Is Cummins Onan 4000w Generator or Inverter model better for Forest River RV with Victron Inverter?
Updated 07/02/2025 | Published 06/17/2025
Question:
We’ve got a 2021 Forest River Sandpiper 38HOK fifth wheel with two 15,000 BTU Dometic A/C units and residential fridge. Headed out to Utah for three weeks of off-grid camping near Grand Staircase. Wondering, what’s the real difference between the Quiet Series Cummins Onan 4000-watt generator (part #?CM32ZR) and the inverter model Cummins Onan QG 4000i (part #CM42ZR) We already have a Victron 2000-watt inverter for our electronics, but just want to be sure we're making the right call for running everything reliably.
asked by: Jone
Expert Reply:
Hey Jone - great question, and it sounds like that Sandpiper 38HOK is built for some serious off-grid adventure! We’ve worked with a few customers in similar setups (shout out to Jeff in CO and Laurie in AZ), and here’s the real-world scoop.
The # CM32ZR Quiet Series is the classic, field-tested 4000-watt model — tuned for low vibration and ideal for running your A/Cs, fridge, and microwave. It’s a bolt-in friendly option that plays well with your existing Victron inverter for sensitive electronics.
The # CM42ZR 4000i inverter model steps it up with lighter weight, quieter variable-speed operation, and clean sine wave output. That’s great if you ever want the generator to directly power your sensitive electronics or charge lithium batteries more efficiently and smoothly.
Since you’ve already got a Victron handling the delicate stuff, the Quiet Series might be all you need. But if you're planning on maxing out inverter you currently have, then the 4000i is worth it for sure! For the slight price difference, I'd recommend just getting the inverter model.
Are you charging from solar too, or relying just on generator + battery? Let us know — we can help optimize your whole off-grid setup for Utah. Safe travels!
Continue Researching
- Search Results: generators
- Search Results: fuel tank
- Shop: Flex Power Mini Onboard RV Generator - 4,000 Watts - Dual Fuel and Inverter - Fixed Mount
- Shop: MORryde RV Generator Slide Out Tray - 25-3/4" x 26-1/4" - 100 Percent Extension - 300 lbs
- Shop: Onan Generator - Quiet Series Onboard RV Generator - 6,000 Watts - Diesel
- Q&A: Replacement for Onan QG 4000 in 2022 Thor Coleman Motorhome
- Q&A: Replacement Onan QG-4000 Generator In A Jayco RedHawk 31XL
- Search Results: slide out kit
- Q&A: Recommended Sliding Cargo Tray For An Onan 5500 Generator
- Shop: Replacement Standard Dual Rack Repair Kit for Lippert RV In-Wall Slide-Outs - Float Side
- Shop: Onan Generator - Quiet Series Onboard RV Generator - 8,000 Watts - Diesel
- Video: Review of Lippert Components Slide Out Replacement Dual Rack Kit - LC26VR
- Shop: CE Smith U-Bolt Kit for Mounting 3,500-lb, Round Trailer Axles - 5-1/2" Long U-Bolts - Zinc
- Q&A: Dimensions of Hangers and Equalizers on Tandem Axle Suspension on 16-Ft Trailer
- Q&A: Will Triple Axle Hanger Kit # APTT5 Work with Leaf Springs E64SR
- Shop: 4-Leaf Double-Eye Spring for 4,000-lb Trailer Axles - 26" Long
- Shop: Trailer Hitch
- Q&A: What is the Difference Between a Class II and a Class III Hitch?
- Search Results: trailer hitch
- Video: Firestone Ride-Rite Air Bags with Easy Mount Compressor Feature Breakdown
- Article: Trailer Wiring Diagrams
- Shop: Trailer Wiring
- Search Results: trailer tires and wheels
- Article: Brake Controller 7- and 4-Way Installation Kit (ETBC7)
- Q&A: Lug Nut Torque Chart for Trailer Wheels
- Shop: Suspension Enhancement
- Video: How to Choose a Trailer Brake Controller
- Search Results: trailer wiring
- Article: How to Measure for Trailer Hitch Drop
- Search Results: trailer jack
on Generators
Jone
7/2/2025
Thanks, Andrew! We're indeed using solar panels alongside the Victron inverter. Do you think the inverter model would integrate better with our setup, or is the Quiet Series sufficient?