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Bruce Henderson (Oonrahnjay)
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Posted on Thursday, October 22, 2009 - 12:42 pm:   

Has anyone had any experience with these? They are variable RPM; they'll put out approx 3600 watts at 1200 RPM at 61 dB/A. The 8/10K watt unit is 3" smaller, 40 pounds lighter, and slightly less fuel use than the Onan 6K watt generator. Also, they come in a kit with auto control, auto shore switching and integrated inverter. They also supply PSW from generator and inverter operation.

It would be kinda like buying the first year model of a new car but the specs look really good.

Any thoughts?
Cullen Newsom (Cullennewsom)
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Posted on Thursday, October 22, 2009 - 4:21 pm:   

On the one hand it looks like a step forward in tech. An integrated system gives the system designer the ability to add/enhance efficiency, much more flexible design. I can think of a few good ideas along this line.

On the other, dependence upon a single proprietary vendor often puts you behind the 8 Ball, at their mercy, rock and a hard place, etc.

First generation of new tech, something to think about.

Also, think about how companies treat their customers at a products End Of Life. I don't imagine you want to buy an expensive, integrated system, and plan to throw it away when the first piece breaks. Will Onan support their little electronic black-box in ten years, and a few product line generations? Or will they push you to "upgrade to the newest version"

Also, it looks like they've invented their own "RVCAN" While CAN is good, and RVCAN is probably a simple protocol, I haven't heard of it. If they've implemented their own little proprietary CAN protocol; which they will not share or publish, then I would run away. I can hear them now, "Other vendors' CAN equipment is not supported, and will void the system warranty"
john w. roan (Chessie4905)
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Posted on Thursday, October 22, 2009 - 6:13 pm:   

Don't let the "quiet benefits sway you that much; a well thought out installation with good sound and wibration absorption materials can effectively deal with this issue. How about both a small and a medium generator that can be run combined when needed? Of course, it will depend on your electricity draw average and peak use demands and a controller to properly handle this. Maybe one that can handle everything but AC. Honda has some small compact units you can carry. Saw and listened to their portable 2000 watt unit; impressive
john degemis (Degemis)
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Posted on Thursday, October 22, 2009 - 6:28 pm:   

I have an Onan RV QD 8000 around a year old. Pulled out the specs on mine and went to their website. Size is the same the new one is 29 lbs lighter and the fuel usage is 20% better at full load, 1/2 load the same as mine.sound level is the 66 at half on mine and 63 on the new one. Mine is microprocessor controlled and variable speed. So it looks like they made an improvement on fuel and packaged it with an inverter and transfer switch and an inside readout that has more info. I have mine hooked to a Xantrex inverter charger with a built in transfer switch and it starts the generator if the batteries get low. They make a good genset. The rest is just expanding on what they normally sell. Smart way to make more money. As for me I like the knowing the track record of the product. With the inverter who makes it? I would think someone else with the Onan name on it. They are a good company and if the price were right, and I was starting from scratch I would consider it.
Bruce Henderson (Oonrahnjay)
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Posted on Thursday, October 22, 2009 - 7:36 pm:   

Thanks to all for your comments. John, I am starting from scratch.
Jim Shepherd (Rv_safetyman)
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Posted on Thursday, October 22, 2009 - 8:38 pm:   

dB/A is only one component of sound (AKA "sound pressure level"). The other component is sound quality. That has mostly to do with the frequency, but can be other things as well.

Consider the sound of fingernails on the chalk board. The sound pressure level can be fairly low, but the sound will drive you crazy.

In the case of variable speed generators, the variable speed drives me crazy (crazier?). I was parked several coaches away from one a few years ago. The sound pressure level was not bad, but the "quality" was obnoxious.

I have sensitive hearing, but I suspect that others have the same problem.

I have made the assumption that this is the AC/inverter type generator. If so, they have been around for several years.

