Guide
The saving does not come from the battery being efficient. It comes from the generator stopping.
A diesel generator's fuel consumption does not scale neatly with output. At 75–80% of rating, an engine is near its best specific fuel consumption. At 20%, it burns far more fuel per kWh produced. At 10%, it is wasteful in a way that also damages the engine.
Temporary power installations almost always run at low load factor, because they are sized for a peak that occurs rarely. So the generator spends most of its hours in its worst operating band.
A battery fixes this by changing what the generator is asked to do. Instead of following a variable site load all day, the generator's only job becomes recharging the battery — a steady, high load it can meet at its efficient point — and then shutting down.
| Generator alone | Battery + generator | |
|---|---|---|
| What the generator follows | The site's variable load | A fixed recharge load |
| Typical load factor | Low, often 20–40% | High, near optimum |
| Hours run per day | Continuous | Only during recharge |
| Fuel per kWh delivered | Poor at low load | Near best case |
| Wet stacking risk | Significant on long low-load running | Largely removed |
| Noise hours | All of them | Recharge windows only |
| Servicing interval | Driven by run hours | Extended, fewer run hours |
Fewer run hours. The generator is off whenever the battery is carrying the load. On a site whose average draw is well below the generator's rating, that is most of the day.
Better hours when it runs. The hours it does run are at high load factor, which is where fuel per kWh is lowest.
Less servicing and longer life. Service intervals are driven by run hours, and wet stacking — the unburnt fuel accumulation caused by prolonged light running — is largely eliminated.
Once a battery is covering the peak, the generator no longer needs to be sized for the site's worst instantaneous moment — only for recharge duty. That frequently allows a smaller, cheaper generator that runs at a good load factor by design.
This is the step most sites miss. Keeping the oversized generator and adding a battery still saves fuel; right-sizing the generator at the same time saves more, and reduces the hire rate as well. See diesel generator alternative.
Questions answered
It depends on how far your average load sits below the generator's rating. The greater that gap, the more hours the generator spends running inefficiently, and the more there is to recover. On a full replacement the diesel spend goes to zero.
The battery carries the site load. When its state of charge falls to a set point, the generator starts, recharges the battery at high load factor, and shuts down again. The cycle repeats.
Yes. Every PulseTrek trailer has a generator receptacle, so an existing genset can recharge the pack without modification to either machine.
Get in touch
Tell us the site, the load and the runtime you need. Our Austin engineering team comes back with a configuration, a runtime estimate and a price.
+1 512-316-7347
info@pulsar.industries
WhatsApp +1 512-585-8293
