Battery power help required

Mstty

So here is the thought and now I need help bringing it to reality or my holes dashed.

I can get a Nissan leaf for approx £4K the 24 kWh model.

I am less interested in using it as an EV but if that's possible then we will use it for local journeys only. I am more interested in this charging itself fully on a cheap overnight EV tariff and running the house during the day.

Has anyone hacked this yet?

pochase

https://eepower.com/news/nissan-to-leaf-could-power-your-home-with-power-control-system/#

I have seen a few hacks but nothing you can buy over the counter.

Ultrasonic

Are you talking about replacing an existing car, or buying this in addition to an existing vehicle? It sounds like the latter but I can't see this getting anywhere even remotely close to stacking up as a money-saving plan. Even just the insurance costs could wipe out any potential saviings.

pochase

Here is a bit more information about the the concept of vehicle to grid and vehicle to home, whereby the later is what you are interested in

https://www.cleanenergyreviews.info/blog/bidirectional-ev-charging-v2g-v2h-v2l

QrizB

Mstty said:

Has anyone hacked this yet?

No hacking required, you can buy all the kit off the shelf.

But it isn't cheap; a new ChaDeMo V2H / V2L charger will cost you a similar amount to your £4k Leaf.

Or a bit less if you buy from China:
https://inverter.en.alibaba.com/product/60719352779-801471302/CHAdeMO_Vehicle_to_X_V2X_and_L_V2L_and_to_home_station_V2H.html

colmel16

i have also thought about this but unfortunately dont think the tech is affordable enough yet to make it viable. 

Things to consider are that a £4k ev will almost certainly not have 24kwh of available power due to degredation and usability. 
The constant charging and discharging could have an adverse effect on the battery .
The cost of the bi directional charger ( wallbox and Indra)
The cost of fitting tech that is not fully mainstream yet.

For me and my elec usage it would take over 10 years to pay for itself and thats just the buying of the EV.

Mstty

So been crunching the numbers

Bear with me I have just blurted this out but hopefully you can follow it

This will replace the second car so I will not take insurance and running costs into the equation as we already have these as costs.

Sale of current second car £3000
£4000 purchase Nissan Leaf 24kwh model

£4000 setup costs

Total cost £5000

Suggest 20kWh still left out of the 24kwh capacity

We would then comply with owning an EV for overnight charging rates

So taking Octopus go rates 7.5p kWh  for four hours then 35.11p kWh outside that

We will only use the car 2-3 days a week for short journeys (less than 20 mile round trips) so it can sit as a house battery most of the time. 

From our monthly usage we expect we could run fully from the overnight charge and have it as a local run around Apr-Sep

April-Sept Charging costs call it 3 hours per night 22.5p per day (we won't use this much as our usage is 8kwh a day average in summer but let's just ball park it for now and the local journeys etc)

In the winter is a bit different we would look to use every bit of the battery to offset out ASHP usage so wouldn't use the car at all as a run around so looking to use 20kwH a day 

SUMMER CALCULATIONS

So 22.5p x 182 days = £41 rounded up

Cost at our current fixed rate of 29.24p (9kwh a day) 

29.24p x 9 X 182 days = £479 rounded up

Summer savings = £438

WINTER CALCULATIONS average 30kWh a day
 
So 22.5p x 183 =  £41 rounded down

29.24p x 20 X 183 = £1070 rounded down

Difference in additional energy used 10kWh a day between 35.11p kwhand 29.24p kWh

5.87 x 10 X 183 = £107 rounded down

Winter savings = £922

Just energy savings over the year £1360

Extra savings yet to be calculated

Cheap local journeys in summer over petrol

Heating the hot water tank on cheap rate 
Running washing machine and tumble dryer on cheap rate 

I think the initial outlay of £5K for us is returned in 30 months when the extra savings are calculated

Am I missing something big here?

pochase

I had a used 24KWh and new 30KWh Leaf myself a few years ago. Real battery was never the nominal 24KWh or 30KWh.

The 24KWh had usable 21.6KWh and the 30KWh a bit more than 27.2KWh. The used one still had full 12 bars, so no battery depreciation. 

Do you have any information what the status of the battery is (how many bars), respectively how many miles and how old?

Here you find a bit more information: https://www.speakev.com/threads/usable-battery-capacity-24kwh-mk-2-leaf-2016.17039/

Please also take into account that you lose about 10% of the electricity in the charging process. as per above article you will need 24KWh to charge to usable 21.2kwh. 

Edit:
One other thing. You have a huge error in your calculation. In your calculation you charge the car for 22.5p per day, which is 3KWh, but your savings are calculated for 9 and/or 20KWh.

You would be charging 3 hours at 7.5KWh = 22.5KHw x 7.5p = £1.69.

Second edit:
With how many KW is your heat pump rated? I believe the maximum output of the Leaf would be around 3KWh for the inverters in the above link. Most heat pumps seem to be 12 to 16KW

Mstty

@pochase

Cheers I knew I had missed it up somewhere working on my spreadsheet now👍

The mitsubishi Ecodan I have the max draw/input power is 2.96 kWh.

pochase

My £1.69 is of course also to high because you always only need to top up what you used the day before.

So going by your calculation for summer is will be more like 67.5p for the 9KWh you assume you will be using..

Does the Leaf you are looking at have the 6.6KWh charger? Basic is only the 3.3KWh charger and the 6.6KWh charger was an optional extra at least for the range of Leaf's you are looking at from the price.

When you get serious about buying a used Leaf get yourself a dongle and an application called LeafSpy for Iphone and Android. It shows you more details about the battery in the used car.

Mstty

Good knowledge thanks yep will build that all in to the calculations👍