Plug in solar, really, is it safe, and what stops anyone doing it, legal or not?

[ericmark]

The intelligent control needs one to give access to the supply company, some solar, and some EV systems can allow the supplier to control when batteries charge and discharge. The Go and Flex Octopus tariffs both have an intelligent and a non-intelligent version, and clearly with the intelligent version you must have a battery which they can control.

I think my son has the intelligent version, and his off-peak rate is lower than mine, and if there is spare energy, his car may be charged at the low rate during the day.

The problem with the non-intelligent Flex is ensuring one does not use grid power 4 pm to 7 pm, I am sure one could manually charge one's batteries before 4 pm and discharge them so they just last until 7 pm, gaining the 30.68p/kWh export rate 4 pm to 7 pm, but 28.5p to 30.68p is not really enough difference to be sure the 2p gain is not lost in the charging and discharging of batteries.

And the 17.1p/kWh is higher than the 10.54p/kWh, so one needs to be careful not to charge the batteries more than required. If the off-peak is the same or less as the payment for export rate, as it is with Go, then one can fully charge the battery with off-peak, and not lose out if the battery is not fully depleted when the sun comes out.

So with Go I do not need to regulate how much the battery charges. With Flex I do. So Flex is not really any good unless using the intelligent system. I could try flitting between Flex in summer and Go in winter, but I want an easy life, and if I had an EV not sure I want to use the EV battery to power the house or the grid? The whole idea of the EV is you leave the home with a full battery, so never need to use a filling station during normal motoring, only when for example you are on holiday do you need to use EV charging points.

This is what I look at the dip in state of charge at its lowest point at 9 am I still had 82% of my battery left, not a problem with Go, but with Flex would want that to be down to around 20%.

 

[Munroast]

The problem with the non-intelligent Flex is ensuring one does not use grid power 4 pm to 7 pm, I am sure one could manually charge one's batteries before 4 pm and discharge them so they just last until 7 pm, gaining the 30.68p/kWh export rate 4 pm to 7 pm, but 28.5p to 30.68p is not really enough difference to be sure the 2p gain is not lost in the charging and discharging of batteries.

the losses around charging and discharging batteries is way higher than you are accounting for
at best your inverter is only going to be 90% efficient - so each time the electric passes through you loose 10%, so when charging frm the grid that is a 10% loss going into the battery then another 10% loss coming out of the battery - then on top of all that there will be the 5% loss within the lithium battery

so 1kwh going in x 0.9 x 0.95 x 0.9 = 770wh coming out

so if you are paying 28.5p per unit then the cost after the losses will be 37p per kWh
(and that is before we get to the wear and tear of the battery that would add around another 3½p , making it 40p per unit)

 

[morqthana]

It's almost as if the system's designed to give people a way to genuinely lower their grid consumption when they can, and contribute to the grid when they can, rather than it being made easy for people to game it and have schedules which are about nothing except maximising their income.

 

[ericmark]

Today actually charging an EV, only a granny charger, and also turned off power to get power to my shed, but clearly if one has an EV one needs more solar panels, and a larger battery.

32 kWh when we normally use 10 to 12 kWh. And this was a granny charger.

 

[ericmark]

the losses around charging and discharging batteries is way higher than you are accounting for

Maybe, but small losses are acceptable, but with large losses, one would want to limit how much the battery is changed with off-peak, and the software is not really designed to do that.

I noted at first, with zero payment for export, that increasing battery size was making it worse not better, and unless using solar prediction, one is looking at average through the year, I don't want to be adjusting how it works day to day, it is set up and forget it.

Be it May or December, the setting are the same, but May 900 kWh and December 100 kWh and my use is 350–450 kWh per month, use a bit more in winter, so winter the off-peak is important, summer not really needed.