Sentry Battery Chargers.

The most reliable battery charger in marine applications The Sentry Battery Charger SFR-series chargers are designed to provide automatic and unattended operation for charging your battery. Its ferro-resonant transformer gradually decreases the charging current as the battery approaches full charge. Once the battery is fully charged, the charger turns itself off until needed again. The charger can be set to “automatic” mode by simply flipping the front-panel switch.

The Sentry charger is equipped with a manual/automatic selector switch, ammeter, full charge, and power indicator, all conveniently located on the front panel. The charger is available in 12V, 24V, and 32V models, with output currents ranging from 20 to 60 amps. It can be powered by 115 or 230 VAC power, and models are available for 50/60 Hz operation.

The charger is designed to monitor all battery banks and comes on instantly when it senses a drop in voltage level in any of them. It matches its output precisely to the load on your DC system. No output trickle to overcharge, dehydrate, damage, or warp your batteries’ cell plates.

The Sentry switchmode chargers are also designed for unattended operation. They respond with the required output when current is requested or the battery needs charging. With its three-step charger, the charger quickly brings your battery up to full charge. Once the battery reaches a “float” condition, the output is reduced to match that requested by the battery. The unit can also directly operate as a power supply to your 12/24 volt systems, should the need arise.

The charger has a manual override function to help crank the engines on weak batteries. Standard Sentry units have negative ground with triple output, allowing up to three separate banks of batteries to be charged simultaneously. A fourth output is available as an option on most models.

An optional remote panel is also available, which can be ordered with the standard unit or added later.

12 Volt Chargers

FR1220/3B, 12V, 20A x3 Outputs, 115V 60Hz Input

FR1240/3X, 12V, 40A x3 Outputs, 115/230V 60Hz Input

FR1240/3XJ, 12V, 40A x3 Outputs, 115/230V50/60Hz Input

FR1260/4X, 12V, 60A x4 Outputs, 115/230V 60Hz Input

FR1260/3X, 12V, 60A x3 Outputs, 115/230V 60Hz Input

FR1260A/3X, 12V, 60A x3 Outputs, 115/230V 60Hz Input

24 Volt Chargers

FR2425/3X, 24V, 25A x3 Outputs, 115/230V 60Hz Input

FR2440/3X, 24V, 40A x3 Outputs, 115/230V 60Hz Input

FR2440/3XJ, 24V, 40A x3 Outputs, 115/230V 50/60Hz Input

FR2460/3XJ, 24V, 60A x3 Outputs, 115/230V 50/60Hz Input

36 Volt Chargers

FR3230/3X, 32V, 30A x3 Outputs, 115/230V 60Hz Input


The Sentry SM chargers can be set for 115 or 230 VAC operation with a simple internal adjustment. They can accommodate switchover. The chargers can work efficiently with low supply voltages and poor-quality AC waveforms from operators. An easy manual switch selects output for gel cell or lead acid batteries. Most Sentry SM models offer three independent outputs for charging three separate battery banks simultaneously. The 12V, 10, and 20 amp models provide two outputs.


The Sentry SM chargers are built to ABYC and UL standards and are CE-certified for export to Europe. The units will not affect other onboard electronics. They are designed with protection against overtemperature, short circuits, and reversed polarity and are equipped with input and output fuses. They are ignition-protected and currently limited.


Operating the Sentry SM charger couldn’t be easier. You turn it on and leave it on. That’s all. Convenient front panel indicators give a readout of the system status. An optional remote indicator panel is also available for mounting outside the engine room.


The optional battery voltage indicator gives you an easy-to-read LED bar graph showing the battery status. The microprocessor-based Battery Supervisor provides a digital display of temperatures, voltage, alarms, and other helpful information for up to three banks of batteries.

Weight 35 lbs
Dimensions 23 × 18.5 × 20 in

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3, 4

Output Voltage

12v, 24v, 32v

Input Voltage

115v-230v, 60Hz, 115v-230v, 50-60Hz, 115v, 50/60Hz

Battery Type



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