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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: neoneddy on July 24, 2018, 10:04:48 AM

Title: No power from alternator , just started leaving campground
Post by: neoneddy on July 24, 2018, 10:04:48 AM
Heading out from gooseberry falls this morning I noticed my Voctron monitor didn't show a good charge coming from the DC side.

We had been making good power from solar all morning, so we're not stuck stuck, but no AC on the road.

I checked the battery connection, looked good , checked the voltage regulator, I see there is a button to press, it was in.

Any ideas?  My volt meter was left on I guess (me) so it's dead at the moment.

Update:
I'm leaning towards a diode replacement, looking for ideas on best practices and where to buy.  Hoping NAPA sells them.
Title: Re: No power from alternator , just started leaving campground
Post by: neoneddy on July 24, 2018, 10:49:51 AM
Checked the relays in the back, specifically the field relay. It was clicking.
Title: Re: No power from alternator , just started leaving campground
Post by: luvrbus on July 24, 2018, 10:59:09 AM
Check the Field on the alternator it should be magnetized,those are not hard to trouble shoot about the only thing that goes wrong to prevent charging is the diode pack goes bad 
Title: Re: No power from alternator , just started leaving campground
Post by: neoneddy on July 24, 2018, 11:02:10 AM
How can I test that? Running or not?
Title: Re: No power from alternator , just started leaving campground
Post by: luvrbus on July 24, 2018, 11:12:11 AM
Quote from: neoneddy on July 24, 2018, 11:02:10 AM
How can I test that? Running or not?

You do it with the engine running or not running the field requires DC to make the magnetic field,if it is magnetized check the diodes on the rear of the alternator   
Title: Re: No power from alternator , just started leaving campground
Post by: eagle19952 on July 24, 2018, 11:41:56 AM
Quote from: luvrbus on July 24, 2018, 11:12:11 AM


You do it with the engine running or not running the field requires DC to make the magnetic field,if it is magnetized check the diodes on the rear of the alternator
yup, just hols a screw driver/pocket knife to the axis point of the rotor shaft. if it sticks, it's the diodes or that which energizes the field .
Title: Re: No power from alternator , just started leaving campground
Post by: neoneddy on July 24, 2018, 11:56:06 AM
I opened the access hatch in the back under our bed and poked at it with a few metal items (hammer, wrench, etc) nothing was sticking.  I tried it with engine off, master switch on and then when running, still the same.

I have a small string of 24v led lights I could use a simple " power / no power" indicator.  Are there any tests I could perform at the regulator? (inside back entry door bay).

Seems like one way or another, there is no field fix for this.  We could cut our trip short or just roll on with no AC.   Solar panels (1950 watts) are keeping us topped up for the moment.

One last thing , if it matters. I've attached a screen grab for our DC power monitor graph.  It shows us making good power and tailing off as the batteries charged until we stopped at our camp site.   Would something like the fields just stop working suddenly?  To me that seems more like a relay or something else.   





Title: Re: No power from alternator , just started leaving campground
Post by: eagle19952 on July 24, 2018, 12:05:40 PM
Quote from: neoneddy on July 24, 2018, 11:56:06 AMTo me that seems more like a relay or something else.

me too.
Title: Re: No power from alternator , just started leaving campground
Post by: neoneddy on July 24, 2018, 12:46:58 PM
So, with the engine running, I took my test light and checked the Field wire and the positive wire on the voltage regulator, both were making power.   Does that tell us anything?   I'll try and find a store to get a battery for my multi meter at the next stop.
Title: Re: No power from alternator , just started leaving campground
Post by: luvrbus on July 24, 2018, 01:06:25 PM
Ok if you have power to field the relay is working,the way those work is the diodes turn the AC current to a DC current,I would guess the diode pack is bad,you can check the field winding with a meter if they are good it will read between 3.9 and 4.2 resistance,that is a gear driven alternator right ? and it is spinning

     
Title: Re: No power from alternator , just started leaving campground
Post by: Lee Bradley on July 24, 2018, 01:57:11 PM
If I'm reading the posts correctly, you have power to the field post and no magnetic field. That nothing is attracted to the case.  I would disconnect the field wire and check for current draw. The field coil should pull about 10 amps if no draw the field coil has an open somewhere. 
Title: Re: No power from alternator , just started leaving campground
Post by: neoneddy on July 24, 2018, 03:08:39 PM
I don't have a way currently to measure the draw on that wire. However I did notice a change in engine pitch when I connected and disconnected the field relay.  Similar to how the engine would not down a tick when you put any other electrical load on it.

I can't tell for sure if it's spinning as it's gear driven.

