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Topic: Charging issues (Read 2775 times) previous topic - next topic

Re: Charging issues

Reply #20 –
We were not running anything at all..we were bringing it home. We lost all voltage and asumed it was the alternator. Found what we thought was a replacement,.worked for a while but now trying to locate the real issue.

Re: Charging issues

Reply #21 –
I discovered my DUVAC alternator was mis wired when replaced by Nacogdoches Motorhome Services. This only became apparent when I deleted my isolator for a B2B charger when upgrading house batteries to lithium. If the ignition wire on the alternator is getting voltage from the alternator or another source then it will back feed into the dash and all heck will break loose. Mine had the sense and excite terminals bridged with the original sense wire cut and turned into the wire loom. Worked so so until I removed isolator. I have a 98 U270 with a C8.3. Chuck has provided you with various options.

Re: Charging issues

Reply #22 –
Quote from: Wpduffey –
I am going to make a few calls and see if I can get my money back from NAPA since what they sold me is not truly correct. then go from there.

There is a good chance if NAPA sold you the wrong alternator, the one it was replacing very well could have been the wrong type also.


Re: Charging issues

Reply #23 –
Quote from: Wpduffey –
We were not running anything at all..we were bringing it home. We lost all voltage and asumed it was the alternator. Found what we thought was a replacement,.worked for a while but now trying to locate the real issue.
You know what that mean: Something is running on its own.

Example: Recently the Studebaker began sounding its own horn at random times.
I pulled the horn relay and looked inside and found rust making an electric connection so I replaced the horn relay.
Horn went sounded off later.  We measured 5V on the signal wire to the horn, normally an open ground.  I think I know why it's conducting.

One of those cheap over the battery cable ammeters may be enough to get you started in your search.  But that electricity is going some where.

And yeah, go for a Leece Neville Duvac or a BIRD* relay.

Any time you run electricity it's a safe guess that you'll lose 0.7V due to the Diode being in circuit.

*Bi Directional Relay Disconnect. Two relays with voltage sensing electronics.

Re: Charging issues

Reply #24 –
Many good replies here, but reading through the original post I don't see that the alternator is necessarily even working...

Re: Charging issues

Reply #25 –
Quote from: Dave Larsen –
...reading through the original post I don't see that the alternator is necessarily even working...
Agree that the condition of the alternator is unknown.  The way it was installed, with incorrect wiring connected to the "I" terminal, may have immediately damaged the voltage regulator the first time the engine was started.  It would require properly wiring the alternator, and then testing it, to see if it is still alive.  But, since the OP hopes to return the Bosch to the store for a refund, it probably doesn't matter if it ever worked.

Re: Charging issues

Reply #26 –
Alright guys, i ordered the proper alternator, brand new! Got it installed perfectly and we are charging again. But only 11.5 volts according to the guage. Im going to get myself a good tester to figure out exactly what it is and work from there.
I have a tender on the batteries but they are 4 years old and it was sitting in storage when we bought it so i may simply have a bad cell in one of them.
I do have good tight clean cables everywhere and good grounds. Nothing looks out of place with that. I actually even added a good chassis ground wire for the alternator as well.
Any thoughts?

Re: Charging issues

Reply #27 –
Quote from: Wpduffey –
Alright guys, i ordered the proper alternator, brand new! Got it installed perfectly and we are charging again. But only 11.5 volts according to the guage.
Any thoughts?
Yes.  Are the batteries fully charged?  Charging system trouble shooting only works when you're starting with known good batteries that are fully charged.  And you've given them 15 minutes to 1/2 hour to recover after engine start.

Re: Charging issues

Reply #28 –
Quote from: Wpduffey –
I ordered the proper alternator, brand new! Got it installed perfectly and we are charging again. But only 11.5 volts according to the gauge.  Any thoughts?
Referring back to earlier posts in this thread, you should now understand that even if you have installed the "proper alternator" it still will not charge properly unless you have a SENSE wire and a EXCITE wire connected to the appropriate terminals on the alternator.  The SENSE wire must be attached either directly or indirectly to the START battery bank.  The EXCITE wire must be hot ONLY when ignition switch is in the ON position.  Have you verified that both of these wires are connected correctly at both ends?

Also, do not trust the dash voltmeter reading until you have verified it is correct.  I recommend checking the charging voltage directly at the start battery bank using your multimeter.
Why?  By checking at the "end of the line" (the actual batteries) you are also checking the condition of every cable and connection point in-between the alternator and the batteries.

Re: Charging issues

Reply #29 –
The alternator is hooked up correctly, exactly as shown in the FT drawings, i identified and traced all the wires from the schematics. All of the wires are numbered so its not that tough!
Btw im not the one that wired it wrong or put the wrong alternator on it in the first place. Im just trying to sort it out starting with the correct parts, wired correctly. One step at a time.
The batteries have been on a tender, i do not know the condition of them yet. They started the coach just fine but they are 4 years old. One could have a dead cell, dropping the voltage.
My volt meter has short leads so im going to get one a little easier to use.
Thanks.

Re: Charging issues

Reply #30 –
Now that you have the proper alternator and it is hooked up properly here is a couple of things to start/continue your troubleshooting.

If the wiring is original check the sense wire where it terminates on the little breaker on the Isolator board. Replace the breaker if it has bad resistance or just replace it as they are cheap and are located in a bad location. This isolator board could have been mounted in a better place as FT engineering failed in this location.

