1. Battery Chargers
  2. Redarc
  3. Battery Charger
  4. Vehicle Battery to Auxiliary Battery
  5. RV/Camper
  6. Trailer
Redarc In-Vehicle BCDC Battery Charger - Dual Input - DC to DC - 12V/24V - 40 Amp

Redarc In-Vehicle BCDC Battery Charger - Dual Input - DC to DC - 12V/24V - 40 Amp

Item # 331-BCDC1240D
lowest price pledge
Retail:$570.97
Our Price: $442.61
You Save: $128.36
Battery Chargers
This item qualifies for Free Shipping
Shipping Weight: 3 lbs
Quantity: 
In Stock
Redarc In-Vehicle BCDC Battery Charger - Dual Input - DC to DC - 12V/24V - 40 Amp Charges/Maintains 331-BCDC1240D
zoom in icon
zoom out icon
Comment field cannot be left empty.
Name field cannot be left empty.

Thank you! Your comment has been submitted successfully. You should be able to view your question/comment here within a few days.

Error submitting comment. Please try again momentarily.

Product Images

In Use/Installed

Customer Photos

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. Call 800-298-8924 to order Redarc battery chargers part number 331-BCDC1240D or order online at etrailer.com. Free expert support on all Redarc products. Guaranteed Lowest Price and Fastest Shipping for Redarc In-Vehicle BCDC Battery Charger - Dual Input - DC to DC - 12V/24V - 40 Amp. Battery Chargers reviews from real customers.
  • All Info
  • Reviews (20)
  • Q & A (115)
  • Videos (3)
  • Photos
  • Why etrailer?

Redarc Battery Chargers - 331-BCDC1240D

  • Battery Charger
  • Redarc
  • Vehicle Battery to Auxiliary Battery
  • RV/Camper
  • Trailer
  • 12V
  • Charges/Maintains
  • DC to DC
  • 200 Ah

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:

  • DC-to-DC battery charger draws power from your vehicle to provide power to an auxiliary battery on your trailer or RV
    • Ideal for larger battery banks rated 200 amp-hours and higher
  • Dual-input device can pull power from 2 sources
    • Connect yellow wire to solar panels (sold separately)
    • Connect red wire to 12V or 24V start battery
  • Multi-stage charging algorithm ensures a complete charge on secondary battery without overcharging
    • Boost stage - provides a constant charge while monitoring auxiliary battery voltage
    • Absorption stage - keeps voltage stable to avoid overcharging while bringing battery up to 100-percent charge
    • Float stage - maintains charge on auxiliary battery
  • Solar power capable - solar panels sold separately
    • Charger automatically draws power from panels before tapping into vehicle battery
    • Built-in MPPT regulator ensures most efficient power transfer possible in all conditions
  • Fully sealed construction with fan-free operation ensures durable performance under harsh conditions
    • Tested to ensure operation in temperatures as high as 176 F
    • Protects sensitive electronics from water, dust, and shock
  • Fault recognition technology prevents damage to batteries from voltage spikes, overheating, and reverse polarity connection
  • Battery isolator function prevents charger from pulling power from start battery when vehicle is off
  • Multiple mounting options for convenient installation
    • Secure the unit in the cabin of the vehicle, along a chassis frame rail, in the engine compartment, or on your trailer
    • Cables, fuses (331-FK60 - sold separately), and connectors sold separately
  • Made in Australia


Specs:

  • Application: 12V or 24V vehicle systems with standard or smart alternators
    • Battery types supported: AGM, gel, standard led acid, calcium, and Lithium ion (LiFePO4) batteries
  • Overall dimensions: 6" long x 4-3/4" wide x 1-1/2" tall
  • Battery capacity range: 200 amp-hours and greater
  • Maximum charging voltage: 15.3V
  • Output voltage: 12V DC
  • Output power: 600 watts
  • Output current rating (continuous): 40 amps
  • Input current (maximum): 40 amps
  • 2-Year warranty


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 40 amps of current to both charge and maintain your auxiliary battery.


Solar Power Compatible with MPPT Regulator

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.


3-Stage Smart Charger

REDARC BCDC Battery Charger LED Indicators

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.


Compatible with Smart Alternators

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.


