Compare Generators Side-by-Side
Select up to 4 generators to compare specs, power output, noise levels, runtime and more. Your compare URL is shareable.
- Cummins Onan P2500i
- Cat RP3600
Quick charts
Each chart uses its own Y-axis scale (so numbers are comparable within a chart).
Running watts
W
Starting watts
W
Noise
dB
Runtime @50%
h
Running watts by fuel
Shows how output changes across gasoline/propane/natural gas (when available).
| Specification | Cummins Onan P2500i | Cat RP3600 |
|---|---|---|
| General | ||
| Product type | Generator | Generator |
| Fuel | Gasoline | Gasoline |
| Inverter | Yes | No |
| Parallel capable | Yes | No |
| RV ready | No | Yes |
| Running watts | 2200 W | Winner: Winner: 3600 W |
| Starting watts | 2500 W | Winner: Winner: 4500 W |
| Noise (lower limit) | Winner: Winner: 52 dB | 0 dB |
| Weight | Winner: Winner: 48 lbs | 125 lbs |
| Run time @50% load | 8 h | Winner: Winner: 13.5 h |
| Run time @25% load | 10 h | Not available |
| Fuel tank | 1 gal | 4.5 gal |
| Fuel gauge | Yes | Yes |
| Approx. dimensions (L × W × H) | 19.8 x 10.5 x 18.3 | 28.4 x 25.2 x 23 |
| Electrical | ||
| Voltage (AC) | 120 | 120V 60 Hz |
| Voltage (DC) | 12 | Not available |
| GFCI outlets | No | No |
| Covered outlets | Yes | Yes |
| Automatic Voltage Regulation | Yes | Yes |
| THD | <3% % | Not available |
| Engine | ||
| Engine | 98 cc Ducar OHV 4-stroke engine | 212 cc OHV 4-stroke |
| Alternator | Not available | Not available |
| Starting system | Recoil | Recoil |
| Warranty | ||
| Warranty | 3 years | 2 years |
| Power by fuel | ||
| Gasoline | Not available | Not available |
| Running watts | 2200 W | 3600 W |
| Starting watts | 2500 W | 4500 W |
| Running amps (120V) | Not available | Not available |
| Running amps (240V) | Not available | Not available |
| Peak amps (120V) | Not available | Not available |
| Peak amps (240V) | Not available | Not available |
| Run time @50% load | 8 h | 13.5 h |
| Run time @25% load | 10 h | Not available |
| Other | ||
| Data center | Not available | Not available |
| Indicators | true | false |
| Compliance | CARB, EPA | CARB, EPA |
| Security | Not available | Not available |
| Spark arrestor | Yes | Yes |
| Neutral | Floating | true |
| UPC | 690781007918 | 815683020005 |
| Core / High-priority specs | ||
| Running Watts (Gasoline) | 2200 | 3600 |
| Starting Watts (Gasoline) | 2500 | 4500 |
| Runtime @ 50% Load (Gasoline) | 8 | 13.5 |
| Runtime @ 25% Load (Gasoline) | 10 | Not available |
| AC Outlet Types | 1x Duplex 120V 20A (5-20R) | 2x Duplex 120V 20A (5-20R) 1x 120V 30A (TT-30R) |
| Electrical & power | ||
| Frequency | 60 | 60 |
| Engine & construction | ||
| Engine Type | Ducar OHV 4-stroke | OHV 4-stroke |
| Engine Displacement | 98 | 212 |
| Engine Oil Type | SAE 10W30 | SAE 30 or 10W-30 |
| Runtime & fuel system | ||
| Runtime @ 25% Load (Gasoline) | 10 | Not available |
| Runtime @ 50% Load (Gasoline) | 8 | 13.5 |
| Safety & compliance | ||
| Overload Protection System | Low oil and overload protection | Low oil and overload protection |
| Low Oil Protection | Yes | Yes |
| Included equipment | ||
| Starting Components | Not available | Oil, funnel, tool kit, and wheel kit |
| Included Accessories | Oil, funnel, and tool kit | Oil, funnel, tool kit, and wheel kit |
| Warranty & identification | ||
| Part Number | Not available | 502-3684 |
| Additional specs | ||
| Summary | The Cummins Onan P2500i is a 2200-watt inverter generator built for users who need portable power without sacrificing runtime or noise control. At 48 pounds and measuring 19.8 by 10.5 by 18.3 inches, this unit bridges the gap between true portability and practical capacity. It can run a microwave, small refrigerator, or circular saw continuously, making it suitable for camping trips, job sites, tailgating, and emergency backup. The 1-gallon fuel tank delivers 10 hours at 25 percent load and 8 hours at 50 percent load, meaning most users refuel once per day rather than multiple times.
The inverter topology produces clean power with less than 3 percent THD, which protects laptops, phone chargers, and sensitive electronics from voltage spikes. Cummins backs this unit with a 3-year warranty, longer than the 2.4-year average for comparable inverter generators. The 52 dBA noise level sits between a normal conversation and light traffic, allowing operation in noise-restricted campgrounds and residential neighborhoods without drawing complaints. | The Cat RP3600 is a 3600-watt gasoline generator built for job sites and RV camping. Its 4500-watt peak output handles startup surges for power tools and air conditioners, while the 3600-watt running capacity sustains multiple household circuits or a single large appliance continuously. |
- Most PowerfulCat RP36003600W running
- QuietestCummins Onan P2500i52 dB
- Longest RuntimeCat RP360013.5h at 50% load
Where to buy
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Cummins Onan P2500i
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Cat RP3600
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