How much does it cost to run a battery tender / trickle charger?
A battery tender / trickle charger costs about 0.2¢ per hour, 4.3¢ a day, $1.31 a month and $7 a year at typical use (24 hours a day for 5 months a year) and the U.S. average rate of 17.99¢/kWh. Smart maintainers draw a few watts holding a full battery; bulk charging a dead car battery at 10 A draws about 100-150 W.
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Cost by setting
| Setting | Watts | Per hour | Per day | Per month | Per year |
|---|---|---|---|---|---|
| Maintaining | 3 | 0.05¢ | 1.3¢ | $0.39 | $2 |
| Charging 1 A | 10 | 0.2¢ | 4.3¢ | $1.31 | $7 |
| Charging 10 A | 100 | 1.8¢ | 43¢ | $13.14 | $66 |
At 24 hours a day for 5 months a year and 17.99¢/kWh.
Cost by hours of use
| Hours per day | kWh/day | Per day | Per month | Per year (all year) |
|---|---|---|---|---|
| 1 hour | 0.01 | 0.2¢ | $0.05 | $1 |
| 2 hours | 0.02 | 0.4¢ | $0.11 | $1 |
| 4 hours | 0.04 | 0.7¢ | $0.22 | $3 |
| 8 hours | 0.08 | 1.4¢ | $0.44 | $5 |
| 12 hours | 0.12 | 2.2¢ | $0.66 | $8 |
| 24 hours | 0.24 | 4.3¢ | $1.31 | $16 |
Cost to run a battery tender / trickle charger in every state
The same battery tender / trickle charger costs $4 a year in North Dakota and $16 in Hawaii, at each state's average residential rate (12 months ending July 2026).
| State | Rate | Per hour | Per month | Per year |
|---|---|---|---|---|
| North Dakota | 12.32¢ | 0.1¢ | $0.90 | $4 |
| Idaho | 12.65¢ | 0.1¢ | $0.92 | $5 |
| Nebraska | 12.86¢ | 0.1¢ | $0.94 | $5 |
| Louisiana | 12.99¢ | 0.1¢ | $0.95 | $5 |
| Utah | 13.32¢ | 0.1¢ | $0.97 | $5 |
| Nevada | 13.36¢ | 0.1¢ | $0.98 | $5 |
| Arkansas | 13.43¢ | 0.1¢ | $0.98 | $5 |
| Tennessee | 13.56¢ | 0.1¢ | $0.99 | $5 |
| Oklahoma | 13.70¢ | 0.1¢ | $1.00 | $5 |
| Montana | 13.84¢ | 0.1¢ | $1.01 | $5 |
| Kentucky | 13.92¢ | 0.1¢ | $1.02 | $5 |
| Missouri | 13.95¢ | 0.1¢ | $1.02 | $5 |
| Wyoming | 14.01¢ | 0.1¢ | $1.02 | $5 |
| Washington | 14.12¢ | 0.1¢ | $1.03 | $5 |
| Iowa | 14.13¢ | 0.1¢ | $1.03 | $5 |
| South Dakota | 14.20¢ | 0.1¢ | $1.04 | $5 |
| Mississippi | 14.77¢ | 0.1¢ | $1.08 | $5 |
| North Carolina | 14.77¢ | 0.1¢ | $1.08 | $5 |
| Kansas | 15.09¢ | 0.2¢ | $1.10 | $6 |
| Georgia | 15.12¢ | 0.2¢ | $1.10 | $6 |
| New Mexico | 15.32¢ | 0.2¢ | $1.12 | $6 |
| Florida | 15.39¢ | 0.2¢ | $1.12 | $6 |
| Arizona | 15.40¢ | 0.2¢ | $1.12 | $6 |
| West Virginia | 15.48¢ | 0.2¢ | $1.13 | $6 |
| Oregon | 15.50¢ | 0.2¢ | $1.13 | $6 |
| South Carolina | 15.64¢ | 0.2¢ | $1.14 | $6 |
| Texas | 15.96¢ | 0.2¢ | $1.17 | $6 |
| Minnesota | 16.22¢ | 0.2¢ | $1.18 | $6 |
| Alabama | 16.44¢ | 0.2¢ | $1.20 | $6 |
| Virginia | 16.48¢ | 0.2¢ | $1.20 | $6 |
| Colorado | 16.58¢ | 0.2¢ | $1.21 | $6 |
| Indiana | 16.94¢ | 0.2¢ | $1.24 | $6 |
| Delaware | 17.79¢ | 0.2¢ | $1.30 | $6 |
| Ohio | 18.25¢ | 0.2¢ | $1.33 | $7 |
| Wisconsin | 18.74¢ | 0.2¢ | $1.37 | $7 |
| Illinois | 18.79¢ | 0.2¢ | $1.37 | $7 |
| Pennsylvania | 20.70¢ | 0.2¢ | $1.51 | $8 |
| Maryland | 21.03¢ | 0.2¢ | $1.54 | $8 |
| Michigan | 21.05¢ | 0.2¢ | $1.54 | $8 |
| New Jersey | 23.78¢ | 0.2¢ | $1.74 | $9 |
| Vermont | 23.80¢ | 0.2¢ | $1.74 | $9 |
| District of Columbia | 24.20¢ | 0.2¢ | $1.77 | $9 |
| New Hampshire | 26.67¢ | 0.3¢ | $1.95 | $10 |
| Alaska | 26.85¢ | 0.3¢ | $1.96 | $10 |
| Connecticut | 27.99¢ | 0.3¢ | $2.04 | $10 |