Versatile Mounting

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:


Redarc BCDC Dual Battery Charger Wiring Guide

To ensure a low-resistance connection, you will want to use MIDI fuses (331-FK60 - 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:


Redarc BCDC Dual Battery Charger Standard Lead Battery Wiring Diagram

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:


Redarc BCDC Dual Battery Charger Lithium Battery Wiring Diagram



BCDC1240D REDARC In-Vehicle BCDC Battery Charger - Dual Input - DC to DC - 12V/24V - 40 Amp

Installation Details 331-BCDC1240D Installation instructions


California residents: click here


Video of Redarc In-Vehicle BCDC Battery Charger - Dual Input - DC to DC - 12V/24V - 40 Amp

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.




Video Transcript for Redarc Battery Chargers - Battery Charger - 331-BCDC1240D Review

Speaker 1: Today we're going to take a look at the Redarc 40 amp dual input multi stage, 12 volt to 24 volt, DC to DC in-vehicle battery charger. This DC to DC battery charger will draw power from your vehicle, provides power to an auxiliary battery on your trailer or RV. It's ideal for battery bank traded 200 amp powers and higher. It does uses a multi-stage charging algorithm, to ensure a complete charge or your secondary battery, without over charging. It has a boost stage, which provides a constant charge, while monitoring auxiliary battery voltage, and it has an absorption stage, which keeps your voltage stable to avoid overcharging, while bringing the battery up to 100% charge. Finally, has a float state, which maintains your charge on your auxiliary battery.It is a dual input device.

It can pull power from two sources. Can use the red wire and connect it to 12 volt or 24 volt start battery. Use the yellow wire and connect it to solar panels. Now, the solar panels we do sell separately on our website. Since this is solar power capable, the charge will automatically draw power from the panels before tapping into your vehicle battery.

It does use a built-in MPPT regulator, to ensure most efficient power transfer possible in all conditions.This is a fully sealed construction. It's a fan free operation, to ensure durable performance under harsh conditions. It is tested to endure operation in temperatures as high as 176 degrees fahrenheit, and this will protect your sensitive electronics from water, dust and shock. Does use fault recognition technology, prevents damage to your batteries from voltage spike, overheating and reverse polarity connection.The battery isolator function prevents the charger from pulling power from your start battery when the vehicle is off. Does have multiple mounting options for convenient installation.

You can secure this unit in the cab of your vehicle, along a chassis frame rail, or even in the engine compartment.The cables, fuses and connectors, we do separately on our website. To install this, it's Part Number 331-FK60. This part is made in Australia. Few specs again, the application is for 12 volt or 24 volt vehicle systems, with standard or smart alternators. The battery types supported are AGM, gel, standard lead acid, calcium and lithium ion.

Battery capacity range, 200 amp hours and greater. Maximum charging voltage is 1523 volts. Output voltage, 12 volts DC. Output power is 600 watts. Output current rating continuous is 40 amps and input current max is 40 amps. Comes with a nice, detailed instruction manual in how it operates and how to install it.The last thing I want to give you the overall dimensions on it. It's a very small unit. Overall length, 6'-1/2". Overall width, including the mounting brackets is going to be right at 4-3/4", and overall height is 1-1/2" tall. That should do it for the review on the Redarc 40 amp dual input multi stage, 12 volt or 24 volt DC to DC in-vehicle battery charger.


Customer Reviews

Redarc In-Vehicle BCDC Battery Charger - Dual Input - DC to DC - 12V/24V - 40 Amp - 331-BCDC1240D

Average Customer Rating:  5.0 out of 5 stars   (20 Customer Reviews)

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.

- 331-BCDC1240D
by:

One year later: Installed this to charge 2 - 100Ah Lithium Batteries from 160 Amp Alternator - It does a much better job than just the alternator itself - the boost speeds up charging by a x4 factor - worth every penny. Highly recommend - easy install with clear instructions. 602885


Comments
After a year of traveling full time the Radarc has proven to be one of the best investments we made. It is so reliable. Would not hesitate to buy another if this one crapped out.
John B - 02/07/2020

66380

- 331-BCDC1240D
by:

Install took a little time. You will need a hydraulic connector press and then you will have to solder connectors. I ordered connectors off of the internet 637835



- 331-BCDC1240D
by:

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. 666008



- 331-BCDC1240D
by:

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! 628464



- 331-BCDC1240D
by:

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. 583167



- 331-BCDC1240D
by:

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. 586562



- 331-BCDC1240D
by:

Have not installed the Redarc in my camper yet, but really appreciated the quick turnaround on my order. Quick shipping was better than Amazon. 728803



