Granny charger

[Plagued]

I don't have a type 2 charger for my Tesla or my leaf, which I've had for over 7 years now. So here's some facts -
If you're not doing a huge amount of driving - say less than 60 miles a day and there's a rapid charger somewhere near if you do ever need to top up, then the granny lead is absolutely fine for charging, and you can get by without a dedicated charger.
Anyone saying they are "safe" to just plug in and walk away is wrong. The chargers are fine, and yes a socket is "rated" for more power, but I have melted two plug sockets in my 7 years both times I would class as dangerous, and both were avoidable if I'd stayed long enough to monitor the plug temperature. The current draw on the socket is not the issue, it's the contact that the plug makes to the socket or the wires in the socket not being correctly torqued that's the issue. The issue is you can't see from the outside of a socket if the contacts are a bit loose/dirty or if the connectors weren't tightened. The poor contact causes heat, which causes increased resistance, which causes heat.... etc etc
So make sure you have a reliable socket and wiring and you'll be fine. If I'm visiting somewhere and I'm not confident the socket is good or I'm using an extension lead you can knock the charge current down to 8A or less in the app if you're in no rush.
One thing to consider now the grant's gone is the Tesla "Granny charger" can pull 32A if you buy the 32A euro connector from Tesla and have a 32A socket installed at home. This would still need the correct DC protected circuit breaker fitting (as it would be a dedicated charging point) and they're about £100.

 

[GlynG]

As I said before, if the plug/socket is getting a bit warm then suspect the socket and swap it - £15 and a few minutes to change.

 

[WannabeOwner]

Tesla app and Teslab app always state my car gains 44 miles added on my 4 hour octopus go overnight charges after AC losses

Assuming 13AMP socket is 2.3kW then 4 hours = 9.2 kWh. 44 miles would be 4.8 miles / kWh which is doable but very frugal driving.

I agree 5 MPH is pessimistic, I should use 7 MPH for such examples ...

My rule-of-thumb is 2.3kW and 3 miles / kWh. Frugal driving will get more than that, motorway driving, some headwind, winter temperatures, a passenger and some luggage then 3 miles / kWh is "safe" - depends on the car too, Model-3 is better than Model-Y which is better than Model-X .

My view is that the only time that these numbers matters is on range-challenged journeys, so a short journey isn't going to be troubled for range, but going longer distance at 70+ MPH with a headwind and cold temperatures is when this will matter, so "If I'm visit the relies for the weekend mid-winter will I be able to charge enough to get home" would be safe calculated at 7 MPH / hour for however many hours the car can be charged.

Regular charging at home, year round, would be better calculated with whatever your average consumption is. If you are averaging 4.8 miles / kWh and charging on Octopus at 7.5p your travel is very cheap indeed.

 

[Undecided_2]

I'd prefer to have the car well charged and be able to go somewhere if I need to.
[/QUOTE]

Others have said the same and to not worry about the battery and my wife says let’s just enjoy the car, the battery has a warranty and besides what’s the big deal if we lose a few miles of range over the years.

We’ve installed a charger in the garage so it will be a nice feeling not paying £1.90 per litre for diesel.

 

[Tony Hoyle]

This. Just enjoy the car. The official advice is to charge to 'daily' for your normal usage, and 'trip' for a trip. Nothing more complicated than that. How you organise that is entirely up to you.

 

[cryo]

There have been plenty of incidents of occasional chargers melting sockets , just go on other forums. Tesla themselves even say it’s an occasional charger when using the 3 pin adapter. If you want a cheap option get a commando! Any electrician will tell you to not use a 3 pin for hours on end at max

One thing during this exceptional weather has made me doubt these statements. Being a low milage user I use the granny charger for my main charge and during the hot weather with my socket being near a south facing aluminum door it got quite warm (ambient air 37C) and the car informed me that the charge had been reduced to 5A from the usual 10A because it sensed a temperature increase in the three pin plug so these granny chargers are smarter than we think. Expanding on this I suspect if the plug temp had continued to increase post the 5A reduction the car would have cut the charge fully. This reduction happened over two very warm daytime occasions and now the temps are back to normal the car is now charging at 10A with no problems. I have checked the plug and remote (wifi) timer socket and they are O/K and now just running at their usual slightly warm to the touch temps. By the way I am an electrician and three pin sockets/wiring are good for continuous use at 2.4KWs as its well within their designed diversity factor. I suspect the commando units will also be thermally protected to limit charge if required.

 

[mikeyg_ev]

I suspect the commando units will also be thermally protected to limit charge if required.

The UMC2 commando adaptor does have a temperature sensor. It's at the side just behind the live & neutral pins. I know because I extracted one so I could make up and adaptor with a different plug.

 

[DaSwede]

What, you mean like this Father in law turned all the heat on at the same time and obviously a lose connection in the filter for the supply tails... Well they do say to get your electrics inspected every 10 years. It had been working fine for best part of 20 years until now...

View attachment 780189

Thankfully we smelt something wrong and isolated the property. But not until the filter in the supply ended up looking like this.

And before anyone suggested something got overloaded, its a 100A filter in an 80A fused supply, with 32A of heaters on potentially full blast, and may be 16A immersion. So well within spec. But continuous high loads do pose an additional risk.

