--- product_id: 3433804 title: "Gen 3 ProSport 20 Amp 12/24/36 Volt 3 Bank Waterproof Marine Battery Charger 43021" brand: "promariner" price: "¥98229" currency: JPY in_stock: true reviews_count: 13 category: "Pro Mariner" url: https://www.desertcart.jp/products/3433804-gen-3-prosport-20-amp-12-24-36-volt-3 store_origin: JP region: Japan --- # 20 Amp rapid charging Waterproof rugged aluminum 3-bank simultaneous charge Gen 3 ProSport 20 Amp 12/24/36 Volt 3 Bank Waterproof Marine Battery Charger 43021 **Brand:** promariner **Price:** ¥98229 **Availability:** ✅ In Stock ## Summary > ⚡ Charge smarter, sail longer — never miss a wave! ## Quick Answers - **What is this?** Gen 3 ProSport 20 Amp 12/24/36 Volt 3 Bank Waterproof Marine Battery Charger 43021 by promariner - **How much does it cost?** ¥98229 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.jp](https://www.desertcart.jp/products/3433804-gen-3-prosport-20-amp-12-24-36-volt-3) ## Best For - promariner enthusiasts ## Why This Product - Trusted promariner brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Power-Packed 20 Amp Output:** Experience lightning-fast charging that keeps your marine batteries ready for action. - • **Built to Brave the Elements:** Waterproof, rugged aluminum design ensures durability even after submersion. - • **Triple Battery Bank Mastery:** Charge three batteries at once with smart amp distribution for peak efficiency. - • **Smart Diagnostics at a Glance:** LED indicators instantly reveal battery health and system status—no guesswork needed. - • **Automatic Battery Reconditioning:** Monthly maintenance mode extends battery life, so you’re always adventure-ready. ## Overview The ProMariner Gen 3 ProSport 20 Amp 3 Bank Waterproof Marine Battery Charger delivers fast, efficient charging across 12/24/36V systems with advanced Distributed on Demand Technology. Its rugged, waterproof aluminum build withstands harsh marine environments, while smart LED diagnostics and automatic monthly battery reconditioning maximize battery health and performance. Perfect for professionals and enthusiasts who demand reliable, hassle-free power management on the water. ## Description The 12V, 6 Amp, 1 battery bank ProSport 6 waterproof battery charger delivers fast efficient charging in a lightweight design.Distributed on Demand Technology utilizes 100% of the available charging amps and automatically distributes charge amongst all the batteries as needed . The result is faster, more efficient charging.Advanced technology eliminates time consuming troubleshooting by clearly indicating system and battery connections are OK or if a fault is present on a specific battery bank.During short or long-term storage, ProSport automatically reconditions all batteries on board once a month for maximum battery life and performance.Compact and rugged aluminum design, dual in-line DC safety fuses for trolling motor and house battery banks. Built-in over-voltage, overload, over-temperature, reverse polarity and ignition protection.Digital LED Display and Battery Type Selector: LED indicators for Charging, Conditioning and Auto Maintain modes in addition to AC power and selected battery type. Review: You get your monies worth; excellent product - Last year Our nitro bass boat was left outside and the 3 bank water proof charger we had on it was submerged in ice water; we had been looking for a new one but every one was 500 plus and there was no way I was allowing that; I jumped on desertcart before Father’s Day and found this three bank charger; we didn’t need to purchase any of the extra accessories bc we already had one on our boat before, much to our surprise it fit perfectly in the original holes from our first bank charger and this one during a heavy rainstorm ended up submerged for a few days bc the plug was left it, once again big shock after draining the boat and allowing it to dry we plugged it right in and it still works! No problems what so ever, love this bank charger! It runs two trolling batteries and the master, we can go out for hours and not worry one bit about battery charge! Love it! And under 200.00! Review: Charges batteries.....3 of them Simultaneously - I"ve had this charger for a few years and it's been working well and makes charging the 3 batteries on my boat an easy operation. Never had an on board charger before, and always charged the batteries 1 at a time which was a huge pain. When I plug this charger in it checks all the batteries and if the connections are good begins to charge them. So it's kinda like a little check on the electrical system as well as charging batteries, and you don't waste your time trying to charge if the connections to the batteries or a fuse are bad. Very handy after a day on the water to simply plug in the charger and go to bed knowing all 3 batteries will be full charge in the morning. Installation was pretty easy, the wires were just long enough to reach the one battery on the opposite side of the boat from where I mounted the charger. My boat is an 18' center console. 