This.
Heat pump or EV charger = very likely to be un-looped.
They should make good any driveway or garden they need to dig up to do the work.
Solar panels and battery - any real world recommendations?
- Thread starter GinG
- Start date
Heat pump or EV charger = very likely to be un-looped.
They should make good any driveway or garden they need to dig up to do the work.
I'm trying to get a proposal for a solar install. It looks like I should be able to quite comfortably get ~16 panels on the east facing roof, 4 on the south facing, and 3 on the west facing. I'd also be getting a decent sized battery and a heat pump installed at the same time. There are a couple of other roofs which could take panels that I'm struggling to get answers out of the installers about. I've got an east facing roof on the ground floor that could fit 6-8 panels, and a north facing roof (main roof) that could take 4 panels. Here are my options:
We'll be in the house for the long term, so don't mind a bit of a higher outlay initially, but don't want to go too crazy. Gut feel is it's between #2 and #3 but would appreciate any insight.
- Option #1 - Stick with the 3 orientations. Simplest and cheapest.
- Option #2 - Extra east facing only. Even with being in the shade all afternoon, they'll likely still generate more than the north panels, BUT I've already got a lot of east facing panels, so if I have a low export limit and fill my batteries on a cheap overnight tariff, then a chunk of the generation would likely be wasted.
- Option #3 - North facing only. Not as much peak generation but perhaps more consistent generation spread over the day?
- Option #4 - Extra east facing and north facing. Obviously generates more, but as well as the extra install costs, it would require an inverter with 5 MPPT's (or require optimisers) so really bumps the cost up.
We'll be in the house for the long term, so don't mind a bit of a higher outlay initially, but don't want to go too crazy. Gut feel is it's between #2 and #3 but would appreciate any insight.
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Rather than doing an inverter with 5mppts it may be more sensible to do one hybrid inverter and one string inverter.
Do consider that the more panels you have, the less batteries you need also because you’ll have more consistent generation above your general power draw more of the time, particularly in the winter and early mornings and late evenings. Panels scale very well when it comes to ROI, the more you have, the more you make (usually). Batteries don’t, once you have enough, ROI actually goes down the more you have.
I would just get the costs and see what makes sense, look at the installed capacity and generation potential of each option vs the cost.
As you’ve got so few south facing panels, your peak generation will not actually be that high, particularly on warm full sun days. As the panels heat up, the less they produce.
For example I’ve got 10kwp split over 9 east 14 west. The 19/6 was a pretty nice day, a few clouds over lunch but otherwise very consistent generation all day. Peak generation was 7.07kw and I was only generating above 6kw for 2 hours. If I had a 6kw export limit, I’d have only clipped 1kwh after house use.
That clipping can also be easily mitigated using batteries. Charge up overnight, dump 1.5kwh by 12pm ready to be filled by clipped generation over the peak period.
This is what my generation curve looked like on 19/6:
This is what it looks like in winter 25/1/25 to be exact. This is about as good as it gets for Jan, most days are not this good. Note the dip at mid day due to panels facing away from south and the scale difference to 19/6:
Edit: images added
Do consider that the more panels you have, the less batteries you need also because you’ll have more consistent generation above your general power draw more of the time, particularly in the winter and early mornings and late evenings. Panels scale very well when it comes to ROI, the more you have, the more you make (usually). Batteries don’t, once you have enough, ROI actually goes down the more you have.
I would just get the costs and see what makes sense, look at the installed capacity and generation potential of each option vs the cost.
As you’ve got so few south facing panels, your peak generation will not actually be that high, particularly on warm full sun days. As the panels heat up, the less they produce.
For example I’ve got 10kwp split over 9 east 14 west. The 19/6 was a pretty nice day, a few clouds over lunch but otherwise very consistent generation all day. Peak generation was 7.07kw and I was only generating above 6kw for 2 hours. If I had a 6kw export limit, I’d have only clipped 1kwh after house use.
That clipping can also be easily mitigated using batteries. Charge up overnight, dump 1.5kwh by 12pm ready to be filled by clipped generation over the peak period.
This is what my generation curve looked like on 19/6:
This is what it looks like in winter 25/1/25 to be exact. This is about as good as it gets for Jan, most days are not this good. Note the dip at mid day due to panels facing away from south and the scale difference to 19/6:
Edit: images added
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Technically, I *think* yes.
Practically, it probably doesn't matter.
TLDR:
There are two forms for equipment to be connected to the network.
A G98 is just a notification, which can be done after the work is completed. IIRC that's got a 3.6kw limit for both import/ export.
