Simple charging system test? Please?

[MSN Member]

From: jipjob1  (Original Message)
Sent: 2/28/2004 8:54 PM

I need to know which end of my ballast reistor to attach my volt meter to make the  test. I cannot determine which post they are talking about, could someone help?

And one other thing my volt meter that shows how much juice I have in each batter is why high on the house battery (17amps ) What do I look for to correct this problem.

And is thier a simple test to check to see if my alternator is working? Thanks jipjob

The attachments show the book page and my drawing. Help



From: jipjob1
Sent: 2/28/2004 11:53 PM

Well tomorrow I'm going down to get a new voltage regulator and see what that does? I will unrap it very gently and plug it in and if its not what the problem is than I will repack it and take it back.

I really would like a simple explanation on how to test the generator? Very simple for a simple mind. That alternator not generator. Thanks Jon

PS for helping the helpless take a look at the attachment and get a laugh



From: DaveVa78Chieftain
Sent: 2/29/2004 12:08 AM

Hi jipjob,
My ballast resistor had been moved from the plate and mounted to the wall behind it by a PO, so I am not sure exactly how it looks when mounted to the plate however,
I see that in step 3 of the Electronic Voltage Regulator Test, it gives a detailed description of the wire colors.  Why are you not able to determine which one is which with that detailed information?
Be that as it may, based on the information you provided, I am assuming you have Electronic Ignition and a Electronic Voltage regulator.  Looking at the wiring diagrams at the back of my Dodge MH manual, I noticed the wire colors to the ballast resistor are different than what is in that write up you have.  One end of the ballast resistor has 2 18 gauge red  wires going to it.  Both of these are the number 1 ignition lead (from the ignition switch).  Based on the write up you provided, i would say you want to hook up to either one of those wires.   The other end of the ballast resistor is the output side.  One terminal has 2 pink wires connected to it.  One of those connects directly to the coil (+ side).  The other pink wire is the Ignition 2 lead from the ignition switch.  Ignition 2 is used to provide the full 12VDC to the coil when the key is in the start position.  The reduced voltage from the ballast resistor is provided to the coil when the key is in the run position.  The other lead on the output side of the resistor is dark green in color.  It is routed back to the electronic ignition module (pin 3).  Been a while since I read it's purpose, but it is used to regulate the coil current during low rpm conditions.  Something to do with the fact at low rpm, there is more current flow in the coil.  As rpm increases, the current is reduced because the on/off cycles are much shorter.  Anyway, if you have 2 Red wires at one end and Pink/Dark Green wires at the other, you want either one of the Red wires for the test.  By the wiring diagram, they would effectively be the battery supply voltage (sense) back to the electronic regulator AND are only hot when the ignition switch is on.
As far as the high voltmeter reading, which I assume you meant 17 volts, not amps, please remember that unless the Dual-Norm-MOM switch is in the dual or MOM position, the voltage you are reading would either be the coach battery or any charger circuits connected to the coach battery.  For the purpose here, I am assuming the Dual-Norm-MOM switch is in the Norm position.  First thing to do is to read the voltage at the coach battery directly.  If it is still 17 volts, then your converter output is way to high.  At that high a level, I would say the battery charger in the converter is bad and not providing any form of regulation.  This will wipe your battery out if it remains like that.  The converter charger output on my 78 Chieftain has an in line fuse in the coach power panel.  If yours does to, you can remove it to stop the overcharging.  The fuse will also have the high voltage on it while the other fuses will be around 12VDC.  The charger circuit on mine is bad, so I removed the fuse and just use a standard battery charger to recharge mine.  Some day, I will have the extra $ to install one of the newer converters that connect directly to the battery.  For now it is a workable situation and I can concentrate on other more pressing matters and the regular battery charger puts out a lot more than the measly 6 amps the old converters put out.  If you have a progressive dynamics converter, I think they still supply replacement parts.  Check their web site.  With that high of voltage, I would suspect the circuit board has bit the dust (no longer regulating the output).

Dave



From: Im-still-Lefty
Sent: 2/29/2004 12:58 AM

Jon, If you just want to find out if the charging system is producing anything, the simplest way is to use a voltmeter to read the voltage at the battery, then start the rig and read it again. the battery should read about 12.7volts with the engine stopped, and about 14.5volts with the engine running. This will only tell whether or not the charging system is functioning, it won't tell which componet is bad,(alternator, or voltage regulator, or a problem with the wiring) It also won't tell you how many amps the alternator is producing. Sometimes an alternator will produce the correct voltage, which is a function of the regulator, but doesn't produce the necessary amperage required to maintain the battery (amperage is limited by the condition of the field coil and brushes inside the alternator.) Lefty



From: jipjob1
Sent: 2/29/2004 1:24 AM

Ok one thing at a time. To make this voltage check at the battery all I haft to do is place my voltmeter on the postive and nagative post . I have done this and the battery is at 12 volts. Now the next thing to do is to start up the old rig and do the same thing and check to see if it at 14.5 volts. If it still at 12 volts than than I have a problem. This check is test is the alternator right? Now I do place the probe for the volmeter on the cables that are attached to the battery? Postive and Nagative Post
Or do I just ground out the nagative side of the volmeter and put the positive side on the negative side of the battery post.?

Sorry for being such a dim wit at this testing but I really want to do it right. Simple and simpler is the game.

One thing I do not understand is the house batter voltage going to at 17 volts like on the gage on the dash when I preform the above test?



