garyemunson wrote:
Battery tenders are not designed to 'charge' batteries. Their purpose is to zero out the battery's normal self-discharging and any minor parasitic draws. Even that can overwhelm the BT if too many things are drawing current.
You need to differentiate between a trickle charger, often called a battery tender and a battery charger with the brand name Battery Tender.
From the Battery Tender website:
The Battery TenderĀ® Plus is a 1.25 amp battery charger designed to fully charge a battery and maintain it at proper storage voltage without the damaging effects caused by trickle chargers. Included is a quick connect ring terminal harness for hard to reach areas and alligator clips for an alternate connection.
Temperature compensated to ensure optimum charge voltage according to ambient temperature.
Automatically switches from full charge to float charging mode.
Reverse Polarity Protection to ensure user safety. Red & Green Lights Alternately Flash in this condition.
Complete 4-step charging program (Initialization, Bulk Charge, Absorption Mode, Float Mode).
Perfect for all lead-acid, flooded or sealed maintenance free batteries (AGM and gel cell).