The Battery Tender Plus 6V/12V selectable charger (022-0211-DL-WH) puts two voltage classes into one 1.25-amp unit. A manual 6V/12V selector switch allows precise matching of charge voltage to the specific battery being maintained. ISM handles everything from that point forward. This is a maintainer, not a fast charger. Owners on user forums describe leaving one on a stored car for 6 to 7 months without issues. The main reason to pay for this model over a fixed-voltage trickle charger is that a wrong setting does real damage. A 6V setting applied to a 12V battery will undercharge it chronically; a 12V setting applied to a 6V battery will overcharge and may damage it. Because the selector is manual, there is no automatic voltage detection.
For fitment, this suits powersports, lawn equipment, and stored cars, and the manufacturer lists 6V for vintage vehicles and pre-1960s equipment; 12V for modern motorcycles, ATVs, cars, trucks, and powersports vehicles. Installation is straightforward. The manufacturer's guidance is to confirm the battery voltage, set the switch, and connect. Owners also run the 1.25-amp charger from a 25 foot extension cord so the unit can stay in the garage. Search terms this page targets include 6V/12V selectable battery tender, 1.25 amp float maintainer for AGM motorcycle battery, and six-volt classic car battery tender.
The manufacturer states that a 6V setting on a 12V battery will chronically undercharge it, and a 12V setting on a 6V battery will overcharge it and may damage it. Set the switch to match the battery before connecting.
Yes. The manufacturer specifically recommends the 6V position for vintage vehicles and pre-1960s equipment, and the switch must be set to 6V before the charger is connected to the battery.
The manufacturer's listing includes a two-in-one cable with both alligator clips and ring terminals, so you can choose a temporary or permanent connection.
Plan for a low-difficulty, DIY-friendly install. Per the manufacturer's Plus-line manual, connect the positive ring or clip to the positive battery post first, then connect the negative to the chassis, and avoid carburetor, fuel lines, or thin sheet metal for that ground. Do not make the negative charger clip or ring connection to the carburetor, fuel lines, or thin, sheet metal parts. Make that connection to the engine block or a heavy gauge metal part of the frame. Before disconnecting, unplug the AC cord first, then remove the leads, as the manufacturer's operating instructions advise. For permanent ring terminal mounting, the manufacturer's installation guide calls for 8mm and 10mm wrenches and dielectric grease, and battery terminals should be cleaned of corrosion first. Verify the voltage switch position before you connect anything.