Also good news, an air bag spring a leak.
Title: Re: No power from alternator , just started leaving campground
Post by: Lee Bradley on July 24, 2018, 04:04:37 PM
The solar on bus will shut down the alternator when the batteries are at full charge. The solar system on bulk will run at 28.8 volts and the bus system is at 27.5 so the solar voltage is high enough that the regulator shuts off the alternator. Charge light comes on and the tach quits. Try running the AC to drop the system voltage and see if the alternator powers up.
Title: Re: No power from alternator , just started leaving campground
Post by: neoneddy on July 24, 2018, 05:30:21 PM
@lee I've had that before , on my monitor I can track exactly how much the alternator is contributing.

Solar  brought me from 52% this morning to 85% this evening, it's combining both systems, house and coach.

@everyone , the Mrs noticed the DC system contributed a little here and there.  So there is that, I've never been able to measure it.  I did get  new battery for the multimeter.  I'll start following the rabbit trail this evening and tomorrow.

Title: Re: No power from alternator , just started leaving campground
Post by: neoneddy on July 24, 2018, 06:05:33 PM
New question for the audience.

http://www.delcoremy.com/The-Latest/2013/March/Tech-Tip-Flash-the-Field

Could this have happened? I'm not seeing any magnetism.
Title: Re: No power from alternator , just started leaving campground
Post by: chessie4905 on July 24, 2018, 06:34:45 PM
This is for off the shelf new or reman unit. Not for one that had been working in the vehicle.
Title: Re: No power from alternator , just started leaving campground
Post by: neoneddy on July 24, 2018, 08:16:37 PM
Ok, more digging at the data, because that's all I can do.

July 22, we left home, power seemed Pretty stable from the alternator, we only really pulled 2800 watts at most. 

July 23,  The battery got lower that night, so while charging the batteries we also tried running the air, pulled a max of over 4000 watts.  Which is still below the 6500 watt max.  During this time you can see in the graph it started to wobble some.  Now some of that is due to the solar panels contributing more over time and the batteries charging up.  But around 16:00 the charging watts went to 0, then picked up again.

July 24th - Today, I have recorded one blip of alternator power at 315 watts or so.   

The more reading I've done, I'm leaning towards some failed Diode(s), now, where to find them?  Tomorrow we're heading for my in-laws with a full shop.  I'm hoping to pull off the back cover and test the diodes there.  Is this something I dare tackle while it's still on the engine?   I have access via the floor hatch.

Any Advice on that?
Title: Re: No power from alternator , just started leaving campground
Post by: luvrbus on July 24, 2018, 10:05:05 PM
You can buy the diode pack from Kirk's Automotive in Detroit Mi  www.kirksauto.com  and you can change those without removing that heavy sucker   
Title: Re: No power from alternator , just started leaving campground
Post by: bevans6 on July 25, 2018, 08:03:27 AM
In this thread I see no mention of system voltages, only power.  It's important to remember that alternators are regulated to a voltage and produce current, not power.  It amounts to the same thing, but the difference is important.  What are the voltages with solar and alternator off, solar on and alternator off, and alternator on with solar off?   Everyone knows the alternator will not turn on if it detects sufficient voltage regardless of load draw.  Voltage is everything when it comes to an alternator.  Also, if a diode is bad you usually see alternator output around 12 volts rather then 13.5 (double for a 24 volt system) at idle with no or light load. 
Title: Re: No power from alternator , just started leaving campground
Post by: luvrbus on July 25, 2018, 08:37:14 AM
 50 D alternators will charge without a voltage regulator when I test one I take the regulator out of the loop and add 15% ,if the diode goes bad on the out put terminal you get no reading from the alternator output,that is probably the bad diode on his 50D but he will figure it out today maybe     
Title: Re: No power from alternator , just started leaving campground
Post by: neoneddy on July 25, 2018, 09:33:33 AM
I can perform that test, solar off, but my voltages aren't much over 26-26v with solar on. Over the last year I've noticed a particular pattern anytime I've run it, the alternator bumps it up to 27-28v.

When I'm at full charge and getting good solar the no gen light will turn on, around 29v , but in summer the AC and whatnot is always on.
Title: Re: No power from alternator , just started leaving campground
Post by: eagle19952 on July 25, 2018, 04:18:22 PM
OK. A thought.
Keep in mind I know very little about solar charge controllers.
Can the solar charge back feed into and against the diodes...and butt into/and/or cause failure of the diodes ?
Title: Re: No power from alternator , just started leaving campground
Post by: neoneddy on July 25, 2018, 06:09:16 PM
I suppose it's possible, I have my house and coach systems linked almost all the time.

I found a shop in Chisholm , MN here that specializes in heavy equipment alternators. Nice being in mining country. I'll learn more in the morning.
Title: Re: No power from alternator , just started leaving campground
Post by: buswarrior on July 26, 2018, 06:50:40 AM
Two charging sources at the same time?

