when that wire burned up too. Keep us up to speed on it, I going to do some more reading on it.
Timmy



From: HeavyHaulTrucker
Sent: 9/23/2004 11:43 PM

No, I replaced the main wire from alternator output to starter relay (where the 14 gage fusible link normally is) with a 4 gage battery cable a couple of months ago.  I also replaced the other fusible link (a 16 gage link) with a 30 amp fuse holder & ATC-type fuse (easier to replace when it blows) which is not blown.

From the wiring diagrams, it appears that this red field wire operates as a "sense wire" for the voltage regulator, sensing battery voltage (along with any voltage drop in the system); the green field wire controlls alternator output by the voltage regulator switching the alternator on or off depending on battery voltage sensed on the red field wire.  The short circuit allowed enough voltage to go through that wire to completely melt the insulation (when the loom behind the steering column & pedals went, I actually watched the loom "unzip" as the wire insulation melted) in a matter of seconds.  My question is, given this large of a "shot" reaching the battery, could it have killed the battery suddenly -- especially if it was marginal to begin with? 

I have had problems with Auto Zone batteries before (this is the 3rd battery in the coach in 4 months) and when the warranty is up I will replace it with a WalMart "MAXX" battery made by Exide (much better quality and durability).  In fact, this particular battery only had a 90 day free replacement warranty -- maybe this is the excuse I need to go get a GOOD battery?

John



From: denison
Sent: 9/24/2004 7:12 AM

I also am stumped. Exactly where did you measure the 10.6 volts? Across what two points? Or was it the reading on a dashboard mounted voltmeter?



From: HeavyHaulTrucker
Sent: 9/24/2004 10:37 AM

The dashboard  voltmeter read just a hair over 11 volts; my multimeter, across the battery terminals, read 10.6 volts.  My Garmin StreetPilot GPS, which has a voltmeter available when you start it in diagnostic mode, read 10.32 volts at the cigarette lighter.

This morning, after tapping everything off of the house batteries (2 130 hr deep cycles), the voltage started out at 6.4 volts after the initial boost from jumping it dissapated.  It is now up to 10.6 volts, and it seems to recover after a current draw -- when I step on the brakes, it drops by about 1/2 volt, then when I let up off the brakes it comes back up within seconds.

I am going to let it run for a few hours -- until the voltage gets up to 14 volts -- then try to do a re-start after checking the resting voltage in the deep cycles.  I have my suspicions about the vehicle battery -- unconfirmed -- but I am now using two known good batteries.  We'll see what happens, I guess.

John



From: HeavyHaulTrucker
Sent: 9/24/2004 10:40 AM

Ooops, I forgot that the voltage regulator is also fed off that 6-wire splice, too.

John



From: denison
Sent: 9/24/2004 2:31 PM

Certainly a battery reading 10.6 volts across its terminals is either about 95% discharged, or has a bad cell. On the other hand, how good is the ground connection between the battery and the frame, and between the frame and the engine block? The typical ground connection between block and frame was originally a not-so-hefty wire running from the back of the tranny, over to the frame. The tranny to engine is a joint, the engine to alternator mount is a joint, also the alt to its bracket is another joint. Each joint can lose a small amount of the voltage. I ran a #2 cable from one of the starter mounting bolts over to the frame, to a bolt-hole location that I sanded clean and coated with anti-oxidant paste; before I bolted my cable on.
That 6 way splice is where the positive 12 volts from the ignition switch is connected to the other locations that need the 12v - anytime the ignition is in the on position. ignition module and resistor, volt reg, instrument panel, turn signals, backup-light switch.
I dont think my Garmin Street Pilot iii has a voltage reading. Other than the little bar-graph with no numbers. 



From: HeavyHaulTrucker
Sent: 9/24/2004 3:15 PM

Denison, first about the Street Pilot III -- hold down the "Option" key while pressing the power key to turn it on.  You will come up with a diagnostic screen where it gives certain signal information, the software version, and the internal & external voltages.  You can also use this screen to do diagnostics on the unit & any data cartridge that is in it.

On to the Winnie... after some reading on the web, I have found that the Dodge charging system is "dodgy" in design.  You have to have battery voltage of at least 12 volts in order for it to charge.  It (at least the post-1977 models) uses a dual field design, which senses battery voltage on one of the alternator field terminals (the one with the 6-way splice) and up to 12 volts is returned on the second field terminal to control charging.  Full alternator output requires a solid 12 volts on this terminal -- anything less lowers the charge rate porportionately.  In my case, since the electric fuel pump takes so much, at only 10.6 volts the alternator is not being instructed to make full output -- thus, no charge.