- 331-BCDC1240D
by:

Is working great in my Silverado to keep auxiliary battery charged for the bed accessories. Just added a solar suitcase to it for charging and using electrical without engine. Thinking about installing the jump circuit just for safety 646758



- 331-BCDC1225D
by:

Review from a similar Redarc BCDC in Battery Chargers


Quick shipping, Haven’t hooked it up ye t. 469810



- 331-BCDC1225D
by:

Review from a similar Redarc BCDC in Battery Chargers


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 677741



- 331-BCDC1225D
by:

Review from a similar Redarc BCDC in Battery Chargers


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”. 594415



- 331-BCDC1225D
by:

Review from a similar Redarc BCDC in Battery Chargers


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. 590921



- 331-BCDC1225D
by:

Review from a similar Redarc BCDC in Battery Chargers


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. 508790



- 331-BCDC1225D
by:

Review from a similar Redarc BCDC in Battery Chargers


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. 601615



- 331-BCDC1225D
by:

Review from a similar Redarc BCDC in Battery Chargers


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. 739139



- 331-BCDC1225D
by:

Review from a similar Redarc BCDC in Battery Chargers


Used for full time suv living and traveling. Kept my lithium battery and fridge up and running with solar as well. Awesome product. 727905



- 331-BCDC1225D
by:

Review from a similar Redarc BCDC in Battery Chargers


Great product. 686891



- 331-BCDC1225D
by:

Review from a similar Redarc BCDC in Battery Chargers


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. 634086



- 331-BCDC1225D
by:

Review from a similar Redarc BCDC in Battery Chargers


Product has worked as stated. 5 stars! 629151



- 331-BCDC1225D
by:

