Posted by: @jamespa

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does it (if accompanied with an instruction that it is intended to be wired in permanently eg to a fused cable outlet?

I'd argue otherwise. Clearly the intention of supplying a short fixed lead with no termination is for the consumer to fit a 3-pin plug. So much so that some manufacturers even go to lengths to state on their website that it's not currently legal to do just that.

Posted by: @old_scientist

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Posted by: @jamespa

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does it (if accompanied with an instruction that it is intended to be wired in permanently eg to a fused cable outlet?

I'd argue otherwise. Clearly the intention of supplying a short fixed lead with no termination is for the consumer to fit a 3-pin plug. So much so that some manufacturers even go to lengths to state on their website that it's not currently legal to do just that.

 

My question was, does it violate the regulations, different question altogether!  

Hopefully it will quickly become academic because desnz will do the same for plug in batteries as they have for plug in solar.

I've just spent a considerable part of my Saturday afternoon reading this thread, and benefited from it.

I am sure many find themselves in my position. I fitted solar just over three years ago when export rate was 18p Kwh and the figures said payback in 6.5 years. A battery by my calculations didn't add up.

But now export is 10p Kwh and payback time has receded into the distant future making a battery a consideration.

However quotes by MCS installers of £5-6000 just kick the payback to infinity and beyond. 🙂

It would appear that plug in solar is something, which at 70 yrs old would make payback in my lifetime a possibility.

But there is no such thing as a free lunch. 🙁

Anyway suggestions to improve my situation are welcome and I have a question regarding the UPS

Should I go to the expense of adding a battery I might as well add one with UPS, which Indevolt does.

I am however uncertain of how it works.

If I decide I want my PC, router,TV and ONT to remain on during a power cut, do I plug them it to the UPS socket  and run from it continually and then when/if the grid goes off ups still powers me? This is the only way I can see it working.

But I'm wondering where the 20ms switch over comes in.

Is the UPS socket just a mains pass through which switches to battery when the grid goes off?

I think it must be.

One last question, what is the output rating of the UPS? 

PS

Thanks for the wonderful forum, so much information.

Posted by: @blizzardgreen

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It would appear that plug in solar is something, which at 70 yrs old would make payback in my lifetime a possibility.

As you already have a (rooftop?) solar system, it's less likely that you'll benefit much by adding a plug-in solar kit with a maximum output of 800W.

You are quite right to be investigating battery storage, however. Just remember that it's unwise to base any financial payback calculation on current tariffs. They can quickly change, or disappear altogether, due to government policy, wars or regulatory reform.

There are a number of differing interpretations of battery storage products which offer a socket that provides power during an outage. Simply calling a socket 'UPS' doesn't necessarily mean that it operates in the same way as the sort of UPS which you might buy for a PC and its monitor.

Equally, a socket labelled 'maintained' might actually operate as a UPS.

There is no agreed standard for naming or the functionality which they offer.

I've just quickly read the Indevolt online descriptions for their Powerflex range.

The UPS socket operates as a mains pass-though which can deliver 3.6kW (16A) to whatever loads are plugged into it.

When there is a power-cut, the power available from the UPS socket depends on how many add-on battery modules you've got connected. With no add-on modules the UPS output is limited to 1kW. You'll need to check if that's adequate to keep your PC, monitor, TV etc all 'live'.

A 20mS switch-over time is very good. It's equivalent to saying "it switches over within one mains cycle".

More important is what happens when the mains power comes back on. It is often the case that it contains spikes and voltage-sags rather than simply providing a clean 240v at 50Hz. I can't find the Indevolt specification for switchover-on-restore, but I'd like to hope there's a delay of several seconds. You don't want to present your PC with iffy voltages when the UPS socket reverts to pass-through mode.

Posted by: @blizzardgreen

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But now export is 10p Kwh and payback time has receded into the distant future making a battery a consideration.

However quotes by MCS installers of £5-6000 just kick the payback to infinity and beyond. 🙂

Whilst I export my excess solar at 12p/hr I have come to exactly the same conclusion re batteries.  These gyus will have to drop their prices to remain competitive once plug in is available in Lidl!.  I expect that's why they have been inventing 'safety issues' with plug in!   