I took my battery up to Hawkeye International Trucks (the closest big battery charger) to be charged; they said it will be done in about an hour.  I will let everyone know if that cures the problem or not after I get the battery in and start her up.

John



From: denison
Sent: 9/24/2004 7:29 PM

Thanks for the handy tip about the little menu in the Garmin unit. It was the -menu- button plus the -on- button on mine. Maybe I should finish reading the handbook it came with! The volts on mine showed 12.1, which reminded me I hadnt charged the battery for over a month. I connected my small 6 amp charger to the battery terminals, and in five minutes the Garmin unit diagnostic-volt function was showing 12.8 volt. I started it up later on, and it went to 14.4 in the first 5 minutes of the engine warming up.
As far as I know the voltage regulators were the same on the mopar products all the way from 1970 up through 1989 and perhaps later. As far as I know the alternators all worked the same too, though with different sized wire/diode banks for the different -amp- ratings. I still think the alternator should happily charge your battery to the low 14 volt range, anytime the battery had enough juice to get the engine started. And the result of a bad cell would be; if the cell was shorted, the ammeter needle would stay at the + extreme. If it was an open cell, the voltage would read up above 15.5 - well above that. I think....
I believe the field coil in the alternator rotor reaches magnetic saturation with about 2.5 volts across the brushes. Any more field coil voltage above that doesn't really make a difference in the output from the stator side.



From: HeavyHaulTrucker
Sent: 9/24/2004 9:20 PM

Well, partial success I think.  I got the battery back from Hawkeye; Kevin (the service manager) said he had to use 2 different charge rates on it, and it didn't seem to want to take a full charge -- but he said that it had enough to start & run if the alternator was working.  So I put it back in the Winnie and fired her up; the charge rate rose to 12.7 volts across the batteries, and stayed right there -- won't charge any higher.  It is charging, though, so the alternator & regulator are working -- I think that this AutoZone cheapie has started to go out.  I am going to get a new Walmart/ Exide battery as soon as I get the money.  This one should do until then.

I think that the battery was marginal when the short circuit happened -- and that was what made it start to fail.  It has not been over-charging, because the water level is good; and heat is not a big issue with the location of batteries on most Winnies.  I think it was just a cheaply made, poor quality battery -- typical of Johnson Controls products, in my experience.

John



From: HeavyHaulTrucker
Sent: 9/25/2004 11:46 PM

Update on the charging problem... it was cured for a while.  It seems that the alternator was not getting a good enough ground through the bracket.  I made up a 10 gage ground wire and connected it from the alternator bolt to a bolt on the frame -- as long as I didn't move her, all was fine.  Charging went back up to 14 volts, even with a marginal battery.

Then I drove her, and hit a couple of REALLY big bumps -- charging quit completely.  I drove her down to AutoZone and exchanged the battery (the manager looked at the sales & return history in the computer, and ended up exchanging the battery and upgrading it to a 750 CCA DuraLast model for nothing).  It was a slight improvement, and got me back to the site with lights on -- but still wouldn't charge quickly.  So I let the engine run for a couple of hours, and then something wierd happened -- while watching my StreetPilot's voltmeter, I saw the voltage rise to 12.9, then break slowly over to 13 volts.  After that, it went to 13.4 volts in a matter of seconds.

Unless I am mistaken, I have a ground problem here; everything was fine until I hit those bumps (real bone-jar'ers!), then she wouldn't charge.  I think that the bumps disturbed the coach's framework just enough to break the ground (my battery ground bolt is in the side of the battery box, which is built into the coach itself instead of bolted to the frame as it should have been) of seriously weaken it.  When charging gets up to the level required to break this threshold, then it charges fast like it should.  Tomorrow, I am going to get a copper braid ground strap from a truck junkyard here and electrically bond the coach & frame together -- hopefully, that will cure the problem for good (bumps or not!).

John



From: HeavyHaulTrucker
Sent: 9/28/2004 6:14 PM

Final update:  Problem is cured -- or should I say both problems.

The first problem, that of the burnt up wiring, was cured first a few days ago.  I again cured it today because I was not getting voltage to the batteries or the cabin.  It turns out that this was unnecessary, because the second problem (which I didn't even know about until I crawled underneath to do a voltage reading) of a glazed alternator belt was the culprit.  I installed a new belt, and she is happily charging at 13 - 14 volts now.

I wish I would have thought to check the belt sooner; I assumed that, because it had been ok then, it would still be.  Apparently, when the field wire shorted, the alternator almost stopped -- the fan & crank kept right on going, sliding the alternator belt through the groove on the pulley.  Can we say, "SMOOTH"?  Thats what happened.

Well, at least now I don't have to worry about that -- both vehicle & house batteries can stay charged.

John