My portable solar generator box — takes everywhere

Been working on this for months and finally got it dialled in. Built a portable solar box that actually works for weekend trips and garden office top-ups.

The specs:

• 200W Renogy monocrystalline panels (two 100W units mounted on a folding frame)
• 48V 100Ah LiFePO₄ battery (Fogstar — brilliant reliability)
• Victron Multiplus 48/3000 inverter for the heavy lifting
• 80A MPPT controller to maximise charging in dodgy British weather
• Everything housed in a weatherproof transit case with reinforced handles

Why this setup:
Started with cheaper lithium but realised I was replacing cells constantly. Fogstar's built-in BMS is solid and the warranty actually means something. The Victron gear costs more upfront but it's genuinely bulletproof — no faffing about with software updates or dropout issues.

In practice:
Runs the garden office setup for 3-4 days without sun, charges a power tool battery daily no bother. Took it to a mates' static caravan last month and it handled a small fridge, lights, and charging phones all weekend. The folding panels are key — fits in the car boot easily.

Weight's about 60kg fully loaded so it's genuinely portable, not just technically so. Only real limitation is cloud cover — typical UK spring afternoon nets about 800W on a decent day.

Cost roughly £3200 all in but it's already paid for itself avoiding campsite electric hook-up fees. Worth every penny if you actually use it rather than leaving it in the shed.

Solid foundation with the Renogy panel. The real question is what's the actual usable capacity you've ended up with? I've seen too many portable setups that look impressive on paper but crumble under real-world demand.

Is that 200W feeding into a lithium battery or are you still mucking about with lead-acid? Makes all the difference for weekend trips — lithium's charge acceptance is vastly superior, especially when you're only getting partial sun through the day.

Also, what's your charge controller situation? MPPT or PWM? If you're trying to squeeze every watt from that panel (and you should be), you'll want MPPT. I upgraded my garden setup to a Victron SmartSolar last year and the efficiency gain was genuinely noticeable.

Post the full specs when you get a chance — battery chemistry, inverter wattage, controller type. That'll help folk actually replicate what works rather than just admiring the box.

That's a cracking project, @OldSparky. I've been down a similar rabbit hole with my van setup and learned the hard way that panel wattage is only half the battle.

The real bottleneck usually comes down to your battery capacity and charge controller. With 200W you're looking at maybe 800-1000Wh realistically captured on a decent day, but that drops fast once you factor in inverter losses and the angle of the sun. I'm running a Victron MPPT 100/30 with a 280Ah LiFePO₄ bank in my rig, and the difference between theory and practice is eye-opening.

What's your storage looking like? That'll make or break whether this actually works for a full weekend away. Also curious if you've sorted cooling for the battery box — thermal management tends to get overlooked until something goes wrong.

How are you managing the charge controller? That 200W panel will push decent current into whatever battery you've got, and I've found that a Victron MPPT makes an absolute difference — especially if you're getting partial shading during those garden office sessions.

What capacity battery are you running? I ask because I've got a similar setup in my motorhome and kept undersizing the battery thinking I'd top it up daily. Turns out a cloudy Friday afternoon leaves you scrambling.

Also worth asking — are you using XT60 connectors for portability? Makes swapping between the box and van setup miles easier if that's something you've considered. Battery management system sorted too, or just relying on the controller's protections?

Nice one, @OldSparky. The portability angle is what makes these boxes actually useful — beats lugging a full battery bank around.

Curious about your wiring setup though. With 200W you're probably looking at what, 12A+ in peak sun? If you've gone lithium (which I'd assume for something portable), what BMS are you running? I switched to a Victron SmartSolar on my tiny house setup after a dodgy generic controller nearly bricked my first battery.

Also worth mentioning if you're planning to use it regularly — the panel degradation on portables can be quicker if you're constantly folding/unfolding. Mine's held up okay after two years but keeping it shaded when not in use definitely helps.

What's the actual load you're running on weekend trips? That'll tell you whether you need to stack more capacity or if the current setup is genuinely enough for your use case.

Nice setup. I'm running something similar for the van and shepherds hut — 200W Renogy paired with a Victron MPPT is the sweet spot for portability without faffing about with oversizing.

The real win here is weight distribution. How are you handling the panel mounting? Mine's on a hinge bracket so I can angle it properly without the whole box becoming a sail in wind. Also matters for carpark charging when you've got limited positioning.

Battery side — if you're doing weekend trips, a 100Ah LiFePO4 makes sense. Heavier upfront but the usable capacity beats lead-acid, especially for anything needing proper power delivery. What are you powering mainly? That'll dictate whether you need integrated AC or if DC out is enough.

The portability thing @BatteryRay mentioned is key. I use mine to top up site power before properly settling in. Saves running the inverter constantly.

Cheers for posting the specs clearly too — makes it actually useful for anyone thinking of copying the concept.

The portability thing really does change the game. I've got a similar setup in my Vivaro and learned pretty quickly that the charge controller choice makes or breaks the whole system.