| New York | 28.39¢ | 0.3¢ | $2.07 | $10 |
| Rhode Island | 29.27¢ | 0.3¢ | $2.14 | $11 |
| Maine | 29.31¢ | 0.3¢ | $2.14 | $11 |
| Massachusetts | 30.43¢ | 0.3¢ | $2.22 | $11 |
| California | 32.99¢ | 0.3¢ | $2.41 | $12 |
| Hawaii | 43.51¢ | 0.4¢ | $3.18 | $16 |
How to cut the cost
- Use a smart maintainer, not an old unregulated trickle charger that overcharges.
- Disconnect it after the season.
- Use one maintainer per stored vehicle only for vehicles sitting more than 30 days.
Cheaper ways to get the job done
Regulates charge and draws little once the battery is full.
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Compare with similar appliances
| Appliance | Watts | Typical use | Per month | Per year |
|---|---|---|---|---|
| Battery tender / trickle charger | 10 | 24 hours a day for 5 months a year | $1.31 | $7 |
| Engine block heater | 750 | 8 hours a day, 5 days a week for 3 months a year | $23.47 | $70 |
| Golf cart | 900 | 10 miles a day | $8.21 | $99 |
| Tool battery charger | 100 | 1 hour a day, 2 days a week | $0.29 | $3 |
| Cordless drill (charging) | 70 | 1 hour a day, 1 days a week | $0.12 | $1 |
| Bench grinder | 400 | 15 minutes a day, 1 days a week | $0.08 | $1 |
| Shop vac | 1,200 | 15 minutes a day, 1 days a week | $0.23 | $3 |
Head-to-head comparisons
Frequently asked questions
How much does it cost to run a battery tender / trickle charger per hour?
A battery tender / trickle charger drawing 10 watts uses 0.01 kWh per hour. At the U.S. average of 17.99¢/kWh that's 0.2¢ per hour. In North Dakota (12.32¢) it's 0.1¢. In Hawaii (43.51¢) it's 0.4¢.
How much does it cost to run a battery tender / trickle charger per month?
At typical use (24 hours a day for 5 months a year), a battery tender / trickle charger costs about $1.31 a month while in use and $7 a year over the 5 months it's typically used, at the U.S. average rate. Enter your ZIP in the calculator above for your utility's rate.
How many watts does a battery tender / trickle charger use?
Most battery tender / trickle chargers use 2 to 100 watts, depending on the setting (maintaining 3 W, charging 1 a 10 W, charging 10 a 100 W). Check the label on the back or bottom for your model's exact rating.
How many kWh does a battery tender / trickle charger use?
About 0.24 kWh a day and 37 kWh a year at typical use (24 hours a day for 5 months a year).
Does a battery tender / trickle charger use a lot of electricity?
No. At about 37 kWh a year it's a small share (0.3%) of the average U.S. home's 10,492 kWh.
Is it cheaper to run a battery tender / trickle charger or an engine block heater?
At typical use, a battery tender / trickle charger costs about $7 a year versus $70 for an engine block heater. So the battery tender / trickle charger is cheaper by about $64 a year. Use the comparison table above to compare them at your own settings.
How can I lower the cost of running a battery tender / trickle charger?
- Use a smart maintainer, not an old unregulated trickle charger that overcharges.
- Disconnect it after the season.
- Use one maintainer per stored vehicle only for vehicles sitting more than 30 days.
Rates updated 2026-10-21: EIA data through July 2026. Typical wattage and usage reviewed against DOE, ENERGY STAR and manufacturer specs. Methodology.