Our Guide To DC to DC Chargers

A battery system for your recreational vehicle is the essential power hub. It is important to make sure that you are equipped with all the tools to ensure that power hub is fully charged and maintained for as long as possible. That’s where a DC to DC charger comes into play!

But with so many brands and models on the market, how do you choose the right charger for your application? We are here to help with our guide to DC to DC battery chargers:

What Is A DC to DC Battery Charger?

A DC to DC battery charger now plays a pivotal role in any recreational vehicle power management system. This type of charger brings the features of a traditional multistage AC (mains power) charger, to the world of off-grid touring.

While your engine is running, a DC charger will pull power from your alternator via your starter battery and safely charge your auxiliary battery.

See diagram below:

DC to DC charger
How A DC to DC Battery Charger Operates

Traditionally this was achieved just using a fused cable from the starter battery to the auxiliary battery. Since the introduction of smart alternators in new vehicles, cable alone is no longer viable.

Let’s run through some pro’s and con’s of these chargers:

Pro’s:
  • Lithium batteries must be charged with the correct charging profile; a DC to DC battery charger is the only way to achieve this.
  • Modern vehicles are now fitted with smart alternators that don’t produce a high enough voltage to charge auxiliary batteries. A DC battery charger will actually apply load to the alternator to achieve the correct voltage output.
  • In order to get the longest possible life span out of your battery, you want the optimal charging profile. Quality DC to DC battery chargers will allow you to select the correct charge profile to your battery type.
  • A good DC charger will often have a built in solar regulator for easy solar panel connection, therefore can save you purchasing another piece of equipment.
Cons:
  • DC to DC Chargers cost more than the old school techniques.
  • You will need to find room to mount this product in your vehicle.

Now we’ve run through the Pro’s and Con’s lets dive into the brands in our range:

Enerdrive:

Available in 12V and 24V, the ePOWER range from Enerdrive are by far the most popular DC to DC battery chargers on the market.

Enerdrive ePower Battery Chargers

Why are they so good?

  • Bang for your buck! 40A for under $500.
  • Built in MPPT solar regulator that can handle up to 500W of solar.
  • Fully programmable LCD display to show which source is charging the battery along with charger status, voltage and amperage.
  • Lithium compatible.
  • Charge output can be manually adjusted up and down.
  • Temperature sensor included.
  • Unmatched after sales support from Australian manufacturer.

Pro tip: to make life easier we have bundled the Enerdrive DC to DC battery charger with the correct breakers, lugs and wiring for all you DIY off-grid legends.

Redarc:

The OG of DC charging, Redarc, have every size covered from 6A up to 50A chargers with 12V and 24V options available.

Why are they so good?

  • Redarc offers the biggest DC to DC charger in the market: Dual Input 50A In-Vehicle DC Battery Charger!
  • Unique to Redarc: “Green Power Priority” Simultaneous solar and alternator charging.
  • Lithium compatible.
  • Tough as old boots! Will work in the extreme heat of the Simpson Desert, up to 80°C and can handle deep water crossings at Cape York.
  • The BCDC range are fully waterproof!
What is a REDARC BCDC and What Does It Do?

Pro tip: Redarc have introduced these new engine mounts so you can tuck it away in the engine bay.

BM PRO:

Looking for a value for money but quality DC to DC charger? We recommend the BMPRO MiniBoostPro 30Ah 12V DC to DC Battery Charger with Solar Input.

Why are they so good?

  • Value for money
  • Lithium compatible
  • Features both solar and auxiliary inputs
  • Multi-stage charge profile
  • Backed by Invicta, who currently have the longest caravan battery warranty on the market (7 years!)

Thunder:

If you’re looking for an entry level but quality and easy to install DC to DC charger with a built in solar regulator, we recommend the Thunder 20 AMP DC-DC Charger

Why are they so good?

  • Cheap
  • Easy to install – very basic
  • Rate of charge starts to decrease at 50 degrees and will fully cut out at 80 degrees
  • Automatic switching between solar and vehicle charging

Pro tip: looking for a entry level all in one solution? We have bundled the Thunder battery box with the DC to DC battery charger for a one stop battery shop.

Victron:

The global leader in recreational, commercial and domestic off-grid power has just released a new DC to DC battery charger range into the Australian market! The range starts at 10A up to 30A depending on your application.

Why are they so good?

  • Value for money option!
  • Offered in both isolated and non-isolated models
  • Features built in bluetooth
  • Does not come with a solar regulator to keep the price down and to ensure you purchase the correct solar regulator to match your panels

To match the right charger to your application give one of our product experts a call on 1300 400 122 or jump on our website to explore our range.

