Inverter generator for RVs

[Gerryl]

I can't figure out why Honda, Yamaha, or somebody doesn't make an 'Inverter' generator for motorhomes. The inverter generators use about 1 tenth the gas that normal RV generators use and are at least half as quiet.

You would think that there would be a good market for that.

[nothermark]

Because most of us would not pay the additional cost given any choice in the matter. Particularly for units that sell for less than $100,000.

[jharrell]

Originally Posted by Gerryl

I can't figure out why Honda, Yamaha, or somebody doesn't make an 'Inverter' generator for motorhomes. The inverter generators use about 1 tenth the gas that normal RV generators use and are at least half as quiet.

You would think that there would be a good market for that.

Cummins-Onan Quiet Diesel 6000 and up are inverter generators:

http://power.cummins.com/sites/defau.../F-1823-EN.pdf

Page 4: "Cummins Onan alternator and Cummins Onan inverter work together efficiently to deliver consistent 120-volt power. "

So basically all class A diesels even the low end ones are using a liquid cooled inverter generator.

[Steve Ownby]

Originally Posted by jharrell

Cummins-Onan Quiet Diesel 6000 and up are inverter generators:

http://power.cummins.com/sites/defau.../F-1823-EN.pdf

Page 4: "Cummins Onan alternator and Cummins Onan inverter work together efficiently to deliver consistent 120-volt power. "

So basically all class A diesels even the low end ones are using a liquid cooled inverter generator.

This is true up to the 10 & 12.5 KW units which are 120/240 generators.

[nothermark]

I am having a chuckle over the idea of a low end DP. Does anyone know the price point for one of them? ;-)

[gemert]

OK, now I'm officially confused. A generator in our applications is a unit that has an engine whether gas, diesel or propane attached to the electrical generator that produces 120VAC. We use the 120AC in our coaches (or from shore power) along with the 12vdc. Typically the Inverter/Charger uses that 120VAC to produce 12VDC to charge the Batteries and run 12VDC items in the coach. When no shore or generator power is available or desired, the inverter "inverts" 12VDC into 120VAC to run 120VAC items in the coach. Those inverter generators you see just have a small inverter in them to provide a small 12VDC charger to charge batteries. This is only a pittance compared with what a big rig needs. They have covered all those concerns in our rigs. The reason they are bigger noisier and use more fuel is because we need them to so they provide what we need. They have done a good job. They could be quieter if they added more insulation. That would take up more room in our coaches and cost more. And come to think of it, mine is pretty darn quiet now!!!

[gemert]

Originally Posted by nothermark

I am having a chuckle over the idea of a low end DP. Does anyone know the price point for one of them? ;-)

Probably Nexus RV as nice as they are for 200K (ish)!

[Rich-n-Linda]

The large generators in motor homes do not directly generate 120 volts AC. They are actually a DC generator feeding a built-in inverter. That inverter is what actually supplies the 120 VAC to the house when running the generator.

A straight generator which directly generates 120 VAC has to run at a constant speed, usually 3,600 RPM. The constant speed is needed so the AC power output remains at a constant and steady 60 hz. At light loads that is very inefficient because the high speed is not necessary at light loads. An inverter/generator can run at a low RPM under light loads, but speed up when the load increases.

One way to tell what you have is to note what the generator does as the load is changed. If it speeds up a little when the AC kicks on, you have an inverter/generator. If it runs at a constant speed no matter what the electrical load is, you have a generator.

All the small generators mentioned by the OP are straight generators which run at a steady 3,600 RPM.

[rgodfrey]

Originally Posted by gemert

OK, now I'm officially confused. A generator in our applications is a unit that has an engine whether gas, diesel or propane attached to the electrical generator that produces 120VAC. We use the 120AC in our coaches (or from shore power) along with the 12vdc. Typically the Inverter/Charger uses that 120VAC to produce 12VDC to charge the Batteries and run 12VDC items in the coach. When no shore or generator power is available or desired, the inverter "inverts" 12VDC into 120VAC to run 120VAC items in the coach. Those inverter generators you see just have a small inverter in them to provide a small 12VDC charger to charge batteries. This is only a pittance compared with what a big rig needs. They have covered all those concerns in our rigs. The reason they are bigger noisier and use more fuel is because we need them to so they provide what we need. They have done a good job. They could be quieter if they added more insulation. That would take up more room in our coaches and cost more. And come to think of it, mine is pretty darn quiet now!!!

