Are Cummins' Onan Generators Any Good? Here's What Owners Say

A reliable generator proves useful in many scenarios, from rural projects and RV camping to vital emergency power. Although, there are some things to keep in mind when choosing the right generator for your home. Cummins Onan portable generators are praised by owners, for things like an extendable handle and remote start technology. These features are found on models like the Onan P4500i Inverter Generator, which buyers rated a 4.3 out of 5 on Amazon. 

Another lauded advantage, is the low noise produced during Onan operation. For example, one enthusiast compared the sound of the Honda 2000 against the Onan P4500i, and found that the Cummins was quieter at 78 decibels with twice the power. Another RV owner and inspector explained the low hum of a motorhome fitted Cummins, blends into the background.

Some do report Onan starting issues, but most others describe remarkable dependability. For example, one review for the P4500i, boasted that over four years, their unit ran nearly 7 days a week for up to 10 hours daily and only experienced one issue. Another RV aficionado reported their motorhome equipped Onan performed consistently for fifteen years, highly recommending it.

Although, there have been a few complaints lodged against Cummins products. For example, when performing maintenance or basic repairs on the RV Onan units, it's been described as challenging, due to space restrictions and what some consider an over-engineered design. Others mentioned the prohibitive cost of proprietary parts with some running up to $1000 and beyond.

Within the Onan product line, there are two types of generators: portable and RV installed units. If your home-on-wheels is missing an on-board unit, you can utilize a portable option, but you should know how to safely hook up your RV to a generator first. The portable options use inverter technology, dual-fuel inverter, and dual-fuel configurations. An inverter generator works a bit differently, producing electricity with less total harmonic distortion.

The Onan P2500i Inverter is ideal for running things like a television or coffee maker with a peak of 2,500 Watts. Dual-Fuel generators like the Onan P4500iDF, can use either gasoline or propane and offer a peak of 4,500 Watts (gas) and 4,050 (Propane) allowing them to run things like an air conditioner or microwave. The most robust portable option, is the Onan P9500DF, which can produce a peak of 9,500 Watts (gas), and 8,550 (Propane), capable enough to provide backup emergency power to a home.

The other variant of Onan generators is designed to be installed onboard an RV for use with boondocking (camping without supplied power), powering onboard appliances like air conditioners in transit, and in case of blackouts. These units come in different configurations that run on gasoline, diesel, and Propane, with 20- and 30-Amp breakers. Depending on the model, you can power RVs from a Class B van (which might need around 2,000 Watts), up to a Class A motorhome with three air conditioners (which could require 12,000+ Watts).