Anyone else running a cheap Chinese MPPT off a single 200W panel — worth upgrading the controller first or the panel?

So I've been running a fairly basic setup in my Transit for about eight months now — one 200W panel on the roof feeding into a 20A Epever Tracer MPPT, then into a 100Ah leisure battery. It's been fine for keeping the phone charged and running a 12V coolbox, but I'm starting to push it a bit with a small inverter for the laptop and I'm noticing the battery sitting pretty low by evening in winter.

I've got roughly £150 to spend and I'm trying to figure out whether to add a second 200W panel (seen some decent-looking ones on Amazon for around £85-90), or whether I should ditch the Epever and step up to something like a Victron 75/15 or even a Renogy 40A controller to handle future expansion. The Epever isn't bad exactly, but I've read a few things suggesting the cheaper controllers can lose a fair bit of efficiency and mess up your charging profile.

Thing is, with just the one panel I'm already under the Epever's 20A limit with headroom to spare, so I wonder if the controller upgrade would make basically zero difference until I actually add more panels. Logic tells me panel first, but I don't want to end up with two panels strangled by a dodgy controller.

Has anyone gone through this exact dilemma? What actually made the noticeable difference to your real-world usable power day to day?

GlenNicola | 847 posts | ⚡ Solar Enthusiast

@Gazza89 The Epever Tracer is actually a decent bit of kit — not "cheap Chinese tat" in the same bracket as some of the no-name stuff floating around. I'd be hesitant to bin it.

Honest answer: before upgrading either, have you checked your wiring losses? A lot of people are losing 10-15% just through undersized cable runs between panel and controller. Sort that first — costs almost nothing.

If you are adding budget, a second 200W panel wired in series will make a bigger real-world difference than swapping the controller. Your Tracer can handle the voltage easily and you'd genuinely feel that extra generation on cloudy Scottish days (or wherever you are!).

What's the actual problem you're trying to solve? Not enough charge, or just curiosity about upgrading?

BirchDaz | 312 posts | 🔧 Van Dweller

@Gazza89 Agree with @GlenNicola that the Tracer isn't the weak link here. Honestly, with a single 200W panel, your real bottleneck is probably that 100Ah battery rather than either the panel or controller. What's your daily consumption like? If you're finding you're regularly draining below 50%, a second battery would likely transform your setup more than any panel or controller upgrade.

That said, if you're dead set on improving generation, a second 200W panel wired in parallel would be my next move — your Tracer 20A can handle it fine up to around 260W safely. Controller upgrade can wait until you're pushing beyond that capacity. What are you typically running off it? 🔌

HY_OffGrid | 203 posts | 🏕️ Static Caravan

Different setup to you (static van, not a Transit) but same principle applies. Went from one 200W to two before touching the controller and the difference was night and day — more panel wins every time when you're on a single unit.

Your Tracer will handle a second 200W no bother, just check your VOC doesn't exceed the 100V input limit if you wire series. Parallel keeps it safer for a 12V system anyway.

Only time I'd say upgrade the controller first is if you're getting weird behaviour or can't pull more than ~60-70% of rated panel output on a clear day. Otherwise battery or panel expansion is your bang-per-pound.

NigeScott98 | 156 posts | 🚐 Van Life

@Gazza89 One thing nobody's mentioned yet — before spending anything, have you checked your cable sizing between the panel and controller? Undersized cabling on a 200W setup can lose you a surprisingly significant chunk of your potential harvest, especially over longer runs. Worth grabbing a clamp meter and seeing what you're actually pulling in versus what the panel should theoretically be producing on a clear day. If there's a big gap, that's your culprit right there and it costs next to nothing to fix. Cheap fix before any upgrade conversation makes sense IMO.