Making the jump to solar

[Black estate]

Well, we've decided to get panels and batteries installed.
Our house is south facing semi-detached in sunny Gosport.
Any advice?

 

[T1 Terry]

Don't be talked into the inverters at the back of the panels, they are heat sensitive and although sunny Scotland might not be one of those places associated with heat, the panels themselves do get hot in the full sun.

Unless you have a white or reflective roof, the double sided panels may show big combined numbers, only measure like for like on the output of the panel face the sun sees ..... if a panel with a better conversion factor, lower losses due to heat and a better output on the sun facing side, for around the same price, they are the ones to chose over and above the bigger advertised total Watts panels
Here is a UK based You Tube that talks about the different panels available at the moment, but as he says in the video, these things are changing all the time


T1 Terry

 

[Everest]

Any advice?

My 2p worth...

a) Go for the maximum number of panels you can fit (obv. limited a bit being a semi)

b) Do an energy audit prior to specifying your system. Specifically what is maximum power draw (in kW) and worst case daily energy usage (kWh) in order to size a) the inverter's output power and b) battery capacity needed to power your house totally from cheap overnight electricity in the depths of winter on a rainy day.

c) Add 20% to the number you calculated in (b).

 

[GaryMG4]

Have a look at @Rolfe thread about circular reasoning for some of the trials and tribulations.

 

[Bam Bam]

Well, we've decided to get panels and batteries installed.

Very good idea!

Our house is south facing semi-detached in sunny Gosport.

South Coast - best place in the country for solar!

Any advice?

Get three or four quotes, as with most things.

At least one from heatable. They offer some 0% finance deals, but selectively.

Octopus could be worth a shout and you can find one or two local MCS approved providers.

Fill up your roof, as @Everest says.

As you've got 2x EV you can't really have too much. If companies drop their export payments you can just dump it in the cars for free driving.

Get the bird protection.

Your decisions are:

• String (probably cheaper) vs. micro-inverters (better if you've got roof that faces in lots of directions or has shading, seems that T1 Terry isn't a fan)
• DC-coupled battery (better for efficiency, but tend to be lower output which might not cover your load if you have lots of things running at the same time) vs. AC battery (less efficient, more expensive, better for backup power)
• How much battery capacity? Over 9kwh is recommended, but 5 is a lot better than nothing. It is usually easier to add on more battery than panels, given the scaffolding need so if you've got a budget fill up the roof first and then spend the rest on batteries.

Will you be getting a heat pump? (We all need to at some point). Bear in mind this will greatly increase your winter power usage, so you'll want more solar and battery for then.

 

[Black estate]

Very good idea!


South Coast - best place in the country for solar!


Get three or four quotes, as with most things.

At least one from heatable. They offer some 0% finance deals, but selectively.

Octopus could be worth a shout and you can find one or two local MCS approved providers.

Fill up your roof, as @Everest says.

As you've got 2x EV you can't really have too much. If companies drop their export payments you can just dump it in the cars for free driving.

Get the bird protection.

Your decisions are:

• String (probably cheaper) vs. micro-inverters (better if you've got roof that faces in lots of directions or has shading, seems that T1 Terry isn't a fan)
• DC-coupled battery (better for efficiency, but tend to be lower output which might not cover your load if you have lots of things running at the same time) vs. AC battery (less efficient, more expensive, better for backup power)
• How much battery capacity? Over 9kwh is recommended, but 5 is a lot better than nothing. It is usually easier to add on more battery than panels, given the scaffolding need so if you've got a budget fill up the roof first and then spend the rest on batteries.

Will you be getting a heat pump? (We all need to at some point). Bear in mind this will greatly increase your winter power usage, so you'll want more solar and battery for then.

I'm with and getting quote from them
Heat pump no as my house is 97 years old with suspended floors
And we got a new boiler last year

 

[Everest]

• String (probably cheaper) vs. micro-inverters (better if you've got roof that faces in lots of directions or has shading, seems that T1 Terry isn't a fan)

Me neither, unless there are mitigating factors. Cost of adding battery capacity becomes much more expensive with micro-inverters and you have no capability in the case of power outage.

• DC-coupled battery (better for efficiency, but tend to be lower output which might not cover your load if you have lots of things running at the same time) vs. AC battery (less efficient, more expensive, better for backup power)

a) Note to self... must book in with spec-savers Not sure why you say DC-coupled (i.e. hybrid) tend to be lower power? Do you have some examples of that?

Further thought... probably best to avoid Givenergy-based system after @Bam Bam's recent experience.

