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Discussion Starter #1
Hi, I’m planning to get solar panels fitted at the same time as buying my EV.

My quote includes PV panels, battery and diverted for heating hot water. If I add a home charging station for my EV, does it matter which type with regard to charging using the solar? I would be able to charge for a couple of hours during most days, making use of the panels. When I’m night-charging, do I need an additional system (like the my energy eddi?) to allowthe extra power to be split between car and water heating? If I get an EV with a 6.6 charger, is that going to be a drain on my panels?

Any solar and EV insights or pearls of wisdom gratefully accepted! My head is swimming with lots of new facts and info, so make it simple! ;)
 

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You're asking a lot of questions that depend on what system your quote is for, which you don't say. I'd agree with @phproxy that Zappi is currently the best option for EV charging with solar. However, if you've gone for an optimised system like the SolarEdge then it's a different answer - at the Solar Storage show on Tuesday they were launching an integrated EV charge point that was looking pretty impressive. Because it's integrated you get full charge point consumption details inside your solar portal, and only pay 5% VAT.

My colleague Jason will be blogging about it, but here's a sneak preview:
 

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Discussion Starter #4
You're asking a lot of questions that depend on what system your quote is for, which you don't say. I'd agree with @phproxy that Zappi is currently the best option for EV charging with solar. However, if you've gone for an optimised system like the SolarEdge then it's a different answer - at the Solar Storage show on Tuesday they were launching an integrated EV charge point that was looking pretty impressive. Because it's integrated you get full charge point consumption details inside your solar portal, and only pay 5% VAT.

My colleague Jason will be blogging about it, but here's a sneak preview:

The quote is through Project Solar. It’s a 4kW system with 14 evolution max life solar panels. The battery is a 3.3kw Duracell energy bank battery. The inverter is Solax and there is a voltage optimiser and hot water “dr” by ecoWürx. Don’t know if that helps at all....
 

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Hi Leila

I work for Myenergi so i can give you any info you need with regard to our products. If you're having solar fitted then our zappi EV charger is ideal. The zappi can alter its charge rate to adjust to the amount of solar you are producing at any time making it possible to fully or partially charge your car on just your solar energy only if you so wish.

It has 3 different modes so all bases are covered depending on your needs. You can also set timers to charge the car between certain hours, say in the night during cheaper tariff hours. You can set limits on the zappi so that it can charge from anywhere between 1.4KW to the full 7KW and it can take into account, what energy is needed in the house and supply that first while charging the pause on your EV until more surplus energy is available.

Ideally you would fit an Eddi to divert power to your water heater but it can work in conjunction with 3rd party diverters too. There is also an app being released before the end of the year which will enable you to have some control of your products remotely. We're also about to release new updates to our products which will further increase their functionality.

I've attached a link to a video which will tell you exactly how the zappi works.


If you have any questions you'd like to know before deciding then give us a call on 0333 300 1303 or email us at [email protected]

Good luck with your install.

Kind regards

Ady
 

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If you’ve got the cash, a Tesla Powerwall 2 will effectively allow you to use stored PV to charge your EV and indeed to run the rest of your house.

The increased consumption yesterday lunchtime was me remotely starting the car charging (at 10a) that used the available solar, and then topped it off from the battery when the clouds came past.

4FFBB80F-031E-4001-BDD6-8DD0375978E6.png


And there was still enough in the Powerwall to run the house for the rest of the night...

Arguably, this is also a better option than a hot water diverter that only offsets very low cost gas energy to heat water while your not home... especially if you normally shower in the mornings before the PV is going.
 

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Discussion Starter #7
Hi Leila

I work for Myenergi so i can give you any info you need with regard to our products. If you're having solar fitted then our zappi EV charger is ideal. The zappi can alter its charge rate to adjust to the amount of solar you are producing at any time making it possible to fully or partially charge your car on just your solar energy only if you so wish.

It has 3 different modes so all bases are covered depending on your needs. You can also set timers to charge the car between certain hours, say in the night during cheaper tariff hours. You can set limits on the zappi so that it can charge from anywhere between 1.4KW to the full 7KW and it can take into account, what energy is needed in the house and supply that first while charging the pause on your EV until more surplus energy is available.

Ideally you would fit an Eddi to divert power to your water heater but it can work in conjunction with 3rd party diverters too. There is also an app being released before the end of the year which will enable you to have some control of your products remotely. We're also about to release new updates to our products which will further increase their functionality.

I've attached a link to a video which will tell you exactly how the zappi works.


If you have any questions you'd like to know before deciding then give us a call on 0333 300 1303 or email us at [email protected]

Good luck with your install.

