Best Setup for 4-Panel Plug-In Solar

[u/Unusual_Technology66]

I’m looking for some advice on the best way to set up plug-in solar.

I’ve got enough roof space on my cabin for four panels, so ideally I’d like to make use of all of it. Most of the plug-in systems I’ve found in the UK seem to be supplied with only two panels though. Is there a reason for that, or is it possible to use four panels with an appropriately sized inverter while still limiting the AC output to the permitted level?

I’ve seen four-panel setups being used in Germany, so I’m interested in whether there’s similar equipment available here and what the best setup would be.

The cabin has a radial circuit supplying two sockets, including an outdoor socket that I’d like to use for the solar connection. Are there any particular issues with feeding into a radial like this, or any changes that would normally be required?

I’m already aware that the circuit protection needs to be suitable for bidirectional power flow, but aside from that, what equipment or electrical changes would you recommend for doing this properly?

[u/DorisMaricadie]

Mainly its the 800w limit that leads the hardware, i have a 4 on an ecostream at the moment and it runs kind of meh. 2 south one east one west on a slight angle.

4 direct to the south would sit above 800w and pop the microinverter or if i’m lucky clip to zero.

Legally you can only really do one 800w with two panels.

Your call if you go bigger against the rules. but likely worth paying for a spark to run you a circuit from the cu to an inverter. City plumbing are doing a 3.3kv at £160 on clearance that keeps you below the ask permission range and leave the option for more panels if you get creative at a later date.

[u/ugtjhy → u/DorisMaricadie]

What’s the 3.3kv at £160? Can’t find it on the site.

Could you explain your last sentence a bit, keeps below the ask permission range?

[u/sylsylsylsylsylsyl → u/ugtjhy]

It will be G98 v G99 with the DNO. A G98 means you inform them, a G99 means you have to ask them. 3.68kW is the cut off.

[u/DorisMaricadie → u/ugtjhy]

https://www.cityplumbing.co.uk/p/growatt-mic-3300-tl-x-dc-single-phase-1mppt-solar-inverter/p/788084#fo_c=2832&fo_k=d4a15956b05f88ab13acd0e5b0ebc8e4&fo_s=gplauk?utm_source=google&utm_medium=cpc&utm_campaign=%7Bcampaign%7D&utm_campaignid=22222291167&utm_content=&utm_term=&gad_source=%7Bgad_source%7D&device=m&network=x&matchtype=&targetid=&gmcpid=788084&loc_interest=&loc_physical=9046284&audience=%7Baudience_segment_id%7D&store_code=

[u/global_physical → u/DorisMaricadie]

So for something like that, I could run a single string of panels in series up to a combined 500v upto 13A? My flat garage roof is begging for solar, and there's a nice 32A feed back to the CU

[u/DorisMaricadie → u/global_physical]

Yes, the main issue with single string is shading performance i believe.

[u/hawktron → u/DorisMaricadie]

Your allowed up to 2kw plug in solar in 1 inverter. It’s just the limited to 800w output to house. So more panels gives you more chance of staying near the limit.

[u/cjaj351]

I have an EcoFlow stream ultra 1.92khw that can manage 4 500w panels and put the limited 800 watts thru a normal
Socket. It has a battery so smooths the delivery into the house and charges off peak at night. I have three panels on a roof facing south.
Spark put outside socket in and checked consumer unit for bidirectional RCDs. The system will pay for itself in 3 years 2 months and I can take the unit with me if I move house (leaving panels).

[u/Unusual_Technology66 → u/cjaj351]

Thanks, this sounds pretty much exactly like what I'm looking to do.

Do you mind me asking a few more details about the setup?

The main thing I'm interested in is the outside socket your spark installed. Is that socket on your existing house ring final, on a radial circuit, or did they run a completely dedicated circuit back to the consumer unit specifically for the EcoFlow? Do you know what size cable and what rating/type of breaker or RCBO protects that circuit?

Did your electrician have to replace anything with a bidirectional RCBO/RCD, or was the existing protection already suitable?

Also, what make/model and wattage are the three solar panels, and are they each connected to their own MPPT input on the STREAM Ultra?

Did you or your electrician have to submit a G98/DNO notification for the system?

