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Frequently Asked Questions
Speed and application — and each is a product series, not a single charger. All use ISM (Infinite Sequential Monitoring) for automatic 4-stage charging and indefinite float maintenance. The Battery Tender® Plus series (1.25 Amp) is ideal for ongoing maintenance of any stored vehicle. The PowerTender® series (3 to 15 Amp) charges and maintains faster and adds Multi-Chemistry support for Lithium (LiFePO4) batteries. The WaveCharge series (Standard and Pro) is an onboard marine and outdoor charger that charges and maintains multiple battery banks simultaneously.
Yes. Lithium (LiFePO4) charging is supported across the Battery Tender® lineup — from the Junior (1 Amp) and the Plus series to the PowerTender® and WaveCharge series. On selectable/Multi-Chemistry models, choose Lithium on the chemistry selector and ISM delivers the correct LiFePO4 charging profile, which uses a higher absorption voltage and a different maintenance protocol than lead-acid. Battery Tender® has been engineering dedicated Lithium charging profiles for over 20 years.
ISM stands for Infinite Sequential Monitoring — Battery Tender's proprietary 4-stage charging algorithm. Unlike a basic trickle charger that delivers constant current regardless of battery state, ISM runs: Initialization (health check before current flows), Bulk Charge (full output restores capacity), Absorption (current tapers as battery approaches full charge to prevent overcharge damage), and Float Maintenance (micro-current holds peak voltage indefinitely). ISM is why Battery Tender® chargers and maintainers can be left connected for months without overcharging.
Match charger output to your battery size. The Battery Tender® Junior (750mA / 1 Amp) and Plus series (1.25 Amp) are ideal for motorcycle and powersports batteries — and can maintain larger batteries too. The PowerTender® series (3 to 15 Amp) is ideal for most car, SUV, and truck batteries (up to 250Ah) and recovers them faster. For golf carts and 24V, 36V, or 48V systems: the PowerPlus line. For marine multi-bank systems: the WaveCharge series (Standard and Pro).
Sulfation — the permanent hardening of lead sulfate crystals on battery plates — forms when a battery sits discharged. Once significant sulfation develops, no charger can restore the lost capacity. Battery Tender® chargers and maintainers prevent it by maintaining continuous float voltage above the sulfation threshold from the moment they are connected. Battery life consistently extends from 2 to 3 years to 5 years or more with proper maintenance charging.


































































































