How to Connect a Solar Panel Blanket to a DC-DC Charger

Using a solar panel blanket with a DC-DC charger is a great way to keep your auxiliary battery charged while camping or touring. This setup helps maintain battery health and ensures your fridge, lights, and other 12V gear stay powered up — even when your vehicle's engine is off.

Below is a step-by-step guide to safely connect your solar blanket to your DC-DC charger.

✅ What You’ll Need

• Solar panel blanket (usually 100W–300W)

• DC-DC charger with MPPT (e.g., Redarc, Victron, Enerdrive, Projecta, etc.)

• Solar Anderson plug or MC4 connectors

• Regulator-free solar panel (DC-DC charger already regulates solar input)

• Solar extension cable (optional for extra reach)

• Correct fuse or circuit breaker (if not integrated)

• Multimeter (for voltage checks)

⚙️ Step-by-Step Instructions

1. Check Your DC-DC Charger’s Solar Input Specs

Before you plug anything in, check the charger’s manual for:

• Max solar voltage input (often 25V–32V)

• Max wattage supported

• Connector type (e.g., Anderson, MC4)

⚠️ Important: Use an unregulated solar blanket. The DC-DC charger has its own MPPT regulator, and adding another can interfere with performance or damage the system.

2. Lay Out the Solar Blanket in Direct Sunlight

• Place the blanket flat and angled toward the sun for best performance.

• Make sure it’s clean and free from shading.

3. Connect the Solar Blanket to the DC-DC Charger

• Plug the solar blanket's output lead (usually Anderson or MC4) into the solar input port of your DC-DC charger.

• Use an extension lead if the blanket is far from the vehicle.

✅ Tip: If using MC4 connectors, ensure polarity is correct — positive to positive, negative to negative.

4. Verify Solar Input on the DC-DC Charger

Once connected:

• Check the charger display or LED indicator to confirm it's receiving solar input.

• Use a multimeter if unsure — expect 18V–22V for a typical 12V blanket.

5. Charging Begins Automatically

When sunlight is strong enough and the charger detects suitable conditions:

• The charger will begin converting solar power to charge your auxiliary battery.

• Most units will prioritise solar over vehicle alternator if both are connected.

? Troubleshooting Tips

? Final Safety Notes

• Fuse your solar cable if it runs more than a metre or enters the vehicle.

• Avoid folding the blanket while connected to the charger.

• Don’t mix regulated and unregulated solar sources into a DC-DC charger.

• Secure all cables to avoid damage in wind or by foot traffic.