No charge from Alternator

[Jkountz]

Ok this morning I went out and checked the battery. 12.62 with the motor off and no recent charging of any kind. I didnt have much time to do anything today I have to be in PA all day but tomorrow I will get the model number for the Genny Dave,
Thanks again!!

[Jkountz]

Ok this morning I went out and again checked the chassis battery, 12.61. Right on the money. So then I finished cleaning every terminal I can and then checked again, same reading. Great. So now I start the motor and she climbs right on up to 13.44 and stays steady right there. This took under a minute and probably more like 30-40 seconds to reach 13.44. Now I have the wife turn on headlights, then heater fan. It slowly dropped down to around 12.60 and seem to settle there. This was after having everything on for say two minutes or so. So then I had her turn everything off and sure enough it climbed right back up to 13.44 the magic number or so it seems for this one anyway. So does this mean Im ok or should it not be dropping so much with the lights and stuff on? I would suspect there would be some drain while using accessories but I dont know for sure.
What say you now o forum friends o mine??

[ibdilbert01]

"It slowly dropped down to around 12.60 and seem to settle there." 

I suspect a regulator issue, as it took a long time to reach 13.44, this should of been instant.    Just out of curiosity, when you rev the engine does the voltage go back up? 

One other thing, at 12.60 your not charging at all, so this would be unexceptionable unless you like to walk a lot.  And not sure if you have done this or not, but check and make sure your belt is tight.

[Jkountz]

I suspect a regulator issue, as it took a long time to reach 13.44, this should of been instant.   
Its brand new too although I guess that doesnt mean much these days. Anyway to test JUST the regulator??

Just out of curiosity, when you rev the engine does the voltage go back up? 
Doesnt make much difference, did not rise or fall depending on RPM of engine.

One other thing, at 12.60 your not charging at all, so this would be unexceptionable unless you like to walk a lot.  And not sure if you have done this or not, but check and make sure your belt is tight.
Belt is properly tensioned and also new.  Any ideas as to why it would be charging without any load except the engine running but when I run accessories its not charging? At least that appears to be whats happening here correct?

[DaveVA78Chieftain]

Reading back through your posts, I notice you keep going back to check the coach battery (MOM switch, dash meter, etc.).   My reason for asking you to actually go back to the coach battery setup and disconnect the B+ leads from them is to prevent them from having any effect on your readings.  If in the circuit, they could be causing false readings.  The goal is to simplify the circuit in order to isolate to the failed component.  A defective coach battery would load the circuit down.  Once we get the chassis charging system working, then we branch out to other areas.

Dave

[Jkountz]

Sorry Dave I should have said something about that earlier, I disconnected the coach batteries the other day so all the testing Ive done recently has been only the chassis battery. When I first started this nightmare I did have them all hooked up but no longer do.

[DaveVA78Chieftain]

At this point:
Coach battery is disconnected.
Chassis battery, Alternator, regulator, and starter solnoid have been replaced.
WIre connections have been cleaned.

Some of the later rigs, possibly yours, had both a dual battery solinoid

which typically loacted in coach battery compartment,
and a battery isolator

This would have been a Winnebago modification, not John Deere.

Do you have anything that looks like a battery isolator.  I am thinking some thing is loading down your circuit.  BAT terminal from from alternator would go to the battery isolator.   There would be leads going to both batteries from there.

Dave

[ibdilbert01]

Its brand new too although I guess that doesnt mean much these days. Anyway to test JUST the regulator??

I agree, don't rule out "brand new" as working.  Just ask TJ and his brand new coil. 

Another question, does your alternator look like this?


or this?


or this?

[DaveVA78Chieftain]

Book says it is either a 70 or 100 amp alternator.
I bet he has a large case 1G (right side one).  Small case 1G is on left.

[Jkountz]

At this point:
Coach battery is disconnected.
Chassis battery, Alternator, regulator, and starter solnoid have been replaced.
WIre connections have been cleaned.

