Battery vs generator cost

Compare the battery recharge cost and generator fuel cost for the same outage load and duration. Enter the average running power of the appliances you plan to support. Use their combined watts, not the battery’s advertised output or the generator’s maximum rating.

Collect the battery’s stored energy, discharge efficiency and continuous output limit. For the generator, use its available output and litres of fuel per hour at that load. Enter the hours of backup needed and the actual fuel price per litre. The result checks whether the entered equipment can support this scenario before comparing costs.

Delivered outage energy = watts ÷ 1000 × hours. Battery runtime = stored kWh × discharge efficiency ÷ load kW. Recharge energy = delivered energy ÷ round-trip efficiency. Generator cost = fuel litres/hour × hours × price/litre.

Use a percentage as a fraction once: for example, 50% means 50 ÷ 100 = 0.5. Use 0.5 in the energy formula; do not divide it by 100 again.

Watts measure power at one moment. Kilowatt-hours, written kWh, measure energy over time. Divide watts by 1000 to get kilowatts before multiplying by hours. Enough stored energy does not mean the battery can supply a load above its output limit.

Recharge cost uses the delivered outage energy and whole-system round-trip efficiency. This efficiency includes the energy lost while charging and discharging. Divide the electricity price in cents by 100 to get dollars. Generator cost uses the full selected outage duration. The cost difference covers that outage only, rather than a year of backup use. Read the hourly and whole-outage costs together. A longer outage needs more energy even when the appliances’ running power stays the same.

These illustrative inputs are separate from your saved answers. Prices, use and performance are held constant for this worked scenario; they are not personal defaults.

Discharge efficiency and round-trip efficiency describe different paths. Discharge efficiency sets how much stored energy can reach the load. Round-trip efficiency sets the electricity needed to restore the used energy. Use the matching figures from the equipment records; do not swap them.

The battery must have enough stored energy for the whole duration. Both continuous output limits must cover the entered running load. Appliance starting surges need a separate check. An average load can hide brief demands that are higher than the equipment can supply.

Generator fuel use must match the intended load. A figure measured at full load may not describe light use. The calculation holds that figure and the load constant. Purchase, maintenance, fuel storage and battery ageing are outside this operating-cost comparison. There is no installation payback result or guarantee of reliable backup.

Use the Australian or Canadian version that matches your electricity bill and fuel prices. Enter prices in the units beside the fields and include applicable tax. A national or regional reference price can differ from your own plan, especially when the battery is recharged at a different time.

Existing daily electricity supply charges are outside this extra recharge cost. Check the dated sources for the method and any stored prices. Your personal load, fuel use and equipment limits still need their own records. The page does not fetch a live fuel quote or verify a particular installation.

Ask a qualified installer to check running load, starting demand, battery limits and safe connections. Take the load list, equipment manuals, fuel-use table and required outage hours. Ask which loads would need to be left off.

Follow the maker’s safety instructions. This estimate does not assess wiring, generator placement or critical backup needs. Speak to the relevant qualified professional before buying equipment or changing the way your home is supplied.