What is a DC to DC Battery Charger?

If you like to live outdoors or live in a vanilfe for a long time, you should have heard of DC to DC Battery Charger, or DC 2 DC Charger, which can help you live off the grid and maintain a life with Uninterruptible electricity. You can use your refrigerator, computer, coffeemaker and air conditioner as you would in a house.

DC to DC battery charger is also called battery to battery charger, as the name suggests, the main purpose is to transfer power from primary battery to house batteries, thus maintaining the secondary battery 100% fully charged all the time. Usually auxiliary batteries are the source of power for our lives usage.

When you live in a vehicles like travel trailer, RV, campervan, caravan and yacht, you will usually install a dual battery system. One battery is called the starter battery and another called the auxiliary battery. The starter battery supports the driving of the vehicle and the secondary battery serves as a life power source.

outdoor camper living
outdoor camper living

This is a very classic configuration, and there are some vehicle installations with 3 battery systems.

Adopting Solar power as mount solar panels to charge the vehicle’s Two batteries is also a popular option, usually it requires hooking a large number of solar panels and a dual battery charge controller, which is somewhat expensive, but also good ROI option. we have DC-DC chargers with MPPT that can be connected to solar power and use solar energy to charge the batteries.

One drawback of using solar panels is you cannot get sunshine always, if you have inadequate panels or the solar controller is not advanced enough, the battery bank won’t get fully charged.

There are many factors affects the solar conversion, insufficient sunlight, cloudy seasons, forest shadow, all of which can cause solar energy not get into your batteries as it should, the lack of sunlight can keep the solar panels from being as effective as they could be, which often happens.

DC to DC battery chargers move energy from the starter battery to the secondary battery to get it 100% power storage, the process is auto fulfilled while the car is running on the road.

Every car comes with a smart alternator that converts the power generated by the car’s engine into electricity to maintain the vehicle’s electronic systems and charge your starter battery, which is the secret to keeping your primary battery always run.

When it comes to alternators, there are two types of current AC and DC we have to know.

AC stands for alternating currents, which is the most common type of current we see in our lives. The household appliances that run in our lives, the traffic lights and street lights on the road all rely on AC power, it supply by the state grid.

DC stands for direct current, which is basically the type of energy provided by batteries, and is also the energy produced by solar energy systems. DC can power small appliances that we carry in our vehicles, such as DC lights, fans, rechargeable batteries, mobile phones and emergency survival radios.

The Benefits of DC to DC Battery Charger

DC to DC Battery Charger is a perfect device when you are away from settlements or can’t find the grid to charge your battery through AC plug, DC 2 DC charger can do the job of charging without hassle, no extra attention is needed and you can charge your battery while driving.

No need to worry about the weather factors, which is always a pain point for PV installers. DC2DC smarter charger is good buddy you can rely on. a fully charged battery is always ready for your mobile phones, Mac and electronic devices.

DC2DC Charger is reasonably priced and easy to hook up, is a great addition to the entire vehicle electrical system.

A type of DC DC charger integrate with MPPT controller can charge vehicle’s battery with solar power system besides it battery to battery charge.

DC to DC Battery Charger with Solar Input 30A 50A Wiring Diagram
DC to DC Battery Charger with Solar Input 30A 50A Wiring Diagram

Advantages of ZHCSolar DC to DC Battery Chargers

Easy to Integrate

DC-DC Battery chargers are capable of charging virtually all types of batteries, including LiPo, AGM, Lead Acid and Gel batteries, which work with modern variable voltage alternators and use multi-stage charging to fully and properly charge your vehicle battery

Plug and Play

You can deploy it with little to no additional expertise, just know the correct size, easy do it by battery label recommends and it will run without supervision.

Easy hooked up on the system.

hook up dc to dc charger a hassle free things to a fixed area, onboard dc dc charger just needs to be mounted on the corresponding bracket.

Easy to Setup

With a digital Display, you can quickly set the battery type and charging parameters, you can also use the dip switch to choose between different battery types.

Fuse and Cooling

For safety, the Fuse must be replaceable. In the process of transferring energy, heat will be generated inevitably, and the DC charger uses an aluminum case for good heat dissipation.

Remote Control

Bluetooth and Remote Control is available to add as extra function. Bluetooth control realized by Phone App and you can also plug a remote display.

Lithium Battery Charge

Lithium Battery is getting more and more popular, it great to be able to charge lithium iron phosphate as which is much more powerful.

Ways to Charge a Car Battery

AC Battery Charger

AC charge controllers are used to charge a 12V battery bank using regular household-type voltage (120VAC, 60Hz). the AC Charger is the most common Charger type to found in RVs and boats.

AC chargers required state grid connection, plug and play, but the downside is that you cannot find one outside the parking areas and family garages, and you have to wait for hours.