Every time I hear one, I grit my teeth

Jim

(Message edited by rv_safetyman on October 22, 2009)
john degemis (Degemis)
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Posted on Friday, October 23, 2009 - 11:59 am:   

I do not know about sound pressure leveles. i do know if you were several coaches away you would have a hard time hearing a quite diesel in a insulated enclosure. I have to look at the meter when I am inside to tell if it running when I am in the coach. Veriable speed make sence you use less fuel at lower demand. And get longer life from the unit. The old units were not very smooth in speed change.
Cullen Newsom (Cullennewsom)
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Posted on Friday, October 23, 2009 - 12:46 pm:   

Out of curiosity, I went ahead and contacted Onan about RV-CAN. They replied promptly, here is the response from them.

quote:

CAN communication protocol is similar to J1939. It is proprietary to Cummins/Onan corporate.



I've asked them a few follow-up questions. If I get anything useful from them, I'll post it here.

As it stands, That renders the following claim in their product literature meaningless.

quote:

RV-CAN Connection To Easily Add Compatible Displays/Equipment


I'll translate that for you: "Easy to add Displays/Equipment from Cummins/Onan, if we ever decide to make any."

Well, why would I care what protocol is used, if I may only source components from a single vendor? It's not as though I expect Onan to sell me a hard-to-add display/equipment.

Warning: The remainder of this post gets pretty ugly, and is mostly just a rant based upon my opinion.

This is really a shame since there are some very interesting advantages in having the ability to integrate control of not just the source of electrical power, but the units consuming the power as well. Some of it could be done with passive listening* to the RV-CAN system, but eventually you reach an artificially imposed limit. Not to mention that you've probably had to add one or more additional CAN systems (one of the major advantages of CAN is that it reduces the number of wires that must be run in a given system/vehicle).

Note that I am not saying the Onan system is bad. I think it is a fine and appropriate application for CAN; and I am sure it works well. But the fact that it is CAN has absolutely no relevance to an end-user.

I find it disingenuous for Onan to assert that RV-CAN is some sort of advantage when it is clear that Onan intends to withhold the only possible advantage for an end-user, which would be compatibility with third party CAN devices. Not that any of it really matters, as there are no CAN-enabled A/C controllers or refrigerators yet. But there are CANbus monitors, which would enable a third party technician or even a DIY end-user to diagnose and or repair a faulty system. Onan's RV-CAN is a proprietary black-box which they will use to force vendor-lock-in, and unnecessary hardware upgrades.

* passive listening to the RV-CAN system is contingent upon reverse-engineering their messages, if they are unwilling to sell/give you the information.
Bruce Henderson (Oonrahnjay)
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Posted on Friday, October 23, 2009 - 2:56 pm:   

Cullen, I appreciate the info that you've gathered and your comments. However (aside from the issue of future support for service, parts availability, and "forced upgrades"), what's a disadvantage of not having a CAN compatibility for a refrigerator or A/C? I mean, if the ONAN system units communicate with each other by CAN and I put a refrigerator on it and it draws the batteries down the the gen system senses that and starts the generator and charges them, what important advantage would there be to having a CAN web between the gen system and the fridge? (Yeah, I can see a consolidated trouble-shooting or fault code system would be nice but if you don't have it, why not just trouble-shoot the individual components like we do now?)

I don't mean to sound argumentative with you, but I'm just trying to understand the real-world disadvantages. I am very troubled that CAN-connected diagnostics and service would be limited to only those Onan service locations that would see enough business to invest in the dedicated CAN diagnostic modules -- it sounds as if service may be very thin on the ground.

And, Jim, thanks for relating your experiences. It troubles me that a system (variable speed) that seems to offer so many advantages could be so undesirable from a noise standpoint. I mean, low noise about the biggest reason for paying the thousands of $$$ for a unified Onan generator unit; if I just wanted power and didn't care about NVH, I could just go to Harbor Freight and buy one of their low-cost units (OK, we know that the HK sh-one-t is just cheap imported carp, but you get my point). It's just a shame that low-noise also brings "bad noise quality".

I'd appreciate more info and discussion here (but I'm sure leaning against one of these "hybrid" systems).
Cullen Newsom (Cullennewsom)
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Posted on Friday, October 23, 2009 - 8:56 pm:   

Bruce,

I am confident that there is nothing wrong with Onan's CAN system, and I haven't any experience that says otherwise.

