Using trickle charging

[Godsense]

Sorry, I was wrong on the number. For me charging at 32A gives 98% efficiency, at 10A is 88-92%

The difference is explained by the car being powered up while charging, which uses about 250W, a larger percentage of the 10A is therefore lost. If you are low mileage it won't add up to a lot of cost however.

Also worth noting that when pre-heating, the car pulls a little more power than a 32A can supply, so your battery can drop a little, on a 10A UMC you'll lose a lot more miles pre-heating.

If you look at Charging Connectors | Tesla UK you'll see the statement

Tesla recommends storing your Mobile Connector (6m) in the trunk of your car, to use as a backup charging solution when traveling.
​

I guess it's up to your own interpretation as to whether that gives you confidence to use it every day, they are expensive to replace once the warranty is done.

That efficiency matches my experience too monitored via Teslamate.
It works for me now especially via the cost of having a EVSE fitted.
There are 2 50kw chargers 5 minutes from my house if the worst came to it. Longer term though I can understand the investment will likely be worth it.

 

[RichardGH]

No extension lead. It’s plugged straight into the socket.

 

[RichardGH]

And I’m not aware of the plug getting hot. It doesn’t even feel warm!

 

[Glan gluaisne]

And I’m not aware of the plug getting hot. It doesn’t even feel warm!

That's very surprising, as the BS1362 fuse in the plug will be dissipating about 0.8 W when the car is charging, and that's enough to make the plug top feel warm usually.

 

[RichardGH]

I usually feel the plug when I unplug before heading for work. By that time it’s not actively charging. It is charging now (having just popped out to get the papers!). Went out to feel it and it is slightly warm but certainly not hot!

 

[Glan gluaisne]

I usually feel the plug when I unplug before heading for work. By that time it’s not actively charging. It is charging now (having just popped out to get the papers!). Went out to feel it and it is slightly warm but certainly not hot!

It should not be hot, as there is a temperature sensor inside the UMC moulded plug to shut the charge point down if the plug does get hot. It's a feature of all BS1363 plugs that they do get warm when passing a high current, as up to 1 W can be dissipated by a BS1362 fuse when in use. It's partially because of the heat generated by the fuse that BS1363 plugs tend to overheat on the line pin, an issue that can then lead to further overheating as the heat causes the spring contacts in the outlet to loosen slightly, increasing contact resistance and causing more heating.

It's very common to find the line side socket on outlets burned from this overheating during inspection, as shown in the photo below (taken from another EV forum where the charge point had caused the outlet to overheat). In fact it's so common, that I can almost guarantee finding signs of overheating during an EICR, especially on any installation that's more than about 15 to 20 years old. This is why it's very sensible to not only ensure that the periodic inspection for the installation is up to date (now called an EICR, due every ten years for non-rented domestic installations) but that all outlets used for heavy continuous loads are in good condition.

 

[Abueloeddie]

A Question on leaving the Tesla Mod. 3 whilst I jet off to Furrin Parts in Mid July….
At the moment I charge via a gable end mounted Wall Box. With Charger plugged in to the Tesla which is fully Inside the garage .The cable stretches easily across to the separate garage and it passes underneath the closed roller shutter door. All works well. Can I leave it unconnected and locked up for a week whilst we’re away ? OR….. Second Question. Can I connect the UMC cable to a 13 amp socket in the garage and just lock the Tesla up for a

 

[ACarneiro]

A Question on leaving the Tesla Mod. 3 whilst I jet off to Furrin Parts in Mid July….
At the moment I charge via a gable end mounted Wall Box. With Charger plugged in to the Tesla which is fully Inside the garage .The cable stretches easily across to the separate garage and it passes underneath the closed roller shutter door. All works well. Can I leave it unconnected and locked up for a week whilst we’re away ? OR….. Second Question. Can I connect the UMC cable to a 13 amp socket in the garage and just lock the Tesla up for a View attachment 940400View attachment 940400View attachment 940401

Other than the trailing wire being a trip hazard, I think that it should be fine to leave it connected (which is what Tesla recommends)
If you want to leave it unplugged for a week it'll also be absolutely fine. I often do that when I'm away (car parked in airport) and you might lose a couple pf percent charge but that's about it.

