EV charging using Solar with Zappi - is it worth it?

sellitnsoon

I am relatively new to having an EV. We were advised to get a Zappi charger as we had solar panels already.  
This may seem like a dim question, but I am not sure if I am understanding correctly.
My query is as follows:
We are on the Intelligent Octopus go tariff and therefore get rates of 7.5p/kWH in the night.
We have a FIT for the solar, which is exported at a rate of 18.5pkWH.  I do have the option to use excess solar on the (rare!) days when it is sunny to charge the car through the Zappi charger.  But then it then it caused me to question whether this is cost effective as we are losing out on the export rate which is higher than it would be charge the car using the reduced rate from the grid in the night? 
Am I better off exporting as much as possible, or am I misunderstanding?
If this is the case, the point of having a Zappi seems pointless over a cheaper charger (which is irrelevant now!)
many thanks

paul991

If your on a FIT the majority of your payment is what you produce not export so makes no difference. unless you have opted to change it you then get a smaller payment for which you export but this is deemed to be 50% of what you produce 

sellitnsoon

paul991 said:

If your on a FIT the majority of your payment is what you produce not export so makes no difference. unless you have opted to change it you then get a smaller payment for which you export but this is deemed to be 50% of what you produce 

oh really?  TBH we had to take over the FIT that was in place when we bought the house.  I just assumed that we got paid for what we export as we provide meter readings.  I had better find out how it works!

Heedtheadvice

"We have a FIT for the solar, which is exported at a rate of 18.5pkWH"

Are you sure you are getting that rate for exporting rather than that rate for FIT for generating irrespective of how much you export?

Broad brush comnent:

Most FIT ( there are exceptions ) gives you a payment  ( the larger ) for generation and a (smaller) payment for export.

SEG is different.

If you get paid for generation ( especially if you get FIT deemed export rather than actual export) any excess that you can use saves you purchase cost whether it is used in your house or added into your EV.

You first need to be clear exactly what you are getting paid for your solar or if you are really on SEG as then it is a different situation and then take it from there....

Edit: written and posted whilst the above was posted....

sellitnsoon

Heedtheadvice said:

"We have a FIT for the solar, which is exported at a rate of 18.5pkWH"

Are you sure you are getting that rate for exporting rather than that rate for FIT for generating irrespective of how much you export?

Broad brush comnent:

Most FIT ( there are exceptions ) gives you a payment  ( the larger ) for generation and a (smaller) payment for export.

SEG is different.

If you get paid for generation ( especially if you get FIT deemed export rather than actual export) any excess that you can use saves you purchase cost whether it is used in your house or added into your EV.

You first need to be clear exactly what you are getting paid for your solar or if you are really on SEG as then it is a different situation and then take it from there....

Edit: written and posted whilst the above was posted....

Thanks, I think that I need to get clarification from OVO as to what I am getting.  I have looked at a statement they have sent and there are indeed two payments.  The generation payment is much larger (nearly 6 times) the amount of the 'deemed export' payment.

From looking at the contract (which is several years old) the export rate is approx 1/3 of the generation rate.

I guess before I hadn't taken much notice as we saw the solar as a bonus - as we didn't install the solar panels.

I just assumed we got paid the export rate for anything we exported and as the only figure they put on the statement is 18pKWH I thought that was what we were getting.  However I see that this is listed as the generation payment.

Confusing!!

So, we are better off using as much solar as poss within the house / charging the car etc?

Exiled_Tyke

Ok so you are on FIT and get paid for what is generated regardless what is exported.  This makes the Zappi slightly more cost effective than if you were on SEG (being paid for actual export). HOWEVER...... it is highly unlikely that the extra cost of the Zappi will ever pay for itself.   I am in almost exactly the same position as you on IO at 7.5p/khW. I own a Zappi and whilst I enjoy the 'free' electricity going into the EV because my night time rate is so low I'm only saving a few pence each day.    You will need to have an estimate of how much you actually export which could be put into the car to get a reasonable answer but unless you have a large system it's unlikely to be beneficial.  One of the issues I have is that a lot of the time I have excess electricity but not enough to cover the minimum charging rate of 1.4kW which the Zappi has. This happens a lot on those occasions where I have been out working during the day and then get back late afternoon when I'd love a bit of a free top up but not enough is coming off the solar panels after the house running needs for when I'm just in. 

Exiled_Tyke

sellitnsoon said:

 

Thanks, I think that I need to get clarification from OVO as to what I am getting.  I have looked at a statement they have sent and there are indeed two payments.  The generation payment is much larger (nearly 6 times) the amount of the 'deemed export' payment.

From looking at the contract (which is several years old) the export rate is approx 1/3 of the generation rate.

I guess before I hadn't taken much notice as we saw the solar as a bonus - as we didn't install the solar panels.