My ranting stems from when I saw the system, I got excited, and thought about all of the neat things that one could do (hypothetically) if one had an inverter and generator system that were controlled electronically, and given that one could also control appliances in the same way For example:

* In a multi-A/C system, one could ensure that all fans stayed circulating and cycle the compressors in a round-robin fashion, while never exceeding current limits.
* Make sure that all A/C's didn't start at once.
* Manipulate generator cycling to minimize the number of starts.
* Programmed thermostat settings by time of day, or other criteria.

The list goes on.. but mainly I was thinking about how one would be able to use a smaller genset to do the work of a larger one by making more efficient use of it. Make no mistake, everything I just mentioned is pie-in-the-sky.


quote:

I don't mean to sound argumentative with you,


No worries!

quote:

but I'm just trying to understand the real-world disadvantages. I am very troubled that CAN-connected diagnostics and service would be limited to only those Onan service locations that would see enough business to invest in the dedicated CAN diagnostic modules


As you should be. I'm sure that I don't have to tell you; but what it means is that in the absence of a shop that's paid the tribute and received the blessing, troubleshooting techniques are left to the following:

* Guessing
* Replacing components in ascending order, starting with the cheapest/favorite/what's been on our shelf the longest.

Since Onan has decided to make it hard to do proper troubleshooting. And this is a personal pet peeve of mine. I liken it to installing specially-keyed lug-nuts or something, and then charging a ransom for the key. As I said in the post before, CAN isn't a feature, if it is a closed proprietary CAN system. You'll be beholden to a single source (Onan), and I never ever want to be in that spot, unless the technology is just so much better than everything else, that there's no practical alternative.
Jim Shepherd (Rv_safetyman)
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Posted on Saturday, October 24, 2009 - 9:38 am:   

Concerning my "noise" experience with variable speed generators, I tried to emphasize that it was not a "loud" issue. It was indeed, pretty quite. However, ***I*** could hear the changing speed of the engine every time the owner turned on some electrical component. This is not an isolated case with me. At the rallies we attend as vendors, I never fail to hear one of these units from many feet away. Drives me crazy.

My point in bringing this up is that inside the coach, the cycling sound may be an irritant.

A constant speed generator is a noise we get used to and our brain tends to ignore the noise. Kind of like "white background noise". I think this is why truck drivers idle their engines when the weather is nice and they could just open their windows. They get the constant noise that they are used to and that makes them sleep better.

From a design standpoint, the variable speed generator makes pretty good sense. I suspect the fuel economy/efficiency is moderated somewhat by the losses in the inverter that is part of the system.

Concerning CAN, it is probably designed around the standard described at: http://www.rv-c.com/ (I just checked and that site seems to be down, but I would guess it is temporary).

Assuming that is the case, any CAN based RV "house" system should be able to see and communicate with the system. However, that takes software in the receiving system. SilverLeaf is a leader in that committee and their house monitor system is probably set up to receive the Onan data.
Cullen Newsom (Cullennewsom)
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Posted on Saturday, October 24, 2009 - 1:25 pm:   

Jim,

Your problem is that you need to hang out near more heavy machinery, rock concerts, etc. until your hearing becomes normal.

I didn't get the impression from Onan that they were using the CiA 501 or 502 standards, as it would be kind of shady for them to call that proprietary. Is this the one you're referring to?
http://www.can-cia.org/pg/j1939/additional/j1939-6.html

quote:

The RVIA set of profiles for recreational vehicle communication

The CiA 501 specification defines the J1939-based communication profile for recreation vehicles. The communication profile uses the CAN high-speed physical and data link layers as well as higher-layer protocols similar to SAE J1939.

The CiA 502 specification defines the recreation vehicle application profile based on the CiA 501 communication profile for recreation vehicle. The application profile defines signals and parameters as well as parameter groups similar as in SAE J1939. However, they are not compliant with SAE J1939 or with other J1939-based application profiles such as ISO 11992 (truck/trailer point-to-point network) or ISO 11783 (in-vehicle network for agriculture and forestry vehicles).