 

[Adopado]

A Question on leaving the Tesla Mod. 3 whilst I jet off to Furrin Parts in Mid July….
At the moment I charge via a gable end mounted Wall Box. With Charger plugged in to the Tesla which is fully Inside the garage .The cable stretches easily across to the separate garage and it passes underneath the closed roller shutter door. All works well. Can I leave it unconnected and locked up for a week whilst we’re away ? OR….. Second Question. Can I connect the UMC cable to a 13 amp socket in the garage and just lock the Tesla up for a View attachment 940400View attachment 940400View attachment 940401

Either approach would be fine … take your pick. If you want to minimise loss of charge don’t keep checking your app and don’t leave Sentry Mode on. If you want to leave sentry mode on then maybe there’s some advantage in leaving it plugged in.

 

[TechnoWatch]

they are expensive to replace once the warranty is done.

£180 from Tesla store… so can get 5 for the price of a installed charger….

 

[GRiLLA]

£180 from Tesla store… so can get 5 for the price of a installed charger….

The price has changed since I wrote that, used to be something like £500 each. Tesla brought the price right down to match the US I assume.

 

[Avendit]

I suspect that if the installer thought the charge point wasn't suitable, this is probably related to something in the house - possibly you are on a looped supply? (means you and a neighbour share a connection, total pain for many things, more so in the future as we move to more electric stuff instead of gas) .

You probably shouldn't override that advice and fit a 32 amp commando, but adding a 16A one would in the long term be safer and faster/more efficient for charging. Almost double the charge speed for not a big outlay. As @MrBadger said, there are rules for any socket that will mostly be used for charging from, so whether you do or don't apply those for a 13A 3 pin or 16A commando you are in the same position, but the 16A is a safer connection standard - thats why the 3 pin is actually rated to 10A.

Also, at 16A, any reasonable ring main should support that, a 32A connection will need special installation.

Lots more info (and arguments) Here's how to charge with 32A commando in UK

 

[TechnoWatch]

The price has changed since I wrote that, used to be something like £500 each. Tesla brought the price right down to match the US I assume.

Fair point, although I thought it used to be £250... but I can imagine some "brand mark up" occurring!

 

[GlynG]

I have been charging my car for 95% of the time using the granny charger, only on a trip will I use the superchargers and have no intention of having a 7Kw charger installed at home.
You will read lots of horror stories regarding constant use of the granny but remember its just a story - like Jackanory (perhaps have to be over 50 to know Jackanory).

The Granny charger will take the 32 amp commando adaptor - so the three pin is an absolute doddle for it to do at a constant 10 amps, the plug has a thermistor in it to monitor temperature as does the lead itself from the charger - the thermistors are those little bumps in the insulation along its length - so you need never worry about heat generation. If heat is produced in excess then the charger will throttle back and lower the amperage.

The only thing i will say - If the socket you are using is an old one then swap it for a new one - a tenner to buy and simple swap over. Old sockets tend to have had a lot of use - inside the socket the connectors are just sprung copper in like a U shape - the pin of the plug is trapped between the bent over spring copper when you plug in - over time the copper wears and as plugs are wiggled when being pushed in or pulled out it can create a looser connection - and a loose connection will create heat.

You will read about a constant 10 amps being something a plug and socket not being designed to do - that's twaddle too, plugs and sockets are not tested and rated as a peak figure - its a constant design load and rating - which is 13 amps and home voltages are rated as 230v - so 2990 Watts.

Granny charger is around 2200 watts inc losses.

majority of homes actually receive 240 volts - so at 13 amps that would be 3120 watts

Ohms law - Watts equals amps multiplied by volts (W=AxV) easy way to remember What Are Virgins
Volts Equals Amps times resistance - V=AxR) - or Virgins Are Rare
Thats the way I was taught to remember it - back in the non PC days