ALL NEW Onan Cummins 2500i inverter generator - I LOVE IT!

For us small motorhome owners with the good old 4KW Onan gas or diesel generators - I wonder if/when Onan is going to come out with 4KW inverter gas and diesel versions?

Combining the legendary Onan reliability with inverter technology for all of their models is long overdue!

FINISHED! Took me awhile to get back to the new install with traveling etc., but I'm pretty much 95% done. Just need to secure the exhaust pipe, route the aux propane inlet and secure the exterior panel to the camper.



My 2013 AF 990 required a totally new approach. First, the HGLAA Spec A (2500i LP) was slightly larger than the original Onan 2.5 KVD. The mounts didn't line up, and the brackets made it too wide to fit in width wise.

I built an aluminum rack sitting on shock absorbers to one raise it up for better front end air draw and two, to use the existing 3/8" mounting holes and three, to mount bolts up through the new rack into the bottom of the Generator tray.



Everything Onan/Cummins supplies is in Metrics. Either spend the extra time to check and recheck your conversions or just buy a metric tape measure for $15 on Amazon. I built a template to get the mounting holes through my rack drilled and sized before I set it in. I braced my large aluminum 1”x2”s with Z brackets and rivets where the bolts mounted to the bottom tray. I used 1/8” thick 2” wide strips to further support the structure. The generator engine is already superbly shock mounted inside the chassis so my aluminum rack with the shock absorbers was almost overkill. I also added some sound deadening material (KILMAT 80mil) inside the entire generator compartment to further cut down on cabin noise – it worked. I mean the difference is unreal.

I have zero vibration into the frame – unlike the old KVD - and the thing is SUPER QUIET. I mean it’s so quiet I intend to ditch the Honda 2000. I believe Onan advertises it meets the National Park regulation of 60db at 50 feet. At 50% load it’s 65Dba at 10 feet.

Overall, it’s a huge upgrade with dramatic improvement. The drawbacks are you have to custom install these into older campers but in my view the improvement in vibration, noise and sound is unbeatable. Be ready to spend some time checking and rechecking your custom mount – I think I put it in two or three times to check for form fit and function – it’s a beast at 110 pounds. Cost is always a negative and due to supply chain issues, I had to wait a few months for delivery. On the plus side, the thing is so quiet I intend to put the Honda 2000 on the shelf and leave the gas cans at home. That in itself is a huge win! Now, if it can be as reliable and easily maintained like the Honda’s it’ll be a keeper.

Prior to installing the new gen, I had to "pop the hood" and take a look inside.

I'm pretty impressed with the nice vibration dampening system it has.

Inside Look

Part number for the remote panel I used it 028-00022
It has a SILENT LCD hour meter.

When I had a generator in my Mash 17k, it used a analog hour meter - think of "old school odometer" like cars up through the 80s had.
That hour meter made a "click" every 10 seconds or so and was really annoying in a small RV

AISURFFISH wrote:
The new AF1150 HAS IT STANDARD NOW. That is due to the inability to getting the regular 2500

ALL RVs that have the 2800/2500 watt generator will include the 2800i or 2500i,

The "inability to get the old one" is because the old one (the HGJBB) has been DISCONTINUED. It was discontinued well over six months ago.

The Inverter model replaced the old model

All I added was the resonator and a new tail pipe. I had to get a new tail pipe because i gave away the old one with my HGJBB when I sold it.

I purchased the tail pipe from a Cummins/Onan Facility in Sumner, WA and had it shipped to me. They were the only ones that had the extended length drop pipe I needed.

What is the item you listed as A602M244 Muffler Accessory Kit?

The Resonator won't degrade generator performance. It softens the harshness of the exhaust note. I'd recommend it for ANY genny installation.

I also had to get a longer propane hose since the propane inlet is on the opposite side from where it was on the HGJBB. I bought a 36" hose from my local RV parts store.

For those interested in the upgrade I just checked with Cummings last week. It's a 20 Week lead time for non OEM customers. They are pumping these out to the OEMs as fast as they can to meet manufacturer demand. You can find them on-line for about a grand more (if you want it quick) than you'll pay to wait.

I put my name on the order list to replace my Onan 2.5 KVD LP Genny which, interestingly enough, the control board failed on coming back from Jellystone last week. Just FYI if your Genny only runs when you have to hold the "start" button down you've had a control board failure. I intend to just drop mine from the camper to replace the board since trying to unscrew the four cover screws that seem to be torqued down by a gorrilla at the factory have been unsuccessful....but I digress.

From my research, here are some of the Part #s you'll need to make the swap:

Part Number Description
A063N9302.5HGLAA-8304
0155-2325Alum Steel TailpipeKit
0155-2449 Exhaust Resonator
0155-1015 Pipe Clamp

The LP input line is on the opposite side of the current model, same with the power. Additionally, the exhaust exits the Driver side vs the passenger side on the current model. Hence the additional Muffler and accessory tailpipe kit. I intend to install the resonator to see if it makes an additional reduction in Db without degrading Genny performance.

The new AF1150 HAS IT STANDARD NOW. That is due to the inability to getting the regular 2500

That new 2500i is revolutionary for truck campers with the propane generators.

deltabravo, can you include the part numbers of the Cummings accessories you needed (exhaust etc.) to complete your install? Or, even links to the pages you found?

I'm sure as time goes on this post will be referenced hundreds of times as folks upgrade to the Onan 2500 HGLAA like me ;) Thanks!!!

deltabravo wrote:
When I went to bed around 9pm, it was 92 degrees out still.

Its 10:00 AM and 94 degrees here. :E :M