Home » Public Forums » GMCnet » For Those Going Solar and Removing Onan...
| For Those Going Solar and Removing Onan... [message #312913] |
Wed, 08 February 2017 09:28  |
TR 1
Messages: 348
Registered: August 2015
Location: DFW
Karma: -7
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Has anyone considered or is currently running one of those belt-driven 120v generators? Looks like these are common on some modern coaches that are going genset-less... They also seem to be used on emergency equipment, and also to some extent on boats.
Was looking for opinions, and if anyone has first hand experience with how well they work, cost, etc... Not sure I'd want to rip out my Onan and install one of these... But if you had a primarily solar coach, I think this would be a nice to have backup if you ran in to a string of cloudy days, unexpected situations, etc.
This company seems to make a fairly popular unit. Looks like they offer 110 and 220v units in the 2-3k watt range. They also seem to offer a voltage regulator to keep the gen's output constant as engine rpms change:
http://www.fabcopower.com/generat/bgen.htm
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX
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| Re: For Those Going Solar and Removing Onan... [message #312917 is a reply to message #312913] |
Wed, 08 February 2017 11:03  |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
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Several years ago, we bought some 5kw units from an outfit that supplied them to the maker of the Navy's riverine boats. Custom mounts for whatever you specified, automatic throttle control for the engine, and a sine wave inverter for the output. In a 350 Econoline, you never ran the engine over 1900 RPM to make 5 KW.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
[Updated on: Wed, 08 February 2017 11:05] Report message to a moderator |
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| Re: For Those Going Solar and Removing Onan... [message #312927 is a reply to message #312913] |
Wed, 08 February 2017 13:02 |
dshafer
Messages: 68
Registered: June 2016
Location: SW Ohio
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I would not want to turn that whenever the engine was running, so unless you had some sort of Mad Max electric clutch that would kill it for me. I would also worry about the frequency. I only read the ad lightly but the engine rpm would cause the cps to fluctuate while driving.
Bottom line... it needs to be disconnected until the emergency occurs.
1977 26 foot 403
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| Re: For Those Going Solar and Removing Onan... [message #312932 is a reply to message #312913] |
Wed, 08 February 2017 13:21 |
TR 1
Messages: 348
Registered: August 2015
Location: DFW
Karma: -7
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A Hamilto wrote on Wed, 08 February 2017 11:33
I guess I am saying if you decide to remove the Onan and use something on the Olds engine to replace it, you won't gain anything by adding another belt driven device to the Olds engine. You already got what you need.
Well, the alternator/inverter wont handle all your power needs... I have a 2500 watt inverter on my coach, but I still use my generator all the time. Less than if I had no inverter, but if I need to run the AC and I'm not on shore power, the generator gets run. Also, I can run the microwave through the inverter, but it pulls a ton of current.... If I'm warming up more than a cup of coffee or a sandwich, I generally start the gen as well.
Also, using the alternator to charge the batteries is very slow. Especially at lower rpm where the alternator puts out little current. I have 4 golf cart batteries, plus the engine battery, which I would imagine is a similar battery setup to someone on solar. Alternator generally does a good job at keeping them topped off... But if I draw down all the batts, I'll run the genset and charge them through the inverter. I can generally get them back to 80ish percent in around an hour. If I had to do that through the alternator at low rpm, it would probably take days...
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX
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| Re: For Those Going Solar and Removing Onan... [message #312933 is a reply to message #312927] |
Wed, 08 February 2017 13:37 |
TR 1
Messages: 348
Registered: August 2015
Location: DFW
Karma: -7
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dshafer wrote on Wed, 08 February 2017 13:02I would not want to turn that whenever the engine was running, so unless you had some sort of Mad Max electric clutch that would kill it for me. I would also worry about the frequency. I only read the ad lightly but the engine rpm would cause the cps to fluctuate while driving.
Bottom line... it needs to be disconnected until the emergency occurs.
Clutching it is an interesting idea... However, I wonder how much parasitic loss it would cause if not generating power for a load? I think it would work the same way as your 12v alternator... When your car alternator is not generating current, parasitic loss is low... As for the CPS, it appears to have an optional regulator that keeps the voltage constant, and I assume it also maintains the cps at 60 with varying engine RPM.