 

[Bam Bam]

Me neither, unless there are mitigating factors. Cost of adding battery capacity becomes much more expensive with micro-inverters and you have no capability in the case of power outage.

Those with micro-inverters would just go with a separate AC-coupled battery, though, right?

a) Note to self... must book in with spec-savers Not sure why you say DC-coupled (i.e. hybrid) tend to be lower power? Do you have some examples of that?

Maybe I'm out of touch on that one.

For Givenergy the AC coupled option offers a higher discharge rate than our hybrid does. We've got a 5kw inverter but you only get that output when the sun is shining. The battery on its own only offers 4kw.

Other companies might offer hybrid systems with better outputs. I suppose it depends how it is set up.

Further thought... probably best to avoid Givenergy-based system after @Bam Bam's recent experience.

Probably for the best, sadly!

Equipment is good but the company are in complete disarray and now planning to charge for cloud services they promised would be 'free forever.'

 

[Bam Bam]

I'm with and getting quote from them
Heat pump no as my house is 97 years old with suspended floors
And we got a new boiler last year

A heat pump is going to work in any house, though it will have to work harder (ie you'll need a bigger one) to recapture the heat that a poorly insulated house is losing.

Fair enough if you've got a new boiler, though. You want to get something out of that investment. Norway should keep supplying us with gas for the foreseeable future, until they too run out.

 

[Everest]

Those with micro-inverters would just go with a separate AC-coupled battery, though, right?

Yes, but won't offer the same capabilities and works out more expensive. If there is a power cut, the batteries won't get charged because the micro-inverters will drop out due to no AC grid.

Maybe I'm out of touch on that one.

For Givenergy the AC coupled option offers a higher discharge rate than our hybrid does. We've got a 5kw inverter but you only get that output when the sun is shining. The battery on its own only offers 4kw.

Other companies might offer hybrid systems with better outputs. I suppose it depends how it is set up.

I see. There are many hybrid inverters with greater power output though. e.g. Solis, Sunsync etc.

 

[Bam Bam]

Yes, but won't offer the same capabilities and works out more expensive. If there is a power cut, the batteries won't get charged because the micro-inverters will drop out due to no AC grid.

Wouldn't the backup system create a local AC microgrid?

I don't have experience to know but I assumed this would the the thinking.

 

[Everest]

Wouldn't the backup system create a local AC microgrid?

The AC coupled storage inverter may have an AC backup, but it would not be connected to the AC-grid connection that the micro-inverters are connected to.

Even with suitable switch-over circuitry, you wouldn't be able to trick the micro-inverters into using a backup grid for the reasons I detailed in this recent posting...

However, IMHO, you should never connect a generating supply to an inverter's backup output.

Inverters will constantly attempt to push the phase by injecting a small frequency shift to the supply to detect if they are still connected to the utility grid. As that is not possible to increase the frequency of the national grid, they know they are still connected. If connected to a locally generated back-up source they may or may not be able to adjust the frequency. If they can't adjust the frequency of the Powerwall, they may be tricked into believing there is a local grid island.

BUT... grid-tied inverters are designed to run wide open at all times - without any control, or somewhere to send the power (the grid, usually - possibly the batteries in the PW until they are near full), they would just damage anything connected to it. Once the grid-tied inverter pushes current to a limited source that cannot take it the really bad day begins

ETA: Caveat: An Enphase-based micro-inverter system does have an ability to charge Enphase battery system during power-outage, with but only with proprietary control systems - but those are ££££ and you get tied in to a proprietary system. It can't be done AFAIAA with 3rd party AC-coupled storage systems.

 

[Bam Bam]

I hope all these debates aren't putting you off, @Black estate. There are a few scammers still out there but mostly the installers will come up with a sensible design for you.

If there are big differences then it might be for the reasons that we've discussed above.

Like with other things, you often get what you pay for, but sometimes you might be paying a lot more for something that is only very slightly better so it might not be worth going for the much more expensive 'Rolls Royce' bells and whistle option.

If you want to explore more then there is a You Tube channel and website Gary Does Solar where he reviews different types of system.

Let us know how you get on with it!

 

[JohnV6]

Yes good luck. I have pv solar, batteries & an EV . A winning combo at the moment.

 

[Gadget Geek]

Urban pidgeons are now taking advantage of new nesting opportunities . . . under PV panels. Their guano is corrosive and can affect the connectors (as I found out to my cost).

Insist on chicken wire around the panels.

 

[JohnV6]

Fully agree I had to retrofit it to mine.