In today’s world of 4WD touring, van life, caravanning, and off-grid adventures, power is everything. Fridges, lights, compressors, and inverters all rely on a dependable battery setup. But to keep your auxiliary battery running efficiently, you need more than just a connection from the alternator—you need a DC-DC charger.
So, what exactly is a DC-DC charger used for? How does it differ from a basic isolator? And why is it now considered essential for modern dual battery systems—especially with lithium batteries?
In this guide, we break it all down and introduce you to a top-rated system: the Zenot 110Ah Lithium Dual Battery System with REDARC DC-DC Charger.
A DC-DC charger (also called a battery-to-battery charger) is an intelligent charging device that:
Takes power from your vehicle’s alternator (starter battery)
Regulates the voltage and current
Delivers the correct charge profile to your auxiliary battery
Unlike a simple isolator or relay, it doesn’t just pass through voltage—it boosts, limits, and customises it based on the battery type and condition.
Here are the main uses and benefits of installing a DC-DC charger in your 4WD, van, or caravan:
Modern vehicles have smart alternators that reduce output to improve fuel efficiency. Unfortunately, this means they don’t always supply consistent charging voltage. A DC-DC charger ensures your auxiliary battery receives:
The right voltage (14.4V to 14.6V)
The right current
A multi-stage charge cycle (boost, absorption, float)
Lithium batteries (LiFePO₄) have specific charging requirements. A DC-DC charger is crucial to:
Prevent overcharging or undercharging
Deliver a regulated charge curve
Avoid damaging your expensive battery
Without a DC-DC charger, lithium batteries will not charge fully or safely from the alternator alone.
Most quality DC-DC chargers include MPPT solar inputs. This means:
You can charge from solar panels and the vehicle alternator
Automatically prioritises solar when available
Ideal for off-grid camping and extended travel
Because the charging is controlled and staged, your batteries last longer—especially AGM, GEL, and lithium types. No more cooking batteries with over-voltage or sulfation due to trickle charges.
A DC-DC charger monitors both input and output voltage and adjusts charging to suit the battery’s state of charge (SOC). Most work as follows:
Engine on – detects alternator input
Charger activates – draws power from the starter battery
Battery check – identifies voltage level of the auxiliary battery
Staged charging – delivers boost/absorb/float cycles
Solar available? – if yes, solar power is used first
You get a clean, consistent, regulated charge regardless of alternator fluctuations or solar conditions.
DC-DC chargers are compatible with:
| Battery Type | DC-DC Recommended? | Notes |
|---|---|---|
| Lead Acid | Yes | Improves lifespan |
| AGM | Yes | Common for 4WD setups |
| GEL | Yes | Requires careful charging |
| Calcium | Yes | Needs higher voltage |
| Lithium | Absolutely | Requires specific charge profile |
➡️ Zenot 110Ah Lithium Dual Battery System with REDARC DC-DC Charger
This all-in-one battery system is ideal for 4WD enthusiasts, campervan owners, or tradies who need reliable power on the go. It includes:
Zenot 110Ah LiFePO₄ battery
REDARC BCDC1225D DC-DC charger
⚡ Pre-wired 12V/USB sockets
Heavy-duty battery box with circuit protection
MPPT solar regulator built-in
Just drop it in your canopy, connect it to your vehicle, and you’ve got a powerful portable power station.
Mount the charger near the auxiliary battery
Connect the charger to:
Starter battery (input)
Auxiliary battery (output)
Chassis ground
Ignition wire (if needed)
Solar panel (optional)
Fuse the input and output lines
Plug in 12V appliances directly to the pre-wired outputs
It’s a complete dual battery system that removes guesswork and works out of the box.
| Feature | Isolator | DC-DC Charger |
|---|---|---|
| Smart alternator compatible | ❌ | ✅ |
| Multi-stage charging | ❌ | ✅ |
| Lithium compatibility | ❌ | ✅ |
| Solar integration | ❌ | ✅ |
| Price | ✅ Budget | ❌ Premium |
| Efficiency | Moderate | High |
Bottom line: Isolators are cheaper but outdated.the industry standard for all serious 4WD, touring, and lithium setups.
When buying, consider:
Amperage Output – 25A is ideal for most setups
Battery Compatibility – AGM, GEL, lithium supported
Solar Input – MPPT regulation preferred
Ignition Trigger Option – for smart alternators
Sealed Housing – waterproof and dustproof for rough terrain
The Redarc BCDC1225D in the Zenot system ticks all these boxes.
At All 12 Volt, we don’t just sell products—we design complete power solutions.
Over 20 years in the 12V game
Australian stock & support
️ Custom wiring solutions
Fast shipping nationwide
Hassle-free returns
Plus, we stock trusted brands like Redarc, Zenot, Victron, Baintech, and more.
Yes, if you’re comfortable with 12V wiring and fuse protection. Otherwise, a licensed auto-electrician is recommended for lithium setups.
Not safely. You need a solar regulator—preferably integrated.
No. It only activates when the engine is running or sunlight hits the panel (if solar is connected).
Technically no, but it dramatically improves charge quality and battery life—so it’s highly recommended.
If you’re running any auxiliary battery system—especially one with lithium—then the answer is a resounding YES.
Charges efficiently and correctly
Works with smart alternators
Supports solar
Extends battery life
Powers your gear without worry
And with an all-in-one system like the Zenot 110Ah Lithium Dual Battery System with REDARC DC-DC Charger, setting it up is easier than ever.
Need help? Contact the All 12 Volt team for expert advice, custom setups, and installation support.
Need help or have questions?
Who does not love the outdoors and camping? It's a great adventure and opens up new destinations and often unexplored places. But you need to be well equipped with the safe and durable caravan and camping accessories for these outdoor activities. It is undoubtedly thrilling and exciting, but unless you take good care of what you need to do and what you should avoid, there's always a chance of an unpleasant experience. It pays to take sound advice from a 4WD specialist when going on a camping trip.