Built-in Onan Generator - inverter compatibility

[jcpainter]

As we were ending our "snow birding" stay in Florida this year, we had Camping World install a Cummins Onan Marquis Gold 5500 generator and a 2000 watt Nature Power pure sine wave inverter/charger.

Our request was for a "pure sine wave" system that was safe for all of our sensitive electronics.

After 2 days of installation we were told that "Everything checked out fine, here's the book to read how to use it". This was late on on Good Friday and the service dept was trying to close. We were rushed out the door.

On our way home to TN, we opted to try out our new system by dry camping in a Wal-Mart parking lot.

I won't bore you with the details, but the system did not work fine. We've since taken it to a Camping World in TN. They had it for two days and are now saying that the two devices (that they sold us and installed in our rig) are not compatible. I believe they said that the inverter is a pure (true) sinewave, but the Onan generator is not. Apparently they are having this problem with other such systems that have been sold throughout the US recently and are "working on a solution".

I've been told that Camping World used to sell the Zantrex inverter and that it worked fine with the Onan generator. Going to the Zantrex site I see that they make both pure sine wave and modified sine wave inverters. I see an old youtube video where the true sine wave Xantrex was sold by Camping World.

Does anyone have the Onan generator described above working with a 2000W pure sine wave inverter/charger? If so, what brand inverter?

Any help in "layman's language" would be greatly appreciated.

[MEXICOWANDERER]

"The oldest Onans used no voltage regulation at all. The faster they spun, the more the output voltage."

I beg your pardon. The voltage REGULATION control process they used is referred to as "saturated field". As long as the Hz was maintained near 60, the voltage was great. So was the waveform. The problem of these older Onans was speed control. This is where me and Woodward Controls made great friends. Even 30 years ago I was getting 60.0 + - .3 Hz speed control. No these generators did not use a Voltage Regulator with ready-to-burn transistors, diodes, and resistors. Basler regulators were so bad back then half the trawlers switched over to saturated field generators.

Below is a superb PDF explanation of the process, also known as "self-regulation"

http://web.uettaxila.edu.pk/CMS/SP2012/etEMbs/notes%5CDC%20Generator%20x-tics.pdf

[BFL13]

Vector portable chargers run ok at full amps from MSW inverters. So that wave form doesn't seem to bother them, at least not that you can notice.

I see from posts in this thread that we have to be careful in not equating poor wave form with MSW. Poor wave form can also mean spikes or whatever.

The Vectors do run at lower amps when on clean 120v, but at "low voltage" from long extension cord or from just having too many Vectors on one 15a circuit. EG, the 40amper will run at 39.x amps instead of the usual 40.4a

Same thing with the 7355 converter. Lower 120v input means fewer then normal DC amps out. Converters mostly have specs that say they need at least 105v.

One of the selling features in the Vector ads is that they will "make up" for low voltage input. I guess that means they will still run, but they sure don't put out full amps then.

However seeing 80 instead of 100 amps is huge compared with those examples.

Ten years or so ago, Xantrex had warnings in their blurb about Truecharge chargers (be similar to the charger in a Prosine 2.0) not running well on some generators due to wave form issues.

[mlts22]

I wonder if Onan could make a model with a PSW inverter and variable speed (like eco-throttle), but either have a battery (or a supercap when that technology gets down the road a bit) or use the house batteries to handle the inrush current from compressors until the engine can get up to speed.

Of course, one could see about having the generator always keep a lithium-ion battery bank charged and have a PSW inverter on that. The result would be extremely clean power until the inverter was at its limit regardless of how fast the generator's crankshaft was spinning.

[DryCamper11]

There are several comments here about problems between the charger and an Onan generator. Those problems often disappear when the gen is loaded. Similar problems are often found when the gen is an inverter gen. The oldest Onans used no voltage regulation at all. The faster they spun, the more the output voltage. They were set at 60 Hz to produce the desired output voltage. The CCK model comes to mind.

Newer gens, including the Onan Marquis series, many Generacs and most other high end gens use a chopping type voltage regulation to control the current through the excitation windings. At low voltage, this seems to make some charger circuits unhappy. Many chargers need the top end of the sine wave voltage to work well. At low loads, some generators don't meet the needs of these chargers.

The most expensive generators (Onans Quiet Diesel series and fancy portable gens) use an inverter to produce the output AC waveform. Again, some chargers just aren't happy with the output from these generators, particularly at low load. it depends quite a bit on the design of the charger's input circuit as to whether there is any problem.

I happen to love my 40 year old Onan CCK. It has no fancy electronics that interferes or interacts with the electronics in chargers and microwaves.