Review from a similar Redarc BCDC in Battery Chargers


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.) 565968


21
21

Ask the Experts about this Redarc Battery Chargers

  • Recommended Mounting Location for Redarc DC to DC Battery Charger # BCDC1225D
    It is advised to install the Redarc In-Vehicle BCDC Battery Charger # 331-BCDC1240D or # 331-BCDC1225D in your trailer and not your truck. I've attached videos of this installation to assist. Specifically we put this product in the front storage compartment of the RV to be close to the wiring that connects to the vehicle and also the trailer battery because the unit installs between those two components. The In-Vehicle refers to the trailer and not the tow vehicle so you can use the...
    view full answer...
  • RedArc BCDC Battery Charger Compatibility with Variable Voltage System and AGM Batteries
    The Redarc In-Vehicle BCDC Battery Charger - Dual Input - DC to DC - 12V/24V - 40 Amp # 331-BCDC1240D is designed to work with smart alternators like yours when you use the 60-Amp Relay Kit for Redarc In-Vehicle BCDC Battery Charger # 331-RK1260. You will also need to use the 60-Amp MIDI Fuse Kit for Redarc In-Vehicle 40-Amp BCDC Battery Charger # 331-FK60. This prevents your alternator being overloaded and it won't back-feed your alternator either. This system is rated for AGM or Lithium...
    view full answer...
  • How to Charge Trailer Batteries with the Vehicle's Alternator and Shore Power
    I do have options for you but the Redarc In-Vehicle BCDC Battery Charger part # 331-BCDC1240D would not accept AC current from shore power and then use that to charge your two AGM batteries while disconnected from the tow vehicle. The Redarc In-Vehicle BCDC Battery Charger would still be needed while driving but when parked you would need to install a power converter to charge the batteries using shore power. The correct power converter will vary depending on the A/h of your batteries...
    view full answer...
  • Recommended Wiring for RedArc BCDC Charger Used for Auxiliary Battery to Power Inverter
    To connect your Redarc In-Vehicle BCDC Battery Charger - Dual Input - DC to DC - 12V/24V - 40 Amp # 331-BCDC1240D, you will need the 60-Amp MIDI Fuse Kit for Redarc In-Vehicle 40-Amp BCDC Battery Charger # 331-FK60. This will protect your vehicle and battery from potentially damaging overcurrent from short circuits or overloads. You will run the Red Wire from your RedArc unit to the fuse, and then from the fuse to the positive battery terminal on your vehicle start battery. I've...
    view full answer...
  • RV Battery Charger and Portable Solar Panel System for Boondocking
    Yes, Redarc DC to DC battery charger # 331-BCDC1240D is the right choice for charging your trailer's 540-amp battery bank. This unit can mount in the cabin of your vehicle, along a chassis frame rail, or in the engine compartment and it will connect to the vehicle's battery for input power, not to your 7-way. Use the heaviest gauge wire you can for all connections. Redarc recommends 6-gauge for runs up to 16-feet and 4-gauge for longer runs; this applies to battery input power, solar...
    view full answer...
  • Will RedArc Battery Charger Work With Solar Panel and 7-Way to Charge Camper Battery
    I reached out to a representative of Redarc who told me that the Redarc In-Vehicle BCDC Battery Charger # 331-BCDC1240D is the correct charger for your application and there will be no interference or conflict with the charges the battery is getting from the solar set up. The input to the BCDC Charger will be sourced from your F-250's start battery (which is going to be on the passenger's side of your 2-battery set-up) with the 60-Amp MIDI Fuse Kit for Redarc In-Vehicle 40-Amp BCDC Battery...
    view full answer...
  • Comparing CTEK D250S and SmartPass vs Redarc DC-DC Charger
    I reached out to my contact at CTEK and the CTEK D250S Dual Battery Charger 12V- 20a, 5 step, Heavy Duty CTEK40186 (discontinued) does utilize the Maximum Power Point Tracker (MPPT) as well. When partnered with the (discontinued) Smartpass CTEK56676 you will be able to run your fridge/freezer as you stated. The Redarc In-Vehicle BCDC Battery Charger # 331-BCDC1240D will also be able to accomplish this so it is a better option for this application. You will also need the fuse kit # 331-FK60...
    view full answer...
  • Trailer Battery Charger and Power Inverter for Coleman Pop-Up Camper with Deep Cycle Battery
    For a DC battery charger to maintain your trailer's deep-cycle battery I suggest the Redarc In-Vehicle BCDC 40-Amp Battery Charger # 331-BCDC1240D. This unit installs in your vehicle and delivers charging and maintenance current to keep your trailer battery topped off. This is made for high-capacity batteries of 200 amp-hours and above. It also allows the option to add a solar panel to provide a secondary power input. You will also need MIDI Fuse Kit # 331-FK60. For an inverter to charge...
    view full answer...
  • How to Have Power When Camping Off-Grid in a 1981 Skamper Popup
    If you are wanting to charge your phones and other electronics without having to plug into a station you can definitely use some batteries to do so. The best solution for keeping your battery charged is to use a battery charger like the Redarc In-Vehicle BCDC Battery Charger # 331-BCDC1240D. This can draw power off of your tow vehicle battery while traveling and as well as a solar panel. We have a variety of solar panels to choose from depending on how much power you plan on using....
    view full answer...
  • Does Redarc In-Vehicle BCDC Battery Charger # 331-BCDC1240D Require Shore Power
    The Redarc In-Vehicle BCDC Battery Charger # 331-BCDC1240D that you referenced does not have a way to run AC/shore power to it. It takes all DC, 12-volt style power sources.
    view full answer...
  • Solar Panel Option for Use with Redarc In-Vehicle Battery Charger # 331-BCDC1240D
    We have a few solar panels that could be used with the Redarc In-Vehicle Battery Charger # 331-BCDC1240D. We have the part # 287-32406 which is capable of 50 watts, the part # 287-32408 which is capable of 100 watts.. No other hardware or install wiring would be needed.
    view full answer...
  • Recommended Vehicle To Trailer DC to DC Charger for Multiple Trailer Batteries
    Your auxiliary power wire gauge at your 7-way along with the discontinued CTEK40186 will be sufficient to charge your trailer batteries. The CTEK D250S will amplify the signal from your auxiliary power to boost it to 20 amps versus the 2-3 amps of a system without the CTEK unit. Changing your gauge of wire to 8 and adding the # DL24086 connections will help slightly but if you are wanting to charge multiple batteries well and more quickly/efficiently, you really will want the discontinued...
    view full answer...
  • Using Redarc In-Vehicle BCDC Battery Charger to Charge Lithium Ion Battery
    The wire that is going to the 12V pin on your Silverado's 7-Way connector is connected to the truck's battery. You should be getting 12 volts of power at the this pin (1 o'clock position) on the connector. The Redarc In-Vehicle BCDC Battery Charger # 331-BCDC1240D referenced in your question is a great option for charging your Lithium ion battery. When hooked up to the truck's battery or alternator, it will do a nice job of maintaining the battery's charge, but to actually charge it...
    view full answer...
