Cummins Onan P2500i vs Yamaha EF2800i

Comparison Overview

Key takeaways

• Cummins Onan P2500i runs quieter at 52 dB and weighs 48 lb.
• Yamaha EF2800i provides 2500 running watts and 2800 starting watts.
• Yamaha EF2800i lasts up to 14.7 hours at 25% load.
• Cummins Onan P2500i is rated for 10 hours at 25% load.
• Both are gasoline inverter generators with a 3 year warranty.

Best use cases

Choose the Cummins Onan P2500i if you want a generator that is easier to live with in close quarters. At 52 dB, it is the better pick for campgrounds, tailgating, and overnight use where noise complaints are a real concern. The 48 lb weight also makes a difference if you are lifting it into a truck bed, moving it around a campsite, or storing it in an RV compartment. With 2200 running watts and 2500 starting watts, it is well suited to charging batteries, running lights, a TV, a laptop, a small coffee maker, and many smaller appliances one at a time. The tradeoff is less power headroom for higher draw loads, and a shorter rated runtime at 25% load (10 hours), so you may refuel more often on long days.

Choose the Yamaha EF2800i if your priority is a bit more muscle and longer time between fill ups. Its 2500 running watts and 2800 starting watts can be helpful for RV use, especially when you are trying to run multiple small loads together or dealing with startup surges. The 14.7 hour runtime at 25% load is a practical advantage for long weekends, extended boondocking, or backup scenarios where you want fewer refueling stops. The tradeoffs are that it is heavier at 68 lb, which can be a hassle for solo carrying, and it is louder at 65 dB, which may be noticeable in quiet camp settings or close neighborhoods.

For light home backup, either can cover essentials like charging, lights, and a fridge in many cases, but the Yamaha’s extra watts can reduce juggling, while the Onan’s lower noise can be more neighbor friendly.

Verdict & recommendation

If your priority is a quieter, more portable inverter generator you will actually want to bring along, the Cummins Onan P2500i is the easier day to day choice, thanks to 52 dB operation and a 48 lb carry weight. If your priority is more output headroom and longer run time for RV trips or longer backup stretches, the Yamaha EF2800i makes more sense with 2500 running watts, 2800 starting watts, and 14.7 hours at 25% load.

Both deliver inverter quality power and both back it with a 3 year warranty, so neither is a wrong pick. Match the Onan to quiet, frequent transport, and match the Yamaha to higher demand loads and longer sessions between refueling.