Tool battery charger vs. battery tender / trickle charger: running cost
A tool battery charger is cheaper to run: about $3 a year versus $7 for a battery tender / trickle charger at typical use and 17.99¢/kWh, a $3 difference.
| Tool battery charger | Battery tender / trickle charger | |
|---|---|---|
| Typical watts | 100 W | 10 W |
| Watt range | 30–300 W | 2–100 W |
| Typical use | 1 hour a day, 2 days a week | 24 hours a day for 5 months a year |
| Energy per year | 19 kWh | 37 kWh |
| Cost per hour | 1.8¢ | 0.2¢ |
| Cost per day | 0.9¢ | 4.3¢ |
| Cost per month | $0.29 | $1.31 |
| Cost per year | $3 | $7 |
| Per year in Hawaii (43.51¢) | $8 | $16 |
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What drives the difference
- Tool battery charger: Tool chargers draw 50-250 W while charging and 0.5-3 W when left plugged in with no battery.
- Battery tender / trickle charger: Smart maintainers draw a few watts holding a full battery; bulk charging a dead car battery at 10 A draws about 100-150 W.
Ways to cut either cost
Eliminates charger standby between uses.
See options on AmazonRegulates charge and draws little once the battery is full.
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Frequently asked questions
Which costs more to run, a tool battery charger or a battery tender / trickle charger?
At typical use and the U.S. average rate (17.99¢/kWh), a battery tender / trickle charger costs about $7 a year versus $3 for a tool battery charger. That's $3 more, or 1.9× as much.
How many watts do tool battery charger and battery tender / trickle charger use?
A tool battery charger typically draws 100 W (range 30–300 W). A battery tender / trickle charger draws 10 W (range 2–100 W). Watts alone don't decide cost. Hours of use, cycling and standby matter just as much.
Rates: EIA, 12 months ending 2026-07. Methodology.