What Size Generator for a Food Truck?
Most food trucks land between 7,000 and 12,000 running watts once a fryer and a griddle are on the list. A coffee cart is a completely different problem: small energy, ugly surges.
Size power for your truck or cart
Generator
15,000 W generator
Needs at least 11,650 W continuous and 10,500 W to start.
Battery power station
41,600 Wh
9 × 5,000 Wh and up (expandable) — needs 9,300 W of inverter and 10,500 W of surge.
A food truck running for 8 hours draws 9,300 W with everything on, peaks at 10,500 W when the refrigerated prep table starts, and uses 30.8 kWh over the session.
What this assumes
- Running watts assume everything can be switched on at the same time. That is the safe way to size a generator, and it is why the number looks high.
- Starting watts are the running total plus the single largest start-up surge — not every surge added together, because two motors rarely start in the same instant.
- Energy uses each item's duty cycle: a fridge compressor runs about a third of the time, an espresso boiler idles at a fraction of its element rating between shots.
- Battery sizing allows 15% for inverter losses and keeps 15% in reserve so you do not finish the day at empty. In the cooler bands it also allows for the capacity lithium gives up, which is about 85% of rated around freezing and roughly 60% in severe cold.
- Generator sizing never plans to sit above 80% of the continuous rating, which is the same thing as adding 25% to your running total. In the warmer bands it adds roughly 2% per 10 °F, or per 5.5 °C, above 77 °F (25 °C) for the output an engine loses in hot air.
- Fuel burn is modelled from published inverter-generator run times and is accurate to roughly ±20% in the real world.
The one question that changes everything
Before any arithmetic: do you cook with electricity or with propane? That single decision moves a truck between two completely different classes of power system.
The setup loaded in the calculator above is an electric truck: a single-basket fryer, a 24 inch griddle, a refrigerated prep table, an undercounter fridge, a hood fan, lights, a point of sale terminal and a hand-wash heater. It comes to 9,300 W running, peaks at 10,500 W, and gets through 30.8 kWh across an eight hour service. That is a 15,000 W generator, and it is not a quiet one.
Take the fryer and the griddle off the list, because they are running on propane, and the electrical load collapses to the refrigeration, the fan, the lights and the terminal. That is a few hundred watts, an inverter generator you can hold a conversation next to, or a battery you can charge overnight and never refuel.
Commercial equipment, honestly measured
These figures include something most wattage charts leave out: what each item draws while it is switched on but not actively working. A steam table holding temperature, an espresso boiler between shots and a warmer sitting idle are all drawing power you have to pay for, and all of them draw far less than their nameplate.
| Equipment | Idle | Running | Starting | Average | Energy per hour |
|---|---|---|---|---|---|
| Espresso machine (1 group, commercial) | 180 W | 1,800 W | 1,800 W | 500 W | 500 Wh |
| Espresso machine (2 group, commercial) | 300 W | 2,800 W | 2,800 W | 930 W | 930 Wh |
| Espresso machine (prosumer, single boiler) | 90 W | 1,350 W | 1,350 W | 280 W | 280 Wh |
| Commercial batch brewer | 120 W | 1,600 W | 1,600 W | 560 W | 560 Wh |
| Espresso grinder (on demand) | 2 W | 400 W | 1,200 W | 20 W | 20 Wh |
| Commercial blender | 2 W | 1,500 W | 4,500 W | 75 W | 80 Wh |
| Electric fryer (single basket) | 0 W | 3,500 W | 3,500 W | 1,400 W | 1.40 kWh |
| Electric fryer (double basket) | 0 W | 5,000 W | 5,000 W | 2,250 W | 2.25 kWh |
| Electric griddle (24") | 0 W | 3,000 W | 3,000 W | 1,350 W | 1.35 kWh |
| Electric griddle (36") | 0 W | 4,500 W | 4,500 W | 2,050 W | 2.02 kWh |
| Panini press / sandwich grill | 150 W | 1,800 W | 1,800 W | 730 W | 730 Wh |
| Steam table (3 well) | 400 W | 1,500 W | 1,500 W | 790 W | 790 Wh |
| Countertop food warmer | 200 W | 800 W | 800 W | 380 W | 380 Wh |
| Refrigerated prep table | 5 W | 400 W | 1,600 W | 160 W | 160 Wh |
| Undercounter commercial fridge | 5 W | 350 W | 1,400 W | 140 W | 140 Wh |
| Undercounter ice machine | 30 W | 600 W | 1,800 W | 320 W | 320 Wh |
| Soft-serve machine (countertop) | 250 W | 1,800 W | 5,400 W | 1,050 W | 1.02 kWh |
| Slushie / granita machine (2 bowl) | 200 W | 1,100 W | 3,300 W | 740 W | 740 Wh |
| Exhaust hood fan | 0 W | 500 W | 1,500 W | 500 W | 500 Wh |
| POS terminal and card reader | 25 W | 60 W | 60 W | 60 W | 60 Wh |
| Hot dog roller | 300 W | 1,100 W | 1,100 W | 620 W | 620 Wh |
| Popcorn machine (8 oz) | 200 W | 1,400 W | 1,400 W | 680 W | 680 Wh |
| Cotton candy machine | 0 W | 1,050 W | 2,100 W | 530 W | 530 Wh |
| Commercial waffle iron | 200 W | 1,400 W | 1,400 W | 680 W | 680 Wh |
| Countertop electric pizza oven | 400 W | 3,200 W | 3,200 W | 1,800 W | 1.80 kWh |
| Heated holding cabinet | 350 W | 1,600 W | 1,600 W | 660 W | 660 Wh |
Look at the gap between the running and average columns for the espresso machine, the steam table and the fryer. That gap is the duty cycle, and it is the difference between a nameplate estimate and a real one. A one-group espresso machine rated at 1,800 W averages 500 W across a normal service, because the boiler spends most of its life idling at 180 W and only pulls the full element load while recovering from a shot or a steam cycle.