Some of the later rigs, possibly yours, had both a dual battery solinoid

which typically loacted in coach battery compartment,
and a battery isolator

This would have been a Winnebago modification, not John Deere.

Do you have anything that looks like a battery isolator.  I am thinking some thing is loading down your circuit.  BAT terminal from from alternator would go to the battery isolator.   There would be leads going to both batteries from there.

Dave

Yes I do have the one that looks like an old Ford solenoid. The top pic you posted there looks exactly like it. From my research it seems to be the 3 terminal type. I have also cleaned all these contacts as well as the place where it mounts onto the chassis. Could this thing be causing my troubles? How do I check it out to see if its doing its job correctly?

[Jkountz]

Yes my alternator is the larger one on the right of Daves pictures there. 70 amp
I havent seen an isolator like the one Dave pictured above. I thought the solenoid looking do dad was a realy/isolator??
If I dont have an isolator which Im 99 percent sure I dont, where should my Bat wire from the Alt be going when it leaves the Alt??

[DaveVA78Chieftain]

The 3 wire solinoid thingy is the battery solinoid.  The MOM switch operates it.  One large terminal to coach battery.  Other large terminal goes to chassis battery and alternator B+ and starter solinoid.  Small terminal lead goes to MOM switch.  When MOM switch applies 12VDC (dual or MOM position) to solinoid it connects coach & chassis battery B+ together.  When MOM is in Norm position, no voltage is applied to solinoid.

I posted a link to charging circuit wiring diagram earlier
http://www.mediafire.com/file/n3s0qokr91juzh8/89_JD_Charging.pdf
It shows the connections.  The cold checks I asked you to perform were based on that circuit diagram.  Was looking for a bad connection.  The values you listed indicated thats good so,
Either you got a bad "new" alternator or something is loading down the circuit.
I was elminating the existance of a electronic battery isolator in the last post as a source of problem.

Dave

[Jkountz]

My in dash voltmeter (the one in the instrument cluster) is not working either. Could this be what they are talking about in this article ---> http://www.misterfixit.com/dedbatt.htm

He states where all the current that charges the battery goes through the gauge, it was causing the problems that guy was having. Just wondering if it were a possibility for my troubles too.

[DaveVA78Chieftain]

No I do not think so.  Would have to be an old style amp meter for current to go through the meter.  Also, you would not see battery voltage at alternator with key off if that happened.  Besides, you should have a remote sense type ampmeter.
Fabicator John reminded us to check grounds.  Connect a jumper wire from alternator case to frame ground (temporary ground) and see if you get proper values then.
Check regulator case grounding.
If this is ok, then we need to try a full field alternator test

Dave

[Jkountz]

No I do not think so.  Would have to be an old style amp meter for current to go through the meter.  Also, you would not see battery voltage at alternator with key off if that happened.  Besides, you should have a remote sense type ampmeter.
Fabicator John reminded us to check grounds.  Connect a jumper wire from alternator case to frame ground (temporary ground) and see if you get proper values then.
Check regulator case grounding.
If this is ok, then we need to try a full field alternator test

Dave

Ok I installed a grounding strap from the grounding terminal on the new alt to the frame. How do I check the regulator case grounding? Not sure about that one. Finally what is a full field alt test?

[DaveVA78Chieftain]

I take it you not watching the gear box chat.
Just make sure regulator mounting is proper
Full field test checks the alternator output while on rig
Is your your ampmeter working on the dash?
Not the voltmeter, the ampmeter.

Dave

[Jkountz]

I only have the in dash meter, I thought It was a voltmeter but maybe its amps? , has a picture of a battery with plus on the right and minus on the left. THen I have the BATT COND gauge off to the right beside my very humorous FUEL ECONOMY GAUGE.