Kind regards

Ady
Thanks Ady, this is a really useful video and I shall likely be in touch shortly to discuss the Zappi and eddi systems. :)
 

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Discussion Starter #8
If you’ve got the cash, a Tesla Powerwall 2 will effectively allow you to use stored PV to charge your EV and indeed to run the rest of your house.

The increased consumption yesterday lunchtime was me remotely starting the car charging (at 10a) that used the available solar, and then topped it off from the battery when the clouds came past.

View attachment 105942

And there was still enough in the Powerwall to run the house for the rest of the night...

Arguably, this is also a better option than a hot water diverter that only offsets very low cost gas energy to heat water while your not home... especially if you normally shower in the mornings before the PV is going.
The system I’m looking at includes a battery, albeit a Duracell one instead of a Tesla. It should allow me to run the house off the stored battery, but would the hot water specific one not be necessary as well?
 

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I not familiar with the Duracell system, but to my knowledge, the Powerwall system has the lowest ‘cost per kWh’ of storage - just over 13kWh in the current version. It also includes surprisingly intelligent software that can charge itself from low cost overnight electricity during the dull winter months when solar production is insufficient to run the house.

Regarding hot water: assuming your on the gas network and have a standard gas boiler then using high quality PV electricity to replace gas heat, which costs you 3-4p per kWh, is almost a bit of a waste. Even more so if the tank of hot water then cools off overnight before you get a chance to use it.

I would suspect that your going to be better off using the electricity yourself so that you don’t have to buy it from the grid after dark.
 

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We run the Eddi and Zappi products on 4.8kW of panels. They are great, and are our way of using/storing energy without a battery. To be honest, battery prices were so high that we couldn't justify the cost versus simply using the grid when it is dark.

A 3.3kW battery is not going to give you much charge at all, so I cannot see it being relevant for charging your car. Sorry if I am teaching my granny to suck eggs, but the battery in your car could be 40kW if its a new Leaf or Zoe, and you're only going to get 3.3kW of that from your battery before it is empty! It would work okay to give you household energy in the dark evenings. or supplement grid supply if you are using a couple of power hungry appliances at once.

Say you fill and empty your battery every day, and your electricity is 15p / kWh. You will save 1,204.5 kWh per year at a total value of £180. How does that stack up against the battery cost, warranty period and cycle lifespan?
 

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The quote is through Project Solar. It’s a 4kW system with 14 evolution max life solar panels. The battery is a 3.3kw Duracell energy bank battery. The inverter is Solax and there is a voltage optimiser and hot water “dr” by ecoWürx. Don’t know if that helps at all....
4 kW is a fairly decent, typical solar size - technically it's 4 kWp so at its peak you could get near 4kW, the rest of the time of course much less. If for the battery you mean it has a capacity of 3.3 kWh (I imagine it can only charge at 1-2 kW) then that's pretty small as others have pointed out. Clearly in the summer it would take less than an hour of good solar before it was full.

Personally I'm very sceptical of voltage optimisers, and as has been suggested above if you have a battery it's not likely that on many days of the year will you have any electricity left over to divert into hot water, so I'm also sceptical that the ecoWurx will have a decent payback (15+ years perhaps?).

Of course, this all depends on what you've been quoted - we would charge about £8k for 4 kWp with a 4.8 kWh battery.
 

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Discussion Starter #12
4 kW is a fairly decent, typical solar size - technically it's 4 kWp so at its peak you could get near 4kW, the rest of the time of course much less. If for the battery you mean it has a capacity of 3.3 kWh (I imagine it can only charge at 1-2 kW) then that's pretty small as others have pointed out. Clearly in the summer it would take less than an hour of good solar before it was full.

Personally I'm very sceptical of voltage optimisers, and as has been suggested above if you have a battery it's not likely that on many days of the year will you have any electricity left over to divert into hot water, so I'm also sceptical that the ecoWurx will have a decent payback (15+ years perhaps?).

Of course, this all depends on what you've been quoted - we would charge about £8k for 4 kWp with a 4.8 kWh battery.
Hmm, ok... thanks for the feedback. The quote I have is just under £10k for the products and installation. The panels have a lifetime warranty; battery 10 years... The numbers seem to add up when I look at them, but I think I'm reaching PV-chat overload and just getting more confused every time I think about it now! :)

I've also been quoted a (guaranteed) payment of £180 per quarter for having the battery, but am not sure exactly where/who that comes from - i *think* from the energy company...., so this makes it worth having (with the additional electricity savings from the battery).
 

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Discussion Starter #14
Have you had a few quotes? Seems pricey.
I've contacted a few other companies but haven't had quotes from them yet. Project Solar have "admitted" that their quote will be higher than the others but have justified it with the quality of the products, length of warranty, guaranteed returns etc. I'm waiting on the other quotes and then weighing it all up...
 