  • Battery Charger to Charge a 12 Volt Trailer Battery Using a Truck Alternator
    The Redarc DC to DC Battery Charger # 331-BCDC1240D is going to be the best option that we have available. You would have an input wire from the truck's alternator and output wires to the battery on the trailer. The 12 volt circuit on the 7-Way may not provide the best results which is why I recommend using the alternator. And if you are so inclined you could also hook up solar panels to this charger for times when the trailer is parked without the truck present.
    view full answer...
  • Redarc Charger for 2018 Chevy Colorado ZR2 with Dual Battery Setup
    The Redarc In-Vehicle BCDC Battery Charger # 331-BCDC1240D that you referenced is the correct charger setup you'd need. It can put out up to 40 amps and is compatible with smart alternators like you have as well. I attached an install diagram that shows how it will wire up (without the solar panel you see pictured) as well as a link to the install instructions as well.
    view full answer...
  • Solar Voltage Input of Redarc In-Vehicle BCDC Battery Charger
    I reached out to a representative of Redarc who told me the Redarc In-Vehicle BCDC Battery Charger # 331-BCDC1240D can accept unlimited current though will have an output only of 40 amps which is what it is rated for. Additionally, it will only work with 12V nominal solar panels so they cannot be connected in series to the charger.
    view full answer...
  • Will the Redarc In-Vehicle BCDC Battery Charger # 331-BCDC1225D Protect your Starting Battery?
    The Redarc In-Vehicle BCDC Battery Charger - Dual Input - DC to DC - 12V/24V - 25 Amp # 331-BCDC1225D has a built in battery isolator function to prevent the charger from pulling power from the start battery when the vehicle is off. This will prevent you from draining your starting battery and leaving you stranded in the boondocks. You are correct in that if this function were not present it would cause issues, but they have accounted for that and built in the isolation to prevent that...
    view full answer...
  • Charger Recommendation for Truck Parked Extended Period of Time in Cold
    What might be your best option is a charger like the CTEK part # CTEK56353. With this you can install the ring terminal quick-disconnect to your battery and then easily plug in the charger when you need to let it sit for a while.
    view full answer...
  • How To Charge RV While Towing With My 2016 Nissan Frontier
    According to my research, the 2016 Nissan Frontier 4.0 does not charge an RV while towing. However, the best way to charge a trailer battery is by using a product such as the, Redarc In-Vehicle BCDC Battery Charger # 331-BCDC1240D. 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. I...
    view full answer...
  • Where Should Redarc In-Vehicle Battery Charger be Grounded?
    When wiring the Redarc In-Vehicle BCDC Battery Charger # 331-BCDC1240D along with connectors # PK12801 and # PK12800 you will want to ground to the tow vehicle chassis. The linked instructions specifically state that "all ground points must be connected to chassis earth". You can see this in the diagram I've added for you to take a look at.
    view full answer...
  • Best Way to Charge Auxiliary Lithium Ion Battery on 2019 Ram ProMaster
    The best way to charge your auxiliary LiFePO4 Deep Cycle Battery from the main battery of your 2019 Ram ProMaster is with the Redarc In-Vehicle BCDC Battery Charger # 331-BCDC1240D. This was designed for larger batteries and it has a built-in smart charging system that reads what kind of battery is being charged and then it adjusts the amount of power output so that the battery isn't damaged and that it gets the most efficient charge possible. Redarc recommends using the 60-Amp MIDI...
    view full answer...
  • Solution for Charging Auxiliary Trailer Battery Through Truck's 7-Way Connector
    In order to activate the 12V circuit on your truck's 7-Way so that you can maintain the charge on the trailer's auxiliary battery, you just need to run a length of 10 gauge wiring like # 10-1-1 (sold by the foot) through a breaker like # 9510 from the truck battery's positive post to the 12V pin on the 7-Way. This is the pin located at the 1 o'clock position (or 11 o'clock when looking at the backside/inside of the connector). Then from there you would wire the corresponding pin on the...
    view full answer...
  • Parts Needed to Charge Enclosed Trailer Battery When Towing
    To charge your auxiliary battery on your enclosed trailer while you are towing you will need the Redarc In-Vehicle BCDC Battery Charger - 25 Amp # 331-BCDC1225D or 40 amp # 331-BCDC1240D. The 25 amp is the most likely choice for you because it is for batteries (or battery banks) with 75 amp-hours to 200 amp-hours ratings, while the 40 amp charger is for 200 amp-hours and above. You will also need the 40-Amp MIDI Fuse Kit for Redarc In-Vehicle 25-Amp BCDC Battery Charger # 331-FK40. So...
    view full answer...
  • Butt End Connectors for Wiring Up Redarc In-Vehicle BCDC Battery Charger # 331-BCDC1240D
    The yellow, red, and black wires of the Redarc In-Vehicle BCDC Battery Charger # 331-BCDC1240D are 10 gauge so for that size wire you'd want to use the yellow butt-end connectors like part # DW05745-5 which are for 10-12 gauge wire. The blue connectors like part # DW05744-5 would work for the rest of the connections.
    view full answer...
  • Does Solar Panel Controller Get Ran to Redarc BCDC Battery Charger
    If the solar panel has it's own controller setup you would bypass it and run it straight to the Redarc In-Vehicle BCDC Battery Charger # 331-BCDC1240D that you referenced as it is designed for unregulated solar panel power. To answer your second question a conflict is not created in the scenario you described. Having the voltage changed twice like you mentioned would not be an issue.
    view full answer...
  • Using Redarc In-Vehicle BCDC Battery Charger # 331-BCDC1240D With Inverter and Solar Panels
    The Redarc In-Vehicle BCDC Battery Charger # 331-BCDC1240D is designed to take two DC inputs like your alternators and solar panel so it would work great without requiring additional steps at all. The 110 volt supply you have would not backfeed through this adapter or cause issues if the shore power was not disconnected like you mentioned.
    view full answer...
  • Can Redarc In-Vehicle BCDC Battery Charger 331-BCDC1240D Accept Fixed Voltage Alternator Input
    Redarc In-Vehicle BCDC Battery Charger # 331-BCDC1240D is designed to accept 12V input power from either an unregulated solar panel, a battery or an alternator. It is perfectly fine to connect it to your 65-amp alternator. I confirmed this with my contact at Redarc. The # 331-BCDC1240D is recommended for charging battery banks of 200Ah or more; for smaller setups you can use # 331-BCDC1225D.
    view full answer...
  • Installing Redarc 331-BCDC1240D DC to DC Battery Charger For Charging Trailer Mounted Winch Battery
    The small gauge wire feeding the 12-v supply feed to the 7-way wouldn't have enough capacity to power the charger, the charger would need to connect directly to the tow vehicle battery using 4 gauge wire, according to the instructions I've linked to and the installation diagrams I've provided. You'll also need a fuse kit like # 331-FK60. I've also linked to an installation video and a help article.
    view full answer...