I think you are mixing up your terminology a little. A "converter" takes AC power and turns it into DC power. An inverter takes DC power and turns it into AC power. As far as I'm aware, all RV's have converter/chargers to charge the house batteries and run DC items. Some RV's have inverters to run AC items when there is no shore power available. These inverters are sometimes separate units and sometimes part of the converter/charger.

Here's a link that explains conventional generators vs inverter generators...

http://www.yamahaef2000is.com/conven...generator.html



Sent from my iPad using iRV2 - RV Forum

[gemert]

Originally Posted by rgodfrey

I think you are mixing up your terminology a little. A "converter" takes AC power and turns it into DC power. An inverter takes DC power and turns it into AC power. As far as I'm aware, all RV's have converter/chargers to charge the house batteries and run DC items. Some RV's have inverters to run AC items when there is no shore power available. These inverters are sometimes separate units and sometimes part of the converter/charger.

Here's a link that explains conventional generators vs inverter generators...

Conventional Generator vs Inverter Generator



Sent from my iPad using iRV2 - RV Forum

Yes I thought I said that, probably didn't do a good job. Our inverters actually have a charger that is a converter in that it takes 120AC and converts it into 12VDC and charges the batteries. The inverter portion of the inverter actually takes the 12VDC from the batteries and "inverts" it to 120VAC. I'm probably going to make matters worse if I keep going but I just verified my usage of the terms and they are correct. I am also pretty sure that my generator is in fact a generator. It runs at a constant speed. It has to to generate 60HZ as you mentioned. As the load on the generator increases it has to use more fuel to maintain that constant speed. My basic electricity and electronics training in the Navy was a year long but 43 years ago so I do not claim to be an expert. But I am pretty familiar. Only wish I was better explaining it! Happy Camping!!!

[twinboat]

The constant 1800 or 3600 rpm rotating things, that we call generators, actually contain alternators. They produce alternating current ( AC )

An inverter generator produces direct current ( DC ) and electronically changes it to 120 volts AC.

The 12 volt engine mounted alternator produces AC current that is directed thru a diode bridge to produce DC to charge batteries. There was a time when actual DC generators were used on autos for battery charging.

[gemert]

Originally Posted by twinboat

The constant 1800 or 3600 rpm rotating things, that we call generators, actually contain alternators. They produce alternating current ( AC )

An inverter generator produces direct current ( DC ) and electronically changes it to 120 volts AC.

The 12 volt engine mounted alternator produces AC current that is directed thru a diode bridge to produce DC to charge batteries. There was a time when actual DC generators were used on autos for battery charging.

I was trying to avoid talking about the rotor that is powered by the engine rotating inside or around the stator. It's really all just a clump of wire with a magnetic field inducing an electrical current in it. As for the details of rotation speed and whether the rotor is the magnet or the wire, I'm afraid it was too long ago. I just know that my generator produces 120VAC. 120VAC is taken by the charger, part of either a converter charger or an inverter (all common terms and 100% accurate...maybe, maybe not.) The charger charges my house and Chassis batteries. When no 120VAC, my inverter uses 12VDC from the batteries to make 120VAC to make my coffee. Sometimes there is a transfer switch and that is a whole other story. Happy camping folks, it's Miller time!!

[nothermark]

FWIW I think you will find the inverter generators are polyphase alternators with rectifiers. In short they make AC then rectify to DC then invert to AC. Using multiple phases and higher frequencies makes filtering the DC input to the inverter simpler.

[gemert]

Originally Posted by twinboat

The 12 volt engine mounted alternator produces AC current that is directed thru a diode bridge to produce DC to charge batteries.

Oh I forgot, that would be called a rectifier.