Size your generator from the running column. Size your battery, and your fuel budget, from the average column. Getting those two backwards is how vendors end up with a generator twice the size they need and a battery half the size they need.
Surge is a separate problem from consumption
The blender is the clearest example on any cart. It draws 1,500 W while it is blending and demands 4,500 W to start, but you run it for seconds at a time, so it contributes almost nothing to your energy total. It can still be the single item that decides your generator size.
The practical fix is free: stagger. Do not pull a shot while the blender is running. Do not start the hand-wash heater and the grinder in the same moment. On a tight setup, staggering two pieces of equipment is worth more than several thousand watts of generator. The "Will it fit?" tab will tell you exactly which items to hold back for a specific unit you already own.
Venue power, when there is any
Plenty of markets and festivals offer a 20 amp outlet and call it power. At 120 volts that is 2,400 watts, and in practice you should plan on less because you are sharing a circuit with the stall next door. Look at the running column above and see how few pieces of commercial equipment fit inside 2,400 watts at the same time. One griddle does not.
If the venue offers 30 or 50 amp service, confirm the voltage before you assume the capacity, and confirm whether it is a shared circuit. Turning up with the wrong plug and no generator has ended more trading days than bad weather.
Next steps
Load your real equipment list into the tool above and switch between the three tabs: size a new system, check how long your existing generator will run on a tank, or test a specific unit against your load. For the espresso side in detail, read what an espresso machine really draws. For the surge rules that decide your generator class, read starting watts versus running watts.
Frequently asked questions
What size generator do I need for a food truck?
It depends almost entirely on whether you cook with electricity. A truck with a single electric fryer, a griddle, refrigeration, a hood fan and a hand-wash heater comes to roughly 9,300 running watts, which needs a 15,000 watt class generator if everything can run together. Move the fryer and griddle to propane and the same truck drops under 2,500 watts, which is a quiet inverter generator.
Can I run a food truck on a battery power station?
Only if you are not cooking with electricity. A full electric service uses over 30 kilowatt-hours across an eight hour day, which is roughly eight of the largest portable batteries sold. Refrigeration, lights, a point of sale terminal and a hood fan, with propane doing the cooking, is a very different story and fits comfortably in a 2 to 3 kilowatt-hour battery.
Why does my generator stall when the blender starts?
Because a commercial blender draws about 1,500 watts running but demands roughly 4,500 watts for the instant its motor spins up. If your generator is already carrying 4,000 watts of heating equipment, that surge lands on top and pushes it past its starting rating. The blender uses almost no energy across a day, which is why this problem surprises people: it is a surge problem, not a consumption problem.
Do I have to add up the starting watts of everything?
No. Add all the running watts, then add only the single largest start-up surge. Two motors starting in the same instant is bad luck rather than something to design around, and adding every surge together will sell you a generator twice the size you need. The calculator applies this rule and tells you which piece of equipment set your peak.
What about the health department hand-wash heater?
It is easy to forget and it is not small. A typical mobile hand-wash station heater draws 1,400 watts, though only in short bursts whenever someone actually washes up, so it adds far less energy than its rating suggests. Size for it in your running total, because it can switch on at any moment, but do not budget a full day of energy for it.
Is a quiet generator worth the extra money for events?
Often it decides whether you get booked at all. Many farmers markets, festivals and wedding venues impose a decibel limit or ban engines near seating, and an inverter generator is dramatically quieter than a conventional open-frame unit at the same output. For a cart whose load is mostly refrigeration and lighting, an inverter generator also burns noticeably less fuel because it throttles down between peaks.