Home charging, is it worth it?

[cduzz]

Is t UK already 220/240V? You’ll charge at a decent rate with the included charger.

Came here to say this; I live in Boston MA USA where it gets pretty cold over the winter, probably colder than most of the UK.

I get by just fine on a 240/20A charge circuit.

If you have time-of-use adjustable costs for your charging and the charging costs are huge, it may make sense to have a higher power circuit installed. If you have a huge commute where you'll need a better than 10 hour turnaround and don't have superchargers around, maybe you'd need a better circuit.

I got the 240/20A circuit because it was cheap / trivial to install. I got it as a test to see if it would be fine or if I'd need to invest in a higher power circuit rather than jumping straight to running new wire, upgrading the house's breaker box, pulling a new feed from the utilities, relocating the meter, etc (IE a huge investment). I also had a convenient charger at work, but haven't been going to the office for more than a year...

I'm not knowledgeable about typical UK circuits, but it looks like a a 13a circuit may be somewhat normal, which means you'd charge at 10A (assuming circuits in the UK are rated for 80% load continuously, again a wild-assed-guess) -- my 2016 90D charges at 7 miles per hour at 10A/240. Is the car going to have to drive 100 miles per day or more (assuming you can just leave it on a charger / in the driveway for 14 hours per day)? It looks like a 32a circuit is also pretty common; if you have one of those you'd basically have a totally usable charging setup.

These solutions assume you'd have a normal outdoor outlet with expected protections (high duty cycle plug, weatherproof box / GFCI), a mobile charger plugged in "permanently" and a way to secure it against theft / mechanical wear. I'd recommend buying a 2nd tesla mobile charger for this with the appropriate adapter for whatever plug you get. I'd expect this to cost far less than your original quote. It'd be slightly less safe and slightly less robust than a hardwired charging setup; for instance you could do stupid things like unplug it naked in the rain while standing in a salt-water puddle; that should still be safe (With GFCI protection) but *I* wouldn't try it... Also the plug could wear out and overheat if you plug/unplug it more times than it is rated for.

 

[Tomilett]

@cduzz yes, UK is 230V for everything. standard plug sockets are 13A and the UMC will take 10A, that's very slow but you can get by on it if away from home overnight or something.

For EV chargepoints you install a 32A charger, this gives the ~7.4kW that will give a full charge overnight. The UMC is capable of doing the exact same rate (with a blue commando adapter) so you can get the same charge rate with a 32A socket, a dedicated breaker from your distribution board and a length of 6mm cable. The rules state that you should also have a dedicated earth spear instead of connecting to the main house earth.

Unless you have a three-phase supply there is no way here of going above ~7.4kW at home, so there's no real difference between using the UMC and using an installed chargepoint, it's just a case of whether you want to have to coil up and load your UMC into the car every time you leave in the morning, or just have a tethered cable to unplug and leave behind!

 

[cduzz]

@cduzz yes, UK is 230V for everything. standard plug sockets are 13A and the UMC will take 10A, that's very slow but you can get by on it if away from home overnight or something.

For EV chargepoints you install a 32A charger, this gives the ~7.4kW that will give a full charge overnight. The UMC is capable of doing the exact same rate (with a blue commando adapter) so you can get the same charge rate with a 32A socket, a dedicated breaker from your distribution board and a length of 6mm cable. The rules state that you should also have a dedicated earth spear instead of connecting to the main house earth.

Unless you have a three-phase supply there is no way here of going above ~7.4kW at home, so there's no real difference between using the UMC and using an installed chargepoint, it's just a case of whether you want to have to coil up and load your UMC into the car every time you leave in the morning, or just have a tethered cable to unplug and leave behind!

I'd argue that with the backstop of supercharging, modest charging like 10a/240v is actually quite viable for many uses. Some people drive more than 200 miles per day, but lots of people don't. I think the myth of "you need big charging capacity" is unnecessarily harming EV adoption. If you have a tiny battery or don't have superchargers / high voltage DC charging convenient to where you live the story changes, also the story changes if you drive 200 miles per day. But you can get by just fine on lower power charging.

 

[iffatall]

I know twenty people have said this already, but it is definitely worth repeating: The convenience and satisfaction of charging at home far outweighs any other option.

Also, as has already been said, supercharging all the time isn't good for the battery.

 

[bob_p]

When Tesla first introduced supercharging, they projected it would be used for long distance charging only - and because that is a relatively average percentage of use - they provided unlimited free lifetime supercharging - and appeared to estimate the lifetime cost to Tesla would be $2000-2500 per vehicle (some early vehicles were charged to activate supercharging), including the fractional cost for the supercharger network.

They evidently didn't think about those customers that would regularly use superchargers - commercial users and urban owners without easy access to overnight charging. And rather than placing restrictions on supercharger usage - they dropped FUSC (which may be a mistake - because it's great benefit for S/X owners - something other manufacturers can't easily match).

Fortunately, EV charging is becoming more widespread - so more urban owners may soon have access to overnight charging, without having to rely on superchargers (which could impact battery life if done on a regular basis).

As for the commercial owners, they should never have expected to get free charging from Tesla...

 

[BioSci]

In my situation, home charging is easy and slightly less expensive (not cheap). Here in the MetroWest suburbs of Boston, our local electricity price is 23 cents per KWH, and the local supercharger costs 25 cents/KWH. One saving grace is that we have Tesla solar panels on the roof which provide about 70% of our annual electric energy. I installed a 240V 30 amp circuit from the basement to the garage and use it at 20 amps for daily charging. In agreement with Tesla's original marketing plan, I use superchargers only for long drives.