How to clean and maintain panels in winter

Winter maintenance is absolutely crucial for maximising output, especially up here where we get proper weather. Snow and ice buildup can absolutely tank your generation figures — I've seen my arrays drop to near-zero on heavy frost days until the sun's had a chance to warm things up.

My approach has evolved over the past couple of years. For the panels themselves, I use a soft brush with deionised water rather than tap water — the minerals in tap water leave residue marks that reduce efficiency. A gentle wipe when it's not sub-zero temperatures is all you need. I avoid pressure washers entirely; they can compromise seals and push water into gaps where it shouldn't be.

The real issue in winter isn't cleaning frequency, it's snow load. If you've got snow sticking, tilting your array at a steeper angle helps it slide off naturally once the sun hits it. I've retrofitted mine to about 50 degrees from the original 35, and it makes a massive difference. Some people fit hydrophobic coatings, but honestly, I reckon regular water beading already does most of that job.

Check your connections and isolators too — corrosion accelerates in damp conditions, and winter's brutal for that. Victron's equipment is bulletproof in my experience, but connectors themselves can corrode. MC4s seem most reliable, though I've had better luck keeping things dry than relying on any coating.

What's your setup like? Are you dealing with snow accumulation where you are, or is frost and moisture the main headache? Curious whether anyone's tried those heated panel systems — seems overkill cost-wise for the UK, but would love to hear if it's actually viable.

Yeah, winter's brutal for output up north. I've got panels on my caravan and the ice buildup is mental some mornings.

Few things that actually work:

Angled panels help massively — snow slides off easier if you've got decent tilt. Mine are at about 45° and it makes a real difference.

Squeegee or soft brush — nothing abrasive. I use a long-handled one from a caravan shop, takes 10 mins and gains me loads of kWh back.

Don't use hot water — temperature shock can crack them. Learned that the hard way.

Honestly though, once there's thick ice, I just leave it. Trying to shift it usually causes more problems than the lost generation. Gets worse in valleys where condensation freezes solid.

What's your array angle looking like? That's often the real limiting factor.

The ice issue is real, but honestly the bigger problem I've found is just keeping them clear of moss and grime — especially in the damp months. Snow slides off reasonably well on mine (45° angle helps), but that green film buildup kills output more than you'd think.

I use a soft brush and distilled water when it's not freezing. Tap water leaves mineral deposits that actually reduce efficiency over time. Learned that the hard way. The Victron monitoring makes it obvious when something's wrong — output just flatlines if there's significant coverage.

One thing worth mentioning: don't be tempted to chip ice off with anything sharp. A mate did that and cracked a panel corner. Just let it slide naturally or use lukewarm water if you're desperate (cold water on warm glass = disaster).

For the boat panels, I've found the portable 100W ones are actually easier to maintain since you can angle them better and they're not collecting as much debris. Might be worth @WillReid considering how you've got yours mounted — sometimes access matters more than you'd expect in winter.

Worth mentioning the angle matters loads — if your array's at a shallow pitch, snow just sits there like a sulky teenager refusing to budge. Mine on the narrowboat's at 45° and it slides off naturally most of the time, saves me climbing about in January.

For the moss and grime @PanelJuji's spot on about, soft brush and distilled water's your friend — tap water leaves mineral deposits that'll dull your output. Some folks swear by those long-handled squeegees for the caravan setups.

One thing I'd flag: if you're up north getting proper ice, a gentle warm water rinse works better than scraping (tempered glass'll forgive it but why risk it?). Just don't do it when it's freezing solid — thermal shock's a pain.

Honestly though, the real winter killer isn't the panels themselves, it's cloud cover crushing your generation for weeks on end. At least dirty panels you can do something about.