The Battery Tender Plus uses a four-step program to charge and maintain 12-volt batteries. It has a simple design and doesn’t require any diagnosis or mode selection – you just connect the charger to your battery’s terminals with either the traditional alligator clips or ring terminal harness and it does the rest.
This charger automatically compensates for the ambient temperature to charge your battery to the optimum level. The charging process has four-steps: initialization, bulk charge, absorption mode and float mode. After the battery fully charges in the charge and absorption steps, the float mode maintains the charge by continuously supplying a small amount of voltage so the battery is at full capacity when you are ready to use it.
The Battery Tender Plus has safety features that ensure you don’t damage it or your battery. Its reverse polarity protection feature notifies you if you haven’t connected the clips or rings properly – lights on the front panel alternately flash red and green so you know to fix the connections before you leave the battery unattended. It also has spark-free circuity to keep the connectors from arcing when they touch together.
The lights on the front panel also indicate the charging status. A solid red light signals that the battery is connected properly and charging. When the red light is on and the green light is flashing, the battery is charged to more than 80 percent and can be used if necessary. A solid green light indicates charging is complete and the battery is ready to use.
One of the Battery Tender Plus’ shortcomings is it cannot charge 6-volt batteries or 12-volt lithium-ion batteries – it can only charge lead-acid and flooded or sealed maintenance-free batteries. It also doesn’t have a quick start mode, so it can’t immediately start a dead battery. You have to leave the device on the battery for approximately 10 hours to charge it to 80 percent capacity.
If you have questions about the Battery Tender Plus, you can reach the manufacturer by either phone or email. In addition, the charger comes with a 10-year manufacturer warranty that covers it against defects and workmanship.