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Your cart is empty.The DC-DC Battery Chargers are the most effective way to charge your house batteries from the starter battery. Compatible with a multitude of alternator types, the DC-DC battery charger offers correct charging for AGM, Flooded, Gel, and even Lithium deep cycle batteries! Featuring a 3-stage battery charger and multiple electronic protections, users can feel confident that their batteries are being charged optimally and automatically. For additional safety, it isolates the input from the output preventing incorrect voltage transmission. Easily install the compact yet sturdy DC-DC battery charger on RV's, commercial vehicles, boats, yachts, and many more applications!
B4 Serrell
Reviewed in the United States on January 24, 2025
We already had installed heavy gauge wire with circuit breakers running from the starter battery to the back of our van, with a dashboard override shut off switch, to charge our prior camping battery that was AGM, but we upgraded to LiFePo4 100Ah. I like that this not only has programmed charging appropriate for this new battery, but can vary from 20A to 40A charging. I used a cigarette lighter plug in the rear of the van as my source of switched 12V acc input to let the charger know the engine was running, and to the same plug added a wire with a small in-line lamp switch to engage or disengage the voltage step-down. Now I just wish I could set up an easy way to switch from this camping battery to an additional 100Ah LFP mini that I bought for extra capacity.
Ian Douglas
Reviewed in Canada on September 9, 2024
20 amp section did not work. Verified that 12v was getting to the connector, but it did not produce any charge voltage/current. 40 amp worked perfectly, but I bought it for the dual functionality so I could recharge the start battery before engaging the full 40 amp section. It looked well built but QA seems to be lacking for the electronics. Sent it back, hope to find another vendor with similar options.
balixjose
Reviewed in the United Arab Emirates on May 3, 2024
Was delivered on time and worked as charm.I liked it.
Eric McAdam
Reviewed in Canada on May 20, 2024
I have not use this product yet however I have quite a big system for quite a few years and I can just tell by looking at this that it’s gonna be very good quality. It’s actually better than what I expected.
Greg
Reviewed in Canada on March 20, 2024
For my needs this unit was great. Researched this and Victron products and decided this met my needs. Bench load tested off a modified 30 amp 12v computer power supply. It worked great. Recommend it. May buy battery monitor and other products off renogy later. Next evaluation is a high amprage 50 to 70 amp 24 volt power supply to wire into 24v 200 amp battery bank.
d
Reviewed in Mexico on November 25, 2024
All good
Ge Las
Reviewed in Mexico on January 30, 2024
Producto de buena Calidad es de gran apoyo ya que aparte de cargar tu batería externa si estas usando en ese momento el inversor suministra los 40 amperes adicionales al inversor por lo que no salen de la bateria dicha corriente por lo que mantiene tu batería cargada más tiempo a diferencia si estuviera apagado dicho cargador.30/Octubre/2024 Instale el segundo Cargador 40 Amperes funcionando al 100% estoy muy satisfecho con la compra. Con los dos cargadores tengo las opciones de realizar cargas de 20/40/60/80 amperes a las baterías de litio.08/Abril/2025 solamente hice algunas modificaciones modifique el disyuntor de salida a 100 amperes hacia las baterías de litio y modifique el cable de las baterías del camion a los inversores de 4awg a 2awg para tener menos perdidas de corriente y calentamiento note una mejoría están suministrando 100amperes de consumo por los 2 inversores de momento están funcionando al 100%. En pocas palabras entran 100amperes a los inversores y sacan 78 amperes a las baterias de litio.
Frank
Reviewed in Canada on September 25, 2023
Installed this in my RV to charge my newly installed LifPo4 battery. Had trouble at first, wouldn't come on. I ran a new ground wire from the trailer connection to the battery and fixed the problem. For some reason it didn't like using the RV frame as a ground path. Very happy, delivers 20 amps as advertised. Wish they had a 30 amp version and the fuse in my F-150 truck is 30 amps from the factory.This is a follow up on the initial installation. It ran good until the fuse blew. I put the amp meter to the power line from the truck and even though it limits 20 amps to the trailer battery the unit itself draws another 13 amps for a total of 33 amps. So I'll need to run a separate 8 awg wire from the truck. I'm surprised that it would require an additional 13amps just to power the unit!
