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Discussion Starter · #1 ·
Hi all.

Just curious, what size solar panel system would you need and what size batter would you need to effectively charge the ampera completely once per day?

What's a rough cost too and when would you break even presuming you do 30-40 miles in the Ampera Daily?

Cheers
 

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Discussion Starter · #3 ·
Takes approx 11.5kWh to charge Ampera on AC.

So to reliably produce 12kWh a day in a British winter? Probably 150kW array...
Is that a serious answer or sarcasm lol? I can't tell.

My house faces perfectly south and has a large roof so I think someone said we can fit 16-20 panels up there. I can't recall what that would be.
 

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As per @RunningStrong and you need the car at home during the day. I'm retired so the ampera can sit charging when the sun's out.
We charge ours from the panels but need a sunny day in spring summer or autumm. The house battery keeps the car charging when clouds go over.
This is 9.6kWp setup and today, a sunny one it generated 15kWh with a peak of 3kW from 11 to 12, this went into the house consumption, cooking, hot water etc., keeps the use of peak rate electricity to 0, topped the battery up but not to the car, not needed today.
The car will get charged on cheap rate this weekend, possibly with some solar if there is excess.
 

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Discussion Starter · #5 ·
I have an Octopus Go tariff and charge the car between 0:30 and 4:30 for a 66% discount on my electric rate.

I think this will be the cheapest option for a long time yet.

I was wondering what size solar array you would need to power the house and charge a 10kw battery (to then charge the car at night) and what's the average size array of a typical house, presuming south facing and a sunny day with optimal conditions.
 

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You need about 12kWh to fully charge the amp but there is a problem, charging and discharging batteries loses power, so to get 12 to the amp you need 14 going into the battery and some clever circuits to prevent the battery powering the house.
Here the battery runs the house if there is not enough solar. In winter the battery is charged from cheap rate, go in our case. It works, very little full price electric is used even in darkest winter.
 

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Solar is tough!

You get loads and loads of power in one big lump in the middle of the day. But only when it is sunny and only in summer.

My best day in December I made 1.5kWh/kWp of installed solar. So to make 11kWh you would need a 7.3kWp solar array. But that was on the best day. The rest of the month was terrible. Lots of days I got 0.1kWh/kWp (or less!) you’d need a 110kWp solar array to power your Ampera on those days.
 

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It's simply not worth trying to be able to 100% charge an EV from solar every day of the year. My 4kW panels (that's the most I see in middle of a perfect summer day) is maxing out at about 1kW if it's a really sunny January day right now (just had 3 of these in a row - wow!) and is giving me 4 kWh daily!!! My January total will be around 80 kWh I expect, enough for nearly 7 Ampoera fillups. So I'd need a 16 kW panel setup plus a large house battery to smooth the dull days - pointless tbh, as I'd be exporting huge amounts during the summer & losing money hand over fist.

You need to consider house consumption as well. I generate 4000 kWh p.a., my house grid use dropped by 1000 kWh p.a., and the other 3000 kWh powers my EV 100% solar for 12k miles p.a.

In summer I charge the Grid up by exporting lots to it, reducing their gas consumption then, and in winter I take it all out again & pay them for the flexibility to do this. My summer max production is 30 kWh, so I could charge 2 Amperas daily with that and power the house as well!
 

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Solar is tough!

You get loads and loads of power in one big lump in the middle of the day. But only when it is sunny and only in summer.

My best day in December I made 1.5kWh/kWp of installed solar. So to make 11kWh you would need a 7.3kWp solar array. But that was on the best day. The rest of the month was terrible. Lots of day days I got 0.1kWh/kWp (or less!) you’d need a 110kWp solar array to power your Amperage on those days.
My best day last December was the 2nd, my 4.2kw Solar Edge HD based system generated 9.233 kwh that day. But still managed to export over 4kwh, As you say, sunny winters day, blue skys, still comes in on big blob you struggle to use it all over a few hours. Batteries coming soon will solve that issue.
 

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We've a standard solar set-up on the roof and over a year it pays us about £200 more than it costs us in electricity - so, we run the car and the house and still have £200 left over - which equates to about the amount we spend annually on petrol... The house is four bed detached, two occupants, and annual mileage is about 3000.

good luck
 

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What the others have been saying really. My baseload usage is about 9kWhr per day when the house is occupied. So to charge your car I'd need to generate 20kWhr as a minimum. I have a 3.7Kpa system split 50:50 on two roofs (west and south facing) with a 4kWhr battery. I got 20 kWhrs for about 30 days between the start of May and the end of July last year (ie 30%of the time). The excess was exported for about 5p per unit.

My December average was 1.5kWhr, but that hides 15 days when I generated less than a kWhr. That suggests as a bare minimum to meet the needs of my house and 11kWhr daily for a car (mine takes 60...so not even thinking about it) I'd need an installed capacity of around 80 kW

There is, of course, no such thing as free electricity. I will try to put as much of the excess as I can into the car (not had it long enough for this to be a thing yet)...which will cost me 5p a unit in lost exports, but that equates to around a penny a mile, which is better than a poke in the eye. 😀

Hope this helps.
 
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