While there look to see where the other wire going to the breaker is terminated to get power.  Some have moved this wire to a battery post rather than hooked in to where the dash air condenser fan is hooked up. This location can send a bad voltage reading if the condenser fan is shorted internally.

Check the isolator to see if one of the diodes have failed. If bad there are several options for replacement/upgrades.

Verify the dash voltage meter is somewhere close so you can see if something is going downhill while you are driving. Those gages are notorious for being off.

This is thoughts of this morning
Mike

Re: Charging issues

Reply #31 –
Quote from: Wpduffey –
The batteries have been on a tender, i do not know the condition of them yet. They started the coach just fine but they are 4 years old. One could have a dead cell, dropping the voltage.
My volt meter has short leads so im going to get one a little easier to use.
Thanks.
This one is easier than you might think and only requires time.  Disconnect the batteries.  Wait three hours. Measure and record the voltage(s).  Come back 24 hours later and measure again, you should have the same readings or higher.  Why higher? Because it takes a lead acid battery 24 hours for the final "charging" chemical reaction to complete after charging voltage is removed.  Lower voltage means an internal short circuit and time for new batteries.

Re: Charging issues

Reply #32 –
Easiest place to check voltage is at the diode-based battery isolator.

Wires are numbered, but center lug is from the alternator B+ terminal.

The two outer lugs are to the respective chassis and house battery banks.

Check voltage between good clean ground and each lug with the engine OFF.

Then, start the engine and bump idle speed up to 1,100 RPM and recheck.

A bad battery isolator can give the same symptoms as a bad alternator.

Re: Charging issues

Reply #33 –
The "proper" alternator may have different voltage regulators, some externally adjustable (desirable), some internally adjustable (most popular), some non-adjustable fixed voltage (not recommended) .

What is the output voltage from the "proper" alternator, and keep in mind the voltage from isolator to battery banks will be lower than alternator voltage.

Measure at isolator, batteries, alternator, as meters at dash may be inaccurately lower due to voltage drop caused by other devices on the wire feeding dash meter.

Re: Charging issues

Reply #34 –
Talked to WP,will check his coach when the rain stops here,only an hour from me.

Re: Charging issues

Reply #35 –
Alrighty then, more confused than was to start with.
New correct alternator, wired according to the FT wiring diagram.
Engine running at 1100rmp
Positive stud on the alternator 2.27v
Nothing measurable on the 2 smaller ones 1-2 volts
Isolator
Left 13.48
Middle 2.28
Right 12.66
Batteries each show 12.67 volts (have been on a tender and turned it off for 30 minutes before starting)
Solenoid  small terminals both read 31.9 volts
Gage reads 11volts (wither meter 11.97)
And I don't see a little breaker that the sense wire goes to.
The 2 coming off the Solenoid are faded and hard to read.

Good news Napa refunded the $500 on the non duvac alternator.
And thank you all again for taking your time to help me.

And I have an belt tensioner idler bearing going out beside the alternator.
Sounds like the aliens have landed. Spray lube quieted it for about 30 seconds.

Re: Charging issues

Reply #36 –
Quote from: Wpduffey –
New correct alternator, wired according to the FT wiring diagram.
Engine running at 1100rmp
Positive stud on the alternator 2.27v
Nothing measurable on the 2 smaller ones 1-2 volts
Isolator
Left 13.48
Middle 2.28
Right 12.66
Batteries each show 12.67 volts
Solenoid  small terminals both read 31.9 volts
Gage reads 11volts (wither meter 11.97)
And I don't see a little breaker that the sense wire goes to.
And I have an belt tensioner idler bearing going out beside the alternator.
2.27v on the alternator positive output post means your alternator is not turning on.  If, with engine running, you are NOT measuring 12+ volts on the alternator SENSE and EXCITE terminals, then the alternator will not turn on.  You need to find the problem with those two wires, and correct it.

The isolator readings look OK.  The center post should read the same voltage as the alternator Positive output post.  The outer lugs should read the same voltage as the battery banks.

I don't know what "solenoid" you are looking at.  There is nothing on your coach that has 31.9 volts DC power.  ?

If you don't see the circuit breaker that the SENSE wire is supposed to connect to, then where DOES the SENSE wire go?

As for the squealing belt tensioner, see the post linked below:

Part Number Collection    (Part Number Collection, Reply #64)

Re: Charging issues

Reply #37 –
You need voltage to both the small posts. One will have voltage all the time and the other should
have voltage with the key turned on. The one with voltage all the time is the sense wire and the
one with the power only with the key one is too power the alternator and the alternator won't
work without power.

Re: Charging issues

Reply #38 –
Start with checking two things-- the two small wires:

The SENSE wire at the alternator.  It should read chassis battery voltage and is the "signal" for how much the alternator needs to output.

It is a small gauge wire and can be broken or connections not clean and tight.  No problem running a new one from chassis battery lug of isolator (or any other location on the chassis battery side of the isolator) to the sense terminal of the alternator.

Secondly, the IGN/excite terminal should have 12+ VDC any time the ignition is on.  Again plenty of easy places in the engine room to get an "ignition hot" signal.

Re: Charging issues

Reply #39 –
OK I have nothing at either of the small terminals with the ignition on.
That wire is marked E6 that goes to ignition on the alternator