I just assumed we got paid the export rate for anything we exported and as the only figure they put on the statement is 18pKWH I thought that was what we were getting.  However I see that this is listed as the generation payment.

Confusing!!

So, we are better off using as much solar as poss within the house / charging the car etc?

I don't think you need to go back to Ovo as you've pretty much got it.  A few additional extras for you: 

The export rate is (usually) the same for anyone on FIT. It's currently about 7p/kwH.  But is only paid for half of your generation as it's deemed export. 
The FIT rate depends on when your system was installed. This one looks to be about 2014 for the rate quoted. 

Both of these increase with inflation 1st April each year.  It is good to get your Spring reading in as close to the 1st April as your meter reading window will allow as I find the electric companies estimate the changes in their favour. Some allow you to submit an additional reading for the 31st March.  It usually doesn't make much difference. 
 
There are threads on here on how to get the most of your system, but generally yes, try to use electricity when the sun is shining. In summer my dishwasher and washing machine go on when it's sunniest (but not at the same time).   Whilst the washing machine has one peak consumption as it heats the water the dishwasher has a second one later on.  My dishwasher starts with a rinse cycle so starts heating about quarter of an hour in and then heats up again about 3/4hour before the end.    I get into trouble at home but I avoid running heavy use appliances at the same time (this includes the kettle and the toaster!) when there is free electricity around.     The one exception to all this is when we get to the shorter days and the system does not produce enough excess electricity so washing machine and dishwasher go on during the night on the IO rate. 

If you have any monitoring it would be best to look at this to take into account the best times of day for production.  Most of my panels face West so I schedule most consumption for the afternoon when they are at their peak.  

Exiled_Tyke

sellitnsoon said:

So, we are better off using as much solar as poss within the house / charging the car etc?

Just seen another issue worth commenting on.    Should you use solar to charge the car?  Again it's not straightforward so: 

1. Most car chargers draw at 7kW. If your panels are producing less than 7kW then you will be paying full price for the excess power (over what the panels produce) which you draw from the grid. 
2. If you do have a Zappi then as you are aware this will allow to only use the spare solar for the car.  However it gets better.  The minimum charge rate is 1.4kW. If the panels are producing slightly less than this the the Zappi can be set to charge at 1.4kW and take the excess it needs from the grid.   If you are paying 7.5p by night and (from July) about 22.5p by day then if you set the Zappi to draw no more than 30% of it's power from the grid and the rest from the panels then you will be no worse off using the EV charger by day.  
3. But note as previously mentioned it's unlikely a Zappi will pay for itself.  

sellitnsoon

So I did call Ovo today, but TBH the person I spoke too sounded very vague and unsure so I don't feel like I can have 100% faith in what they said!  But some of it does reflect the info that is given above.
I have a generation meter and we are paid for what we generate whether we use or export it - so we may as well use it!  Plus we get paid for 'deemed export' and she appeared to say that we get paid an extra, but lesser amount for the amount that we export (this was where she was vague).

So I think as I was misunderstanding previously about how the FIT worked I know now that it is worth charging the car with any excess solar.  I have it set just to top up in the car via the Zappi *if* there is enough sun - which seems to be in short supply this year!

Thanks for the advice and enlightening me!  

ecraig

I don’t have FiT, but do have a zappi.
for me it’s more convenient to: export my energy at 15p kWh via octopus, import energy overnight for 7.5p kWh, and crucially, more useful for me to charge overnight when I’m sleeping. 

For me I weighed up the pros and cons of the zappi but decided to go with the zappi (vs ohme) because zappi has built in WiFi (ohme has a SIM card) and I believed (and feel I made the right choice) that zappi has a better tariff integration with octopus.

I paid £999 fully fitted for my zappi, and I think the smart tariff integration and WiFi connection is worthy of the money. But the myenergi app is terrible. 

Exiled_Tyke

sellitnsoon said:

So I did call Ovo today, but TBH the person I spoke too sounded very vague and unsure so I don't feel like I can have 100% faith in what they said!  But some of it does reflect the info that is given above.
I have a generation meter and we are paid for what we generate whether we use or export it - so we may as well use it!  Plus we get paid for 'deemed export' and she appeared to say that we get paid an extra, but lesser amount for the amount that we export (this was where she was vague).

So I think as I was misunderstanding previously about how the FIT worked I know now that it is worth charging the car with any excess solar.  I have it set just to top up in the car via the Zappi *if* there is enough sun - which seems to be in short supply this year!

Thanks for the advice and enlightening me!  

Yep that's the answer. One small thing though.  If you do set the grid percentage at 20 or 30% then on those occasions where you are not quite there with solar production the charger will keep going and cheaply. e.g. if say you have to draw 300w from the grid and 1.1kW (so 20% grid use) from the solar then you are essentially paying 6.6p per unit to charge the car.  hardly a big saving but you are still better off than the IO night  rate.