How Much Does It Cost to Charge a Power Station?

The arithmetic

Two steps, and the second is the one people skip.

Step 1: capacity in kilowatt-hours. Divide watt-hours by 1,000. A 1,000Wh unit is 1 kWh.

Step 2: add charging losses. Charging is not free — some energy becomes heat in the charger and the cells. Efficiency is typically 85–90%, so multiply by about 1.15. verify

1,000Wh  ÷ 1,000        = 1.0 kWh stored
1.0 kWh  × 1.15         = 1.15 kWh drawn from the wall
1.15 kWh × $0.17        = about $0.20

Full charge, by size and by state

Electricity prices vary more across the US than the battery sizes do.

verify on the rate figures — check your own bill for the number that applies to you, and note that many bills add per-kWh delivery charges on top of the supply rate.

Even at the expensive end of the table, a full charge of a large unit costs less than a cup of coffee.

The number that actually matters: standby

This is the question underneath the question. People want to know whether leaving it plugged in all year is wasteful.

A power station left plugged in draws a small continuous current for its display, its battery management system and its Bluetooth radio. Typical standby is a few watts. verify

5W × 24 hours × 365 days = about 44 kWh a year
44 kWh × $0.17           = about $7.40 a year

Against the alternatives

Where charging cost sits relative to everything else in this category.

The car row is the interesting one. Charging from a car is dramatically more expensive per kilowatt-hour than the wall, and people do it anyway because during an outage the wall is not an option and the car is sitting there.

On solar: panels do not pay for themselves against a 20-cent charge. At that rate a 200W panel would need thousands of charges to break even. Buy panels because there is no grid to plug into, not to save money on charging.

Where the real cost is

Not the electricity. Three other things dominate.

The purchase. By a wide margin. Whether the unit costs $400 or $1,200 matters vastly more than a lifetime of charging it.

Whether you bought the right size. A unit too small to do the job is 100% wasted regardless of how cheap it is to charge, and a unit far bigger than you need is money that could have bought panels or a second unit. Work out the number before worrying about running costs.

Battery lifespan. A LiFePO4 pack rated for 3,000+ cycles used four times a year will outlast the electronics around it. An older NMC unit rated near 500 will not. That difference is worth hundreds of dollars and it never appears on an electricity bill — the comparison is here.

Does it make financial sense at all?

Straight answer: not as an investment, and that is the wrong frame.

A power station does not generate savings. It prevents a specific loss — a freezer of food, a night without a CPAP, a work day lost because the router was dead. Whether that is worth the purchase price depends entirely on how often your power actually goes out.

We ran the honest version of that arithmetic in is a solar generator worth it, including the cases where the answer is no.

The short version

About 20 cents to fill a 1,000Wh unit. A few dollars a year to leave it plugged in.

Neither number is worth managing. Leave it plugged in, and spend your attention on buying the right size instead.