Mer
Reviewed in Canada on August 21, 2023
Hooked it up and no go; light on, no output. So basic trouble shooting procedures. give it a hit :) And it started :) tapped it again; it stopped, Clap on, cap off, repeatable flaky, I know this is a good product so I am returning it and getting another. 2nd one works perfect.
David Smith - DaveTech.CA
Reviewed in Canada on November 10, 2023
It's important to use high quality heavy guage wire. I bought a 20 amp which works great in my car.I wired using 4 guage real copper ( better to thick than too thin).Also used proper fuses and breakers.If you don't know what you are doing see a professional.I added a toggle switch on my dash as I don't want it turning on and off every time I start the car.Charges my 2 x 100 ah trunk batteries just fine.Be careful to make sure you have the dip switches set correctly.
Magnus Clarke
Reviewed in Canada on August 29, 2022
Works exactly as advertised.I use this unit to charge my house bank of batteries on my boat.I have added a two minute delay to allow the starter battery to get some charge before the full 40 amps from this charger kicks in. With my motor below 1100 RPM, this sucks juice from the start battery and the alternator. Above 1100 RPM and they both charge at the same time.Someone asked why there is an amp cutting switch. E.g. this unit can be triggered to cut the output to 20 amps from the full 40 amps. To me, this would be valuable if you are doing a lot of idling. Depending on how you have it wired and how many amps your alternator kicks out, cutting the amps would prevent you draining your start battery by feeding this charger while idling. Once you trigger the amp cut it does not stop until you restart the charger, you must shut it down to get it to reset that feature.Solid piece of hardware, good documentation.I did a long trip with it and watched it cycle through bulk, the absorbtion stage, then go into float mode, it does it all smoothly and managed 4 large 135 AMP hour batteries at once with no difficulty. It modified the time for the stages based on the starting state of charge and the loads placed on the system while running, totally dynamic and automatic.
Gr8toutdoors
Reviewed in Canada on June 2, 2022
Believe the bad reviews this company is producing garbage and not backing it up no customer service and no refunds. I have used mine less than 6 months and under 100 hours and it doesn’t work and blows 250 amp fuses could end up costing you way more the company is selling garbage in a box and literally says we don’t care and is aware there getting away with it, I had electrical company look inside after no response from the company and they said it is made as cheaply as possible. There are much better options pass on these poorly constructed and zero customer service companies just because there on Amazon or some you tubers use the product.
Customer
Reviewed in the United States on May 25, 2022
I installed these units to charge the 2x 600ah battery bank(s) shown above.My instalation draws power from a 250 amp engine alternator.The charging units have primary input and output hookups of solid metal with machine screws to secure the wires. They also have 2x additional wire inputs. One wire input activates the unit, it will not charge untill voltage is applied to the "D+" terminal. This allows it to fuction as a battery isolator relay, whereby it wont charge untill its told to by the activation wire. It also has a second activation wire for a 50% power mode. This knocks the charging amperage down to 30 amps, and I highly reccomend wireing this lead to a toggle switch.I installed 2x units and found that a 250 amp alternator cannot power more than one of these at idle engine speed. At highway speed and higher rpm, I can run both units at 60 amps. but at night time with all lights on in the RV, I can only run one at 60 amps and the other at 50% power without overdrawing the alternator.The installation instructions indicate that they "may draw upto" 90 amps, but upon installation i havnt seen more than 65 amps.I installed 2 of these units which is kinda crazy, i did it by isolating two battery banks with a giant diode array, in the form of a battery isolator diode set installed "upside down" on the negative terminal side. but take note that a 250 amp alternator can barely power both of them when tacked ontop of the other electrical load for the RV.Installing one unit with a common 130-150 amp alternator it would be advised to install the amperage reduction function to avoid overtaxing the alternator at low engine rpm.The units have internal cooling cans that SUCK AIR from the electrical input side, and EXPEL AIR on the electrical output side. This information is only apparent AFTER installation, so ill include it here.2 gauge cable worked fine.to install the activation leads, unscrew the tiny screw above the wiring opening, insert the wire, then tighten the screw. This information is not included in the instructions so i include it here.Since you will probibly wire the activation lead to turn the unit on whenever the engine is running, advise installing an interupt switch for that lead, or a giant battery disconnect switch for the voltage input as I did.
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