3 full seasons later this charger looks and works like new ## Features - The 12/24/36V, 20 Amp, 3 battery bank ProSport 20 Plus waterproof battery charger delivers fast efficient charging in a lightweight design - Distributed on Demand Technology utilizes 100% of the available charging amps and automatically distributes charge amongst all the batteries as needed . The result is faster, more efficient charging - Advanced technology eliminates time consuming troubleshooting by clearly indicating system and battery connections are OK or if a fault is present on a specific battery bank - During short or long-term storage, ProSport automatically reconditions all batteries on board once a month for maximum battery life and performance - Compact and rugged aluminum design, dual in-line DC safety fuses for trolling motor and house battery banks. Built-in over-voltage, overload, over-temperature, reverse polarity and ignition protection - Digital LED Display and Battery Type Selector: LED indicators for Charging, Conditioning and Auto Maintain modes in addition to AC power and selected battery type ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B00F5EBTGA | | Amperage | 20 Amps | | Battery Charge Time | 10 Hours | | Best Sellers Rank | #919,364 in Automotive ( See Top 100 in Automotive ) #1,688 in Battery Chargers | | Brand | ProMariner | | Built-In Media | battery charger | | Color | Yellow/Black | | Compatible Devices | Boat | | Connector Type Used on Cable | DC | | Current Rating | 20 Amps | | Customer Reviews | 4.6 out of 5 stars 1,326 Reviews | | Global Trade Identification Number | 00031669430211 | | Input Voltage | 36 Volts | | Item Dimensions D x W x H | 6"D x 14.5"W x 8.5"H | | Item Type Name | Waterproof Battery Charger | | Item Weight | 8 Pounds | | Manufacturer | ProMariner | | Mfr Part Number | 43021 | | Model Number | 43021 | | Number of Ports | 3 | | Output Voltage | 36 Volts | | Product Dimensions | 6"D x 14.5"W x 8.5"H | | UPC | 656727420579 690579678177 031669430211 | | Unit Count | 1.0 Count | | Warranty Description | 24 Months | ## Product Details - **Brand:** ProMariner - **Color:** Yellow/Black - **Item Weight:** 8 Pounds - **Output Voltage:** 36 Volts - **Product Dimensions:** 6"D x 14.5"W x 8.5"H ## Images ![Gen 3 ProSport 20 Amp 12/24/36 Volt 3 Bank Waterproof Marine Battery Charger 43021 - Image 1](https://m.media-amazon.com/images/I/71UNw3VgBlL.jpg) ![Gen 3 ProSport 20 Amp 12/24/36 Volt 3 Bank Waterproof Marine Battery Charger 43021 - Image 2](https://m.media-amazon.com/images/I/71yffmwkuwL.jpg) ## Questions & Answers **Q: Does this unit have a cooling fan? Does it overheat?** A: No fan. Yes it over heats. Mine died after a month and MFG service and support link, nor the registration lik work on their website. Unable to get through via phone. Had to buy a new one. I went with Charles Marine charger. Superb charger. Beware of this one. **Q: I have a single starting battery (one bank) .Then I have two deep cycle batteries in parrallel (bank 2). Do I need a 2 or 3 bank charger?** A: you failed to give the the voltage, type, and size of batteries, and what they are being used for, but going with the information you submited. providing all of the batteries are 12v d.c. you require a 2 bank charger, but if i were you, i would order the 3 bank charger for future battery expansion, i would connect one of the charger outputs across the neg & positive terminal of the stand alone 12v dc battery, and i would then connect the second charger output lead across the 12 v dc neg & positive terminal of one of the 2 batteries which are tied in parallel. the charger in question permits the 3rd charger output to be connected to the 3rd neg & positive post of the 3 rd 12 v dc battery which is tied in parallel. but if i were you, i would first contact the manufacture reps, before you do anything, tell them your set up, and see what they think. in any event good luck, and above all do not forget to ware the proper safty equiptment prior to doing any work on any batteries. **Q: I am installing this into my sailboat. What is the 110v amperage draw?** A: The power consumed by any electric unit is equal to the Operating voltage V times the current I. or Power = V*I in watts. If this charger is charging 2 batteries at 12 volts each and drawing 10 amps for each battery the power used is 12 * 10 = 120 watts each. So the ideal power used would be 240 watts for the two batteries. The AC source must supply power in the same way so you need 110 volts times I amps = 240 watts. Therefore the current, I, drawn would be 240/110 or around 2.2 amps , but you never have ideal energy exchanges because of heat loss and other things. So I would think you would need to have a source that could provide at least 5 amps @ 110 volts or around 600 watts at maximum usage. Much less current is needed for trickle charging.This gives you a margin of error of over 200% so should be OK. Hope this helps **Q: 2 engine start and one thee battery house set ...so i need a 5 bank charger?