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Maintain the charge on your RV's battery with this dual-input, DC-to-DC smart charger. Unit installs in your vehicle or trailer and pulls power from your solar panels before tapping into the vehicle battery. Great for boondocking and dry camping.
Features:
Specs:
The Redarc BCDC dual-input battery charger allows for easy charging of a DC battery while you're on the move. Most battery chargers require that you plug into an AC outlet, but this DC-to-DC charger pulls power from your vehicle's start battery instead. The BCDC also has solar power capability so that you can keep your secondary battery charged while you're parked at a remote campsite. This means that you can go off the grid without worrying about being without power.
This charger connects directly to your battery, rather than pulling power from your vehicle via the trailer connector. This is to ensure that it's able to fully charge your auxiliary battery. A standard 7-way trailer connector is limited to 10 or 15 amps of current, which will not be able to fully restore a battery for use. But this charger can transfer up to 25 amps of current to both charge and maintain your auxiliary battery.
This charger can pull power from 2 different sources. The first input accepts charge from your vehicle's battery. The second input on this dual-input unit is designed to receive power from solar panels (sold separately). The built-in maximum power point tracking (MPPT) regulator on this unit ensures that the charger will get the most power possible from your panels at any given time. An MPPT regulator is able to determine the point at which your solar panels reach their maximum output. Then the regulator can simulate that load on the panels to effectively draw the most power possible. This type of regulator is more effective than traditional ones at gathering power from solar panels and at drawing power in low-light conditions.
Built-in Green Power Priority, or primary solar selection, ensures that power is pulled from your solar panels first. The BCDC will only tap into your vehicle's battery when necessary. This will save your vehicle battery from unneeded stress. It also has a built-in battery isolator function to prevent the charger from pulling power from the start battery when the vehicle is off.
The BCDC battery charger can be used to charge AGM, gel, standard lead acid, calcium, and Lithium ion (LiFePO4) batteries. An LED on the front panel of the unit will illuminate to show the charge profile, confirming that you've wired the charger correctly based on your auxiliary battery type. This LED will be solid while the unit is charging, and it will flash when the unit is in standby mode. Additional LEDs on this panel indicate where the charger is pulling power from, and what stage of the charging process the unit is in.
This smart charger completely and efficiently charges your auxiliary battery in 3 separate stages. This ensures that the battery reaches maximum capacity without being overcharged.
The first stage of the process, the boost stage, begins when you start up your vehicle. In this mode the charger will maintain a constant current to the auxiliary battery to quickly help it regain power.
Once the unit detects that your auxiliary battery is nearing its maximum charge, the charger will move into the absorption stage. In this stage it will slowly supply the needed current to safely reach 100-percent capacity on the auxiliary battery.
The final stage is known as the float stage. In this stage the unit monitors your auxiliary battery for drops in power and supplies the needed current to keep it fully charged. If a drop in power is detected, it will revert back to the first stage and begin the charging cycle over.
A number of newer vehicles on the market have ECU-controlled, variable-voltage alternators designed to reduce emissions and boost performance. This type of alternator varies its voltage based on the driving conditions. When the alternator voltage is low, the system can drop below 12.7V, which would deactivate a standard isolator or battery charger. However, with the Redarc BCDC battery charger, this is not an issue. Simply connect the blue override wire to the vehicle ignition and the charger will recognize that the car battery is still receiving a charge from the alternator, even if the voltage has dropped. The charger will modify its voltage requirements so that it can continue to pull power until the start battery drops to 12V, as opposed to the standard 13.2V.
This unit can be mounted in a variety of places to best suit your application. Use the 4 mounting tabs to secure the unit in the cabin of your vehicle, along a chassis frame rail, in the engine compartment, or on your trailer. The charger should be mounted as close as possible to the auxiliary battery being charged to prevent current loss. The farther the current has to travel, the more amperage is lost. A larger diameter wire will allow more current to flow through it, which can offset the current loss that occurs with longer lengths of wire. As a result, it is recommended that you use a heavier gauge wire to cover longer distances. The table below outlines the recommended wire size for a given length of cable:
To ensure a low-resistance connection, you will want to use MIDI fuses (331-FK40 - sold separately) when connecting the BCDC to your batteries.
For a typical lead acid battery setup, refer to the wiring diagram (shown with fuses and optional LED and solar panel - sold separately) below:
For a typical Lithium ion (LiFePO4) battery setup, refer to the wiring diagram (shown with fuses and optional LED and solar panel - sold separately) below:
Customer Satisfaction Score:
98% were satisfied with this product
2% of customers were not satisfied
Ratings & Reviews
Good quality. Is holding up after a year of use. My trailer stays in the garage most of the time, so this only gets used when I am out camping or leaving it in the drive way on occasion.