Plug in will pay back for me even with the cap of 800W output to my house and I intend to buy as soon as they are fully legal (or maybe before so long as its not me that is doing something illegal!).  I have a ToU tarrif and an ASHP which means its at least as useful in winter as it is in summer.

Posted by: @blizzardgreen

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It would appear that plug in solar is something, which at 70 yrs old would make payback in my lifetime a possibility.

But there is no such thing as a free lunch. 🙁

Anyway suggestions to improve my situation are welcome and I have a question regarding the UPS

Should I go to the expense of adding a battery I might as well add one with UPS, which Indevolt does.

I am however uncertain of how it works.

If I decide I want my PC, router,TV and ONT to remain on during a power cut, do I plug them it to the UPS socket  and run from it continually and then when/if the grid goes off ups still powers me? This is the only way I can see it working.

 

Plug in battery isnt yet fully legal, it looks like it may be a few months behind plug in solar

As I understand it the UPS works as you describe.  What I am not sure is whether, when the grid is connected, you can draw 800W from the plug in connection simultaneously with 800/3000W from the socket on the back.  Is so this has some potential use and opens up some higher rate discharge opportunities.  One thing is sure ie that there is no feed to your house electrics when the grid is down, the feed is to a socket on the back.  

TBH Im not entirely sure what this feature is for.  Maybe as a UPS for your computer/networking equipment (but it doesnt, sofaik, support the clean shutdown protocol that proper UPS devices support), maybe for your freezer?  Its a difficult feature to place.  I am discounting it in the buy/dont buy equation because I already have a UPS for my networking equipment and the marginal value over that is, in practice,  close to negligible for me.

Posted by: @blizzardgreen

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One last question, what is the output rating of the UPS? 

I think its 800W unless you fit an expansion battery in which case its 3kW.  

Posted by: @transparent

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Posted by: @blizzardgreen

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It would appear that plug in solar is something, which at 70 yrs old would make payback in my lifetime a possibility.

As you already have a (rooftop?) solar system, it's less likely that you'll benefit much by adding a plug-in solar kit with a maximum output of 800W.

 

 

My total consumption is around 8Kwh per day, On average summer days my panels produce <> 16 so say 10 is given to the grid and 2 or 3  purchased overnight.

That's pretty good, I'm a few pence up but if I had a 5 or 6 Kwh battery I wouldn't have to buy any overnight and as the days shorten it should get to a point where my excess carries me through till the sun comes up again.

My quick back of a fag packet calculations says for seven months I wouldn't spend a penny.

For  the remaining five I'd need to buy  a total of 482 units. about £150.

and for the occasional summer day when the panels produce 26 or more I can flog the surplus to the grid for the princely sum of 10p 

Posted by: @transparent

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Posted by: @blizzardgreen

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It would appear that plug in solar is something, which at 70 yrs old would make payback in my lifetime a possibility.

 

 

You are quite right to be investigating battery storage, however. Just remember that it's unwise to base any financial payback calculation on current tariffs. They can quickly change, or disappear altogether, due to government policy, wars or regulatory reform.

 

Posted by: @jamespa

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Posted by: @blizzardgreen

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But now export is 10p Kwh and payback time has receded into the distant future making a battery a consideration.

However quotes by MCS installers of £5-6000 just kick the payback to infinity and beyond. 🙂

Whilst I export my excess solar at 12p/hr I have come to exactly the same conclusion re batteries.  These gyus will have to drop their prices to remain competitive once plug in is available in Lidl!.  I expect that's why they have been inventing 'safety issues' with plug in!   

Plug in will pay back for me even with the cap of 800W output to my house and I intend to buy as soon as they are fully legal (or maybe before so long as its not me that is doing something illegal!).  I have a ToU tarrif and an ASHP which means its at least as useful in winter as it is in summer.

Posted by: @blizzardgreen

↑

It would appear that plug in solar is something, which at 70 yrs old would make payback in my lifetime a possibility.

But there is no such thing as a free lunch. 🙁

Anyway suggestions to improve my situation are welcome and I have a question regarding the UPS

Should I go to the expense of adding a battery I might as well add one with UPS, which Indevolt does.

I am however uncertain of how it works.

