Anyone running leisure batteries off solar in a van? Real-world mileage appreciated

Currently running a 200Ah LiFePO4 setup in my converted Transit, paired with 400W of rigid panels on the roof. Been doing this for about eighteen months now, so happy to share some observations.

The reality is considerably more nuanced than the spec sheets suggest. During summer months, I'm genuinely self-sufficient for light usage—laptop, water pump, fridge, modest lighting. However, once you factor in heating, hot water, or prolonged cloudy periods, you'll quickly realise you're draining reserves faster than anticipated.

My actual experience: On a decent sunny day, I'll gain roughly 60-80Ah back into the battery. But that's with the van parked optimally—not angled under trees or beside buildings. Winter? I'm averaging perhaps 30Ah on a good day, which barely covers baseline consumption.

A few pedantic points worth considering:

• Battery chemistry matters enormously. LiFePO4 accepts charge far more efficiently than lead acid, particularly in lower temperatures
• Panel angle is critical. Fixed roof panels are convenient but suboptimal for seasonal variation
• Your actual power draw is probably higher than you think. Most people underestimate consumption until they're tracking it properly

I've invested in a Victron BMV-712 monitor—essential for understanding what's actually happening in your system. Costs roughly £180 but pays dividends in troubleshooting.

What's your intended usage pattern? That'll substantially influence whether solar alone is realistic or if you'd benefit from auxiliary charging whilst driving.

Been running something similar in my converted Sprinter for just over a year now—200Ah LiFePO4 with 400W panels. Real talk though: those figures look great on paper, but the actual output varies wildly depending on where you're parked and the season.

What I've found is that winter charging is genuinely poor. Even with decent sun angles in December, I'm getting maybe 40-60W on a good day. Summer's brilliant—easily hitting 300W+ midday—but that's when you're least likely to need topping up anyway.

One thing worth mentioning: positioning matters more than you'd think. Even partial shade from trees or buildings tanks the output disproportionately. I've had to be quite deliberate about where I park to maximise south-facing exposure.

What's your usage pattern like? That'll make a big difference in whether 400W is sufficient for your needs.

Solid setup, both of you. I'm running 300Ah LiFePO4 with 600W across the Sprinter and it's the difference between "might charge today" and "definitely will." The math is brutal in winter—expect maybe 40-50W real-world output on a grey December afternoon, not the nameplate figures.

That said, 400W is plenty if you're disciplined about consumption. My rule of thumb: assume half the rated output for UK conditions, factor in panel angle (mine are tilted at 30°, rigid panels are less forgiving than adjustable), and honestly just accept you'll be running the leisure battery down some days.

@FormerMariner1 @VanKev—what's your typical daily draw looking like? That's the real variable. A 2kW inverter habit kills even the best solar setup.

Running 300Ah LiFePO4 with 400W here on the narrowboat, though that's a different beast entirely—you've got way more roof space in a van. Real talk though: 400W is tight if you're not parked in direct sun regularly. Winter especially, you'll notice it.

The sweet spot I've found is honest about your usage patterns first. Are you running a fridge 24/7? That changes everything. If you're intermittent (weekends, summer touring), 400W + 200Ah works. If you're full-time or winter camping, @MarineGeoff's got it right—600W minimum takes the stress off.

One thing I'd stress: get a decent MPPT controller. Don't cheap out there. Victron's the gold standard but Renogy does the job if budget's tight. Poor charge controller management will kill your solar gains regardless of panel count.

What's your actual usage looking like?

@FormerMariner1 and @VanKev, that's a decent sweet spot you've both hit. I've been running 280Ah LiFePO4 with 600W in my motorhome for nearly three years now, and I'd say the real variable nobody mentions enough is how you're using the van.

If you're parked up most days—even in winter—400W is genuinely workable. The issue comes when you're moving every couple of days and relying on partial charges. That's where the extra panel wattage matters.

What's your typical usage pattern looking like? Fridge running 24/7, heating, that sort of thing? Because I've noticed the maths changes dramatically depending on whether you're stationary or nomadic. A mate with similar specs to yours went from frustrated to delighted just by adjusting his pitch angle seasonally—sounds daft but the winter gains are real.

Also worth factoring in: panel degradation. My 600W setup realistically nets about 520W effective capacity now. Still very comfortable, but worth knowing for future planning.

Got 400W on my shepherd's hut setup (essentially stationary, mind you) paired with 200Ah LiFePO4, so I'm in that ballpark with @FormerMariner1. The real variable I've noticed is how you actually use the power rather than what you've got installed.

Winter's the killer—even 400W struggles in November/December if you're relying on it. Spring through autumn though, I'm rarely dipping below 50% charge if I'm sensible about consumption.

One thing worth mentioning: panel angle matters massively in a van. You're not getting year-round optimal angle like a fixed install, so expect less than the nameplate would suggest in winter months. I'd honestly rather have 600W and accept the weight/complexity than wish I'd gone bigger once you're living with it full-time.

What's your actual consumption looking like, @FormerMariner1?

Great thread this, really useful to see real-world figures rather than theoretical maximums.

I'm running 200Ah LiFePO4 with 300W of panels on my Sprinter conversion — been at it about two years now. One thing I'd add that nobody's mentioned yet is the impact of panel angle. Being fixed to a flat roof, I reckon I'm losing 20-30% compared to what I could harvest if I could tilt them. Anyone using those hinged tilt mounts? I've been tempted but worried about wind resistance on the motorway.

Also worth flagging for newer folks: winter up in Yorkshire is a completely different world to summer. My October-to-February output is genuinely shocking compared to June-August. Managing expectations around that has probably been the biggest learning curve for me. 😄

Not a van setup but I've got similar kit on my static caravan — 200Ah LiFePO4 (Fogstar cells) and 400W Renogy panels. Stationary like @JA_Solar so slightly different beast, but the consistency is actually useful for tracking real figures.

Summer here in Scotland is genuinely decent once you get a run of clear days — hitting 80-90% of rated output isn't unusual. Winter is brutal though, angles all wrong and daylight's short. That's where your battery capacity really earns its keep. I'd honestly say size the bank bigger than you think you need.

Interesting thread. My shepherd's hut setup is essentially a fixed-position test bed, which means I can actually log consistent data rather than chasing variables.

One thing worth flagging that nobody's mentioned yet: panel orientation matters enormously beyond just tilt angle. My east-facing bias gives me usable charge from around 07:00 rather than waiting for a south-facing array to hit optimal angle. For a van that's frequently parked overnight and drawing loads in the morning, that earlier harvest can be genuinely significant.

@IanHenderson79 — what MPPT controller are you running with those Renogy panels? Curious whether you're seeing any clipping losses at peak summer output.