Battery Tender Instructions

The Battery Tender, which is manufactured by Deltran, is a battery charging device which allows you to trickle-charge a depleted battery. The basic Battery Tender will recharge a battery at a rate of .75 amps/hour. If you own the Battery Tender Plus, however, it will charge at a higher rate of 1.25 amps/hour. When the battery has finished charging, the Battery Tender will automatically switch to maintenance mode, thus ensuring the battery will not go dead once again. For this reason, a Battery Tender is highly useful for batteries in storage or those installed in vehicles that are infrequently used.


1. Put on safety goggles and access the battery if it remains in a vehicle. If necessary, remove any guards/shields in place over the battery terminals. You may need a small wrench or pliers to accomplish this.

2. Ensure that all cords and cables are safely out of the way of any of the vehicle’s moving parts, e.g., the fan blade or the hinges on the hood.

3. Connect the red ring or clip on the Battery Tender to the positive post of the battery. If the battery is still in the vehicle, you must then connect the black ring or clip to an unpainted part on the chassis of the vehicle. This could be a bolt or bracket. Do not connect the negative clip to a fuel line or any part of the carburetor.

4. Plug the Battery Tender’s power cord into an electrical outlet. If the cord won’t reach, you may need to use an extension cord.

5. Allow the Battery Tender to charge the battery. The exact time will vary. A completely discharged battery may take up to 16 hours to charge at .75 amps/hr. If you’re using the Battery Tender Plus, it may take approximately 9.6 hours for the dead battery to fully charge. When the battery has a full charge, a green indicator light will appear on the Battery Tender.

6. Unplug the Battery Tender’s power cord and disconnect it from the battery, beginning with the negative clip first. If you wish to keep the Battery Tender connected to the battery, the Battery Tender will go into maintenance mode. While in maintenance mode, the Battery tender monitors the battery and charges as needed.