Car Battery Charger 7 Stage 12V Portable

Solar Charge Controller for RVs

if you have enough space for the panels to installed on the roof of RV and Trailers, it’s great to have RV solar kits to installed, include Solar Panels, RV Charge Controller and Solar Batteries.

solar power has some downsides, but it is absolutely worth the investment. While it is a hefty cost upfront, it gives you the ability to go boondocking on public land rather than having to stay in a crowded RV park with hookups.

If you have Dual Battery Installed, Dual Battery Solar Charge Controller is must on the purchase list, it helps you full charge the battery bank with solar input. dual battery charger keeps the service battery fully charged without supervision.


Vehicle Engine Charge

Vehicle’s alternator Charging systems deliver electrical energy to power your vehicle while it’s running and sustains the battery’s charge, you can add the isolators to charge the house battery with extra power of primary battery.


Diesel Generator

The diesel engine is a very old and efficient way to charge a car battery. not much people use it to charge a car battery nowadays. The annoying thing is that it’s too noisy.

DC to DC Smart Charger

the DC to DC Smart Battery Charger is what we talked in this article. it charges the secondary batteries in rvs by transfer power from the start battery while on the road or parking.

12v dc battery charger setting

How does the DC to DC Battery Charger Works?

The B2B charger is a smart device that starts working when it connected to the battery system.

As all chargers work, it lift the Input voltage and flow to low voltage device to complete the power transfer.

Quality DC DC Smart Charger has 3 stage Charging Process:

Stage 1: Boost- this delivers maximum voltage to a low battery in the initial charging.

Stage 2: Absorption- this is a continual charge that is maintained until the battery current demand reaches less than 4 amps.

Stage 3: Float- this is essentially a lower charge that maintains the battery at around 13.3 volts or essentially fully charged.

DC to DC Charger vs Isolators

the main role of an isolator is to isolate the start battery and secondary battery.

Vehicle’s alternator will automatically charge the starter battery during the driving, and when the drive battery is full, it will automatically switch and charge the life battery with smart isolator.

Isolators sometimes can be treat as BMS(battery management system) as it prevent the secondary battery from drain by the starter battery.

Isolators used to be very popular, but we not recommend this kind of isolator as it do not work well with modern vehicle variable voltage alternators.

Another disadvantage of the isolator is it still requires vehicle engine to charge the life battery, which means it can only be charged while it is running, whereas a DC to DC charger transfers power directly from one battery to the other without having to think about it.


FAQ about DC to DC Battery Charger:

What size dc to dc charger do i need

what size dc to dc battery charger you need is a ever asked question, you can find various type of charger rated 10A, 20A, 30A,40A, 60A and 100A on the market. which size to pick required some math, good thing is, it’s not complicate.

The easiest way is looking to the recommended charging current on the battery label, it always tell you what size charger to use.

Another way is to do a simple math with following formula:

AGM: Charger Amp rating = Battery Ah capacity * 20%

Lithium: Charger Amp rating = Battery Ah capacity * 50%

Lead-acid Batteries: Charger Amp rating = Battery Ah Capacity * 25%

So, a 100Ah AGM can use a Charger up to 20A

100Ah Lithium can use a Charger up to 50A

DC chargers with overdischarge protection will prevent the starter battery from being drained by the home battery.

Solar or DC-DC Charger

Both solar and DC-DC chargers are great solutions, they can even be combined. take which one usually depends on your vehicle condition and how much money you want to put on, some vehicles has no much roof space to applied the solar panels, in this case, a DC to DC charger is more recommended.

it cost a lot applying a complete RV solar panel kits, it requiring a full set of solar panels and a proper charge controller, solar solution demands a bigger investment than a DC DC charger.

Dedicate design Wall mount Solar Charge Controller and Solar Dual battery charger is recommended when applying solar panel kit for the camper trailers.

What is an on-board DC to DC charger?

On-board means the smart charger is originally designed for easy installation in vehicles and marine, the compact overall does not required too much space to put on.

On-board chargers can be easily and quickly integrated into the vehicle, seamlessly integrating into your vehicle’s electrical system without the need of additional transportable charging unit.

Is a DC to DC charger worth it?

It is a worthwhile investment in terms of its powerful ability and reasonable price, and it is becoming increasingly popular.

What makes a perfect DC DC Battery Charger

the thing is a perfect solution does not exist,every charging options come with pros and cons, it can be challenging to decide which option is best for your lifestyle. The simple answer is, don’t rely on just one.

Things to consider before purchase: Charging Method, Type of battery, Battery amp-hours, charger Size and vehicle conditions.

If you spend a lot of time outdoors without grid source, Solar panels can be a great addition, but we always recommend adopt the DC to DC Charger as the main method to keep the house battery 100% full. things happen and weather condition always affect the solar energy capture.

By having multiple sources of power generation, you can full-proof your dream off-grid lifestyle. We recommend having both a DC to DC charger and a portable solar generator or solar panel solution available when living off-grid.

Explore our entire range of ZHCSolar products to find the perfect energy solution for your setup.

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