I have no experience or knowledge regarding the Genset you mentioned nor have I ever heard of it. However, the big question I would have if I was considering one is where I would have to go to get warranty service on it if needed and availability of parts. If you are in say Oregon and the nearest service for a Northern Lights Genset is in Chicago you would be kinda out of luck. A name brand Genset such as Onan is fairly easy to get service or repair if needed.
I can't say I have ever seen a NL in operation. Howevver, your description of Onan is incorrect -many Onan models designed for RV's run at 1800 RPM including the Marquis, Emerald Plus, and the Quiet Diesels that actually run from 1600-3250 at lower ratings and 1800 at higher. Only the Micro series run at 3600. In fact, Onan sells what they call a standard diesel unit that is comparable to NL in that it is not enclosed i.e is skid mounted and uses a standard diesel engine and it runs at 1800 also. The difference between the standard skid mounted diesels and the Onan enclosed engines/diesels is apples and oranges. You don't say application planned but if operation in National parks (noise/spark suppression)are a consideration or you need to mount in an enclosed space rather than on a skid your choice may be significantly different than if otherwise. ANd as notd in earlier message, I believe Onan service locations will be more common.
Hi Sylvie:- Northern lights is primarily a marine diesel unit. I don't know how they have added the rad but make sure that the unit you buy has a rad, because marine units use the lake or ocean water to cool the engine.?
Gensets run at different RPMs depending on their design. Skid mounted diesel units mostly run at 1800 RPM. The engines are designed for that and they get a very long life from the engine, typically more that 30,000 hours. These units are used mostly for remote power applications and high end RVs. Most RV genset especially gas or propane units run at 3600RPMs. You can use a smaller engine to get the same KW. (higher rpm, more power).
Portable gensets (not mounted RV types) such as Honda or Yamaha are going more and more toward inverter technology so they operate at variable speed. This saves on fuel and engine wear for applications when not a lot of power is being drawn from the genset.
As some of the other posters have said -- Stay with the brand names. Onan has service all over the continent, even up into Alaska and all along that route. Honda and Yamaha as well.
Onan makes gensets for RVs of all types even the 1800RPM Diesels, they will be more money than the Northern lights but not much more. Also remember what I said about the rad. Depending on where you are buying from the unit might need to have a rad installed. Buying a proper RV genset will prove to be better in the long run.
Hi. I am brand new here, but just read this thread on Northern Lights generators. I am familiar with them as being a marine use generator only. We had one on our boat in Baja. Like another poster mentioned I would investigate the cooling system required in a land/RV based application.