Newbie UK questions

[mmca22gr]

I have a Nissan Leaf 2.0 and awaiting arrival of a Model 3 sometime in the next 6 weeks.
I am on Economy 7 electricity (cheaper rate for 7 hours at night)
I do not have solar PV - an estimated system would generate 3384 Kwh per year with a 4Kw system
I used 10,537Kwh in a year.

could I use the powerwall 2 to charge from the grid on the lower night time rate and then use that during the day?
Would I be able to charge the Powerwall 2 from 0-90% in the 7 hour period?

I am using on average 28Kwh a day so 13Kw Powerwall would help

 

[MarkJ]

How much of the daily 28Wh is for charging the current Leaf?

 

[MarkJ]

Solar with or without a PW makes no financial sense so if that is your only /main reason you are going to be disappointed.
A PW can charge in under 4 hours.
My advice would be a cheap and GREEN tariff such as Octopus Go (4 hours @5p, rest at 14p). Charge both cars off peak. Use delay timers on washing machines etc.
If you highly value having your house on a big UPS, love gadgets, have spare money doing nothing, and don't intend to move house in the next 15 years, then go for it!

 

[mmca22gr]

The Leaf is about 8000 miles per year as will the Model 3
Can only get Economy 7 in Northern Ireland - none of other Octopus type deals are available. so 7 hrs nighttime at £0.8p vs £0.16p daytime.
So could use a PW2 charge in 4hrs at £0.08p to discharge 13Kw during the day?
13 * £0.08p * 365 = £380 a year.
won't move house but £7k for a PW is - as you say - a vanity project in truth.
Will look to find a green supplier in Northern Ireland

 

[MarkJ]

I agree with your rough numbers. Although a PW2 with backup gateway is listed at £7.8k with installation on top of that so the return is even harder to justify.

 

[mmca22gr]

yes
at £380 a year savings then it would be mental to buy a PW2 for £8k with a 10 yr warranty.
Think I will stick to the economy 7 for now.
the public charging network on the island of Ireland is free at the minute - hopefully they start charging later this year. I say hopefully because it will stop the freeloaders and leave the network free for those who need it. Nothing worse that pulling up to a charge point and some local has driven 5 miles to charge their car because it is free