From: jipjob1
Sent: 2/29/2004 2:02 AM

Ok I was just outside and started up the Beauty and the amp meter on the dash is reading 14 amps for the main battery  and the house is reading about 16 volts. But! when I go back to the batteries are at each one of them is reading just at about 12 volts with the old rig running. How can this be? Does the battery with a full charge produce more voltage at the amp meter when the rig is running? Boy what have I got myself into? Well like I said befor tomorrow I will go down and buy another votage regulator.



From: DaveVa78Chieftain
Sent: 2/29/2004 12:34 PM

jipjob,
What type of rig are we working on?  Your profile implies you have a 88 Mini-winnie.  If so, that will change things as far as details are concerned.  Most here will be think 70's era winnies

Dave 



From: jipjob1
Sent: 2/29/2004 1:28 PM

I'm the rich cat on the block I have 2 motor homes. No I paid oft the Old Winne when I got it a couple of  years ago and just wanted a unit that was up to date with all modern equipment and I just like the Class C Winnebago's. Now the 88 has only 39,000 miles on it and it has been  taken very good care of and gets about 9 to 10 mpg on the open road. I don't want to part with my Classic as its like part of me, even if I can't get her to opperate just the way she should.  Its my big hobby and now to take oft that alternator and have it checked out down at Shucks. This is just time consuming but when retired I have all the time in the world. Jipjob (I really don't relish the thought of getting under the old beast but I've got to know)



From: jipjob1
Sent: 2/29/2004 5:09 PM

Ok I took out alternator and took it down to Shucks and it tested ok and then put in tempory regulator and still did not fix problem. Now guess what I looked at  the volt gage on dash and its reading high to start with!!!!!!!!!!!!!!!!! So maybe I don't have a problem with to much juice going to the batterys maybe it just needs a Voltage  meter to correctly read the volts on the dash. Going down to part store and give them back their regulator and get a new voltage meter. On and on and on I go and wherever it stops I don't know?Jipjob



From: UluzYarx
Sent: 2/29/2004 6:48 PM

Hi Job Job,
I suspect that your dash volt (amp?) meter reads inconsistently.
If it is an amp meter, then 14 amps and 17 amps may well be OK.
~
Volts is like water pressure in a hosepipe.
Amps is like the number of buckets of water you get out the hosepipe in an hour.
Fat hosepipes give you more water at the same pressure, just the same as fat wires give you more amps at the same voltage.
Please don't be too picky with that guys, a blind man on a charging horse would be pleased to notice the flaws in my rough and ready comparison.
~
There is no way that I can think off by which an alternator can charge the engine battery at the right voltage and the house battery at too high a voltage.
~
It is normal for the engine battery to get the right voltage while the house battery to get less than the right voltage because it is at the end of a long (thin) wire.
The house battery usually stores electricity less efficiently than the engine battery because its colder than the engine battery.
~
If one of your batteries is getting 16 volts then it will be short on water.
If it ain't short on water, stop worrying.
~
There is no way the gizmo that shares the electricity out between the engine and the house batteries can increase the voltage supplied to either battery.
No way short of a miracle that is.
If you've got one that performs miracles, patent it quickly.
~
Lefty published a list of places that test alternators for free recently - take it off, get it tested - be a happy.
~
Incidentally, how much is a modern , used, one wire alternator from a scrapyard in the States?
If you fit a new regulator to an old alternator, you may just be putting new wine in old bottles.
~
Dave



From: denison
Sent: 2/29/2004 7:17 PM

The voltmeter on my 72 dashboard reads about 16 volts when the engine is running, though the terminals at the battery only read about 14.5 or 15. The difference is either the voltage drop through all the wires going back to the batteries, or the aged Stewart Warner voltmeter on the dashboard, or both. I would make sure your frame to engine ground strap is in good shape, or replace it. And clean down to shiny metal where you bolt it in.
The ignition resistor used with the electronic ignition has two resistances in it. One is about 1 ohm, and I think it goes between the 12v and the coil. The other one is about 5 ohms, and feeds into the electronic ignition module, not to the ignition coil itself. I think. If your rig is old enough to have only a single ignition resistance, I believe it is 1 ohm, at room temperature. It would be higher as the thing gets hot. denison 



From: Im-still-Lefty
Sent: 2/29/2004 8:36 PM

First, Read the post from Dave, It was very well detailed, and well written. then read it again! After you do that, read it one more time.  Just kidding, O.K., Let's start with the basics, You have 12v. at the batteries with the engine running but a different figure reading at the dash gauge. Either the gauge is wrong, or voltage is getting out of the alternator but not to the batteries. Here's how to find out which, Take your voltmeter and put the red lead onto the back of the alt. on the large post with the red wire on it, take the black lead and put it on any metal bracket bolted to the engine, you may need to scrape a small place clean as electricity won't flow through paint. You should read 14.5v at the back of the alt. with it running. If it does



From: jipjob1
Sent: 2/29/2004 9:46 PM

Ok I got my new voltage gage in but in the process I shorter something out and now my dash lights won't work. I managed to get up an under the dash an checked all the fusess out and they were ok. I have a question the one that says dash fusess on the fuse holder that should have poweer to it right? Well right now thier isn't any and I can't seem to find the lead to this terimal. This terminal is located on the bottom on the left hand side. Also I noticed that my alternator is still not getting juice back to the battery. Only one more thing to check and that is thing and that's all I can call it for now that seperates the house battery and main battery and has the main generator wire in the middle. Ok now what to hell does this do and should I replace it?

Oh yes one more thing after getting volt meter installed in dash and it shows the right voltage for both battery's now. I turned on my lights and the voltmeter won't show anything. But when I turn lights back on the volt meter works like a charm.

Well it sink or swim in this opperation and now I'm just treading water. Tomorrow I will play with the dash lights again.  Is thier any symatics on the wiring for the dash anywhere that might help me? Thanks jon