Diesel, petrol or inverter generator: which to choose?

Choose petrol for occasional use and small loads (2 to 7 kW in our Bison range), an inverter set to power electronics with stable current and little noise (2.3 to 5 kW), and diesel for long running hours and higher power (from 5 kVA to 2,000 kVA).

Diesel, petrol or inverter: what are the differences?

The right choice depends on how long the generator will run and how much power you need. The table sums up our four families, with the power ranges we carry.

The small Bison diesels are single-phase. Brux offers both single-phase and three-phase models. The whole water-cooled range is three-phase.

When should you choose a diesel generator?

Choose diesel if the generator must run for long periods or deliver more than 7 kW. A diesel engine uses less fuel per kWh produced than a petrol engine, and it is built for long running hours.

Above 7 kW, our whole range is diesel. Our diesel range starts at 5 kVA with the Bison BS7500DSE and goes up to 2,000 kVA. See our silent diesel generators from 5 to 15 kVA and our water-cooled diesel generators from 13 to 2,000 kVA. For several running hours a day, choose a water-cooled diesel.

Diesel is less volatile than petrol, so it is safer to store. Even so, store it in a closed container, away from heat.

When should you choose a petrol generator?

Choose petrol for occasional use and small loads. For short use, a petrol set is lighter and cheaper to buy than a diesel of the same power.

Our Bison petrol generators range from 2.0 to 7.0 kW. The Bison BS3500H (2.8 kW) weighs 40 kg and has a recoil start. The Bison BS8500H (7.0 kW) weighs 90 kg, has an electric start and comes with wheels and a handle.

Petrol is more volatile than diesel. Store it in a closed can, away from heat and from the running generator. Refuel with the engine off.

When should you choose an inverter generator?

Choose an inverter set to power electronics with stable current and little noise. An inverter generator converts the alternator's output electronically. It delivers a stable voltage and frequency that suit computers and electronics. It usually also adjusts engine speed to the load.

The datasheets of two of our Bison inverter generators state:

• total harmonic distortion (THD) below 2% for the BS2500iS and the BS6250iE;
• a noise level of 67 dB at 7 m for both models.

The Bison BS3500iS (3.1 kW) weighs 23 kg. It has electric and remote start.

What about small air-cooled silent diesels?

Between petrol sets and large generators, small air-cooled silent diesels cover 5 to 15 kVA. They run on diesel and have an electric start.

The Brux BX6500DSE is one example: 5.75 kVA (4.6 kW), single-phase 220 V. It starts with a button or a remote control and has an ATS socket.

These air-cooled sets are made for intermittent running. For several running hours a day, compare them with a water-cooled set: see our guide air-cooled or water-cooled.

How does the finder help you choose?

For air-cooled sets, our finder asks for your fuel preference: petrol, diesel or no preference. It then compares your need with the models in our range. Use it to work out your generator size.

Frequently asked questions

Which generator for computers and an internet connection?

An inverter set. Its voltage and frequency are stable. The datasheets of the Bison BS2500iS and BS6250iE state a THD below 2%.

Can a petrol generator run several hours a day?

That is not what it is designed for. A petrol set suits occasional use. If the generator has to run for several hours every day, choose a water-cooled diesel: it uses less fuel per kWh produced and it is built for long hours.

Sources: manufacturers' datasheets (Bison and Brux generators, Perkins engines), MK Energies & Services finder method.