A G99 is done for stuff which is over that limit, and you must have the completed response and any work done by the DNO before connecting the equipment.
It depends, the DNO may allow it with restrictions. If the charger has a CT clamp and can curtail its power draw based on the total grid load, they tend to allow it.
Once you have been unlooped you can up that restriction to 80/100A depending on what they install, probably 80 these days.
We are talking EV chargers rather than generation equipment so its a different form.
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You haven't specifically said it this is the case (but it's kind of implied from option 4), are you intending to run those 3 west panels on one MPPT? If you are, then you probably have a problem already.
It does depend on the exact inverter you intend use, but just 3 panels cuts it rather close for what most inverters will tolerate for the minimum input voltage on an MPPT. And even if it does just squeak over the minimum, it's likely to be a little problematic and you take an efficiency penalty for being so far away from the nominal bus voltage anyway. I'm usually very pro "all the panels", but that probably isn’t the way to go here if it is what you were intending. A work around would be to combine those 3 panels with the 4 south facing ones into one MPPT. This does require optimisers on all of those 7 panels, but it solve the voltage problem while still keeping that aspect in play.
Yes, I believe the plan is to put them on one MPPT. None of the installers I've spoken to so far has mentioned that as an issue though :-/. Unfortunately, due to the shape of the roof, there's lots of 'bitty' roofs so we can't fit any more on. The quotes are using the SigenStor EC 10.0SP inverter with Aiko 465W panels.
To be honest, I'm not too fussed by the kit spec just yet as the build is going to take a long time so the tech will likely change by the time I get around to installing it, but I do need to know which roofs will have panels on so I can get an accurate quote from the builder.
thinking of getting an EV in the next 6 months or so, how do i find out if my electricity supply is looped?
my ex-neighbour, before they moved out, says it's a loop system (1968 build)
national grid isn't so forthcoming with any enquiries. "fill in the EV form" they say, but the EV form asks if my property is looped...well IDK!
this is my supply, consumer unit top right of the pic
any ideas OCUK?
my ex-neighbour, before they moved out, says it's a loop system (1968 build)
national grid isn't so forthcoming with any enquiries. "fill in the EV form" they say, but the EV form asks if my property is looped...well IDK!
this is my supply, consumer unit top right of the pic
any ideas OCUK?
Given it’s a 63A fuse, it might be but it’s not conclusive alone.
To be 100% sure you are on a loop you’d see two thick black cables going in where the 63A fuse is. That would identify you at the first house.
However, the second property would only see one so you don’t know without looking at both of your neighbours supplies.
Your DNO will know and they’ll action it when your installer fills in the form before they install.
To be 100% sure you are on a loop you’d see two thick black cables going in where the 63A fuse is. That would identify you at the first house.
However, the second property would only see one so you don’t know without looking at both of your neighbours supplies.
Your DNO will know and they’ll action it when your installer fills in the form before they install.
so there's no way of finding out before then? (short of going to my neighbours and asking to look at their meter)
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Is there a preferred EV charger I should state on the Go application? A few years down the line I’d like to get a hybrid but currently can’t.
You don’t need an EV charger for Octopus Go.
There are two tariffs:
Go - 5 hours at 7p
Intelligent Go - 6 hours at 7p plus ‘intelligent slots’, this tariff requires a compatible car or charger.
You want to top one not the bottom one.
Basically, no. DNOs are allowing restricted charger installs on looped supplies so it’s not really an issue.
They will un-loop you and you can de-restrict the charger.
awh boo...guess i'll start looking for installers then
any recommendation as to which brand of charger is good?
octopus £999 for a myenergi zappi supply + install seems pretty decent
the only thing that worries me is if the installer knows how to integrate it with the pv system and not screw the install up (charger/PV) - or is this simple and hence a non-issue?
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It’s simple if it’s just PV, slightly more complicated if it’s PV+batteries.
PV only - it doesn’t really matter. They’ll whack a CT clamp on the main tails and the charger will see your grid export.
If you have batteries you want to make sure your charger is connected in its own CU immediately after your meter so when you put your CT clamps on your battery can’t ‘see’ the load from the charger.
yeah it's a PV+battery system, i can see the CT clamp for my PV system (with the black + white wires)
hopefully they don't balls it up
might just email spectrasolar for a quote seeing as they were the ones that did my PV+battery install
i only intend to charge overnight on cheap rates anyhow, so there won't be any battery use to charge the EV
If you go on Intelligent Go (or any other smart tariff that may come along), you will not control when the car charges. It can charge at any time which is why you don’t want your battery to be able to see the load from the charger.
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