Marine Battery Chargers | Onboard Boat Battery Chargers

Yes — that is exactly what Battery Tender® WaveCharge chargers are designed for. Once each bank reaches full charge, ISM automatically transitions to float maintenance mode, delivering a precisely regulated micro-current that holds every battery at peak voltage indefinitely without overcharging. This applies to both lead-acid and Lithium battery chemistries — select the correct chemistry per bank and ISM delivers the right maintenance protocol for each. Leave the charger connected from the last day of the season through to the first day back on the water — every battery will be at 100% when you return.

Battery Tender® WaveCharge multi-bank chargers charge and maintain up to four 12V batteries simultaneously — each bank operating as a completely independent charging circuit at full output. Unlike a single-output charger with a Y-adapter, WaveCharge does not split its output between banks. Each bank has its own chemistry selector for lead-acid or Lithium (LiFePO4), so Bank 1 can maintain a lead-acid starting battery while Bank 2 charges a Lithium house bank — simultaneously, at full output on each, with the correct ISM profile for each chemistry.

Battery Tender® WaveCharge and PowerPlus marine chargers support all standard marine battery chemistries — flooded lead-acid, AGM (Absorbent Glass Mat), gel cell, sealed maintenance-free, and Lithium (LiFePO4). WaveCharge models include a per-bank chemistry selector so different battery types can be charged simultaneously on different banks with the correct ISM profile for each. For 24V, 36V, or 48V trolling motor and propulsion systems, the Battery Tender® PowerPlus line covers all voltages with Multi-Chemistry support for both lead-acid and Lithium at each voltage.

IP67 is an independent ingress protection rating certifying complete dust protection and water immersion resistance to 1 meter for 30 minutes. For a marine charger, this means WaveCharge and PowerPlus units withstand direct spray, splash, bilge moisture, and the humidity extremes of coastal and saltwater environments — permanently mounted without any protective enclosure. Standard indoor battery chargers are not rated for these conditions and will fail.

Yes. Every Battery Tender® WaveCharge charger carries UL marine ignition protection certification — the independent certification required for charging equipment installed in enclosed spaces near fuel systems. This certifies that the charger will not produce ignition-capable sparks during operation or connection in the presence of fuel vapors. Do not install any charger in an engine room or compartment near fuel unless it carries UL marine ignition protection.

The right charger depends on your number of battery banks, voltage, and how quickly you need them recovered. For standard 12V systems with a starting battery and one or two house banks, WaveCharge Standard (3 Amps per bank) handles overnight charging and WaveCharge Pro (10 Amps per bank) delivers faster recovery. For boats running a 24V or 36V trolling motor system, the Battery Tender® PowerPlus 24V 20 Amp or PowerPlus 36V 18 Amp provides dedicated on-board charging at the correct voltage. For 48V trolling motor systems — including the Rhodan 48V — the PowerPlus 48V 15 Amp delivers full ISM charging and Lithium-compatible maintenance for 48V LiFePO4 packs.

Connect a Battery Tender® WaveCharge bank or PowerPlus on-board charger directly to the trolling motor battery and leave it connected throughout winter storage. For Lithium trolling motor batteries, set the bank or charger to Lithium mode — ISM delivers the correct LiFePO4 maintenance protocol, which differs from lead-acid float. For lead-acid trolling motor batteries, continuous ISM float prevents sulfation — the permanent hardening of lead sulfate on battery plates that occurs when a battery sits discharged. A battery maintained at float voltage through winter consistently delivers full capacity when the season opens, year after year. For 24V, 36V, or 48V trolling motor packs, use the corresponding PowerPlus voltage model for correct per-voltage charging.