Adding an EV charger - existing PV setup

noitsnotme

Martyn1981 said:

noitsnotme said:

Reed_Richards said:

ecraig said:

It’s almost more cost effective to charge overnight where I can purchase <15p kWh, and therefore export excess solar generation at 15p.

It seems it would be more cost effective to save the money buying an Ohme (or something else) and profiteering from a better solar export rate.

> Am I thinking straight?
> What would you knowledgeable people recommend, please?

I'm not certain that there is a tariff which allows you to both purchase at <15p per kWh overnight and export at 15p per kWh.  If such a tariff exists it IS more cost effective, there's no "almost" about it.  And unless you do a lot of driving each day it may be more cost effective to just use a "granny charger" than even a cheaper wall box like an Ohme.  

Intelligent Octopus Go is 7.5p/kWh import between 23:30 and 05:30 (sometimes extra smart slots outside of that).  Pair that with Octopus Outgoing and you can export at 15p/kWh.

Many people with a qualifying EV or charger, solar and batteries do this, myself included.  My house battery is fully charged overnight, along with the EV when it’s needed.  The house battery then powers the house all day while 100% of my solar is exported at the 15p rate.  99%+ of my import is at 7.5p/kWh.

Many thanks for the info, but my brain immediately said I could export for more than I import (with a battery, as you describe), so something sounds a bit wrong. But then again, daytime rates atm are so high, that I suppose Octopus can make money buying daytime leccy (PV export) at 15p.

I checked the Octopus site, and they seem to suggest an export rate of 8p/kWh if you have OG:

Right now, you can’t be on Octopus Go together with Outgoing Fixed or Agile (the price is so good it’d be like a double discount!) Instead, we’ve created a great export option just for Octopus Go customers. On Outgoing Fixed Lite, you’ll export power at a rate of 8p / kWh.

But .... I note this refers to OG not IOG, but I get a gateway error when I try to look at the Octopus Outgoing + IOG.

Bit frustrating!

I’m getting the bad gateway error too for this page - https://octopus.energy/smart/outgoing/

 Here is the original press release - https://octopus.energy/press/sunny-money-octopus-energy-quadruples-export-rates-for-smart-tariff-customers/

“Octopus Energy’s ‘Intelligent Octopus’ customers now able to join ‘Outgoing Octopus’”

ecraig

Strange that their website is buggered.

IOG is definitely compatible with either fixed 15p export, or agile export.
Here’s a useful matrix of import and export compatibility

Martyn1981

Thanks guys, this is really interesting to me, so very helpful.

Been pondering a big battery for years (seems like decades), but with cheap night rate for BEV charging, and a decent export rate, it actually has quite an impact on what battery size might be better for me. Also improves the economics of a PV expansion, for a winter boost, since the increased summer export may have a bit more value.

Just to note, I assume that as leccy prices improve over the next few years, as Europe reduces gas demand to balance out the shortfall (loss of Russian gas), then the economics of daytime/summer PV export will change, but it all helps for now.

Solarchaser

I have a zappi, I have experience of using a few other chargers, but much more experience with the zappi.

The zappi can be set up to never use battery (most folk do that), or use battery, or take priority over charging the battery, or let the battery charge first.

It also has a lovely interface, how can you not love this:-


As you can see, I was making the most out of winter cheap rate here, and the Zappi was ramping down to 2kw as I was approaching the 24kw max import setting I'd set it to.

When I got the zappi it was not on intelligent list, but the car was, I understand it is on the intelligent list now.

Is it worth it.. dunno,  it was when I got it, and is a great bit of kit with which I can set charge times and solar or not through an app, which is nice.

However I now understand you can get a commando socket to EV plug which would save using an ev charger at all, and thats gotta be under £100 to DIY, and you can set charge times on the leaf itself, so maybe that's better.

I was unaware you could import at 7.5p and export at 15p on intelligent. 
Knowing that gives me a real quandary. 
As I now have an excessively large battery, and a large amount of solar, it could be the point in time to completely reverse my mindset, which has been until now, to import as little as possible.