[BFL13]

docj wrote:

BFL13 wrote:
Wonder if you went from the frying pan to the fire wrt the charger portion of that and the Onan.

http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/27264550.cfm

The thread in this link discusses design issues relating to the Magnum ME2012 inverter which is a MSW device. They may or may not be relevant to the OP's situation since he says he is having an MS2012 FSW inverter installed.

Yes, but I meant the charger portion not the inverter portion. The business about doing 80 instead of 100 from the non-inverter gen.

[MEXICOWANDERER]

First of all THANK YOU for following up on your original post. It's nice to for once not follow footprints leading to an abyss.

Regarding funky electronics behavior and gensets. A non-inverter genset MUST be allowed to start, spin-up and stabilize its speed in order to stabilize frequency more or less at 60 hz. Then and only then, should a switch be thrown putting the unit on-line. If a succession of loads are to be applied, the HEAVIEST load (the highest wattage usually a motor) must be started first, then a progressive adding of loads, the second greatest the the third, etc. This is normal genset protocol from 200 watts to 200 megawatts. Utilities, also have a protocol they use when putting a generating plant on line.

What happens when you OOOPS overload an inverter generator by not observing this protocol. So solly chally, you got yourself a SQUARE WAVE inverter. Even the megawatt DC system will revert to square wave if it is overloaded. But you can bet the buttons on your britches the safely shunt overload relays are going to go C-L-A-C-K !!! at 55Hz.

[EsoxLucius]

I am still wayne_tw wrote:

jcpainter wrote:
...we had Camping World install a Cummins Onan Marquis Gold 5500 generator and a 2000 watt Nature Power pure sine wave inverter/charger.

Its too late now, but having Camping World install anything was your first mistake.

No, the first mistake was not purchasing a Magnum Inverter/Charger in the first place. The only Nature Power Inverter/Charger is the 38330 which does not have an established track record. A Magnum MS2812 will cost about the same, do the same job, and work fabulously with an Onan generator.

Good luck with your Magnum Inverter/Charger!

[docj]

BFL13 wrote:
Wonder if you went from the frying pan to the fire wrt the charger portion of that and the Onan.

http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/27264550.cfm

The thread in this link discusses design issues relating to the Magnum ME2012 inverter which is a MSW device. They may or may not be relevant to the OP's situation since he says he is having an MS2012 FSW inverter installed.

[BFL13]

Wonder if you went from the frying pan to the fire wrt the charger portion of that and the Onan.

http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/27264550.cfm

[jcpainter]

Camping World replaced the Nature Power 2000 with a Magnum inverter.

They ran it through testing and it appears to have fixed the problem. I say "appears" because we have not put it through real world usage yet. We plan to do that later this month.

They put the GFI circuit back on the inverter, thank goodness.

Jetnjeff295 wrote:
Our inverters pass through circuit went out, near the time you got your 2000 installed! We got the Nature Power 3000 as a replacement for our Xantrex. All seem to work fine. GFI Powers half the bus, just as before.

Would like an update on your new congig.

Our Onan 7500 appears to have shrapneled, but that is a different story.

Jeff O'Hara
2004 Fleetwood Rvoluotion 40c Diesel Pusher.

[Jetnjeff295]

Our inverters pass through circuit went out, near the time you got your 2000 installed! We got the Nature Power 3000 as a replacement for our Xantrex. All seem to work fine. GFI Powers half the bus, just as before.

Would like an update on your new congig.

Our Onan 7500 appears to have shrapneled, but that is a different story.

Jeff O'Hara
2004 Fleetwood Rvoluotion 40c Diesel Pusher.

[time2roll]

GFI circuit and microwave most certainly can be powered by the inverter.
Mine are and work fine. Xantrex actually recommends pushing power through a GFI. And many inverters have a built in GFI outlet as the only option.

BTW 2x GC2 is a bit light for heavy use like microwave.

[joebedford]

FWIW on my old rig, when I started my Onan 5500 without any significant load, the clock / display on the microwave would go crazy. If I added more load like an air conditioner or heater, the microwave would behave normally. Obviously something about the no load power being produced by that generator was 'funky'.

I have an Onan 5500 in the current rig - it does not display any 'funky' behavior.

I don't have an inverter - when I want AC power, I run the generator.

[John___Angela]

docj wrote:

John & Angela wrote:


No this is not true. A properly installed inverter has no problem running microwaves wether it is on a GFI. Circuit or not. Having said that, if your inverter produces a modified sine wave instead of a sine wave there are some devices that may not like it. For example, the microwave in our little C class did not like a modified sine wave. The one in our A class didn't care. We now have only sine wave inverters but the original inverter in the A was a modified sine wave. Served us well for nine years before it smoked. 458 Xantrex.

The Magnum inverter specified by the OP is a pure sine wave unit. This information is irrelevant.

It was intended as general information in the hopes it would further inform those in the group with less knowledge on the subject.

happy trails.