[Jkountz]

So the latest in my charging saga is, I went out yesterday and checked the battery again, 12.57. Then I started the motor and checked it, once again 13.40. I went in and checked the output of the alt on the BAT terminal. 14.38. Then I turned everything on lights, heater fans etc. Checked the battery, 12.25. Checked the BAT terminal of the Alt and still had a solid 14.3!! What the heck?? I was beginning to think the trouble might be the new Alt was bad but its still putting out what its supposed to, its just not getting to the battery when accessories are running. So what now I wonder??

[ibdilbert01]

Does your alternator charge wire piggy back onto the starter solenoid, then to the battery?

[Jkountz]

Yes it does. Also going back to Daves original test he outlines on page two of this thread I got some different readings now.
First I bought a new multimeter. My old one was iffy so I thought Id make sure that wasnt the problem. Ok so per Daves test this is what I did.
Checked the battery 12.6
Checked the BAT terminal at the Alt with engine off 12.6
Turned the key all the way on but engine off I took a reading at the regulator at the S terminal.......10.9 volts!!
This is also supposed to be the same 12.6 volts right? Could I have finally found the problem??
Also when I got this regulator I bought one for an F-350, closest thing I could find. Does it need to be a certain rating or something since my Alt is a 70 amp?? I thought they would all be the same thing but maybe theres a high output regulator or something?
And my next question is, what could be screwing up my regulators? Meaning, is there something that could have fried the last one and now the new one too?

[DaveVA78Chieftain]

Slow down and relax.  The values your posting tell us a whole lot and that is not that you have a bad regulator or alternator.
First lesson kiddy's is it is a must to have a good multimeter with good batteries in it.  Your going to chase your bum around the barn yard if you don't.

I want you to double check that your getting something like 13.6 at the battery but 14.3 at the alternator.  If so, then there is a bad connection in the Alternator line.  Just double check that please.  We will get to isolating the problem in the next post.

I also want you to reverify the cold checks again.  Purpose is to identify the circuits that have bad connections.  The low S lead value tells me either the ignition switch has bad contacts or one of the connectors is corroded.  That can also cause the regulator to have a bad reference value to compare to.  So, please just recheck the cold checks as a baseline to start from.

Dave

BTW if anyone desires to do a little lite reading, here is a site that provides a lot of info about many aspects of a typical charging system.  Principles are basic for all design implementations.   W%

http://www.madelectrical.com/electrical-tech.shtml

[Jkountz]

Ok Dave I did the cold checks again and Im getting 12.57 all across the board with the exception of the S terminal of the Reg. It has like 11.2 today. Then I started the motor and watched the meter across the battery, it slowly rose up to about 13.4 then eventually 13.6. Now when I turned some accessories on it dropped down to 12.40 and hung there. Sooooooooo I went in and checked the BAT terminal on the Alt and with the motor running I had a solid 14.35 volts steady.
So theres the situation as of today on a side not I did manage to get my generator running. It was a bad connection on the genny itself. Loose spade connector. Crimped on a new one and VAROOOOOOOOOM!!!
So the day wasnt a total loss!!

[DaveVA78Chieftain]

From 72-79 Chiltons
Page 1 - http://i286.photobucket.com/albums/ll120/BaileyDave/RV%20Electric/FordCharging01.jpg


Page 2 - http://i286.photobucket.com/albums/ll120/BaileyDave/RV%20Electric/FordCharging02.jpg


Page 3 (Has circuit diagram for 90 amp ammeter version) http://i286.photobucket.com/albums/ll120/BaileyDave/RV%20Electric/FordCharging03.jpg


Dave

[DaveVA78Chieftain]

