DMX Power Catalog
Inverters vs. generators
Where each one wins on a service vehicle — surge, running cost, noise and upkeep.
The short answer
Which one suits the work?
On most utility vehicles an inverter outperforms a generator and costs less to run. The more a load needs a big inrush and modest running power — an air compressor, a water pump, electro-fusion gear — the more an inverter suits it.
A generator still wins in one case: sustained high running power with little or no peak demand, above about 5 kW, or loads that run for hours at a stretch. A large heater is the clearest example.
New to inverters? Introduction to mobile power inverters covers what one does and how to size it.
Side by side
How they compare
The figures below are for DMX Power inverters rated by the UL continuous-duty method, so they compare like for like with an engine generator’s continuous rating.
| What matters | Engine generator | DMX Power inverter |
|---|---|---|
| Continuous power | Oversizing to cover peak wastes the excess as fuel burn and shortens engine life. | Rated for continuous duty by the UL method, with no penalty for the surge headroom. |
| Maintenance | Oil every 200 hours; drain the fuel and run the carburettor dry before storing more than 30 days. | None beyond inspecting the batteries once a year. |
| Output frequency | Tied to engine RPM, so it varies. Motor-driven tools will not tolerate a wide swing. | Regulated to 60 Hz across the operating range. |
| Output voltage | Can wander outside the ANSI 110–127 VAC band, and those excursions damage loads. | Held inside the ANSI specification, closely matching utility power. |
| Peak output power Inrush, for starting a motor | Poor — typically 110–125% of its continuous rating, so it has to be heavily oversized to start some motors. | Very high — often three to four times its UL continuous rating, drawn from the battery. No need to oversize. |
| Standby draw Idle or quiescent power | The engine must run whatever the load — noise, fumes, fuel and wear for nothing. | 25–50 watts at idle, and full power available instantly when a load appears. |
| Specification | DMX Power inverter | Engine/generator set |
|---|---|---|
| Continuous power | 3,600 watts | 3,600 watts |
| Motor starting | 2 HP | ½ HP |
| Peak output power | 16,320 watts | 4,500 watts |
Two units matched on continuous rating. The difference is entirely in what they can start.
| Cost | Inverter | Generator |
|---|---|---|
| Initial, per watt | $0.62–0.76 | $0.50–0.75 |
| Installation | $200–400 | $400–800 |
| Maintenance, per year | $150–300 (batteries) | $300–500 average |
| Operating, per year | Near $0 — it draws from the vehicle’s alternator and battery, and only when AC is actually demanded. | $1,000 and up, depending on fuel consumption and hours run. |
Indicative figures carried over from the original comparison; treat them as relative, not current pricing.
| Advantage | What it means on the vehicle |
|---|---|
| Automatic | Electronic control means less for the operator to think about. |
| Convenience | Power effectively the same as utility supply, and it will run every type of load. |
| Economical | Minimal maintenance across an industrial ten-year life. |
| Efficient | Out-performs every other conversion method. |
| Peak output power | No need to buy more continuous power than you need just to start a heavy inrush load. |
| Pollution free | No exhaust at the point of use, which matters more as air-quality standards tighten. |
| Quiet | Nearly noiseless, with no vibration. |
| Rugged | Built for high vibration with quality construction methods. |
| Safe | No fuel, no lubricants, no moving parts, very little heat, and multiple protective features. |
Choosing one
Sizing it for your loads
Match the inverter to the largest combination of loads you will run at once, and to the surge if you are starting motors — DMX Power rates every inverter in horsepower so it can be compared directly against an engine generator.
Browse the inverter catalog, or talk to us about the loads you need to carry and we will help you size it.