Hi, apologies if you’ve already covered the following….
We are currently renovating our home. We have solar but no battery and do not intend to get a battery. I’d much rather replace our existing Volvo XC40 Recharge with a V2H/V2G vehicle. Currently we charge the Volvo using only a standard wall socket.
With our switch board and most of our electrical wiring being replaced in our renovation what should we advise our electrician to do so that we can easily install V2H/V2G when it is widely available?
Regards, Kevin
Hi Kevin – I don’t think I’ve answered your question directly here at TheDriven. Mind-you, I get asked it so often during my public talks that the slide pack now includes one devoted to the topic.
It’s also one that’s covered in the course for electricians I was involved in both writing and delivering.
All the above adds up to my long-winded way of saying ‘that’s a great question’!
The short answer is that although it would be unwise1 to install a V2G charger yet (unless you are part of the ongoing Australian trials of the tech), there are things you can do now to avoid spending twice later.
The longer answer is what these are. 😉
The first is to ensure the new switchboard allows plenty of room for expansion. (By expansion I mean not just for additional circuit breakers and their associated cables, but to allow space to install energy monitors and sensors). I generally allow double the size switchboard that is needed for the current number of circuit breakers. (For example: if there are to be 12 circuit breakers now, I pick a switchboard capable of taking at least 24). I also use switchboards with plenty of room inside. (Some are smaller inside than others!)
The additional cost is minimal: the difference between the price of a 24-way switchboard over a 12-way one is around $30-$40. There is one proviso though: the space available for the switchboard can limit the maximum size. However, as you’re doing a major renovation, you should either be able to make the room for a good sized one, or take the opportunity to move it to somewhere that has the room.
The next consideration is to run a cable sized to take 32A (7kW2), even if you only intend for now to put an ordinary power point on the end of it. The difference in cable cost is in the order of a few dollars per metre, as compared to the labour cost of getting a bigger cable re-installed later. (Especially if the route is open now, but will be built over later).
Also – make sure the electrician allows an extra metre or two of cable at either end. (V2G systems vary in the need for extra boxes to be installed near the charger and/or near the switchboard. Leaving some slack in the cable will enable easier repositioning later). Â
The third consideration is to some degree optional, but I do suggest installing a data cable between the charger location and the switchboard. (Or from both the charger and the switchboard to the home’s data hub if going down that path). Either way, ensure there is enough slack in the cable for repositioning the ends later – as per the electrical cable.
It may not be needed if the future charger and wall box are WiFi enabled, but data cable is cheap and as you have a major renovation going on: installing it might only be an hour of extra work now (plus $10-$20 of data cable) – but it will certainly take a whole lot longer if it is needed later! Â
I do by the way Kevin have one final thought/question for you. If you want the car to provide back-up power for the home’s basics in the event of a power failure lasting more than a few hours – what if the power failure happens whilst you’re away for the weekend in your V2G capable car?
Or for that matter, during a major power failure when it is off for several weeks and you need to go elsewhere to recharge and come back to resupply the house. (This BTW happened here in Victoria in June 2021 after a windstorm took out a substantial part of the poles and wires network in Melbourne’s hilly outer suburbs).
Without a battery, there is no power supply until the car returns. If you live in an area with a potentially flakey power supply, it may be worth at least considering a small home battery system as part of the mix. Enough to soak up part of a day’s worth of solar and provide a day or two of minimal load.
Hope that all helps? There are a lot of variables in play here. Your electrician will also be much better positioned to advise you on the specifics of how the above applies to your home and electrical layout. However, you are doing all the right things in thinking ahead when doing major electrical work.
Notes:
1. I say ‘unwise’ for three reasons: the first is they are currently very expensive to buy (and install). The second is the vehicle manufacturers do not currently warranty their batteries outside of the limited trials. Use of V2G now outside of these trials will void your battery warranty. The third is the software and operating systems in V2G chargers available now are still somewhat car specific. A V2G charger bought now may not work with a particular V2G capable car bought once the feature is formally launched.
2. I am assuming your house is single phase. If three phase: install a 32A three phase cable, even though for now you will only use one phase for the power point with only a single phase circuit breaker for it in the switchboard. Just ensure the electrician leaves space next to the single phase breaker to install a three phase one later!