Do you have a question about this Battery Charger?




  • Why etrailer.com?

    At etrailer.com we guarantee:
  • Highest quality battery chargers for the best price.

    Our Lowest Price Pledge ensures you will never overpay for the parts you need.
  • Real product know-how.

    We make sure that the products we sell are what we say they are, and that they work the way they are supposed to work. Get real advice from a real person who has the knowledge and expertise needed to solve your problem.
  • Most detailed, accurate battery charger information available.

    Because we take providing accurate product information seriously, we take our own detailed product photos, demo videos and installation videos, as well as verify measurements, instructions, and vehicle fit information.
  • Installations, made easy.

    We love helping people and have the most highly-trained customer service, hands-on experience, step by step videos and installation instructions.
  • Fast shipping.

    Your order is automatically routed to get out of our warehouse and to your door as quickly as possible. Receive free shipping on orders over $99.
  • Personalized service for life.

    We provide one-on-one, personalized service from the ordering process through the life of your product.
  • Trusted since 1946.

    We've been serving customers since our parts store first opened in 1946 and continue to be recognized by our customers, our vendors and third parties for exceptional service.
  • Returns Policy

    Need to return an item? No problem. Please read our Returns Policy for more information.

Info for this part was:

Expert Research:
Mike L
Expert Research:
Jameson C
Expert Research:
Adam R
Edited by:
Lindsey S
Installed by:
Jeff D
Installed by:
David F
Video Edited:
Jacob T
Video Edited:
Chris R
Video by:
Dustin K
Updated by:
Sarah W
Updated by:
Kristina F
Updated by:
Matthew E
Written by:
Brian T

At etrailer.com we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time. Let us know if anything is missing or if you have any questions.


Product Experts Available Now!
Call 800-298-8924