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX
[Updated on: Wed, 08 February 2017 13:38] Report message to a moderator |
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| Re: [GMCnet] For Those Going Solar and Removing Onan... [message #312935 is a reply to message #312913] |
Wed, 08 February 2017 13:50 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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If you really want to evaluate the possiblity of using a 120 vac alternator
of high capacity on the engine, take a look at the alternator section of a
portable generator, or even the Onan that's in the coach. That's
approximately the size an engine-driven equivalent would be -- there's
really no reasonable way to significantly reduce the size. My engine
doesn't leave enough room in its compartment to mount such a device,
especially if one adds the clutch I'd consider essential.
JMHO,
Ken H.
On Wed, Feb 8, 2017 at 10:28 AM, Mark Sawyer
wrote:
> Has anyone considered or is currently running one of those belt-driven
> 120v generators? Looks like these are common on some modern coaches that
> are
> going genset-less... They also seem to be used on emergency equipment,
> and also to some extent on boats.
>
> Was looking for opinions, and if anyone has first hand experience with how
> well they work, cost, etc... Not sure I'd want to rip out my Onan and
> install one of these... But if you had a primarily solar coach, I think
> this would be a nice to have backup if you ran in to a string of cloudy
> days,
> unexpected situations, etc.
>
> This company seems to make a fairly popular unit. Looks like they offer
> 110 and 220v units in the 2-3k watt range. They also seem to offer a
> voltage
> regulator to keep the gen's output constant as engine rpms change:
>
> http://www.fabcopower.com/generat/bgen.htm
> --
> Mark S. '73 Painted Desert,
> Manny 1 Ton Front End,
> Howell Injection,
> Leigh Harrison 4bag and Rear Brakes,
> Fort Worth, TX
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] For Those Going Solar and Removing Onan... [message #312936 is a reply to message #312933] |
Wed, 08 February 2017 13:59 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Frequency output in alternators is a product of RPM'S, and the design of
the stator. If you do not stay within the recommended frequency design of
whatever you have plugged in, bad juju sometimes happens and you let out
the smoke from within. Automotive engines are difficult to stabilize for
specific exact RPM'S without governors. If loads are constant, you can get
close, but with changing loads, RPM'S and frequency will vary.
Onan engines are quite stable in RPM'S due to their 10 ball governor
on the camshaft. They literally are quicker in response to changes in load,
than the humans operating them.
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Feb 8, 2017 11:38 AM, "Mark Sawyer" wrote:
> dshafer wrote on Wed, 08 February 2017 13:02
>> I would not want to turn that whenever the engine was running, so unless
> you had some sort of Mad Max electric clutch that would kill it for me. I
>> would also worry about the frequency. I only read the ad lightly but the
> engine rpm would cause the cps to fluctuate while driving.
>> Bottom line... it needs to be disconnected until the emergency occurs.
>
>
> Clutching it is an interesting idea... However, I wonder how much
> parasitic loss it would cause if not generating power for a load? I think
> it would
> work the same way as your 12v alternator... When your car alternator is
> not generating current, parasitic loss is low... As for the CPS, it appears
> to have an optional regulator that keeps the voltage, and I assume the cps
> at 60 with varying engine RPM.
>
>
>
> --
> Mark S. '73 Painted Desert,
> Manny 1 Ton Front End,
> Howell Injection,
> Leigh Harrison 4bag and Rear Brakes,
> Fort Worth, TX
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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| Re: For Those Going Solar and Removing Onan... [message #312937 is a reply to message #312913] |
Wed, 08 February 2017 14:17 |
A Hamilto
Messages: 4508
Registered: April 2011
Karma: 39
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TR 1 wrote on Wed, 08 February 2017 13:21Well, the alternator/inverter wont handle all your power needs... Depends on what those needs are.Quote:I have a 2500 watt inverter on my coach, but I still use my generator all the time. Less than if I had no inverter, but if I need to run the AC and I'm not on shore power, the generator gets run. Also, I can run the microwave through the inverter, but it pulls a ton of current.... If I'm warming up more than a cup of coffee or a sandwich, I generally start the gen as well.