** A: Your description is not 100%, but it sounds like you need three Banks. One for each starting battery, and one for your group of house batteries, assuming they are all tied together. ## Customer Reviews ### ⭐⭐⭐⭐⭐ You get your monies worth; excellent product *by B***N on July 13, 2020* Last year Our nitro bass boat was left outside and the 3 bank water proof charger we had on it was submerged in ice water; we had been looking for a new one but every one was 500 plus and there was no way I was allowing that; I jumped on amazon before Father’s Day and found this three bank charger; we didn’t need to purchase any of the extra accessories bc we already had one on our boat before, much to our surprise it fit perfectly in the original holes from our first bank charger and this one during a heavy rainstorm ended up submerged for a few days bc the plug was left it, once again big shock after draining the boat and allowing it to dry we plugged it right in and it still works! No problems what so ever, love this bank charger! It runs two trolling batteries and the master, we can go out for hours and not worry one bit about battery charge! Love it! And under 200.00! ### ⭐⭐⭐⭐⭐ Charges batteries.....3 of them Simultaneously *by C***G on January 31, 2018* I"ve had this charger for a few years and it's been working well and makes charging the 3 batteries on my boat an easy operation. Never had an on board charger before, and always charged the batteries 1 at a time which was a huge pain. When I plug this charger in it checks all the batteries and if the connections are good begins to charge them. So it's kinda like a little check on the electrical system as well as charging batteries, and you don't waste your time trying to charge if the connections to the batteries or a fuse are bad. Very handy after a day on the water to simply plug in the charger and go to bed knowing all 3 batteries will be full charge in the morning. Installation was pretty easy, the wires were just long enough to reach the one battery on the opposite side of the boat from where I mounted the charger. My boat is an 18' center console. 3 full seasons later this charger looks and works like new ### ⭐⭐⭐⭐⭐ If you have an issue with Only the Blue AC light on *by N***J on April 6, 2020* Please use the following for troubleshooting steps: Tools Required: 1. Large Flathead Screwdriver or coin 2. Diagonal cutters, Metal File or Sandpaper Time Required: Approx. 5 minutes 1. Disconnect AC power from the charger. 2. Confirm all charger cables are connected correctly to batteries. 3. Remove the programming cap from the wire end of the charger’s end cap using a screwdriver or a coin. 4. Reconnect AC Power. At this point, you should have the following LED’s a. Blue AC power LED b. Green Battery type LED (Gel) c. Red Flashing Analyze/Charge LED i. If you only see the Blue LED, please contact us, and we will begin the warranty replacement process. 5. Disconnect AC power. 6. Programming cap alteration: a. Using a metal file or sandpaper, remove approximately half of the material from the unthreaded portion of the programming cap. i. Approximately 1/8th inch of material will be remaining. 7. Ensure there is no debris in the programming cap hole, or on the cap itself, and reinstall the programming cap. 8. Reconnect AC Power. At this point, you should have the following LED’s a. Blue AC power LED b. Red Battery type LED (Flooded/AGM) c. Red Flashing Analyze/Charge LED i. If you reencounter the issue, remove more material from the unthreaded portion of the programming cap until the charger is functioning properly. ii. The charger must reset to register the correct position of the programming cap. d. The charger is now functioning properly and will follow the operation outlined in the manual. Please Note: The standard warranty is two years from the purchase date for the original owner. If you would like to send your charger in for evaluation, please don’t hesitate to call us at 1-800-824-0524. ## Frequently Bought Together - ProMariner Gen 3 ProSport 20 Amp 12/24/36 Volt 3 Bank Waterproof Marine Battery Charger 43021 - Maradyne Havasu Hydronic Automotive Heater, 12V, 2-Speed, 20,000 BTU/Hr 177 CFM Under Dash Mount; 3-2.5" Louvers - Walker 35594 Exhaust Pipe Spout 1.625" Inlet (OD) 1.25" Outlet (ID) for Honda Accord --- ## Why Shop on Desertcart? - 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016 - 🌍 **Shop Globally** — Access 737+ million products across 21 categories - 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price - 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members) - 🔒 **Secure Payments** — Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.jp/products/3433804-gen-3-prosport-20-amp-12-24-36-volt-3](https://www.desertcart.jp/products/3433804-gen-3-prosport-20-amp-12-24-36-volt-3) --- *Product available on Desertcart Japan* *Store origin: JP* *Last updated: 2026-05-17*