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18 thoughts on “Our Guide To DC to DC Chargers”

  1. I am setting up a 25ft bus on solar. I would appreciate some advice on panel size, inverters and basically everything in between, plus the batteries. I would be looking at a enerdrive or red arc system. I will have coffee machine, laptop and some other 240v appliances to run. I am allowing around the $6000 mark, however I will go higher for the best system

      1. Hi, I’m considering a 400Ah (2x200Ah) LiFePO4 battery bank and panels. I’m new to all of this, but 200Ah + 720W solar seems like too little battery bank? What am I missing?

        I’m also wondering what I should understand about the DC2DC battery charging amp configuration with 400Ah battery bank. Do I need a 60A charger, or will 40A do?

        Thanks so much.

        1. Hi Shay,

          Ideally with the 400Ah bank, you would use the 60A charger. The 40A will suffice, but the 60A will be faster. 720W is suitable for charging either 200ah or 400ah battery banks.

          Please let us know if you have any further questions.

  2. I’ve been using a 20amp DC to DC charger with 500ah AGM battery system and a high amp alternator with 175 amp idle, max 220 amp.
    Recharging has been slow and want to increase the amperage use with DC to DC charger.

    Should I use a 40amp DC to DC charger or a 60 amp?

  3. Hi,

    I have just installed an Enerdrive DC2DC charger and was wondering. When i am running my Ctek trickle charger in the case of no sun and no charge from my car, do i connect this directly to the battery or should i run it through the Enerdrive charger?

    Cheers

    Pete

    1. Hi Pete,

      It would normally be connected straight to the battery. Please ensure your CTEK charger has the correct charge profile for your battery type and is safely fused as per the user manual.

      If you have doubts, we recommend contacting an auto electrician.

      Thanks.

  4. Hi
    We are doing up our Ford Transit Custom now and recently purchased a 150W solar system with flexible panels and charge controller. This will charge a 100Ah LiFePo4 battery. This was all part of one pack. We now also want to connect this battery to the starter battery which we believe is connected to a smart alternator. I was considering purchasing the Victron 30A DC DC charger. Is this an adequate solution or do I need to up the size.

    1. Hi Volker,

      The Victron 30A DC to DC Charger is a suitable option, it has a lithium charge profile. Be sure to install as per the installation manual with the appropriate cabling and fuse ratings.

      Please let us know if you have any further questions.

  5. Hi guys.

    For my van im looking at installing a 40amp thunder dcdc charger and a 325w panel to go with my 170ah agm house and 75ah marine starter battery.

    I already have all the hardware just need the wiring, fuses and terminals. What would you recommend for these?

    Thanks

    1. Hi Leon,

      This is really a design question which we do not offer. Cabling and fuses is governed by the distance between components and peak load.

      The information should be found in the hardware manuals when in doubt, contact a marine or auto electrician for installation.

  6. Hi!

    Thanks for the great information. I was wondering about Projecta and whether they have a DC to DC charger and where it would stack up compared to the others mentioned?

    Thanks

  7. Hi,

    I’ve got a 40A Enerdrive Dc2dc unit charging a 240Ah bank (AGM – planning to upgrade to 360Ah). Fridge is a 95L and am often off grid for 4-5 days. Currently charging off a 200w solar blanket, which struggles to keep up over that period if there is any cloud. Can an Anderson 2-1 connection be used to join x2 of these blankets into the dc2dc solar input? Any considerations I should take?

    1. Hi Judah,

      Yes, you could connect the two solar panels in parallels. It is best to buy another of the exact same solar panel. If they are 12V panels, the charger will be able to accept that much wattage. Be sure to check with the manufacturer of the panel to confirm the best way to connect them in parallel.

      Ensure cabling is sized correctly to manage the increased current.

      Please let us know if you have any other questions.

  8. Hi Jessica

    Great article.
    I plan to run 2 x 50 litre fridges from one 135 amp Lithium battery. I will power via a 370 watt panel on the roof of my dual cab ute. Should I buy a 25 or a 40 amp DCDC charger ?

    Thank you

    1. Hi John,

      Thanks for your question.

      We recommend a 40A DC to DC Charger. The best value for money option is the Enerdrive ePOWER 12V 40A DC to DC Battery Charger. This is cheaper than the Redarc 25A DC to DC Charger and you get an extra 15 amps.

      We also offer the Enerdrive 40A DC to DC Battery Charger with Installation Kit which includes all the wiring, lugs and circuit breakers you will require for installation.

      Please let us know if you have any further questions.

      Kind regards,

      Jessica.

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