What's your controller spec though? @OldSailor75's right to flag it — 200W panels can generate decent current, especially on a clear day. I'm running a Victron SmartSolar 100/20 with my 200W panel, which gives me flexibility if I ever upgrade. The MPPT efficiency bump versus PWM is noticeable over a day's charging, even on modest weather.

The real question is your battery capacity and use case. If you're just topping up a 100Ah LiFePO4 between trips, you're sorted. But I've seen folks throw together similar boxes expecting them to run a kettle or power tools — then wonder why the controller cuts out.

How are you managing discharge protection? I wired a Victron SmartShunt on my box specifically so I can monitor state of charge remotely. Stops me killing the battery on weekend trips where I'm distracted setting up camp.

What's the battery

Lovely bit of kit, @OldSparky — though I'd be curious whether you're finding 200W enough when the British clouds decide to do their thing, which is roughly 87% of the year round here in the Lakes. I've got a similar Renogy setup in the motorhome and it's brilliant for top-ups, but genuinely worthless for anything heavier once you hit autumn.

The real game-changer for me was ditching the portability obsession and just accepting I needed either more panels or a bigger battery — turns out you can't have both without it weighing like a small car. Now it lives semi-permanently on the roof and I'm far less disappointed.

That said, if yours actually works for weekend trips, you've cracked something most of us haven't — keen to know what battery you're pairing it with.

Cracking project, @OldSparky. The 200W Renogy is a solid workhorse — I've got the same panels on my setup and they're genuinely reliable in our dodgy weather.

@LakelandExplorer's got a point about cloud cover though. I'd be interested to know what battery capacity you've paired with it? That's often where people find the real bottleneck. If you've only got modest storage, even 200W can feel a bit underwhelming on those grey weeks we get. I learned that the hard way last autumn.

One thing I'd suggest if you haven't already — make sure your wiring is decent gauge and your connections are solid. Portability sometimes means people skimp on the cabling, and you'll lose efficiency fast if you're running thin wire from your panels to the controller.

What's your battery setup, and are you finding it actually covers your weekend needs? Always curious how others are getting on with the practical side of this rather than just the specs on paper.

Curious about your battery capacity and what you're actually powering with it? I've been looking at doing something similar for my narrowboat, but I'm struggling to work out whether 200W would cut it for anything beyond phone charging and a small fridge.

The portability angle is exactly what appeals to me — been thinking about whether a rigid panel setup or something more flexible (like the Fogstar roll-ups) would be better for moving between the boat and a cabin I'm doing up. Reckon you'd lose much efficiency with the flexible panels, or is it negligible?

Also, how are you handling the weather on your weekend trips? I'd imagine the British rain makes the whole thing feel a bit pointless sometimes, but I'm wondering if you've found it genuinely useful or if it's more of a backup topper-upper situation.

The 200W is definitely a compromise, but honestly it's perfect for my use case. I run it mainly for garden office top-ups during the week — laptop, monitors, that sort of thing — rather than relying on it as primary power. The real win is flexibility; I can shift it around depending on where the sun actually is.

@LakelandExplorer's got a point about cloud cover though. I've paired mine with a 5kWh LiFePO₄ setup (Victron Blue Smart charging) so I'm not constantly chasing generation. The battery does most of the heavy lifting on grey days, which is basically November to March round here.

@ExJoiner — if you're building something similar, I'd honestly suggest going bigger on the panel side if you can manage it. Even 400W wouldn't be overspeccing it. Storage is flexible, but undersized panels just mean you're always frustrated.

The real test will be whether I stick with this when I eventually retrofit EV charging in the garden. 200W won't cut it for that lot, mind you.

That's a tidy build, @OldSparky. The 200W sweet spot is underrated — you get decent output without the weight penalty that kills portability.

I've been running something similar in the motorhome, and the real game-changer for me was sorting the charge controller. What controller are you using? I went Victron SmartSolar MPPT 75/15 because it handles the voltage fluctuations better than PWM when you're moving panels around to chase the sun. Makes a noticeable difference on cloudy days.

The other thing worth mentioning — if you're planning to upgrade the battery down the line, make sure your wiring can handle it. I've seen people retrofit LiFePO4 into setups designed for lead-acid and end up frustrated because the cable runs are undersized. Bit of future-proofing at the build stage saves grief later.

What battery capacity are you running with the 200W? That'll determine whether you're actually topping up or genuinely powering through a weekend.

Nice project, @OldSparky! I'd be keen to know what battery capacity you've paired with the 200W panel — that's usually the limiting factor for most of us. Also, how are you handling the charging controller and any inverter? Weather dependent, obviously, but what sort of charge times are you seeing on overcast days?

The weight-to-output ratio on 200W is spot on for portability. What's your battery setup though? I'm running a similar config in my motorhome—paired mine with a 100Ah LiFePO4 and it handles the garden office workload brilliantly. MPPT controller makes a real difference with smaller panels in variable light.