Need Help: How to integrate a battery into balcony solar that isn't ECOFLOW STREAM

Right, so the balcony solar crowd are finally waking up to the fact that bolting a glorified power bank to your railing isn't the only option — welcome to the rabbit hole, friend! 🐇

The honest answer is it depends enormously on what inverter you're running. If you've got something like a Hoymiles or APsystems micro-inverter, you're working with AC coupling territory, which means you need a battery system that can play nicely on that side of the fence.

A few routes worth considering:

• Victron Multiplus (even the compact 500W) paired with a Fogstar Drift LiFePO4 battery — dead reliable, properly supported in the UK, and Victron's VRM portal is genuinely excellent
• DIY 12V or 24V LiFePO4 pack with a decent BMS (Daly or JK are popular here) feeding a hybrid inverter — more faff, more satisfaction
• Some folks are using Renogy all-in-one units with reasonable success, though I've heard mixed things about their BMS comms

The pedant in me must point out that "balcony solar" in the UK sits in a regulatory grey area — anything over 800W feeding the grid needs notifying to your DNO, so size accordingly and keep receipts.

My own setup runs a 24V Fogstar pack through a Victron MPPT, and the difference versus an all-in-one unit is night and day for data visibility alone.

What inverter/panels are you actually working with? That'll narrow this down considerably — there's no universal answer here, much as we all wish there were. Others here will have strong opinions too, so pile in!

GlenNicola | 📍 Scottish Highlands | ⚡ 2.4kWh LiFePO4 | 🌞 800W panels

@OldSailor ha, brilliant way to put it!

The key thing nobody mentions upfront is that most balcony inverters (your Hoymiles, Deyes etc.) are grid-tied — they can't directly charge a standalone battery. You'll need either a hybrid inverter setup or a separate MPPT charge controller feeding your battery bank, then a small inverter pulling from that.

Worth checking your DNO's rules too before going down this route — adding storage changes the notification requirements in some areas.

What inverter are you currently running? That'll determine which path actually makes sense for your setup. Some folk here have had great results with Victron SmartSolar controllers keeping costs reasonable without locking you into a proprietary ecosystem. 🔋

Really curious about the practical side of this — what does the actual wiring topology look like when you're constrained to a balcony install?

Specifically wondering:

• Are people running a Victron SmartSolar MPPT between panels and battery, then a separate inverter to feed back into a socket?
• Or is there a tidier all-in-one unit that handles MPPT + inverter + battery management without needing a full blown Multiplus setup?

My motorhome uses Victron throughout but that's a very different beast — dedicated cabling, proper fusing, space for a Fogstar or similar LiFePO4 under the bed.

A balcony setup presumably has to play nicely with a standard 13A socket and stay within whatever your landlord/building regs allow. Is anyone actually doing this legally and safely in the UK, or is it all a bit grey area?

What does a compliant setup actually look like in practice?

@WattLiz for balcony setups the typical approach is:

Panels → MPPT charge controller → battery → grid-tie microinverter

The microinverter needs to be one that'll accept DC from a battery bank rather than panels directly — Victron MultiPlus is overkill for a balcony but works properly. Some people use an Envertech or similar battery-input GTI instead.

Trickiest bit is keeping it within the 800W balcony solar rules whilst actually storing anything useful. I'd look at a small Fogstar Drift LiFePO4 — solid cells, sensible BMS, won't terrify your landlord.

Main constraint is usually where the battery physically lives. Mild weather it's fine on the balcony but in a UK winter you want it somewhere that doesn't drop below freezing or your LiFePO4 charging cuts out.

@Harry1965 that topology works but worth flagging — your microinverter needs to be the battery-input type, not panel-input. Most cheap ones off Amazon aren't. Look at the Deye or Hoymiles HMS series specifically.

Also the MPPT matters more than people think here. Victron SmartSolar is overkill for most balcony setups tbh, a decent Renogy or EPever unit does the job for less.

Battery-wise, Fogstar Drift 12V or 24V LiFePO4 is probably the most sensible UK option right now without going full EcoFlow money.

One thing nobody mentions — check your DNO situation. Some suppliers are getting twitchy about battery-backed grid-tie even at these small scales.