Solar panels and battery - any real world reccomendations?

[sanaxe1]

@HungryHippos and I had a split we used as typical UK. I cant remember where we got it from.
I scaled it to 3900kwh hours as thats my expected generation. Monthly split for that 3900 as per below. Should give you an idea.
This is 5.4kwh of panels with 5% allowed for shading.

Jan-23​	117.5​
Feb	175.7​
Mar	343​
Apr	429.3​
May	467.8​
Jun	526​
Jul	545.7​
Aug	448​
Sep	351.3​
Oct	233.9​
Nov	164.2​
Dec	97.7​

Thanks. My Work is fitting me a UPS at my home for free ( incase of power cuts) Its a 3000w hybrid invertor with 4.8kwh batteries. The system can take Solar but only upto 1200w input. I've seen i could buy 6 x 230w 3 year old panels for £400 total . So im trying to work it out if its worth installing such a small solar system. The fitting will be free by my mate but ill need to buy all the rails etc.

 

[Mercenary Keyboard Warrior]

Gone for the backup power option as well
Er indoors said it was worth it, who am I to object

 

[Mercenary Keyboard Warrior]

Thanks. My Work is fitting me a UPS at my home for free ( incase of power cuts) Its a 3000w hybrid invertor with 4.8kwh batteries. The system can take Solar but only upto 1200w input. I've seen i could buy 6 x 230w 3 year old panels for £400 total . So im trying to work it out if its worth installing such a small solar system. The fitting will be free by my mate but ill need to buy all the rails etc.

For not that much more you could get 6x 400w or so.
If your going to that level it seems more logical to me.
Assuming your talking roof mounted

 

[b0rn2sk8]

I wouldn’t bother. How often do you actually get power cuts?

I think I’ve had 1 in the 3 years of living in Suffolk and non when I lived in Norfolk for 5 years.

 

[Mercenary Keyboard Warrior]

I wouldn’t bother. How often do you actually get power cuts?

I think I’ve had 1 in the 3 years of living in Suffolk and non when I lived in Norfolk for 5 years.

Its a balance right

I think we have had a couple over last 5 years, but we had one about 1-2 months ago and it was frankly darn annoying due to the timing.
Happened about 5:45pm and came back on around 6:15pm
The annoying thing more than anything is not knowing how long it will be
Do we throw out the dinner that has just got to tepid temp and go grab a takeaway or hold out and wait (initial estimates were 2 hours to reconnect)

As they grid allegedly gets closer to having issues the benefit seems to be more likely to happen.

Its just over £1 a week over 10 years so went with it in the end.

 

[Tavis75]

Yes, I went for EPS, not full islanding, but will run all my sockets. Powercuts are rare but annoying when they happen and of course, there is talk of these 3 hour rolling blackouts this winter, so looking forward to being able to avoid those if they happen! Was only £200 in my case though, so definitely seemed worth it at that price. Of course, the only issue is that if it's an unexpected powercut then no guarantee that the battery will be at a decent level, unless you run it with a permanent safety buffer.

 

[Ron-ski]

Its not just power cuts, we occasionally get the odd dip in power, and that's enough to reset clocks, and computers may go off, except my server which is on a UPS.

 

[Mercenary Keyboard Warrior]

Yes, I went for EPS, not full islanding, but will run all my sockets. Powercuts are rare but annoying when they happen and of course, there is talk of these 3 hour rolling blackouts this winter, so looking forward to being able to avoid those if they happen! Was only £200 in my case though, so definitely seemed worth it at that price. Of course, the only issue is that if it's an unexpected powercut then no guarantee that the battery will be at a decent level, unless you run it with a permanent safety buffer.

Yes indeed if your using all your battery power then you could get to the point its virtually flat before a cut.
However the window for that being an issue for me would be pretty small so probably wouldnt be holding back for this purpose.
Unless it had been kind of predicted, such as rolling blackouts

Its not just power cuts, we occasionally get the odd dip in power, and that's enough to reset clocks, and computers may go off, except my server which is on a UPS.

I wonder how good they are in this circumstance, do they kick in quickly enough to avoid any dip like that.

 

[Journey]

I wonder how good they are in this circumstance, do they kick in quickly enough to avoid any dip like that.

In the system Ron-ski is building, the inverter when setup correctly means everything goes through the actual inverter and the cut over time is in the low few milliseconds so it would be seamless, some other systems do actual require quite a bit longer than that, and even a manual intervention with certain setups.

 

[Mercenary Keyboard Warrior]

In the system Ron-ski is building, the inverter when setup correctly means everything goes through the actual inverter and the cut over time is in the low few milliseconds so it would be seamless, some other systems do actual require quite a bit longer than that, and even a manual intervention with certain setups.

Thanks yeah that was my recollection there is a potential for a very brief outage.

I will see if I can find anything in the specs.

I know I have had a few dips in the past where some things didn't like it, you heard them reset and others carried on as if nothing happened
PC stayed on for example, I guess the PSU smoothing managed to cope with the issue where as BT box reset itself

 

[Ron-ski]

I wonder how good they are in this circumstance, do they kick in quickly enough to avoid any dip like that.

As @Journey said above, Victron states the following for the Quattro.

The main output has no-break functionality. In the event of a grid failure, or shore or generator power being disconnected, the Quattro takes over the supply to the connected loads. This happens so fast (less than 20 milliseconds) that computers and other electronic equipment will continue to operate without disruption.

