No power from alternator , just started leaving campground

chessie4905 · 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.

neoneddy · 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?

luvrbus · 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

bevans6 · 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.

luvrbus · 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

neoneddy · 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.

eagle19952 · 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 ?

neoneddy · 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.

buswarrior · 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

luvrbus · July 26, 2018, 07:26:37 AM

He should have a isolator of some type between the 2 systems

neoneddy · 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.

luvrbus · 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

neoneddy · 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.

chessie4905 · 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

Lee Bradley · 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.