How do I Size a Day Tank for a Diesel Generator?

Many homeowners use diesel generators for producing electricity, both for emergency use and supplemental power for areas without direct electrical service. Knowing the amount of fuel the generator will use in one day is helpful when choosing a supplemental fuel tank for the generator. The amount of fuel a generator uses in one day is found by calculating hourly use and then multiplying by 24.

Things You'll Need

• A portable diesel fuel can with graduated measurements, full
• Pencil and paper
• --or--
• Calculator
• Stopwatch, timer or clock

Instructions

1. Fill the generator's standard fuel tank. All generators have an integral fuel tank. You will be calculating the capacity of a supplemental, day-use tank.

2. Start the generator and note the time. Run the generator at full power for one hour. Shut the generator down. Be as precise as you can in running the generator for exactly one hour.

3. Record the amount of fuel in the portable diesel fuel can. Fill the generator's integral fuel tank from the can. Record the amount of fuel left in the can. Subtract the second fuel measurement from the first and record the result. This is the amount of fuel the generator uses in one hour.

4. Multiply the amount of fuel used by the generator in one hour by 24. Record this figure. This is the amount of fuel the generator will use in one day and is also the size of day-use tank needed for the generator in question.