3,200 W continuous, an 8.5 litre tank and 6 hours at 75 percent load: the MF3900i carries the heaviest load in this comparison. At 73 dB(A) at 7 metres it is also the loudest of the machines whose noise is published properly.
What its figures are worth
- Continuous power 40 %3200 W · 10/10
- Price per continuous kW 25 %241.6 USD per kW · 9.5/10
- Noise at 7 metres 20 %73 dB(A) · 4/10
- Weightnot published by the maker
Scale applied at 85%: criteria with no published figure drop out and the remaining weights are renormalised. Weighting: Continuous power 40 %, Price per continuous kW 25 %, Noise at 7 metres 20 %, Weight 15 %.
Choose it if
- A site running a mixer and a circular saw together.
- Backing up a house with several appliances.
- Starting without a pull cord, thanks to the electric starter.
Skip it if
- Close neighbours: 73 dB(A) at 7 metres.
- Carrying by hand: weight is not published, it rolls on wheels.
- Small leisure use: the power is oversized.
Published specifications
| Specification | Stated value |
|---|---|
| Continuous power | 3200 W |
| Maximum power | 3800 W |
| Noise at 7 metres | 73 dB(A) |
| Sound power LwA | 96 dB(A) |
| Weight | not published on the page we consulted |
| Fuel tank | 8.5 L |
| Stated runtime | 6 h à 75 % de charge |
| Displacement | not published on the page we consulted |
Before you plug anything in
- Never in an enclosed space. Not a garage, a basement or a shed, even with the door open. A generator gives off carbon monoxide, an odourless gas that kills. Outside, away from doors and windows.
- Never wired straight into the consumer unit. Back-feeding a house through a double-male lead sends current into the grid and endangers the people working on it. The connection goes through a changeover switch fitted by a qualified electrician.
- An extension lead rated for the load. A lead that is too thin heats up. On site, 2.5 mm² cable and a sensible length.
- Store fuel outside in an approved can, and refuel with the engine off and cool.
What the maker shows
Frequently asked questions
Where does this machine's score come from?
It is calculated, not awarded. Five measurable criteria are weighted, and each value is mapped onto a scale relative to the other machines in the comparison. For this machine, 85% of the scale could be applied: criteria the maker does not publish drop out rather than being replaced by an estimate.
How much power does a self-build site need?
Add up the machines that run at the same time, then allow a margin. An 800 W mixer and a 1,400 W circular saw already ask for 2,200 W continuous, plus the start-up peak. For that pair, a machine around 2 kW continuous is too tight; aim for 3 kW.
Can an inverter generator run a laptop?
Yes, that is the point of it. Inverter technology produces a clean sine wave, usually under 3 percent distortion, which electronics tolerate. A conventional AVR generator suits power tools but not always sensitive devices.