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Discussion Starter #15
If you’ve got the cash, a Tesla Powerwall 2 will effectively allow you to use stored PV to charge your EV and indeed to run the rest of your house.

The increased consumption yesterday lunchtime was me remotely starting the car charging (at 10a) that used the available solar, and then topped it off from the battery when the clouds came past.

View attachment 105942

And there was still enough in the Powerwall to run the house for the rest of the night...

Arguably, this is also a better option than a hot water diverter that only offsets very low cost gas energy to heat water while your not home... especially if you normally shower in the mornings before the PV is going.
I haven't really got the spare allowance for a PowerWall at the mo (or anything else that says "Tesla" on it ;) )....

This may sound like a very stupid question, but if I have a 30kW EV, does that mean it will take 30kW to fully charge the battery? My current household energy usage is 10kW per day, so that would effectively be triple my current electrical bill (ignoring the solar panels)? Even if I used half the range allowance (i.e. drove approx. 50miles per day) and charged half of the battery every day, that would be approx. £75 per month on charging.

My potential solar panel system should basically generate a little over what I currently use in the house - does this mean that I'm still going to be pretty much wholly reliant on the grid for charging the EV? Similarly, if I am using almost as much as the panels generate, would I actually be able to store much in a battery anyway? (I worked out that the difference between my expected panel generation and my actual usage over the past 12 months is 1.6kW per day).... Sorry if these are daft questions - I'm just trying to get my head around all of the new info in it!
 

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but if I have a 30kW EV, does that mean it will take 30kW to fully charge the battery? My current household energy usage is 10kW per day, so that would effectively be triple my current electrical bill (ignoring the solar panels)? Even if I used half the range allowance (i.e. drove approx. 50miles per day) and charged half of the battery every day, that would be approx. £75 per month on charging.
Yes to the first - but you will almost never arrive home with 0% battery. 30 days in a month, 50 miles a day = 1500 miles a month. At £75 that's 5p a mile. Many (most?) of us charge at night on Economy 7 tariff which should cost ~half that.

Have you calculated the petrol cost?!
 

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This may sound like a very stupid question, but if I have a 30kW EV, does that mean it will take 30kW to fully charge the battery? My current household energy usage is 10kW per day, so that would effectively be triple my current electrical bill (ignoring the solar panels)? Even if I used half the range allowance (i.e. drove approx. 50miles per day) and charged half of the battery every day, that would be approx. £75 per month on charging.
It doesn't matter how big your battery is, it's the distance you drive (and how efficiently) that affects how much charge you need. So start from your average annual mileage, divide by your average miles per kWh across the year (allowing for charging losses), divide again by 365, and that tells you the average kWh to charge your car each day.

Sent from my Pixel C using Tapatalk
 

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I drive about 35 miles a day in my Leaf, last night it took 11.5kWh to charge the car.
For a rough calculation on the electricity you will use take your annual mileage and divide it by 3. That will give you a rough estimate of the kWh's you will use over the year if you drive reasonably efficiently. Divide by 2.5 of you will just drive and not be thinking about how many miles you are getting.
The mi/kWh the car reports is only part of it, it doesn't allow for charging losses, preheating the car etc.

If over half of your total electricity use will be going into charging the car it is probably worth switching to an E7 tariff. It isn't for everyone but if you at doing a lot of miles then it's worth it, especially if you can get onto a 5p per unit night rate.
I switched to E7 and our household combined 36000 miles a year has added about £55 a month to the electric bill.

You can always ask Trevor Larkham for an actual quote on the solar and battery install, they do an estimate without having to visit your home. When we had solar installed the first person to come round sounded very convincing and all his numbers looked good, but we went with a local company in the end who installed twice the amount of panels for 20% more £. Obviously the payback on those is much quicker.
 

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Discussion Starter #19
Thanks - this is very helpful.

So, another variable has entered the ring... economy 7 tariff.

I’m at home a fair bit off and on during the day. I run a washing machine pretty much at least once a day and a tumble dryer daily in winter. I won’t do those overnight, mainly for safety reasons. We have a small/medium fish tank (light, filters, heater) running 24hrs and a dehumidifier we run overnight in the winter; fans overnight in the summer. Otherwise, we heat the water for an hour overnight/early hours and then often top up with an hour in the evening for washing up/baths etc. I can charge the car a bit during the day or overnight. The car looks as though it will use at least 50% of our total energy, but more likely 60%. Last year, I did 20k miles in my car, although even if it drops to a low 12k, it will still need take 50% of our household electric. I *think* it sounds as though E7 would make sense for us...
 

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If I used half the range allowance (i.e. drove approx. 50miles per day) and charged half of the battery every day, that would be approx. £75 per month on charging.
Lets say for argument you did. That would mean you would have spent around £300/month on diesel.
So you'd be £225 up.
 
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