DC To DC Battery Charger: Buying Guide For The Best DC To DC Chargers

When it comes to battery chargers, DC charging is often the best option. However, considering that most of the electricity we utilize is AC, the conversion between them requires sophisticated equipment. Whether you need to revive a dead battery or a faulty solenoid that can’t recharge it, you might look for a DC-DC charger.

Throughout this guide, we’ll examine how such devices work and the method to choose the best DC-to-DC chargers for specific applications.

What Is a DC to DC Battery Charger?

A DC-to-DC battery charger involves transferring electrical energy from a DC source to the battery, which already stores energy as DC. It works on the principle of electric potential balancing, which is that a current flows through two electrical sources as long as there is a voltage imbalance.

While most batteries ship with an AC to DC charger, there might be times when you need to charge the battery from other reserves or through the alternator from a vehicle. Yes, there are methods for direct connections, but a DC-DC charger ensures that the energy transfer is swift and safe.

Why Do I Need A DC-DC Charger?

You may need a DC-DC charger for the following scenarios.

  • You have a dead battery, and connecting a regular charger may be unsafe.
  • Your regular charger is out of order.
  • You’re operating an energy-extensive vehicle, like a pickup truck or an RV, and you need to recharge the secondary batteries.
  • There are no regular outlets available close to your location.
  • You need to recharge using spare charged batteries.

How Do DC to DC Chargers Work?

Most DC-to-DC chargers are simply energy regulators that transfer excess energy between two electrical sources. The energy transfers from a higher voltage device to a lower one. A DC-DC charger appropriates that process by keeping the flow of electrons consistent. It prevents the process from reversing once you reach substantial charging states on a single battery.

A DC charger can draw power from an alternator, a charged battery, or a converter with a suitable voltage output. You need only make sure the fuses are in their correct positions and you can prevent any accident from occurring.

Benefits Of a DC-DC Charger

You can gain several advantages from using a DC-DC charger to restore a battery. A few significant ones are listed below.

  • A DC-DC charger provides you with a safe backup to recharge your battery in an emergency situation.
  • It retains your battery lifespan for longer than conventional chargers. You can also use it as a trickle charger to revive dead batteries.
  • Unlike battery isolators that work on the same principle, a DC-DC charger can charge your battery to the total capacity.
  • You can use the charger to charge multiple batteries simultaneously and configure it to suit the battery type.
  • DC-DC chargers are usually lightweight and convenient to carry in a backpack or a glove box.

What Size DC-DC Charger Should You Choose To Buy?

Before installing a DC-DC charger for your home or RV, it helps to consider a few criteria before making a purchase.

Type of Battery

DC batteries can belong to various categories. You can buy an AGM, FLA, gel, or lithium-ion battery for your vehicle or inverter. You must ensure that the charger is compatible with your battery type.

Size of Battery

The battery size is a determining factor in selecting the correct DC charger. Since each size class varies with the displacement and orientation of the battery terminals, certain chargers won’t fit with the battery. In addition, restrictions persist on where you can fit the charger to hold the system together firmly.

Install location

You must install your DC-DC charger in a dry location, away from rain, dust, and direct sunlight. It should also remain inaccessible to children and pets. If you install one under the bonnet, you need additional waterproofing. For chargers installed within the passenger compartment, you need wire extensions to reach the battery.


You must always go for a battery charger that has a higher voltage capacity than what you intend to charge. In most cases, it’s best to get a charger that’s capable of delivering at least 50% more than the required voltage.


Most DC-DC chargers are compatible with specific applications. You can examine the fine print before confirming your purchase to ensure that the device fulfills its intended role.

Top Best DC to DC Charger for a Car Battery

When shopping for a compatible DC charger, you can come across thousands of products online and offline. In order to smoothen the process, here are our top picks that you can buy online or at your nearest electronics store.

Renogy 12V 20A DC to DC On-Board Battery Charger

Renogy makes a DC charger that works with flooded, gel, AGM, and lithium batteries. It uses multi-stage charging in RVs, SUVs, commercial vehicles, boats, etc., with a peak output of 20A. Its compact design lets you install it conveniently in any car or room. You can also avail of 30A, 40A, and 50A variants per your requirements.

Wagan EL7410 12V 25A DC to DC Battery Charger

Equipped with advanced microprocessor technology, the Wagan EL series of DC chargers let you charge any battery through AC or DC sources. The most significant part is that it doesn’t require you to configure anything, as the charger automatically applies the relevant settings after scanning the battery. It’s compatible with regular power grids, other batteries, alternators, and solar power systems.

Victron Energy Orion-Tr Smart DC-DC Charger

Victron brings a smart digital angle to the seemingly analog DC charging field. You can configure the Orion-Tr charger from your smartphone using Bluetooth, allowing you to monitor the charging status without messing with the wires. While the base version has a current limit of 30A, you can connect multiple units to increase the load and charge multiple batteries at once.

Powermax PM4 100A Power Converter

If you need to power a massive power setup, then the Powermax PM4 should be your preferred DC charger. It is a 100 Amp charger with a Built-in 4-stage circuit that keeps all connected batteries in optimal condition. It can source power from most sources without requiring manual configurations for cutoffs.

How To Install a DC to DC Battery Charger?

Installing a DC to DC battery charger is pretty straightforward. You can do it by following the steps mentioned below.

  1. Analyze your battery charging requirements and create a space to snugly fit the charger.
  2. Prepare an insulating base over the location to prevent current leakage and electrical fires.
  3. Screw the required charger in place with adequate tools. Make sure the vehicle is not turned on, and the battery is disconnected.
  4. Connect the positive end of the charger to the positive terminal of the battery and vice versa.
  5. Extend the connection to the alternator or other power sources that shall feed the charger.
  6. Check the battery charger by turning the engine on after all the connections are complete. You can use a multimeter to determine that the output is displayed on the charger.

See full this video: How to install DCDC Charger onto Battery Box

Frequently Asked Questions

Is a DC-to-DC charger worth it?

Yes. Even though it’s more expensive than a regular charger, a DC-to-DC charger can charge your battery as well as retain its lifespan. It functions much like a trickle charger without the delay in charging cycles.

Can I use an AC-to-DC converter to charge a battery?

Yes. Although, it’s best to analyze the output current and voltage before connecting it to a battery.

How many batteries can a DC-DC charger charge?

It depends upon the precise version. Most of them are suitable for charging just one battery. However, there are variants that you can utilize to charge up to four batteries simultaneously.

Can a DC-to-DC charger charge two batteries?

Yes, provided it has the necessary extensions and the charger maintains its electrical potential when charging multiple batteries. It helps to go through the available user manual or check in with a trusted electrician before turning on the charger.

Where should I mount my DC to the DC charger?

It’s best to mount a DC-DC charger in a safe, dry place that’s out of reach of children and pets. In the case of a vehicle, it’s best mounted below the hood or in the trunk.

Does a DC-to-DC charger increase the voltage?

No. A DC charger only charges a battery to its rated voltage. You can’t overcharge a battery using such a charger.

How long does a DC to DC charger take to charge a battery?

It depends upon the current output of the charger. Most chargers can charge a 12V battery from 30% to 90% in less than 2 hours.

How is an AC-to-DC battery charger different from a DC-to-DC battery charger?

An AC-to-DC charger has a rectifier that dampens the AC current, converting it to DC. On the other hand, a DC-to-DC charger balances the flow of charges to charge any battery as required.


A DC battery charger is an invaluable tool to have in your possession. You never know when you might get stranded and might need to recharge your battery through unconventional means. With this guide handy, you can shop for the best DC to DC chargers that suit your application.


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