Also, using the alternator to charge the batteries is very slow. Especially at lower rpm where the alternator puts out little current. I have 4 golf cart batteries, plus the engine battery, which I would imagine is a similar battery setup to someone on solar. Alternator generally does a good job at keeping them topped off... But if I draw down all the batts, I'll run the genset and charge them through the inverter. I can generally get them back to 80ish percent in around an hour. If I had to do that through the alternator at low rpm, it would probably take days... Yeah. I forgot that the OEM alternator might be as piddly as 60A. So you would need to replace it with 100A or so. But the chassis alternator should put out close to capacity at a little higher than idle. I don't know how many times I have hooked up jumper cables to a dead car and can hear the engine lug down. So I know it puts out a lot of current, even at idle. I do suppose that getting it up over 1000 RPMs would be better.
I would probably build a wooden jig or something to put under the accelerator pedal with a brick on top to get to 1000 RPMs or so needed to charge the house battery bank before I would install some kind of 60Hz 120VAC alternator on the chassis engine (which would have to run at somewhere around 1500 RPMs, IIRC, when I was looking at those things).
When he mentioned solar in the title, and said he wanted to remove the Onan, I figured roof AC wasn't part of the equation.
Other than that, NO charging source will charge the batteries any faster than any other. It all has to come from the converter/charger, which is the limiting factor. You must have a pretty high output converter/charger to charge your house battery bank in about 3 hours. But that could charge from the engine alternator in the same amount of time (not efficiently, but...) Make sure the wire from the isolator to the converter/charger is big enough for that. Discounting the roof AC, charging the battery bank doesn't matter if it is on shore power, a magical 60Hz 120VAC generator running off the engine, or the chassis alternator. The converter/charger is the bottleneck.
If roof AC will be required when not on shore power, removing the genset is foolish. The Olds engine will burn twice as much fuel as the Onan if it is powering the roof AC.
If all that is needed is battery charging (and no roof AC), then the Onan can go away, and a 1 - 2kw Honda genset can do the job.
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| Re: For Those Going Solar and Removing Onan... [message #312941 is a reply to message #312913] |
Wed, 08 February 2017 16:30 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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Rectify it and invert it to 60HZ 120V. Now the engine speed follows the load. The ones we tried worked fine. We just weren't crazy about running a Ford V10 for four - six hours at a time and reverted to Onans in future trucks. There wasn't any dollar savings. They weren't as large as the Onan alternators, but they weren't mice either. The inverters were pretty good sized. The servo throttle controls worked OK, the fly-by-wire one did somewhat better. I suspect Rostra made both of them.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: [GMCnet] For Those Going Solar and Removing Onan... [message #312942 is a reply to message #312941] |
Wed, 08 February 2017 16:46 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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There exists out there a form of engine speed control for applications like
air compressors and alternators that are intended for use with lighting
applications that are not frequency sensitive. They work similar to cruise
controls, and are about as accurate. Rostra may in fact be a manufacturer
of some of them. My experience with them is with service trucks that tire
stores use for roadside tire repair, and line repair trucks that need
strong lighting for storm damaged power lines. Their accuracy is good
enough for that use but lacks the precision for audio and similar
equipment. Be careful what you buy. I burned up some expensive Fender
amplifier equipment by using non stabilized frequency controlled inverters.
Built a portable marching band power supply for electronic guitars. Learned
expensive lessons there.
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Feb 8, 2017 2:31 PM, "Johnny Bridges via Gmclist" <
gmclist@list.gmcnet.org> wrote:
> Rectify it and invert it to 60HZ 120V. Now the engine speed follows the
> load. The ones we tried worked fine. We just weren't crazy about running a
> Ford V10 for four - six hours at a time and reverted to Onans in future
> trucks. There wasn't any dollar savings. They weren't as large as the Onan
> alternators, but they weren't mice either. The inverters were pretty good
> sized. The servo throttle controls worked OK, the fly-by-wire one did
> somewhat better. I suspect Rostra made both of them.
>
> --johnny
> --
> '76 23' transmode Norris upfit, 76 26' Eleganza(?) with beaucoup mods and
> add - ons.
> Braselton, Ga.
> "The road goes on forever, and the party never ends" --Robert Earl Keen
>
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| Re: For Those Going Solar and Removing Onan... [message #312955 is a reply to message #312913] |
Thu, 09 February 2017 10:45 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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Those are the controls used with the engine alternators. Most audio equipment wants to see a fairly clean sine wave for power... even the stepped square wave stuff gives them indigestion, as you've seen. Usually it isn't so much the frequency as the waveform which creates the grief.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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