 

[Mercenary Keyboard Warrior]

Thanks guys, cant find anything specific in the details for the one I am getting

 

[Freefaller]

Its not just power cuts, we occasionally get the odd dip in power, and that's enough to reset clocks, and computers may go off, except my server which is on a UPS.

I have a few UPSes dotted around the house but that would help avoid that. However all the critical stuff has a UPS I can live with a few brown outs. We've had 4 power cuts over the last 7 years none lasting more than 3 hours.

However it is a cool feature to have if you can have it.

 

[Dunk05]

The installer is reluctant to apply to the DNO for a G99? It's the kind of installer I'd avoid if they can't be bothered to do an hours work, and e-mail a form to the DNO. These half baked installs that are supposed to last 20+ years, but if/when running an almost full electric household simply won't be suitable for the most part.

Anyhow, you'll be fine with the Growatt's x3 that are in parallel as they can each charge at a maximum rate of ~1.6kW, so a total of almost 5kW which is more than the 3.68kW inverter could delivery anyhow. I would really push for the 5kW inverter so you can run more amps outwards, for when you have heavy demand, which is easy to hit for short periods of times.

I want to give them the benefit of the doubt, keep it simple / G99 may add 3 months to the wait time, they can't order the bigger inverter without it / there's a 6 week lead time on even the SPH36000 but..

I got in touch with groWatt support and they confirm what you said and the ML33rta's charge / discharge increases with additional batteries to the limit of the inverter. The installer said they don't, another red flag

 

[reef]

Just booked in ours. We've gone for a 4.8Kw array (12 x 400w panels) + 7.5Kw Battery. It came in at about £11.8k including scaffolding with bird protection, which we'll definitely need! Roof is SE facing so gets the sun from 5am until close to 4pm in June.

We're quite heavy users (5000-5500kwh/year) and run air con in the summer (up to 17-20kw per day) so our electricity bill alone is now around £2000 a year. Hopefully it'll make a big difference.

Wait time appears to be 6-8 weeks, though I'm expecting more like 12-16 weeks judging by how it is at the moment. When getting quotes, figures and lead times were all over the place - as high as £15k in some cases! Couldn't get below £11k. I guess it's a sign of the times when there's a risk of prices going up massively again in April.

 

[SoliD]

Contemplating adding some panels to my garage roof next year when/if prices return to some sort of normality, it's a double 5.5*5.5m or so, could probably get a fair few panels on there, it's connected up, but I wouldn't be able to run anything back from the garage to the house as the driveway recently all redone and won't be being dug up! I would be happy to do it myself, but wondering what self install kit anyone has used or I could potentially look at. Would probably go for E/W facing to generate some in the morning/evening to balance off against my South facing roof.

 

[Mercenary Keyboard Warrior]

My installer has come back to say the switchover time is 10 seconds on grid outage with Solax

I wasn't expecting Victron speed switching but seems a little slow.
Still I guess its auto so at least the things like fridge etc will be fine, just things like cooker etc that don't like being switched off (have to reset clock) will need to be coxed back into life

 

[Journey]

Contemplating adding some panels to my garage roof next year when/if prices return to some sort of normality, it's a double 5.5*5.5m or so, could probably get a fair few panels on there, it's connected up, but I wouldn't be able to run anything back from the garage to the house as the driveway recently all redone and won't be being dug up! I would be happy to do it myself, but wondering what self install kit anyone has used or I could potentially look at. Would probably go for E/W facing to generate some in the morning/evening to balance off against my South facing roof.

You don't really need a kit, you can just buy what fits your needs best.

Are you saying you have 5.5m both high and wide, on two faces? So a total of 60.5m2? If so that is a lot of panels/generation potential, and you could use some of the larger panels that work out slightly less £/pW, e.g. the 600w Canadian solar that are 2.17m x 1.3m, that would allow 8 panels in portrait (per side) assuming your measurements are correct, so 9.6kWp if you have two sides, the panels in question are about £260 inc VAT.

 

[Freefaller]

Just booked in ours. We've gone for a 4.8Kw array (12 x 400w panels) + 7.5Kw Battery. It came in at about £11.8k including scaffolding with bird protection, which we'll definitely need! Roof is SE facing so gets the sun from 5am until close to 4pm in June.

We're quite heavy users (5000-5500kwh/year) and run air con in the summer (up to 17-20kw per day) so our electricity bill alone is now around £2000 a year. Hopefully it'll make a big difference.

Wait time appears to be 6-8 weeks, though I'm expecting more like 12-16 weeks judging by how it is at the moment. When getting quotes, figures and lead times were all over the place - as high as £15k in some cases! Couldn't get below £11k. I guess it's a sign of the times when there's a risk of prices going up massively again in April.

£12k is actually really good. I can imagine you despite a/c easily saving £500 a year. We're heavy users too as our appliances are quite old, don't have ac as we're a lizard family that enjoy hot weather but if you time it sensibly I reckon you may be are to run your AC for "free" on good solar days. It's just at night that will drain the batteries.

 

[b0rn2sk8]

One of the goals I have for the system I am looking to have installed is for the inverter and battery storage combo that can automatically charge from off peak electricity when it’s sensible to do so. For example, projected low solar production days or an agile tariff. I’d want 9/10kwh of storage.

I’m happy for that to be offloaded to home assistant or something similar if needed, as long as I don’t need to sit there and do it on the daily or go and physically program an inverter that will end up in the loft.

One option is the Tesla power wall but I have pretty much discounted it due to lead times.

Are there any other systems I should be looking out for/requesting when I am getting quotes from installers?