Jim,
Based on what you told me about the actual hookup on your rig, even though the right hand ammeter type drawing on page 3 is from the 72-29 era, it is still functionally the same as what you have.   It does show a mechanical regulator but the principles and connections are the same for a electronic regulator like yours.  You can even see a reference to a shunt ammeter setup.   In days gone by, the ammeter was inserted into the circuit in series (current had to flow through it to get to the battery).  If the ammeter failed, you car was dead too.  The engineers changed from a series ammeter to a shunt style ammeter to overcome that weak point.  They now take a short section of wire (shunt) with known resistance (milliohms) and measure the voltage drop across the wire with a millivoltmeter.  They simply rescale the voltmeter to correspond to the amperage value for a given voltage drop.  They sale these types of setups on ebay (with digital meter).  Every remote coach (and solar cell) battery monitor circuit on the market today uses this sort of setup because it is safer.  You can add this sort of monitor yourself to both the coach and chassis side for relatively low cost.  They sell shunts in vasrious sizes from 25 amps to over 200 amps.  The dash amp meter in your JD chassis uses the shunt design.

I need to bring out some things that can stump a lot of people when comparing RV setups to car setups.  The battery in a car is normally very close to the alternator and typical expected voltage indications AT the battery of 14.1 to 13.2 volts as representing a good charging indication.  In an RV we unfortunatly have long cables (up to 10 or more feet) and additional connections (ie battery isolation solinoid) that in and of themselves create resistance in the circuit back to the battery.  While large cables help reduce this resitance, it is still there.  The net effect though is that you can have up to 1 volt drop in voltage from the alternator BAT terminal to the battery itself (ie. a 0.5V loss due to cable resistance results in a 13.6 to 12.6VDC indication at the battery).  So, the reading of 14.3 at the alternator with 13.6 at the battery is not completly unexpected.  That 13.6 value will change depending on the charge state of the battery.  Lower if fully charged, higher if discharged.   What is worrisome is if when you turn on other components (lights, heater, etc.) is if the battery reading drops below 13.2VDC indicating that the alternator is not able to produce enough current to keep up with the overall system demands (battery charge plus rig operations).  Clean connections along the battery path are an absolute must in order to maintain a healthy battery.

The  regulator uses the A terminal to sense what the total system voltage is (not just the battery).  It maintains a level of 14.1 volts at that terminal.  Actually it is trying to maintain 14.1VDC at the soldered junction point of all those wires in your wiring diagram.  That junction point allows a standard voltage level to be seen by most all devices in the entire chassis electrical system.   The regulator provides control current to the alternator over the F terminal based on the A terminal sense.  As loads (lights, heater, etc.) or battery condition change, the voltage at regulator pin A changes and the regulator responds accordingily.  Corrosion in connector pins, burnt contacts in the ignition switch/battery isolation solinoid, or partially burnt fusible links can cause a high resistance and incorrect voltage readings.  The regulator can only respond to the voltages it is presented with.    Bad voltage due to bad connections = incorrect charging system operation.

Dave

[Jkountz]

Well gang its been another week and Im still at it. I actually drove the beast about 30 miles or so just to see what the charging system was actually doing under real operating conditions. (plus I just wanted to drive it some!!)  I got some long test leads with some aligator clips and hooked those to the battery and to my voltmeter so I could monitor things as I drive, well ok the wife monitored things while I drove. If Im going down the road just driving along with nothing on, I get around 13.4-13.8. The second I hit the brakes with turn signals, or turn the headlights on or heater fan, it drops way down to 12.1 to 12.8. So no surprise there its doing the same thing as it was in the driveway.
There isnt a connector or a terminal end that I havent cleaned and cleaned again that I can physically see anywhere. I have yet to find any soldered connections but I did find quite a few fusible links. I dont know how to actually test these for proper resistance without skinning the insulation off the wire or something.
I also havent checked the ignition switch yet, I didnt feel good about tearing my steering column apart and thats where my switch is, not in the dash. I was going to research that today and see how the switch is removed.
Im starting to think a couple of for sale signs are in my future, Im totally exhausted and burned out trying to find this problem although I do appreciate everyones help and suggestions here, you guys have sure taught me alot about this and for that Im grateful.