I'm not sure how the old coach systems would respond, but they were intended to run alone?

That old alternator and regulator is like an old John Wayne/Clint Eastwood style loner character? My hunch, it doesn't like to have a partner?

Happy coaching!
Buswarrior
Title: Re: No power from alternator , just started leaving campground
Post by: luvrbus on July 26, 2018, 07:26:37 AM
He should have a isolator of some type between the 2 systems
Title: Re: No power from alternator , just started leaving campground
Post by: neoneddy on July 26, 2018, 07:34:09 AM
The guy here in Chisholm turns out to be a bus nut! That's the good news, the bad news is he won't touch the alternator, too big, he's never worked on them.

Looks like we're running green this trip, it's in the 60s today but overcast, but we got a full charge last night at the in-laws.
Title: Re: No power from alternator , just started leaving campground
Post by: luvrbus on July 26, 2018, 08:54:04 AM
If you are unable to do the work on the 50 once removed a shop is going to charge you from 800 to over a 1000 bucks to rebuild that jewel,I have friend that just took a hit for over 3 grand for a 50 Delco exchange on the road
Title: Re: No power from alternator , just started leaving campground
Post by: neoneddy on July 26, 2018, 07:48:12 PM
So I fiddled with the voltage regulator yesterday. I don't know if I turned it up or down, nothing seemed to be working.

We got a full charge last night at the in-laws, then tonight we pulled out for the last leg of our trip and I noticed 100-200 watts seeming to come in from the coach side... So I turned on an AC unit... Sure enough it shows 1000+ watts coming in, exactly what the AC unit is pulling. Only odd part is I'm not hitting 27-28 v like normal.. just touching 26-26.2 .

We were able to put 70 miles on with AC and charged batteries. ... I don't know what's going on except it must be the voltage regulator? I'll adjust it in the morning to try and get it up into the 27-28v range.

I also ended up calling Kirks, they'd do $720 rebuild with a core. That was my plan... Now??  I don't know.
Title: Re: No power from alternator , just started leaving campground
Post by: chessie4905 on July 30, 2018, 12:56:21 PM
If you need a replacement alt... Here

https://www.ebay.com/itm/Delco-Remy-10459121-50DN-R141-High-Output-Alternator-24V-270A-NEW/123113660993?epid=1334301951&hash=item1caa256241%3Ag%3AuF0AAOSwyGBa63a0&_sacat=0&_nkw=delco+50+dn+drive+gear&_from=R40&rt=nc
Title: Re: No power from alternator , just started leaving campground
Post by: Lee Bradley on July 30, 2018, 01:51:39 PM
Quote from: neoneddy on July 26, 2018, 07:48:12 PM
So I fiddled with the voltage regulator yesterday. I don't know if I turned it up or down, nothing seemed to be working.

We got a full charge last night at the in-laws, then tonight we pulled out for the last leg of our trip and I noticed 100-200 watts seeming to come in from the coach side... So I turned on an AC unit... Sure enough it shows 1000+ watts coming in, exactly what the AC unit is pulling. Only odd part is I'm not hitting 27-28 v like normal.. just touching 26-26.2 .

We were able to put 70 miles on with AC and charged batteries. ... I don't know what's going on except it must be the voltage regulator? I'll adjust it in the morning to try and get it up into the 27-28v range.
I also ended up calling Kirks, they'd do $720 rebuild with a core. That was my plan... Now??  I don't know.

Pulling a 1000 watts, I am not surprised that the system voltage is down a volt or two. That is on the order of 40 amps and depending on where your volt meter is connected you can have some voltage drop across the wiring.
Title: Re: No power from alternator , just started leaving campground
Post by: neoneddy on March 02, 2020, 07:44:33 AM
Sorry to bring up an old old topic.  I just hate finding unresolved forum posts myself, and I was looking this up for my own reference and realized I never resolved it.

We replaced the alternator, everything works like before.  The new 50DN puts out 28.4v with a 3000w load without dropping much of anything. 
Title: Re: No power from alternator , just started leaving campground
Post by: windtrader on March 02, 2020, 08:31:14 PM
Thank you. Great data point on current. The OEM site lists this spec


Performance Output   24 Volts 270 Amps which is 6,480 watts, so 3,000 seems reasonable as a safe continuous output number.


This is irrelevant for charging LA batteries due to their very limited charge rate but of great interest for those few seeing the light with Lithium storage systems.
Title: Re: No power from alternator , just started leaving campground
Post by: neoneddy on March 02, 2020, 08:35:07 PM
Eh... My AGM bank will gladly soak up 80 amps or more if it's around 50% .. and will do so until 80% or so (600 AH @ 24v / 2 = 300 / 80 = 3.75 hours).  I'll take all I can.