Discover in this review whether the Cummins ONAN P2500i is the right inverter generator for you and what options you would prefer instead.
Cummins ONAN P2500i review in short
At first sight, the features of the Cummins ONAN P2500i may look solid.
However, with how common technical issues are in reviews and the higher price, you will likely prefer alternatives.
For example, our top pick for the best 2500 watt generator is the Westinghouse iGen2500.
This inverter generator is better than the Cummins ONAN P2500i in many ways.
Pros
- Nice run time
- Quiet generator
- Easy to carry around
- Good fuel efficiency
- In-depth performance tracking
Cons
- Somewhat high amount of technical issues
- Pricey generator for this power level
- You may need more power
Some of the best uses for the Cummins ONAN P2500i include:
- Camping
- Tailgating
- Running certain power tools
Cummins ONAN P2500i performance in important categories
The mini review, pros, and cons already say a lot but you may want to see how the Cummins ONAN P2500i performs in certain categories before making your conclusion.
| Performance Category | Cummins ONAN P2500i Score* | Performance Category | Cummins ONAN P2500i Score* |
|---|---|---|---|
| Power Capacity | 5 | Fuel Efficiency | 8 |
| Run Time | 7.5 | Ease Of Use | 7.5 |
| Quiet Operation | 9.5 | Portability | 9.5 |
| THD | <3% | Price Category | $$ |
| Reliability Reputation | 5 | Overall Expert Rating | 5.5 |
| Current Price | Check Price |
Individual reviews compare the specific model to portable generators in general and sometimes scores are based on customer input
Cummins ONAN P2500i review table of contents
Cummins ONAN P2500i key features
Other details can be helpful too but the key Cummins ONAN P2500i features in the table below give you a relatively good idea of the main purposes of this portable generator.
| Feature | Cummins ONAN P2500i Detail |
|---|---|
| Fuel Type | Gasoline |
| Starting Watts | 2500 Starting Watts |
| Running Watts | 2200 Running Watts |
| Run Time @25% Load | 10 Hours |
| Noise Levels | As Low As 52 dBA |
| Outlets | (1) Duplex Of 120V 20A 5-20R Outlets, (2) USB Ports, (1) 12VDC 8A Outlet |
| THD | Less Than 3% |
| Warranty* | 3 Years Limited Residential And 1 Year Limited Commercial |
| Price Category** | $$ |
| Check Current Price |
*Warranties can vary from seller to seller
**Price category at the time of writing
What will the Cummins ONAN P2500i run?
It is easy to see in this review that the Cummins ONAN P2500i offers 2500 starting watts, 2200 running watts, 20 amps, and 120 volts.
However, knowing what devices this much power can run is not always straightforward.
The article on what a 2500 watt generator can run goes more in-depth but the few general statements right here can already be helpful.
Some of the bigger devices the Cummins ONAN P2500i should be able to run individually are a small window AC system, certain circular saws, and certain bench grinders.
You can also run a few small to medium devices with the Cummins ONAN P2500i.
One example of a combination this portable generator should be able to run is a refrigerator, slow cooker, and electric drill.
Keep in mind that individual brands of these device categories can have different needs.
Ideally, you would figure out the power needs of the exact things you want to run to make sure the Cummins ONAN P2500i can handle them.
Cummins ONAN P2500i customer reviews insights
At first, the Cummins ONAN P2500i looks like somewhat pricey but good 2500 watt inverter generator.
However, this model is a great example of a portable generator that is not as great as the list of features suggests.
More specifically, there are a somewhat high number of reviews where customers have technical issues with their Cummins ONAN P2500i right from the start or relatively soon.
It does seem customer support often takes care of these issues after a few back and forths.
However, with the good alternatives available, the technical issues in the reviews of the Cummins ONAN P2500i are definitely disappointing.
Cummins ONAN P2500i alternatives
With the technical issues in the reviews and the somewhat higher price, you are likely interested in what Cummins ONAN P2500i alternatives there are.
Our top pick for the best 2500 watt inverter is the Westinghouse iGen2500 which is better than the Cummins ONAN P2500i in many ways.
Additionally, you can consider the WEN DF250i if you like the idea of a dual fuel feature and don’t mind the lower number of customer reviews.
Lastly, you could prefer the Honda EU2200i over the Cummins ONAN P2500i if you value reliability and durability and don’t mind paying more for these things.
Is the Cummins ONAN P2500i worth it?
Even if the customer reviews were not so negative, the Cummins ONAN P2500i would be a relatively pricey inverter generator for its features.
Add the relatively high number of technical issues to this and it should become clear that the Cummins ONAN P2500i is likely not worth it.
Instead, you want to consider some of the alternatives for similar amounts of power or stronger generators if you want to run more devices.

Other Cummins ONAN P2500i specs
There are also other Cummins ONAN P2500i specs I did not mention in the review yet. You can find these in the table below.
Additionally, you can look at the Cummins ONAN P2500i manual for even more details about things like certain parts and how to use this generator.
| Specification | Cummins ONAN P2500i Detail |
|---|---|
| Voltage | 120 Volts |
| Portable | Yes |
| Fuel Tank Capacity | 1 Gallon |
| Fuel Efficiency (kWh Per Gallon) | 5.500 |
| Outlet Covers | Yes |
| Engine Displacement | 98cc |
| Recoil Pull Start | Yes |
| Electric Start | No |
| Low Oil Shutdown | Yes |
| Fully Enclosed Design | Yes |
| AC Frequency | 60 Hz |
| Remote Start | No |
| Built-In Digital Smart LCD | Yes |
| Hour Meter | Yes |
| Fuel Gauge | Yes |
| Wattage Meter | Yes |
| Run Time Remaining | Yes |
| Engine Type | 4 Stroke |
| Remote Generator Operation | No |
| Parallel Ready | Yes |
| Wheels | No |
| CO-Minder | No |
| Country Of Origin | Not Mentioned |
| Dimensions | 19.75″ L x 10.5″ W x 18.25″ H |
| Weight | 48 lbs (21.8 kg) |
| Check Current Price |
Cummins ONAN P2500i FAQ
How long will a Cummins ONAN P2500i run?
A Cummins ONAN P2500i will run about 10 hours on a full tank of gas at 25% load.
How much oil does a Cummins ONAN P2500i take?
The Cummins ONAN P2500i has an oil capacity of 11.8 fluid ounces which is about 0.35 liters.
How many decibels is a Cummins ONAN P2500i?
A Cummins ONAN P2500i is rated for “as low as 52 dBA”.
There is no mention of what load or distance this amount of decibels is measured at.
What fuel does a Cummins ONAN P2500i use?
Cummins mentions their ONAN P2500i use unleaded gasoline
(10% ethanol or less) as fuel.
How much does a Cummins ONAN P2500i weigh?
A Cummins ONAN P2500i weighs around 48 pounds (21.8 kg) without any fuel or oil.
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