Using my MPPT 100/30 with new panels

Been down a similar road recently — my old semi-flexibles started delaminating after a few summers on the cabin roof, so I swapped them out for a pair of Renogy 175W rigid panels instead. Went rigid partly because the flexibles just didn't last, but I get why people stick with them on curved surfaces.

Anyway, the bit that tripped me up was configuring the Victron MPPT 100/30 correctly for the new array. A few things worth checking if you're in the same boat:

• Voc at low temps — UK winters push Voc up noticeably. Run the numbers before wiring anything in series
• Battery charge profile — make sure it's set for your actual battery chemistry, easy to overlook when you're focused on the panels
• Absorption voltage — worth double-checking if you've switched from AGM to lithium (Fogstar cells especially seem fussy here)

The 100/30 has a 100V max input, so if you're stringing three panels in series, check your combined Voc doesn't creep over that on a cold morning. Three panels at ~24V Voc each gets tight depending on the spec sheet.

Has anyone else noticed a meaningful difference in yield between semi-flex and rigid on a fixed mount? I suspected I'd see a gain just from better ventilation underneath, but curious whether others have proper data rather than just gut feel.

Would be good to hear how you get on with the BougeRV ones — brand isn't one I've used personally but I've seen a few folk on here mention them.

@EmmaEdwards82 rigid panels are absolutely the right call — my semi-flexibles did exactly the same thing on my static, proper nightmare to peel off once they've bonded properly.

Worth double-checking your Voc in cold conditions with those 175W panels before you wire them up. Two in series could push close to your MPPT 100/30's 100V input limit on a frosty morning, especially up north. Run the numbers using the lowest expected temp for your location — Renogy's spec sheets have the voltage temp coefficient buried in there.

If they're wired in parallel you're fine, just limited on the current side. The 30A charge limit will clip your output a bit at peak but honestly not worth stressing over — you'll rarely see perfect conditions anyway.

What battery bank are you running?

@EmmaEdwards82 really sorry to hear about the delamination — did that happen within the warranty period? Wondering whether Renogy honoured anything there.

I'm looking at a similar swap for my narrowboat setup and have been eyeing those same 175W rigids. Quick question though — with the MPPT 100/30, what's your combined panel voltage coming in? I want to make sure I'm not accidentally straying outside the controller's input limits if I wire two panels in series rather than parallel.

Are you running them in series or parallel on your cabin? I imagine shading might be a factor depending on tree cover around you.

@EmmaEdwards82 worth double-checking your array voltage before you wire those 175W panels to the MPPT 100/30. The "100" is the max PV input voltage — Renogy's 175W panels typically have a Voc around 23–24V, so series configuration would put you near 48V Voc which is fine, but factor in cold morning temperatures as Voc rises significantly below 25°C. In the UK that matters more than most people realise. Also confirm your combined Isc doesn't exceed 30A on the charge side. Running two 175W panels in parallel should give you roughly 10A Isc total, well within limits. What's your battery bank voltage — 12V or 24V? That affects how you'd ideally configure the string. I run a 24V bank and found parallel wiring on similar wattage panels left power on the table compared to series.

@24V_Queen is right but let's be precise — the 100 in MPPT 100/30 is the maximum PV open-circuit voltage, not Vmp. With two Renogy 175W panels in series you're looking at a Voc around 48–50V depending on the exact spec sheet, which is fine. Where people get caught out is wiring three in series, or forgetting that Voc rises in cold weather (roughly +0.3% per °C drop below STC). Run the numbers at your minimum winter temperature.

The 30 is your max charge current — at 24V bank that's 720W input ceiling, so two 175W panels is about right. At 12V you'd be wasting potential.

What voltage is your battery bank @EmmaEdwards82?