A portable panel — usually a folding blanket or briefcase — is the single best upgrade for off-grid Mars caravan use. It solves the biggest fixed-panel problem (shade), adds capacity for winter and cloudy days, and unlike rooftop panels you can angle it directly at the sun. Here's how to add one properly.

Why Bother When You've Got Roof Panels?

Roof panels are great when:

• You're parked in open sky
• It's sunny
• The sun is reasonably high overhead

They're not great when:

• You're parked under a tree to get shade for the van
• You're in winter sun (low angle)
• You're under heavy cloud and need every photon you can catch
• You want to park the van in shade but still produce power

A portable panel solves all four. You can put the van in shade and the panel in sun.

The Two Main Types

Solar Blanket

• Flexible, folds into a small carry case
• Lighter, easier to store
• Common sizes: 100W, 150W, 200W, 250W, 300W
• Lies flat on the ground — slightly less efficient angle than a tilted briefcase, but easier to deploy
• More expensive per watt than briefcase panels

Solar Briefcase (Folding Glass Panel)

• Two glass panels hinged together in a frame, with built-in legs
• Stands at a tilted angle for better sun capture
• Generally cheaper per watt than blankets
• Heavier (10–20kg for 200W) and bulkier — takes up more storage
• Common sizes: 120W, 160W, 200W

For most Mars owners, a 200–300W solar blanket is the sweet spot — stows easily in the front boot or under a bed, deploys in 30 seconds, and produces enough to make a real difference.

How to Connect It to Your Mars System

This is where it matters whether you do it right.

Option 1 — Plug Into an Anderson Plug on the Van

Most Mars caravans have an external Anderson plug (50A Red) wired to the solar input. You plug your portable panel directly in and the van's solar regulator handles the rest.

Things to check:

• Confirm your van has an Anderson solar input — check during handover or with your branch.
• Confirm whether it has its own regulator on the portable panel's lead, or whether it goes straight to the van's regulator. Most Mars setups expect the portable panel to be unregulated (van's regulator handles it). If your portable panel has its own MPPT on its lead, you may need a different cable.
• Check polarity. Anderson plugs are reversible by design, but the wiring inside isn't. Plug it in wrong and you can damage the panel or the regulator.

Option 2 — Portable Panel With Its Own Regulator + Battery Connection

Some portable panels come with a built-in regulator and croc clips or a battery terminal connection. This bypasses the van's regulator entirely. Works, but:

• You need to know where to connect — usually direct to the battery terminals.
• Avoid connecting two regulators to the same battery in different ways unless you've talked to a 12V tech — they can argue with each other.

Easiest path: use the van's Anderson plug and let the van's regulator do the work. Talk to your nearest branch before buying a panel — they'll tell you exactly what spec connects cleanly.

Sizing — How Much Solar Do You Actually Need?

A starting point:

More is generally better, with diminishing returns past 300W for most setups. Past that point, battery capacity becomes the limit, not panel capacity.

How to Get the Most From a Portable Panel

• Angle it at the sun. Roughly perpendicular to the sun beam. Adjust 2–3 times during the day if you're maximising. A flat panel produces around 70% of what a properly angled panel produces.
• Keep the cable as short as practical. Voltage drop on long thin cables can lose 5–10% of output. The cables supplied with most panels are sized correctly — don't extend them with thin wire.
• Watch for shade. Even partial shade kills output. Trees move shadows during the day — move the panel as needed.
• Don't leave it down in storms. Hailstones, gusts and falling branches can write off a $400–$800 panel quickly.
• Roll it up at night. Reduces theft risk and weather exposure.
• Clean it occasionally. Same as fixed panels — dust and dirt cost output.

Combined With Fixed Roof Panels — Does It Just "Add Up"?

Roughly yes, but with caveats:

• The van's regulator has a maximum input current. If you exceed it, you don't get the extra — the regulator clamps. Mars regulators are typically sized to handle a portable panel addition; check with your branch if you're going large (300W+).
• Battery acceptance is the other limit. Once the battery is close to full, neither rooftop nor portable can push more in.
• Real-world output of 200W roof + 200W portable is rarely 400W — more typically 300–350W under good conditions because of timing, angles, and regulator behaviour.

Brands That Play Well With Mars Setups

We won't endorse a specific brand — there are several that work well: Hardkorr, Drivetech 4x4, Kings (entry-level), Enerdrive, REDARC. Talk to your branch about what they've seen work cleanly with the regulator in your specific build.

What to Ask Before You Buy

1. What's the rated wattage?
2. Is there a built-in regulator, or unregulated?
3. What connector — Anderson, croc clips, custom?
4. What's the open-circuit voltage (Voc) at peak? Must be within the van regulator's input range.
5. What's the warranty? Look for 5+ years on the panel.
6. What does it weigh, folded? Where will you store it?

The 30-Second Decision Tree

• Mostly powered sites? Don't bother.
• Off-grid sometimes, mostly summer? 150–200W blanket.
• Off-grid often, all seasons? 200–300W blanket.
• Want maximum capacity in a serious off-grid setup? Add a second roof panel or 300W+ portable.

Related: How Your Mars Solar System Works· Why Your Solar Isn't Keeping Up· Lithium Charging Below 0°C