If I decide I want my PC, router,TV and ONT to remain on during a power cut, do I plug them it to the UPS socket  and run from it continually and then when/if the grid goes off ups still powers me? This is the only way I can see it working.

 

Plug in battery isnt yet fully legal, it looks like it may be a few months behind plug in solar

As I understand it the UPS works as you describe.  What I am not sure is whether, when the grid is connected, you can draw 800W from the plug in connection simultaneously with 800/3000W from the socket on the back.  Is so this has some potential use and opens up some higher rate discharge opportunities.  One thing is sure ie that there is no feed to your house electrics when the grid is down, the feed is to a socket on the back.  

TBH Im not entirely sure what this feature is for.  Maybe as a UPS for your computer/networking equipment (but it doesnt, sofaik, support the clean shutdown protocol that proper UPS devices support), maybe for your freezer?  Its a difficult feature to place.  I am discounting it in the buy/dont buy equation because I already have a UPS for my networking equipment and the marginal value over that is, in practice,  close to negligible for me.

Posted by: @blizzardgreen

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One last question, what is the output rating of the UPS? 

I think its 800W unless you fit an expansion battery in which case its 3kW.  

 

 

 

I would be buying it to grab the excess solar, and taking the UPS as a bonus.

Having now read the consultation response I note that plug in solar will be limited to one per circuit not one per household.  That introduces additional possibilities, particularly if the concept is eventually carried over also to plug in batteries.  With 2*800W (and assuming the one per circuit limit is eventually carried over to batteries) I can run my ashp plus my base load other than in the very coldest weather.  This is getting better and better. 

Move over MCS guys, your monopoly days in solar and batteries are coming to an end.  

Posted by: @transparent

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A 20mS switch-over time is very good. It's equivalent to saying "it switches over within one mains cycle".

More important is what happens when the mains power comes back on. It is often the case that it contains spikes and voltage-sags rather than simply providing a clean 240v at 50Hz. I can't find the Indevolt specification for switchover-on-restore, but I'd like to hope there's a delay of several seconds. You don't want to present your PC with iffy voltages when the UPS socket reverts to pass-through mode.

Convention in the industry is that 20ms is not a UPS it's an EPS no more. That is because the ATX standard that defines home computer power supplies only requires they survive a 10ms drop. Anything doing switchover is also useless in the case of things like spikes caused by things like nearby lightning strikes. You need an actual double conversion system for that.

20ms is "did that light flicker" but it's not enough to stop some wifi routers rebooting and sometimes PCs rebooting or worse still silently corrupting stuff. Obviously if you have a laptop that's a non problem 8). It's really a question of what you are trying to do - 20ms is fine for most stuff other than PCs and the efficiency cost of a double conversion system is not usually something you want to pay on loads of devices that don't need it.

The MCS solar/battery game is coming to an end anyway. The existing regulations say MCS or an electrician trained in solar who is a member of an equivalent professional body - which is anyone who can sign stuff off. At the moment the "trained in solar" bit is the problem but the professional bodies are requiring that people doing solar, EV chargers and some other bits are now trained specifically in that area so the issue with many electricians not being solar trained is going to change to "if they can do solar then their sign off should qualify you for SEG"

For plug in it's also interesting as the third option for SEG payments is at the energy company discretion but requires the energy company ensure the installation is safe - hence the Octopus scheme. If parliament declares that plug in solar is safe, then plug in solar is safe, which means suppliers would be able to offer SEG on plug in systems.

The 800W limit and multiple devices on different rings is btw a lot better than I think many people realize. Some other countries allow this and there are existing systems that are not just smart enough to export or fill loads over 800W total but are smart enough to do things like spot one battery is way down and predictively charge one battery from the other by back feeding 800W between them and taking an upfront efficiency hit to cover the expected load pattern, and to balance them when AC charging.

Posted by: @jamespa

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Having now read the consultation response I note that plug in solar will be limited to one per circuit not one per household.  That introduces additional possibilities, particularly if the concept is eventually carried over also to plug in batteries. 

We already do this - non grid tie self installed panels plugged into self installed battery/inverter stacks running the main air/air heatpumps. All directly connected, no house wiring except the battery charging side for winter. Doesn't count on our G99 (which is why we did it originally).