Small solar panel10watts

Got a 10W panel on my van roof purely for keeping the Victron BMV-712 ticking over when she's parked up for weeks — turns out it's also just enough to slowly charge my phone if I squint at the sun and pray. 🙏

Thing is, a panel that small lives or dies by what controller you pair it with — chucking a massive MPPT at it feels like using a sledgehammer to crack a nut, so I went with a basic PWM job and honestly it does the trick for trickle duties.

Few things worth knowing from experience:

• Shading kills a 10W panel embarrassingly fast — even a cable shadow will floor your output
• Placement angle matters more at this size — fixed flat on a van roof you're leaving serious watts on the table
• Check your self-discharge rate — a 10W panel barely beats a lazy battery draining itself on standby loads

Would love to know what everyone's actually using these tiny panels for — I suspect half of us have one buried in the garage that was someone's grand off-grid starter dream before reality hit. 😂

What's the smallest panel anyone's found genuinely useful rather than just decorative?

@RussHunt82 haha love it — the "squint at the sun" method of power management 😄

That tiny trickle is genuinely underrated though. I've got a similar setup on my transit with a small Renogy panel doing exactly the same job — just keeping the Victron happy while she sits on the drive.

One thing worth doing if you haven't already — set a float voltage on your controller so it's not constantly pushing even those few watts into a full battery. Saves your cells long term.

Also if you ever want a proper phone charge without the squinting, a 10,000mAh power bank topped up occasionally does the trick nicely alongside that panel. Cheap solution that just works.

@RussHunt82 That's actually a really sensible setup — the BMV-712 draws next to nothing so your 10W panel should keep it happy indefinitely whilst parked. Worth checking your panel's actual output on a decent day with a multimeter though; I was surprised how much mine dropped just from being slightly off-angle. Even a small tilt makes a noticeable difference if you can manage it. Also make sure your controller (if you're running one) isn't drawing more standby current than the panel's putting in on a cloudy day — caught me out once! For phone charging you might find a small USB power bank topped up slowly works better than trying to draw directly. Every little helps when you're just in maintenance mode. 🙂

@RussHunt82 10W panel doing the work of a full solar array — Victron engineers somewhere are sweating nervously into their coffee wondering why nobody's buying bigger kit.

Worth noting though: if you're parked for weeks in a UK winter, that 10W rated panel is probably delivering about 4W of existential disappointment on a good day — worth checking your BMV's self-consumption figures against realistic January irradiance before you come back to a flat battery and a very smug panel doing absolutely nothing.

Ran a 20W on my motorhome for the same job for two years — overkill in hindsight, your 10W is plenty for the BMV-712 since it only pulls around 4mA on standby. Worth chucking a proper Victron SmartSolar MPPT between panel and battery though, even a tiny 75/10 — a cheap PWM controller on a small panel is basically handing back 30% of your already-meagre watts to physics. Also make sure you've got a decent blocking diode or the controller handles reverse current, otherwise at night that 10W panel quietly drains the very battery it's meant to protect — seen it happen more than once and it's a painful lesson.