Can I use my EV as a battery on wheels to power my off

Dear Bryce, Thank you very much for your articles on bi-directional charging. This is probably as much a comment as a question, but here goes. I am building an adaptable house for one person in the upper Blue Mountains west of Sydney, to lastme for about 30 years until I die (fingers crossed). As you probably know the climate there is cooltemperate, and significantly cooler and less humid than Sydney (Smogney). My block is at 1,030metres above sea level. (Before anyone asks, it will be built far in excess of current bushfireprotection standards. "Future-proofing" is my middle name.) The plan is to have it finished around Christmas 2023. Famous last words! It will be a PassivHaus and off grid (though suburban). The roof will have a generous covering ofsolar panels. It's north facing and not shaded, because that was one of the criteria I had whenlooking for land. All I know is that solar panels have come down in price and continue to do so, moreso than batteries, so it will probably make sense for me to have as many PV panels as possible. The difficult part is that the upper Blue Mountains region is prone to long periods (i.e. days on end) ofmist. This is good for a whole lot of reasons but definitely not for PV electricity generation. My aim isto use an EV battery to top up the house battery/batteries when they get low. Effectively I should, ifthe house batteries get low, be able to go a short distance (eg Katoomba shops) and charge the carup, and bring the electricity home to top up the house batteries. I’m retired so I can use electricitydirectly off the roof during the day for things like the washing machine, substantially avoiding thephysical inefficiencies of having to store it for use at night. All fine in theory, but there's not much to choose from in Australia's EV market at themoment. Hopefully our EV dam is about to break. A common response to the situation I’ve described is that I shouldn't go off grid, and use the grid totop up the house batteries on the occasions they get low. That's logical and cheaper as far as I know,but I’m committed to giving fossil fuels (from utilities, governments and car manufacturers) thefinger, emphatically, permanently and with indescribable satisfaction. I’m therefore resigned topaying more as a capital expense, but hope to run the house for peanuts. I don't want a generator asbackup, and being a suburban location I probably wouldn't get permission for one anyway. This plan makes even more sense when you realise (I understand) that EV batteries have 4 or 5 timesthe capacity of a typical house battery. Given that on average cars are said to spend about 90% oftheir time sitting in the garage (certainly mine will), not using them for V2H or V2G is an inexplicableand criminal waste of resources. In addition, not being able to use the EV battery for V2H (I’ve ruledout the Nissan Leaf for a number of reasons) means I will have to buy more house batteries to lastme over the long misty periods. I’m monitoring the pending introduction of the Subaru Solterra as that ticks most of my boxes,although if it has CHAdeMO it's not great, close to obsolete in fact. It may be that I should just getany old car (or keep my current ICE car) to last me till about 2027 when there will be better choice

and the charging technology is more mature and cheaper, and buy more house batteries in themeanwhile. Sad, but that's the predicament Australia is in. Yours in anger and frustration! John.

Hi John

I hear your pain re the delay in V2X for the winner of the Plug War between the two DCcharging systems/plugs – CHAdeMO and CCS. (V2X by the way means vehicle to ‘something’, i.e.getting power out from the battery instead of just charging it).

It really feels like CCS are dragging out the process. However, developing the earlier CHAdeMO V2X capability was also not particularlyfast, it just got in first. CHAdeMO was designed with it in mind back in 2009, but only became astandard in 2014. CCS sadly wasn't designed with it in mind so they are late to the party… but bydoing so, they should at least be better at it given technology has moved on a lot since 2009: theCHAdeMO V2X capacity is best described as ‘clunky’.

The delay in CCS having it has a lot to do with ensuring there is one agreed set of standards for CCSto communicate with the car, V2X unit in the house (which will enable the safe supply of power fromthe EV to the switchboard) and to/from the grid. However, given CharIN (the CCS controllingconsortium) is bigger than the EU in terms of large auto and charging industry players and works onachieving consensus before moving forward, they can seem slower moving than a Greenland glacierat times ….

In your situation, a V2H car would be ideal to act as a large battery back-up to an off grid system.Unfortunately, it's unlikely that the manufacturers will even offer V2H (vehicle to home) or V2G(vehicle to grid) capability from a CCS equipped car for at least another 12 months … then theequipment manufacturers have to build/test their units … and then the various electric supplyauthorities have to agree to let them be connected.

In addition, here in Australia COAG (Council of Australian Governments) here have agreed to notreturn to the issue of V2G connectivity until 2025, so it is going to be a while before we can installCCS V2H systems here.

You also can't easily build your own V2H system for connecting a CCS EV via the switchboard asthere are no CCS V2H/G cars yet – plus the supply authorities would be unlikely to let you use itunless considerable expense has been made to get an engineer to design and sign it off as safe: theWiring Rules (AS/NZS 3000) apply to all 240/415V AC systems, on or off the grid.

Also: the V2L that is currently available in CCS cars is via the AC socket. V2H/G for CCS I believe isgoing to be through the DC pins, so we are waiting on the draft standards being accepted: mind-you,many test units are in the development or testing phases. As I keep saying though, none will beapproved to buy and install here until at least 2025/6, so your 2027 timeline is definitely the mostlikely for getting reasonably priced V2X connection boxes.

In the meantime: being off-grid, you will still need to have a stationary battery system to power youat nights and when your EV is away. It is only the size of that stationary battery that would differ ifyou have a bidirectional capable EV.

Seems to me then therefore you have four options:

As I often say in my public talks: looking back at historical transitions, they seem almost instantaneous and very directed, but when you're in the middle of one – they can seem very slow and determined to go down the wrong path at times. CCS V2X systems are on the way, but they won't be available tomorrow.

Hope that helps John?

Cheers

Bryce

Bryce Gaton is an expert on electric vehicles and contributor for The Driven and Renew Economy. He has been working in the EV sector since 2008 and is currently working as EV electrical safety trainer/supervisor for the University of Melbourne. He also provides support for the EV Transition to business, government and the public through his EV Transition consultancy EVchoice.