I recieved the Redarc bcdc 1225d charger today. This will not be installed for awhile but after looking the unit over, seems to be of high quality. Small but somewhat heavy for the size l would think very good internal components. I chose this over others due to what appears as a better water proof unit. Also the wiring is heavier. Im hoping this unit will last yrs in my setup. I gave 4 stars due to non install yet and packaging.
I haven't installed yet, but have heard good things about the product. I have a 4x4 that sits at the airport for 6 months, currently being charged by a 170 w solar panel, feeding both battery's, so the redark will provide charging to the second battery when the car is run. With fridge load, solar not enough.
I ordered the BCDC1225 on Friday and received it on Monday, before noon ... how great is that! Everything appears to be in order. I'm looking forward to getting this charger hooked up to run the fans in the trailer that I carry my dogs in (it's a specially designed trailer which remains cool, but moving air keeps them even more comfortable). Notably, the help that I've received even BEFORE ORDERING has been outstanding. I will turn to etrailer.com for all future trailer-related needs.
(Once installed, I'll post a performance review.)
I have used this in my custom camper for one year. It is connected to a Size D gel cell enology battery that drives an inverter to power fridge, micorwave, tv and lights. I have never had an issue with vehicle battery or the gel cell even when used overnight. Works as advertised.
After one year of working with the charger, it performed perfectly with solar or managing the duel battery set up. A no brainer charger.
This works as advertised. I charge a battery in my truck camper with the solar input and from the truck alternator. You really need to run large gauge wires from the truck battery to the camper battery though.
I am looking forward to installing this product. My research showed that this is the optimal DC to DC charger for our needs. I don't know if we will make use of the dual input option but I specifically ordered this model in case we decide to add a solar panel in the future.
This unit will be installed in our small vintage Aladdin travel trailer for use during dry-camping trips so that the accessory battery will be charged between campsites where we will have shorter stays and travel frequently between camps.
The product works great - I currently use it in the back of my truck to charge a 100 AH LI battery. My next step is to use the solar charging feature and see how it works swapping back and forth between truck / solar recharge.
I bought this to help manage an auxiliary battery I'm installing in my F150 to run CB and ham radios and other 12VDC gizmos. I bought the 25A unit because I wanted the solar MPPT controller for a small 130W foldup panel I keep in my truck for emergencies. The 12A Redarc unit doesn't have the MPPT controller. I also favored the Redarc unit over a similar Renogy unit because the Redarc unit is much smaller and seems designed to fit into much smaller space. Not knocking the Renogy unit. It just seems designed to fit into a cabinet or closet in an RV. As I won't be installing this for a few weeks, I'll give my initial impressions then update later if can. First, etrailer slapped the postal sticker on the original product packaging. It's bad enough with porch pirates stealing packages when they can't see what's inside. This was just advertising "please steal me". Second, the Redarc unit looks well constructed and designed. The power wires are larger than required for the amperage and are tin-plated for corrosion resistance. However, the three (3) signal wires (orange, blue, and greed) are bare copper. Yes, they aren't carrying current or aren't carrying much current, but they are still susceptible to corrosion, especially if you choose a frame or rail mount outside of the cabin. Third, I disagree with Redarc's suggestion to crimp then solder the power wires. No OEM car manufacturer in the world solders. Anything that vibrates like a car or airplane should only use crimp connections. Vibration will ultimately cause solder joints to fail. Crimping done correctly is gas tight and provides its own strain relief. Finally, I think you can add a switch to the blue wire to manually turn off the alternator input if you so desire. The details vary depending on the alternator type, and I need to experiment with the setup first before giving out wrong information. When/if I post an update, I will provide instructions for the switch.
Fantastic product.! I mounted it on the outside of my power supply box connected to the auxiliary battery on my camp trailer. It’s seen sun, rain, snow, mud and dirt, keeps my battery charged and handles all the switching between solar panel and alternator charging. Made in Australia which is the next best thing to made in the USA.
This thing is amazing and is the solution for anyone who wants to charge a battery more than a few feet from the alternator. I have a truck with a bed mounted battery which is about 22 feet of wiring from the main battery and it charges perfectly. My Dometic fridge in the bed has been running non stop for a year with one small solar panel a marine battery and this charger connected to the alternator and solar
Works as advertised. It bumps the charging voltage from my Tacoma up to where I can get 20 amps charging current into the trailer battery even while the engine idles. The unit makes up for the voltage drop through the trailer 7 pin connector and about 35 feet of wire plus the ground circuit.. The integrated solar controller works as well as the separate controller the REDARC replaced. Installation could be easier, the REDARC unit has large wire pigtails that must be butt spliced. It would be easier if the unit used a clamp style terminal block.