Both profiles are being developed in co-operation with the Recreation Vehicle Industry Association (RVIA).




From the brief reply they gave me, I am guessing that they used the parts from j1939 that made sense, and made up what didn't in the empty message space. But that's just a guess.

FYI, I've never done any J1939 stuff, but I have done a couple of shabby proprietary CAN systems.
Jim Shepherd (Rv_safetyman)
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Posted on Monday, October 26, 2009 - 11:04 am:   

Hi Cullen. I held off answering your post until the RV-C website was back on line. The link is: http://rv-c.com/

I have only a basic understanding of the work being done by RV-C. I think the website will give you a ton of information on what is being done in this area.

We are in the process of designing a system to talk to the RV-C communication system. When we get further along, I suspect we will be a bit more knowledgeable {grin}.

I apologize that I have caused this thread to drift a bit.

Jim

(Message edited by rv_safetyman on October 26, 2009)
Cullen Newsom (Cullennewsom)
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Posted on Monday, October 26, 2009 - 5:22 pm:   

Jim,

Thanks for that link. I didn't know about rv-c.

Cullen
RJ Long (Rjlong)
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Posted on Monday, October 26, 2009 - 9:35 pm:   

Bruce, Cullin, Jim -

I'm coming a little late to this party, but can you decipher RVCAN & RV-C for me?

TIA,

:-)
Jim Shepherd (Rv_safetyman)
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Posted on Tuesday, October 27, 2009 - 9:30 am:   

Hi RJ

RV-C is a protocol for various devices to communicate with some sort of control center. This is done over a twisted pair of wires and is often referred to as multiplexing.

It is the technology that is used in electronic engines. There they use SAE specified technolog (J1708 and now, the more powerful J1939). One pair of wires goes to the front and is attached to the data port. Those two wires (along with two power wires) supply all of the engine data that can be displayed by a ProLink, DDC Pro Driver, or SilverLeaf.

Many of the top end motorhomes have a similar system for the house where things like 120V power information, generator info/control/tank monitors, etc are all reported over a pair of wires to the main display module.

Lots of manufacturers are making their equipment compatible with this protocol. I would guess that is what Onan is doing. Most top end inverters can communicate. We are working on making our fire detection/suppression system compatible.

Pretty neat technology. Instead of needing a ton of displays, you can do it all on one display.

The RV industry did not want to get involved with SAE, and went about setting their own standard.

Jim

(Message edited by rv_safetyman on October 27, 2009)
Tom Christman (Tchristman)
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Posted on Thursday, October 29, 2009 - 12:32 pm:   

Personally-I would run as far away from Onan as you can. Onan builds there gensets to require LOTS of maintenance using ONLY Onan parts (even the Kubota engines are different). Use a genset that has universal parts-like Kubota, Yanmar, Isuzu, etc engines, and a Seimans, Marathon, etc alternator end. Manufacturers like Powertech (if you're on the east coast) and Wrico International (if you're on the west coast) are a couple of good examples. I'm using the 13 kw Wrico with remote radiator on my truck conversion. Good Luck, TomC
Tim Brandt (Timb)
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Posted on Thursday, October 29, 2009 - 3:22 pm:   

I have a 15KW powertech that has been bulletproof. currently 4000 hours
john degemis (Degemis)
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Posted on Friday, October 30, 2009 - 12:18 pm:   

"Onan builds there gensets to require LOTS of maintenance using ONLY Onan parts"

My owner’s manual only calls for two things for regular maintenance oil change and air filter change. Since it is air cooled I do not even have to change antifreeze. Is it the best on the market? Maybe not but it is pretty nice. The gas onans are a maintenance headache but the diesels are a different animal. Computer controlled, Self-diagnostics, pure sine wave output. All in a nice quite easy to install package. For the money I am happy with mine. But If I were planning to run my generator 12 hours a day every day I would go with something heaver duty. But since my inverter runs everything but the air condoners when I am driving or when I am dry docking. My generator will get limited use.
john degemis (Degemis)
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Posted on Friday, October 30, 2009 - 12:41 pm:   



(Message edited by degemis on October 30, 2009)

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