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ProMariner

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

  • Based on 1,811 reviews
Condition: New
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Availability: In Stock.
Fulfilled by Amazon
Arrives Thursday, Jun 11
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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: Gray/ Yellow


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


Item Weight: 7.2 Pounds


Output Voltage: 36 Volts (DC)


Output Voltage: 36 Volts (DC)


Input Voltage: 120 Volts


Battery Charge Time: 5 Hours


Current Rating: 20 Amps


Amperage: 20 Amps


Connector Type Used on Cable: Battery Clamps


Number of Ports: 3


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


Item Weight: 7.2 Pounds


Color: Gray/ Yellow


Brand: ProMariner


Mfr Part Number: 44021


UPC: 031669440210


Manufacturer: ProMariner


Model Number: 44021


Item Type Name: boating-battery-chargers


Built-In Media: Battery charger, AC/DC power cables


Unit Count: 1.0 Count


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Thursday, Jun 11

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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Leasing options through Acima may also be available during checkout.

Learn more about financing & leasing here.

Similar Products

Top Amazon Reviews

    • 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
    • Charged
Pattern Name: Charger Style: 12/24/36V, 20 Amp, 3 Bank
Worked great. Easy to install. Fit perfect
Reviewed in the United States on April 13, 2026 by CDG_BMW
    • Great Product Great Product
Pattern Name: Charger Style: 12/24V, 20 Amp, 2 Bank
Review Image by 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 Reviewed in the United States on June 11, 2025 by Matt
    • 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
    • Good condition
Pattern Name: Charger Style: 12/24V, 20 Amp, 2 Bank
Good product was excellent condition for being a used one will definitely buy again
Reviewed in the United States on January 29, 2026 by Brett Dunlap
    • ,Good value, easy install instruction, but
Pattern Name: Charger Style: 12/24/36V, 20 Amp, 3 Bank
Initial start uu ok. A week or so later (new) batteries were flat. No fault ead on panel. Traced to a loose ground wire on one battery. Seems to me there should have been a panel redout code so indicating (a common problem), would have saved much diagnosis and tracing time!!
Reviewed in the United States on November 18, 2023 by David Lambert
    • Easy to connect and it is super quite.
Pattern Name: Charger Style: 12/24/36V, 20 Amp, 3 Bank
This is the second unit I have purchased. The first worked great but I hade a major short circuit that fried one of the 3 leads. the unit performs as listed in their promo
Reviewed in the United States on May 17, 2026 by Leo D. Peloquin
    • Great charger for the money!
Pattern Name: Charger Style: 12/24V, 20 Amp, 2 Bank
This has held up for 2 years now.
Reviewed in the United States on May 6, 2026 by Ian C

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