DC-DC Chargers vs DC-DC Converters — What's the Difference?
If you've been shopping for DC-DC gear and found yourself staring at DC DC charger and DC DC converter boxes wondering which one you actually need — you're not alone.
Let's clear it up.
What They Have in Common
Both DC-DC chargers and DC-DC converters take DC power in and put DC power out. That's where the similarity ends. They're two completely different tools that happen to work with the same type of electricity.
DC-DC Chargers: For Charging Batteries
A DC-DC charger is a battery-to-battery charger. Its job is to take power from one battery (usually your vehicle's starter battery, which is being topped up by the alternator) and use it to safely charge a second battery — your house/leisure battery.
The key word here is charge. A DC-DC charger doesn't just dump voltage from one battery to another. It runs a proper multi-stage charging algorithm (bulk, absorption, float) that's tailored to whatever battery chemistry you're running — lithium, AGM, gel, you name it.
This is critical because modern smart alternators output variable voltages that would not properly charge batteries if you just connected them directly.
When you need a DC-DC charger:
- You have a campervan, caravan, boat, or motorhome with a house battery
- You want to charge that house battery from your vehicle's alternator while driving
- Your vehicle has a smart alternator (almost all modern vehicles do)
- You're running lithium batteries (these absolutely require managed charging)
Victron's DC-DC charger range at LUX Solar:
- Victron Orion-Tr Smart DC-DC Charger — The popular choice. Available in isolated and non-isolated versions, with Bluetooth for monitoring and configuration via the VictronConnect app. Models from 12/12 through to 24/24 configurations, with outputs up to 30A.
- Victron Orion XS DC-DC Battery Charger — The new kid on the block. Victron's latest generation with 98.5% efficiency, VE.Direct integration for full system monitoring, and configurable input/output currents. If you want the best, this is it.
DC-DC Converters: For Powering Devices
A DC-DC converter does something completely different. It converts DC voltage from one level to another — and its output goes directly to a device or appliance, not to a battery.
Classic example: you have a 24V battery bank but you want to run a 12V fridge. A DC-DC converter steps that 24V down to a stable 12V output that your fridge can use. No charging algorithm, no battery management — just clean, stable voltage conversion.
When you need a DC-DC converter:
- You need to power a 12V device from a 24V battery system (or vice versa)
- You need to power a 48V device from a 12V or 24V source
- You're running sensitive electronics that need a specific, stable voltage
- You're stepping voltage up or down for a specific appliance
Victron's DC-DC converter range at LUX Solar:
- Victron Orion-Tr DC-DC Converter (Non-Isolated) — Compact, efficient (95%+), and dead simple. Available in a wide range of input/output voltage combinations.
- Victron Orion-Tr DC-DC Converter (Isolated) — Same concept, but with galvanic isolation between input and output. Use this when the two systems can't share a common ground.
- Victron Orion DC-DC Converters (High Power) — For bigger loads, with remote on/off capability and adjustable output voltage.
- Victron Orion IP67 DC-DC Converter — Fully encapsulated, waterproof, shockproof. Built for harsh environments like engine bays and exposed marine installations.
The Quick Test
Am I charging a battery, or am I powering a device?
- Charging a battery → DC-DC Charger
- Powering a device at a different voltage → DC-DC Converter
Isolated vs Non-Isolated (For Both)
You'll notice both chargers and converters come in isolated and non-isolated versions. Quick breakdown:
Non-isolated means the input and output share a common electrical ground. This is fine for most standard vehicle and marine setups where everything is grounded to the same chassis.
Isolated means there's no electrical connection between input and output sides. You need this when the two systems must be electrically separated — think ex-military vehicles, boats with specific grounding requirements, or camper conversions with non-metallic habitation areas.
Our advice: if you're not sure, go isolated. It works in all scenarios and costs only marginally more.
The common mistake we see, and how to avoid it
Someone wants to charge their house battery while driving. They search "DC-DC 12V to 12V," see a converter that's cheaper than the charger, and think "same thing, right?" Wrong.
A DC-DC converter will output a fixed voltage — say 13.8V. It won't run a proper charging cycle. It won't protect your lithium battery from overcharging. It won't talk to your BMS. For battery charging, you need the charger. Full stop.
On the flip side, if you just need to run a 12V accessory from a 24V system, don't buy a charger — you'll be paying for battery management intelligence you don't need.
Want a Plug & Play Charging Kit?
Off-grid solar can be confusing, especially when you're building a system from scratch. That's exactly why we built the AnyKit™ Solar Design Tool. It takes the guesswork out of system design by automatically recommending compatible components for your setup — including the right DC-DC gear - and optionally a plug & play wiring kit to help you get it connected.
Design your system with AnyKit™ →
Within AnyKit, you can select the right DC DC Charger model and generate a complete wiring kit with cables, fuses, and a wiring diagram.
Still stuck? Email us at technical@luxsolar.co.nz — we'd rather spend five minutes helping you pick the right product than process another return :-)