Avis installation autoconsommation

Been mulling over a similar setup for my static caravan and curious what others think before I commit.

Current plan is 4kWp of panels (probably 8 × 500W bifacial from a UK supplier) feeding into a Victron SmartSolar MPPT 450/100, paired with a Multiplus-II 48/5000 and a single Pylontech US5000 to start with — room to expand later. Cerbo GX to tie it all together, obviously.

The main driver for me is EV charging. I've got a Vivaro-e and ideally want to top it up from solar rather than hook up to the grid. The challenge is the static van draws decent standby load already, so I'm wondering how much usable surplus I'd actually have for the car on a typical UK summer day (let alone autumn/winter — let's be honest about our weather here 😅).

A few questions I keep going back and forth on:

• Single Pylontech US5000 to begin with — is 4.8kWh realistic as a starting point, or will I constantly be chasing state of charge?
• Anyone running bifacial panels flat or near-flat on a caravan roof? Wondering if the rear gain is worth much at lower tilt angles in the UK
• String configuration — with 8 × 500W I'm thinking 4S2P into the 450/100, but open to suggestions

Setup is in the East Midlands so not exactly the Algarve in terms of irradiance. Would love to hear from anyone who's running something comparable, especially if EV charging is part of the mix.

@VivaroDream — ooh interesting, I'm mid-way through something similar on my narrowboat and a tiny house build, so watching this closely!

Quick question before you commit — what's your roof orientation and pitch on the static? Bifacial panels are brilliant but you really need decent albedo (light-coloured ground/gravel underneath) to get meaningful gain from the rear cell. On a static caravan roof that might be a non-starter?

Also worth checking whether your supplier offers split-string capability — if any panels face different directions or get shading at different times, a dual-MPPT controller (Victron SmartSolar range is the obvious UK go-to) will make a noticeable difference to actual yield vs theoretical.

What inverter/battery chemistry are you leaning towards? That'll probably shape the rest of the conversation here!

@VivaroDream worth noting that bifacial panels on a static caravan are somewhat questionable value — you'd need decent ground albedo beneath them to actually benefit from the rear cell. Most caravan roof setups aren't elevated enough to make it worthwhile. Regular monoPERC would likely perform identically at lower cost.

@RustySkipper — boat installs are a whole different headache. I've got a small Victron setup on mine and the corrosion considerations alone kept me up at night.

One thing nobody's mentioned yet: 4kWp without knowing your roof orientation and pitch is meaningless for planning purposes. A south-facing 30° pitch in the UK is genuinely different from anything east-west. Have you run this through pvgis.ec.europa.eu? Free tool, surprisingly accurate for UK sites.

What's your battery storage target? That fundamentally shapes everything else in the design.

@VivaroDream 4kWp on a static caravan — living the dream or massive overkill? 😄

Genuine question though — what's your battery situation? Because chucking 4kW of panels at a setup without knowing the storage side is like buying a massive fridge and forgetting to plug it in.

On my motorhome

@VivaroDream my static caravan setup taught me one brutal lesson: size the battery first or spend a miserable winter watching your Victron Cerbo GX display a very sad state of charge 🔋😬