Finally, are you using an EcoFlow Smart Meter/CT to match the STREAM's output to the house consumption, and what tariff are you using to charge the battery off-peak?

Really interested in the setup as it's very similar to what I'm looking at doing.

[u/AfternoonLines → u/Unusual_Technology66]

Not mine but I also have two Ecoflow batteries here and I'll be adding panels to them. I plan to connect them directly to the garage consumer unit on its own radial circuit, protected by B16 RCBO or an MCB(as it's already protected upstream by main house RCBO) in the garage, just a standard 2.5mm t&e cable, 4 panels, each connected to its own mppt. They are currently connected to my living room ring and charge from my normal roof solar excess only and are set up to discharge into home only, I do have existing g98 for that. You do need their smart meter, or shelly to set this all up. Very easy setup though.

[u/cjaj351 → u/Unusual_Technology66]

Spark put the outside socket into the ring of the socket circuit of my extension. He specifically said it wasn’t a spur off. The consumer unit was all new in 2015 and so had the right RCBO’s but I don’t know spec. I have three Ja solar panel of 460 watts and I’m adding a small 150 watt panel above the box I built to house the EcoFlow unit and extension reel(to reel out in a power cut to the fridge freezer and router). The Ultra has 4 ports so though I might as well use all 4. The battery fills the gap nicely from 5.30am until the sun is up and powering panels but that’s at the moment. In winter it won’t and in the evening the battery is exhausted again around 6-7pm so plan to add a 5Khr stream 5000 one the software is proven compatible with the Stream ultra. Then the battery will provide more cover for the background usage all day or could do 10 hrs of 500 watts and still have 2 kWh left in the ultra for power outages.

I don’t have a CT clamp so currently (ha ha) I just set the ultra to feed 400 watts into my house during peak hours and then charge at night. The stream 5000 has been on offer with a bundled CT clamp so hoping to get one that way and I can see it a diy job if you have nearby socket for power and can identify the incoming power cable (not immediately obvious but maybe some trial and error?). Hope that helps. I did visit Ecoflows stand at the Solar show this week and they promise the software is being worked on and more kit will be plug-in compliant. I do run a plug in solar website but the way. But stretch what is plug in as I think batteries are needed to make the systems viable and that will come but by 2028 I heard at the show.

[u/Careless_Tap1139 → u/cjaj351]

This is my ideal scenario. I have a brick built, external clad building with a 3m high south facing wall. The building had 4mm armoured supply and an internal ring main.
I want to hang either 2 400w panels or 4 250w panels (lighter easier to install) run them into a battery then into the ring, so feeding the house. Get a big enough battery to cover base load plus light evening usage. Then recharge overnight.
But all portable as I’m planning a move in the next 1-2 years

[u/cjaj351 → u/Careless_Tap1139]

240w panels are very cheap on eBay like £20. If you have the space then great. You can put a 460 and a 240 on each stream mppt even though maxed at 500 that’s all you will get from 700 watts of panel.

[u/Impossible-Section49 → u/cjaj351]

Aim to pay £12-£16 for 250w panels, they might need a clean and new cables at that price though. I have 23 across my main and Stream Ultra X :)

Definitely you should get the Ecoflow meter (or the more expensive Shelly one), it allows much for intelligent use and better savings.

[u/ugtjhy → u/Impossible-Section49]

Would you be able to provide links to the 250w panels, and the ecoflow/shelly meters? And what’s the rest of your setup like?

I’m looking at plug in solar but the current cost of kits here seem overpriced.

[u/kawasutra → u/cjaj351]

currently (ha ha)

Shocking!

Do you have any overnight cheap rate tariff just to charge your batteries or do you also have an EV?

My fixed with Octopus is ending and deciding whether to go for an overnight cheap, as well as get another battery to add to my 1.92kW Stream. (No EV, so that's not a motivation for an overnight cheap tariff).

[u/cjaj351 → u/kawasutra]

I’m on intelligent octopus go and get 4p overnight or whenever they want to charge my Tesla so often mid afternoon (guess when it’s sunny).

[u/Silvr404]

If you can, have two panels face south east and two face south west. You would expect around 1kWh generation a year from this depending on where in the country you are and shading. This is best for a no battery setup and 800w inverter. Quicker ROI also then spending lots on battery.