Cummins Onan P2500i vs Firman W01784

Comparison Overview

Analysis by AJ Quick

Mechanical engineer and founder of RightGenerator

Key takeaways

• Cummins Onan P2500i provides 2200 running watts, 500 more than the Firman W01784
• Firman W01784 weighs 45.9 lbs, about 2 lbs lighter than the Onan P2500i
• Cummins Onan P2500i runs up to 10 hours at 25% load versus Firman's 9 hours
• Both are inverter generators producing clean power safe for sensitive electronics
• Both carry a 3-year warranty and run on gasoline
• Noise levels are nearly identical at 52 dB and 54 dB respectively

Best use cases

Choose the Cummins Onan P2500i if you need a portable inverter generator that can handle a broader range of tasks. With 2200 running watts, it can comfortably power a small RV air conditioner, a full-size refrigerator, or several devices at once during a power outage. The 10-hour runtime at 25% load means you can run it overnight without refueling, which is a real convenience for camping trips or extended blackouts. Cummins is also a well-established name in power generation, and the Onan line has a strong reputation among RV owners specifically. If you plan to use your generator for RV travel, tailgating with multiple appliances, or as a light home backup unit, the P2500i gives you more flexibility without adding significant weight.

Choose the Firman W01784 if your power needs are modest and you want to save a bit of money and weight. At 1700 running watts, it handles the basics well: charging phones and laptops, running LED lights, powering a small TV, or keeping a CPAP machine going at a campsite. It weighs just under 46 lbs, making it slightly easier to toss in a truck bed or carry to a remote site. The 9-hour runtime at quarter load is still respectable for weekend camping. However, you should be realistic about its limits. Running a microwave, a space heater, or an air conditioner will likely push it past its capacity. If you know you'll stick to lighter loads and value every dollar saved, the Firman is a capable, no-frills option.

Both generators produce inverter-quality power, so either one is safe for laptops, phones, and other sensitive electronics. The tradeoff really comes down to how much wattage headroom you want versus how much you're willing to spend.

Verdict & recommendation

If your priority is having enough power to handle unexpected loads or run larger appliances, the Cummins Onan P2500i is the stronger choice. Its 500-watt advantage in running power and extra hour of runtime at light load give it more versatility for RV use, home backup, and situations where you might need to plug in one more device than planned. If your priority is keeping things light, simple, and affordable for basic camping or emergency charging, the Firman W01784 handles those tasks without issue.

Neither generator is a bad pick. The real question is whether you'll use that extra wattage. Buyers who tend to add "just one more thing" to the power strip will appreciate the Onan's headroom, while minimalists who pack light and plan carefully will find the Firman does everything they need.