Published September 13, 2026 · Reserve Current editorial guide · Updated September 24, 2026
Quick answer: Recharge cost = energy added ÷ charging efficiency × your electricity rate. Charging a 1,000Wh battery from 20% to 100% adds 800Wh; at 90% efficiency that is about 0.889kWh from the wall, or about $0.18 at an example rate of $0.20 per kWh.
Use the energy you actually add
Charging from half full is different from charging an empty battery. For an estimate, multiply nominal capacity by the increase in state of charge. A 1,000Wh battery going from 20% to 100% adds 800Wh of stored energy before accounting for charging losses.
Include charging losses
At an illustrative 90% charging efficiency, adding 800Wh requires about 889Wh, or 0.889kWh, from the wall. At a user-entered rate of $0.20 per kWh, the energy charge is about $0.18. This is an example rate, not a claim about your electricity bill or a national average.
Know what the estimate excludes
The calculation covers the variable energy charge. It excludes taxes not included in your input, time-of-use changes, demand charges, standby consumption after charging and the cost of the battery itself. Using a battery does not create free electricity; round-trip losses mean you purchase more energy than you later receive.
Compare the right benefit
Backup capability, convenience and portability may be why you buy a station. A low cost to recharge does not mean a short financial payback. For savings from changing charging times, you also need actual tariff differences, losses, cycle use and equipment cost. Use the recharge-cost tool for the narrower electricity calculation.
Frequently asked questions
How much does it cost to recharge a 1,000Wh power station?
From 20% to 100% it adds 800Wh. At an illustrative 90% charging efficiency that takes about 0.889kWh from the wall. At $0.20 per kWh the energy charge is about $0.18. Use your own rate.
Does a power station save money on electricity?
Not by itself. Round-trip losses mean you buy more energy than you later use. Any savings from charging at cheaper times depend on real tariff differences, losses, cycle use and the cost of the equipment.
What does this estimate leave out?
Taxes not included in your rate, time-of-use changes, demand charges, standby consumption after charging and the cost of the battery itself.