Keep your trailer's battery charged with this single-input, DC-to-DC smart charger. Unit installs in your vehicle or trailer and pulls power from your vehicle battery to charge your auxiliary battery. Great for dump trailers and pop-up campers.
Features:
Specs:
The Redarc BCDC single-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.
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.
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 12.0V, as opposed to the standard 12.9V.
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 dump 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 (RED76FR or RED86FR - 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 - sold separately) below:
For a typical Lithium ion (LiFePO4) battery setup, refer to the wiring diagram (shown with fuses and optional LED - sold separately) below:
Average Customer Rating: 4.9 out of 5 stars (76 Customer Reviews)
Keep your trailer's battery charged with this single-input, DC-to-DC smart charger. Unit installs in your vehicle or trailer and pulls power from your vehicle battery to charge your auxiliary battery. Great for dump trailers and pop-up campers.I'm charging a house battery that powers a 12 volt refrigerator. Very simple install. Not giving this unit a 5 star rating because the 12 volt input and charging wires exiting the unit are 12 gauge wire and they get fairly warm to the touch. The instructions that come with it list 10 gauge wire as the minimum wire size to use to connect it.
Rbberfish - 05/28/2022This worked exactly as I hoped. I needed something to limit the current coming out of a cigarette lighter so I could charge a lithium battery from that lighter. Worked perfectly.
eTrailer was helpful in showing me this solution.
Most modern 1/2 ton pickups have "energy efficient alternator" as part of the battery management system. That means if the battery management system senses that your truck battery is fully charged, it lowers the output of the alternator. This means that the alternator voltage is insufficient to charge the camp trailer battery. This Redarc device will take the lower voltage from the alternator and boost it up to charge the camper battery. It works as intended and solved a big mystery for me as to why the camper battery didn't gain charge during long drives from one campground to another
I installed this in a 2017 Oliver Legacy Elite II travel trailer, because I had installed Battle Born lithium batteries and there was no way my truck was going to charge them properly. The actual installation was fairly painless, but I had to run bigger wires from the front of the trailer back to the batteries, which are located over the axles. I get a solid 10.5 amps continuously now, even though my Land Cruiser is only putting out 13.5 volts when connected. It works as advertised and I do recommend it. I took one star off because I think it is over priced, but that is be expected for an Australian import.
Review from a similar BCDC in Battery Charger
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 - 04/23/2022Review from a similar BCDC in Battery Charger
This unit has performed as expected. My batteries are mounted inside a plywood box in the back of my van. All the connections for the Redarc are inside the box so it has a very clean install on the exterior of the box. The two DC switches in the picture allow me to disconnect the input line to the Redarc from the vehicle's electrical system and the second disconnects my Battle Born batteries from everything. I only shut off the system when I take it into the van dealership for maintenance, and that is only precautionary.
Bill A - 07/03/2021Review from a similar BCDC in Battery Charger
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 - 08/01/2020Review from a similar BCDC in Battery Charger
Great product…works as advertised
Very rugged construction and you can mount it anywhere
Mounted this into the battery box on my 2021 Airstream
Fabulous customer support from Redarc
Endorsed by Battleborn
Well worth the price
Review from a similar BCDC in Battery Charger
Watching the etrailer video along with product instructions made install easy and straightforward. We are traveling Alaska and charger is working perfectly. Would highly recommend this dc to dc charger.
Review from a similar BCDC in Battery Charger
I installed a BCDC1240D (with optional fuse kit) in my Winnebago Revel (Mercedes Sprinter). The instructions are clear and I was able to figure out the wiring requirements pretty easily. I wired the Redarc with a switch to change between profile C (winter) and B (summer). The batteries are mounted below the vehicle so I probably need profile B at higher temperatures in the summer.
I have included a picture of the Redarc installed in the passenger's seat pedestal in the van. Most of the wiring in there is Mercedes and Winnebago. You should be able to identify the Redarc (bottom center), and the two fuse holders (fuses not yet install) near the blue tape.
Review from a similar BCDC in Battery Charger
This battery charger is awesome. Delivers 40 amps of power for my lithium batteries while driving. So far, no problems with my 125 amp alternator using this device. Used it on a two month Utah trip.
Would by this again.
Scott H - 03/04/2022Review from a similar BCDC in Battery Charger
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.
Review from a similar BCDC in Battery Charger
I have 300ah Lifepo4 batteries from Renogy..
300 watt solar.. this unit will charge via solar or vehicle.. one or the other .. whichever has more power.. I see the lights on and see it working.. the reason I like this unit is because my batteries are only being charged from one charging source. This is safer and will improve battery life.
I just wish it could have a battery and voltage meter.. I guess I need to buy a battery monitor.. This is almost the perfect device.. it needs a display for battery life and voltage.. I would love to know what it is doing.
Review from a similar BCDC in Battery Charger
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.