Too easy. Does what it is deaigned to do.
Had to modify a Law Enforcement Vehicle with limited space.
Voltage and charge test Alesha’s proved “solid”.
Work great. Charges from the trailer plug and a 100 watt solar panel on the roof. Never have to charge the winch battery. No worries all winter when the trailer just sits. Would buy again.
Great product.
"Great piece of kit!" Seriously well worth the beans. The REDARC allows me to charge my trailer battery while towing. The trailer's converter supplies 13.6 VDC, which is not sufficient to charge my on board battery. The REDARC brings this DC voltage up to approximately 14.7 VDC. So my Truck charging system provides the trailer battery while travelling, and the on board trailer converter,(while AC CONNECTED at the site), sends DC voltage to the REDARC via the Solar Panel Input side of the unit, as I do not have a solar panel. I called Australian support number, and asked if this was an acceptable means of connection. They were most helpful and knowledgeable.
Chas. C.
5/2/2021
Two camping seasons and ZERO SNAGS with the REDARC BCDC unit! Real nice
The entire process of viewing products on line and ordering the items I needed was easy. The items I ordered arrived in a timely manner and in great condition. Each item operates as expected and I am very satisfied with my purchase.
Patrick
11/28/2025
The Redarc In-Vehicle BCDC Battery Charger works like it should. I installed it in a FourSeason truck camper that is connected to a 200ah LiPO battery. The system manages the batteries well.
The right product for new Ranger with a Four Wheel Camper.Install was easy, compact , maintains two deep cycle agm batteries and monitors 100 amp solar for a complete package. Was able replace my 3 way fridge with a 2 way for better service.
Easy to install. Instructions that come with all Redarc products are straightforward. It's working great so far charging a 105 Ah battery that is running a fridge/freezer, some lights, and assorted other gadgets.
Works well, good hardware solution for second battery charging- only wish it could use the second bat as a jumper for primary- solar charge is a nice feature.
I highly recommend it. Adding a dual battery setup and using the Redarc BCDC1225D to charge it was the best addition to my rig. Very simple to install and etrailer.com customer service is Tier 1.
The charger works great. Here is a picture of the system I built for it. The battery is a Battle Born 100 amp hour LiFePo, it’s also charged by (2) 100 watt flexible solar panels. It has (2)- 12 volt receptacles, (2)-dual USB receptacles, and a 750 watt modified sine wave inverter. It runs a small refrigerator, led lights, and various other electronic devices flawlessly. I’m very satisfied with the Redarc unit.
This unit has worked fine for me. Once wired up I can pretty much forget about it and know that it's charging my house battery whenever I start my vehicle. Probably more important is the automatic disconnection it makes from my starting battery & vehicles charging system when I shut down the vehicle. As well the convenience of adding a solar panel to the system to charge the house battery while the unit still AUTOMATICALLY chooses the best option to charge and disconnects anytime I shut down the vehicle. There are a LOT of different devices/ electronics to accomplish this but the Redarc seems to combine many features/connections in one convenient unit. I have not had the solar portion hooked up yet BUT my understanding is that when I get ready to do so I will NOT need to order a separate MPPT charge controller as that is a built in feature of the unit. These units are a bit pricy for up front cost but seems to provide a lot of features all in one compact unit with a fairly simple wire connection to get it up and charging.
Dusty
4/23/2022
A year later and Redarc is still working flawlessly! BatteryLifeline brand seems to be maintained in a strong state of charge. So far this seems to be a high quality and proven unit to do what its advertised to do. And if you have any questions, the guys Down Under in Australia are right on the line to happily help you. Thanks Mates for a great product. Goodayh Mate
Thanks etrailer for bringing this product to the USA market. I found the REDARC chargt talked about on Australian “caravan” blogs before etrailer had it for sale and considered trying to buy it from an Australian vendor. I use the BCDC1225D to charge my 200 amp hour lithium battery in my truck camper. I have 350 watts of rooftop solar and ran 8gauge wiring from the truck battery through a bed mounted Andersen connector. The very compact size of the unit allowed me to tuck it away in a small space in my camper. I wired it up just as suggested in the instructions and it worked perfectly. I’m getting the full 25 amp charge that the solar panels will provide at midday and get the added benefit of being able to charge at the same rate while driving in the dark. The thing works great. Thanks again etrailer for bringing this product to the USA market
Chris J.
8/1/2020
I’m still loving my Redarc. Five Stars!
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Bob H.
1/19/2021
Works great. Don’t have to worry about the trailer battery freezing during the winter.