View attachment 780190

Your problem are the components inside the box. They are rated for a maximum of 275 VA. You're lucky the house is still there!

 

[DaSwede]

Your problem are the components inside the box. They are rated for a maximum of 275 VA. You're lucky the house is still there!

For clarification, 275 VA is equal to 275 W. The granny charger will crank out 2000W+ so a no-go

 

[ACarneiro]

Your problem are the components inside the box. They are rated for a maximum of 275 VA. You're lucky the house is still there!

Funny, I would interpret that as being rate for 275Volts AC
It says 275VAC, not 275VA.
You couldn’t run a house on 275VA (obviously)

 

[DaSwede]

Funny, I would interpret that as being rate for 275Volts AC
It says 275VAC, not 275VA.
You couldn’t run a house on 275VA (obviously)

You're probably right on that one! Anyway, something tells me that the filter design was not meant to be used for a continuous load of 3kW for hours. But the good news is that the owner had a good nose to smell the melting plastic!

 

[DaSwede]

You're probably right on that one! Anyway, something tells me that the filter design was not meant to be used for a continuous load of 3kW for hours. But the good news is that the owner had a good nose to smell the melting plastic!

I did my homework now on our wonderful thing called Google. The Nobo System 500 mains filter is rated at 2kW so still valid comment that it is overloaded.

 

[MrBadger]

I did my homework now on our wonderful thing called Google. The Nobo System 500 mains filter is rated at 2kW so still valid comment that it is overloaded.

That was probably a panel heater. Filter definitely rated at 100A as you can see in the picture below although not clear if that’s 100a across 3 phases or 33A/phase which by the time you added another 16A on top of 32A of heating then I could see issues but as per below, nothing of note in 20 or so years across 100 or so dwellings.

It was a terminal that was a bit loose, along with a poor installation that was squeezed into a tight space. Everything installed and working fine for 20+ years from original build - along with probably 100 similarly spec’d dwellings across 3 sites - I think we would have seen many other problems by now if all of those have 32A of heating hanging off an ~8A rated filter.

 

[Scoopscat7]

So having read this thread and knowing I only drive 70 miles a day on a couple of days a week. The rest varies but average of 35-40 miles so averaging 47 miles a day over the last couple of weeks. What are the views on using a granny charger and being able to cover this type of mileage.

 

[MrT3]

So having read this thread and knowing I only drive 70 miles a day on a couple of days a week. The rest varies but average of 35-40 miles so averaging 47 miles a day over the last couple of weeks. What are the views on using a granny charger and being able to cover this type of mileage.

You will charge at around 7 to 8 miles per hour so you shouldn’t have any issues other that having to charge more frequently/long duration compared to a 7 kWh wall charger.

 

[Adopado]

So having read this thread and knowing I only drive 70 miles a day on a couple of days a week. The rest varies but average of 35-40 miles so averaging 47 miles a day over the last couple of weeks. What are the views on using a granny charger and being able to cover this type of mileage.

If you are hoping to do economic home charging then that can be the challenge. Most cheap rate options will be limited to perhaps 4 hours or so. This means splitting your sessions across multiple nights. The other issue is you would be best to plan to provide some degree of weather protection if not charging in a garage e.g. a dry box for the UMC.

 

[Overworked]

I bought a wall charger but one year later have yet to install it. Public charging and three pin plug suffices as I get about 10mph from it.

I also bought a heavy duty extension cable recommended here that has a drybox end and “letterbox split” option at the other end which I have used in hotel car parks.

 

[Martinb999]

My sister uses her Granny charger all the time. She does about 150 miles per week if she's lucky. Her set up uses a timer in the plug socket to come on at 0030 and off at 0430 each day for cheap rate (5p). The socket is in the garage and she has a hook on the wall outside with the cable coiled on so that every time she parks the car up on the drive she just plugs it in and so far (almost 3 years) she's had no range issues.

 

[Jason71]

I bought a wall charger but one year later have yet to install it. Public charging and three pin plug suffices as I get about 10mph from it.

I also bought a heavy duty extension cable recommended here that has a drybox end and “letterbox split” option at the other end which I have used in hotel car parks.

to average 10mph you would have to be averaging 230wh/m year round and that is excluding any charging losses, preheat, sentry, or other losses which are going to be somewhere in the region of 15-30% based dependant on your circs so for that to be true your average year round driving wh/m would have to be somewhere between 170-209wh/m. Even an SR+ is not going to achieve that.
If you did a true measurement by dividing the number of miles covered by the number of hours on charge you would be more likely to find
7m/h summer 5m/h winter for an LR M3/Y maybe slightly better for an SR+M3

 

[Jason71]

My sister uses her Granny charger all the time. She does about 150 miles per week if she's lucky. Her set up uses a timer in the plug socket to come on at 0030 and off at 0430 each day for cheap rate (5p). The socket is in the garage and she has a hook on the wall outside with the cable coiled on so that every time she parks the car up on the drive she just plugs it in and so far (almost 3 years) she's had no range issues.

that makes perfect sense but I would say 150miles is near the limit of what you could do that way in winter without straying outside of the 4hours every night