Perhaps now it actually makes sense to charge fully overnight and export everything including spare battery capacity during the day.

Some thinking to be done for sure

Infact perhaps the best way to approach it is agile export between 4pm and 7pm at full chat through the batteries would be say 3 hours at 7kw, 21kwh at 30p, 365 days a year would be £2300, which is nearly double my energy bill.

Edit. From what I see the average for South Scotland between 4-7pm on agile export is 15p over the last year, so actually the normal 15p export at any time makes more sense, though you could argue that exporting between 4-7pm is more green and ethical as it tends to be when the grid is dirtiest.
So I will think again, bit perhaps directing all solar to export and additionally setting batteries to full export from 4pm would be a good balance of green, ethical and money saving.

As a rough and fairly believable guideline, my lux inverters seem to give an 88% round trip, so if I was to say store 10kwh for export, I'd say 7.5p x 10 x 1.12 = 84p
10 kwh exported at 15p =150p, so a "profit" of 66p which is £241 a year for a spare 10kwh of battery if you have it.

Could be interesting for many people with batteries @EVandPV

Exiled_Tyke

Apologies for going off topic but what do you think of Eddi? I should be getting a new cylinder soon and wondering whether Eddi is worthwhile or not? I'm guessing that with the house battery and car there won't be too much excess electricity for hot water and am probably best heating over night on Intelligent Go. OK I know that answer is 'it all depends' but a few opinions would really be appreciated. 

Screwdriva

Exiled_Tyke said:

Apologies for going off topic but what do you think of Eddi? I should be getting a new cylinder soon and wondering whether Eddi is worthwhile or not? I'm guessing that with the house battery and car there won't be too much excess electricity for hot water and am probably best heating over night on Intelligent Go. OK I know that answer is 'it all depends' but a few opinions would really be appreciated. 

It's a great diverter! But unless you're on a FIT tariff, makes zero economic sense even at the cheapest import rates these days. 

If your home can accommodate it, a Mixergy iHP makes so much sense as a replacement hot water cylinder. 

Reed_Richards

So do the Octopus tariffs work so that you can't export and get money for it during the hours when importing is cheaper than exporting?  I'm currently on deemed export and my smart meter measures total export but it doesn't report by the half hour; I don't think it reports export at all.

Solarchaser

Exiled_Tyke said:

Apologies for going off topic but what do you think of Eddi? I should be getting a new cylinder soon and wondering whether Eddi is worthwhile or not? I'm guessing that with the house battery and car there won't be too much excess electricity for hot water and am probably best heating over night on Intelligent Go. OK I know that answer is 'it all depends' but a few opinions would really be appreciated. 

I'm very happy with it.
I'd strongly recommend to get the additional module with it and to buy a couple of pt1000 temperature sensors if you do decide to get one.
The additional module also has 2 programmable relays, I use 1 to drive a destrat pump between my two tanks and one to run pid heaters on off peak.
I essentially use the eddi as the computer which controls all my hot water (bearing in mind I use the tanks for central heating too).

However screwdriva makes a good point about fit, I am on fit and export makes around £125 /year unmetered, but if I moved to metered export on the octopus 15p export, then it would make more financial sense to heat at 7.5p and export the solar for 15p.
Well, it would if I export more than 1700kwh annually, which I don't at the moment,  but am considering. 

Exiled_Tyke

Thanks again. I'm too am on FIT with deemed export and as I don't export very much it's really not worth the hassle of changing it to SEG.  But of course all the extra I get is in summer when I need hot water and no other heating. I'll have a think about this

ecraig

Well, having had a good chat with Octopus today, they seem to be significantly cheaper than the local installers I’ve had quotes from.
they seem to think they would include all the ct clamps and a Harvi since they would wire straight into the supply meter and not touch my consumer unit.
I am extremely surprised they are so much more cost effective, but on the flip side they have a longer wait time for installation.
Decisions, decisions..,