Review from a similar BCDC in Battery Charger
This is a fantastic unit. Very easy to hook to the camper batteries, using both the solar and alternator charging functionality. Used this without any issues on a 14 day trip. The instruction manual is well written and very clear.
No more worries about the state of charge of my batteries even after a long day of driving with the camper because the battery charge level will be greater than 90% when arriving at campsite despite having a refrigerator running in the camper. Will now be able to leave solar panels at home for a short 2 day camping trip.
A few times, the battery level was in the 60%-65% charge level and it was charged back to 80+% within a few hours of driving. Just be aware that getting the lead-acid batteries from 90% to 100% takes a much long time because it has to be a constant low current.
Purchasing from etrailer was an excellent experience - received it in Canada within 2 days or order.
Review from a similar BCDC in Battery Charger
"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. B - 05/02/2021Review from a similar BCDC in Battery Charger
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.
Review from a similar BCDC in Battery Charger
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.
Review from a similar BCDC in Battery Charger
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.
Review from a similar BCDC in Battery Charger
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.
Review from a similar BCDC in Battery Charger
Easy Install. Great instructions. works perfect.
Review from a similar BCDC in Battery Charger
This thing is just great. It is rock solid in construction and function. Everywhere I go now in my Arctic Fox slide in and F350, bu two 100AH LiFePo4 batteries are charging at 45 amps along the way. The fact that the Redarc is weather proof allowed me to mount it outside under the camper skirt running my 4awg battery cables along the bottom of the camper right to it.
Review from a similar BCDC in Battery Charger
Brilliant product! Charges trailer battery while you drive!
When full-timing (almost always dry camping) we frequently found it necessary to run the generator *after* arriving at a new campsite because the “charge” line on the 7 blade RV connector delivered so little power. This fixes that: It delivers a full 40 amps to our two ~100AH flooded batteries (Walmart 29DC), which will take them from 50% to 80+% charge in less than 2 hours, our usual travel time between sites, eliminating the need to run the generator completely on most days (and we don’t skimp much on electricity, using the microwave and watching movies most evenings and a forced air heater all night).
A few tips:
1) It draws 43 amps from the vehicle, so you really need the 4 awg wire to the trailer and a heavy-duty disconnect (we used a 150 amp which works well with 4 awg).
2) At full draw the vehicle battery was at 12.8 volts at idle, so it’s right at the limit: You definitely don’t want to be drawing down the starting battery. This is on a Nissan Frontier with a 130 amp alternator, meaning you also wouldn’t want to use it on a vehicle with a smaller alternator unless you’re sure you’ll always be running it above idle and/or without lights/AC/etc. on.
3) A hydraulic crimper would of course be preferred but I used a hammer crimper which worked fine. Just be sure you shrink-tube the connection since hammer crimpers can penetrate the lugs. To get full thickness into the lugs, either fold the wire in half, run the wires (8 awg from the unit, 4 awg from the line) past each other when making a butt splice, or half-fill the lug with strands cut from your 4 awg wire and then push the line in around them. I connected it to the lugs on our inverter since there were already 4 awg lines running from that to the batteries.
4) Hookup was easy, running a 4 awg line from the truck battery to the bed not so much. I fused it of course, but it’s definitely not something you want to chafe or real drama could ensue. The maximum usable distance from the vehicle to the unit is much longer than what the manual says (e.g., if your batteries are in the back of your trailer), but you must ensure that it’s at least 4 awg all the way. Using vehicle and trailer chassis grounds are fine: You don’t need to run a negative line except for a short one between the truck and trailer frames (i.e., don’t use the hitch as a ground connection).
5) Be sure you disconnect the charging line on the trailer plug. The manual doesn’t mention this, but if you don’t you’ll lose charging capacity because some of your power will feed back through that wire.
6) I used the 15V setting to maximize charging time efficiency. It quickly trips back to 13.6 volts once reaching that (much quicker than our equalizing multistage charger, for example) so no worries about overcharging. With the standard 14.6 volt cutoff you’re giving up significant amount of charging if you only drive a short time.
7) It’s 93% efficient (according to tech support) but does run pretty warm when at full output for a long time. It should be installed in area with ventilation and definitely not in an engine compartment.
8) Redarc tech support was awesome when I had questions about the installation.
Scott R - 07/04/2020Review from a similar BCDC in Battery Charger
Excellent product, easy install. If you want the option to charge and maintain an Auxiliary Battery from main battery or solar, this is an excellent compact unit. Installed this unit a year ago for a Four wheel camper. Maintain a charge on the road and camping off road, still working strong, no longer need to charge battery in the off season using solar switching, awesome for camping and maintain healthy battery.
Thanks to etrailer for offering Redarc products, ease online ordering, support and on time delivery, outstanding. Highly recommend doing business with etrailer and buying this product and the Bulldog connectors!
Bill K - 04/15/2020Review from a similar BCDC in Battery Charger
It's been a great product for me, it's completely autonomous, I just trust that my batteries are always charged!
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