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ProMariner

ProMariner 44021 ProSport HD Waterproof Marine Battery Charger, 20 Amp, 3 Bank

  • Based on 1,811 reviews
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$260.99 Why this price?

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Returnable until Jan 31, 2026

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Pattern Name: Charger


Style: 12/24/36V, 20 Amp, 3 Bank


Features

  • ProSport HD 20A Triple Bank Waterproof Marine Battery Charger (Part Number 44021) replaces the old ProMariner Gen 3 ProSport 20 plus (part number 43021)
  • ProMar Digital Technology: Microprocessor and software controlled charging technology for fast, precise charging
  • Distributed-On-Demand Technology: 100% of all available charging amps are utilized by distributing unused charging amps to any one or combination of all batteries as needed
  • Heavy Duty Tri-Surface Extruded Heat Sink Design: Upper, lower and rear facing heat sink design for optimal cooling while delivering true rated constant current charging amps during its two charge mode
  • Expanded LED Display with Completion Status Gauge: LED fuel gauge style completion status. Four color multi-stage mode LED status bar. Multi-stage Charge Mode, System Check OK, individual Battery Status and Battery Type indication

Description

The new ProSport HD features a lightweight, tri-surface heatsink design. This delivers significantly faster charging through optimal cooling, while delivering true rated constant current charging amps during charge mode. Fully automatic multi-stage charging enhances battery performance while extending battery life.

Brand: ProMariner


Color: Unspecified


Product Dimensions: 8.7"D x 16.4"W x 6.3"H


Item Weight: 7.2 Pounds


Output Voltage: 36 Volts (DC)


Product Dimensions: 16.4 x 8.7 x 6.3 inches


Item Weight: 7.2 pounds


Item model number: 44021


Batteries: 1 Unknown batteries required.


Date First Available: November 22, 2019


Department: Unisex-Adult


Manufacturer: ProMariner


Frequently asked questions

This product is currently out of stock. Please check back later for shipping info.

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Similar Products

Top Amazon Reviews

    • Great charger
Pattern Name: Charger Style: 12/24V, 12 Amp, 2 Bank
So far this appears to be working great, charging and maintaining my boat batteries Easy to use with clear directions, easy to install
Reviewed in the United States on October 26, 2025 by BigG
    • Great Product
Pattern Name: Charger Style: 12/24V, 20 Amp, 2 Bank
Review Image by Matt Matt
I had the original version of this charger in our Crownline for 8 years and loved it. It worked perfectly, and kept the original batteries that came with the boat working great for that entire time. That is, until it got struck by lightning... So I ordered this, updated version of the same charger. It is exactly as nice as the old one with some nice upgrades including the charging gauge and the easier method of selecting the battery chemistry. I was extremely happy with the first one and would still have it if not for our mishap. I expect this one will carry on as the old one did, keeping my original batteries topped up when the boat is sitting. ... show more
Reviewed in the United States on June 11, 2025 by Matt Matt
    • Works well, a good smart charger... be sure to run separate cables for each battery
Pattern Name: Charger Style: 12/24V, 8 Amp, 2 Bank
Replaced my old Guest unit which had failed (due to my mistake, running the engine while charging). The old unit used one common ground wire for both batteries. After checking on a couple boat wiring forums, I decided this unit would work better by running a separate ground for each battery. Even though the batteries' grounds are connected at the battery bank, I learned that the individual ground wire for each battery will allow it to monitor and charge each battery individually, to account for different charge levels. That's the theory anyway... I'm still not sure it's correct, but the manual says to have individual +/- for each battery too. So that's what I did, and ran another ground. Other than that installation was pretty easy. I like the charging cycles, IIRC there are 5 "smart" stages, I've been a fan of those smart chargers for years, my batteries seem to last longer with them. The last stage is maintenance, so I'll just leave it connected over the winter. All in all I like it a lot. I'm pretty sure my old Guest unit failed while running and charging simultaneously, I had it for years but this was the first time I'd forgotten to stop charging before running the engine. But I've seen varying opinions on whether that's possible or probable. Regardless, I will never charge and run simultaneously again, just in case. Word to the wise... ... show more
Reviewed in the United States on September 16, 2021 by TW
    • Great product 👌
Pattern Name: Charger Style: 12/24/36V, 20 Amp, 3 Bank
Looks good, works great, I'm extremely satisfied with this product I definitely recommend it
Reviewed in the United States on August 31, 2025 by Rw Wilson
    • Great product-easy install!
Pattern Name: Charger Style: 12/24V, 12 Amp, 2 Bank
Easy to install (this was the best part-template included for pilot holes and 4 quick screws to attach it with) and instructions made it easy to understand the connections/setup based on different battery requirements.
Reviewed in the United States on October 3, 2025 by Amazon Customer
    • 3 gang battery charger
Pattern Name: Charger Style: 12/24/36V, 20 Amp, 3 Bank
The unit was quite easy to install and has performed well.
Reviewed in the United States on September 13, 2025 by Robert M. Saindon
    • Great product. I've been using it for a year and I'm still happy with it.
Pattern Name: Charger Style: 12/24V, 20 Amp, 2 Bank
I bought this product one year ago it's been maintaining 2 lead acid banks in my trawler with no problems. Very good value.
Reviewed in the United States on September 26, 2025 by Michelle Z.
    • got to have
Pattern Name: Charger Style: 12/24/36V, 20 Amp, 3 Bank
works so good
Reviewed in the United States on December 7, 2025 by richard drew

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