Yes. Both of the above are true....

... albeit without any of the technical explanation which supports those statements!

Personally, I still think NESO should be engaging in a nationwide public information campaign.
All the initiatives by DESNZ to promote plug-in solar, EVs, domestic battery storage and heat-pumps are suffering for the same reasons – insufficient knowledge of energy matters.

Keeping the electrical circuitry complexities aside, I wonder whether such small battery storage systems can be used in niche usecases. For example, when you run the dehumidifier to dry clothes indoors, and that consumed about 1 to 1.5 kWh a day. If you can keep one such battery in the utility room, charge from off-peak and later run the dehumidifier on an off-grid mode using the AC sockets in the battery. Also, you can plugin and use your iron in an off-grid mode. Basically, if you can shift 1.5 kWh of daily usage from October to March to off-peak, probably there are savings to be made and can recover the initial cost in about 5 years. Given the 6000 cycles most such batteries seem to last, you can save for many years to come. If you can plugin your solar panels and then use the battery in off-grid mode for such usecases, even better 

@transparent 

Posted by: @transparent

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Yes. Both of the above are true....

... albeit without any of the technical explanation which supports those statements!

Thank you.  I am grateful for the detailed technical explanation however I personally find it easier if I first understand in summary what I am trying to understand, before trying to understand the detail (ie I prefer 'top down').  

The thing I find most concerning TBH is not the effect of plug in solar, its that apparently a situation can occur where the test button on an RCBO doesn't reveal a fault with the RCBO.  For me that is a test button that is not fit for purpose!  That said I doubt many ever use these buttons!

The IET seem relatively relaxed about it if you read the briefing here, recognising the risk (which may occur with any generator installed prior to 2024, not just plug in) but urging a proportional response and pointing out that the fault, if it occurs, results in an installation which is no less safe than an installation to 17th ed regs, which of course many will still be.  

As a matter of interest I checked my own solar installation, done in 2011.  It is protected by its own RCBO independently of the protection for the ring main.  I don't know whether its a bidirectional RCBO or not, nor which way round it has been wired if its unidirectional.  It occurs to me that, if I were to interpose a 13A socket between the generation meter and the CU, I could plug in a compliant plug in battery with negligible additional risk.  Thats beginning to look tempting given the business-case busting prices for 'professional' installation. 

Posted by: @transparent

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personally, I still think NESO should be engaging in a nationwide public information campaign.
All the initiatives by DESNZ to promote plug-in solar, EVs, domestic battery storage and heat-pumps are suffering for the same reasons – insufficient knowledge of energy matters.

Having spent several mornings on a stand on our high street promoting energy efficiency, I know how difficult (frankly its nigh on impossible) it is to engage people in these matters.  The vast majority simply aren't interested, and a fair proportion of those who might be interested are prevented from action by their landlords.  The promise of cost savings really doesn't seem to cut it (cost of living crisis - what crisis?), and as soon as you go into any detail they have more pressing things to do. 

Frankly I think people are much more likely to respond top a pile of cheap solar panels at the checkout, alongside the sweets (or the online equivalent), than they are to a publicity campaign!  This is another plus for plug in, its a feasible impulse purchase, which people love.

This discussion has raised along the way (at least) two more questions:

• If I have two generators (eg an AC coupled solar inverter plus a battery inverter) how do they avoid fooling each other into thinking the grid is connected even though it isn't?
• @editor says above that the Indevolt will operate in Island mode when connected to the house distribution network.  I cant see how that is compatible with the disconnection requirement

@transparent do you know when bidirectional RCBOs we’re introduced in the UK?

@chandykris the flexibility of plug-in batteries is really interesting. For starters it’s very portable. Each stack weighs around 10kg, so you don’t want to be moving it all the time, but you can move it around the house with relative ease.

Apart from the technical complexities, what you’ve described is bang on. You can charge from excess solar, and this unit from Indevolt has a three pin socket on it, so you can plug appliances straight into it and draw directly from it.

Later this year, Indevolt are also dropping a smart plug that will communicate directly with the battery so you can create ‘smart’ tasks along the lines of what you’ve just described without lugging the unit around. 

@editor That's good to know about the 10kg weight. At that weight, you could easily move this around and even use this as a backup power option for the home. If you haven't set up backup power for the whole/part of the home from the fixed batteries. I guess, for people who WFH, you could just plug the router into the AC sockets of the plugin battery and continue working in case of a power cut. Or plugin the router and a TV in the evening for entertainment. If the price is right, my girls might get an odd request of a plugin battery as my birthday present!!

Posted by: @chandykris

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If the price is right, my girls might get an odd request of a plugin battery as my birthday present!!

Terrific idea. I'll also see if I can convince Indevolt to give us some discount codes for RHH members.

Posted by: @editor

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do you know when bidirectional RCBOs we’re introduced in the UK?

i don't know. But Proteus was manufacturing them in the UK before the IET amendment to make them compulsory for circuits supplying generation devices.

They were still busy changing the silk-screen labelling when I spoke with them about 8 months before the IET notification.

Posted by: @editor

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Later this year, Indevolt are also dropping a smart plug that will communicate directly with the battery so you can create ‘smart’ tasks along the lines of what you’ve just described without lugging the unit around. 

How is that connecting? WiFi?

is there an RS485 port to allow 3rd party controllers to give commands?

@transparent not sure... it was a quick passing comment, but I doubt the smart plugs will have RS485 ports. Probably WiFi only.

Posted by: @transparent

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Posted by: @editor

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Later this year, Indevolt are also dropping a smart plug that will communicate directly with the battery so you can create ‘smart’ tasks along the lines of what you’ve just described without lugging the unit around. 

How is that connecting? WiFi?

is there an RS485 port to allow 3rd party controllers to give commands?

I guess my reason for asking is that if you've had a CU fitted in the past x-years, the likelihood of you having a bidirectional RCBO is slim. 

Posted by: @editor

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Posted by: @transparent

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Posted by: @editor

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Later this year, Indevolt are also dropping a smart plug that will communicate directly with the battery so you can create ‘smart’ tasks along the lines of what you’ve just described without lugging the unit around. 

How is that connecting? WiFi?

is there an RS485 port to allow 3rd party controllers to give commands?

I guess my reason for asking is that if you've had a CU fitted in the past x-years, the likelihood of you having a bidirectional RCBO is slim. 

 

Yes but you may, like me, have the PV on a separate circuit protected by its own RCBO (a 2011 install).  I dont know if the RCBO is bi directional or unidirectional and, if the latter, which way round its connected.  However if it fails the consequence will be limited to the PV circuit.