How Many Hours Do I Trickle Charge a Battery?

by Virginia A. Gorg
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Battery trickle chargers come in a variety of types and sizes, including those made for motorcycles, cars and boats. Its purpose is to help your battery maintain its charge when the battery is unused for long periods. Purchase a trickle charger at an automotive supply store, a retail store such as Sears or Wal-Mart, or online at various sites including J.C. Whitney. If you are unsure which charger you need, ask a knowledgeable salesperson to help you.

Automotive Batteries

A fully discharged automotive battery may take up to 20 hours for full charging. The length of time is dependent upon the RC rating (reserve capacity). A battery with an RC of 60 and 2 amps could take 20 hours to charge, while a battery with an RC rating of 60 with 30 amps may take only one hour to fully charge.

Batteries and Tractors

Batteries for motorcycles and garden tractors are rated on an AH (ampere hour) schedule. An AH battery rated at 12 with 2 amps will generally take about seven hours to recharge from a 70% discharge rate. A similar battery rated at 32 AH with 2 amps could take up to 18 hours to fully recharge.

Marine Batteries

A deep cycle (marine battery) also carries AH ratings. It is not recommended to charge deep cycle batteries with only 2 amps. A deep cycle battery with an AH of 55 and 6 amps could take 10 hours to charge, while a similar battery with 105 AH and 30 amps will take about 4 hours to charge.

General Information

Your trickle charger should come equipped with settings for the type of battery (such as 6 or 12 volts). Other features may include a rating switch (for amps), a timer and an automatic or manual charge switch. When you are not using your trickle charger, you should clean the clips and store it in a dry location.

Safety and Warnings

Check all dials and switches on your trickle charger to correctly set the volts and amps. Be sure to connect the negative (black) clip to the negative (ungrounded) battery post first. Once that connection is made, connect the positive (red) to the positive battery post. Be sure you do not reverse polarity. Once both connections are properly made, plug in your charger and turn it on. Once charging is complete, unplug the charger and disconnect in the opposite order of connection. Consider wearing safety glasses when working with batteries to protect your eyes and face in the event of a discharge or explosion.

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