EV charging - 3 pin / granny charger

[tallstevef]

Hi All,

Am seriously looking at EV's after an enjoyable test drive of an i3s, and the ongoing fuel shortages. I do have a few questions about charging though...

My garage and drive is separate from the house, but the garage does have power. Effectively I have a back garden with the garage at the end.

Q1 - Assuming I use a 3 pin charger, are there any do's and don'ts about charging via this method?

Q2 - will the Garage setup/location hinder a "proper" charge point install? I have a new build with an 80a main fuse...

Q3 - Any friendly / recommended EV charging specialists in or around the Gatwick area that I could talk to?

Many thanks,
Steven

[Mr E]

Q1; you’ll cap at about 2KW, so adding 6-8 miles of range an hour depending on car/driving style.

[tallstevef]

Am still getting used to the "charging maths" so to speak - I was looking at a new 120ah / 42kw i3 / i3s. My driving is pretty limited, working from home but with trips to shops (3 or so miles) or family (20 miles each way) and the occasional trip out or drive to other offices (60 miles each way). I suspect that a full charge of 170 miles or so would last me a week, so plenty of time to charge up.

I just wondered if there were any long term effects of charging for that long / often via a 3 pin plug...

[anonymous-user]

I have been charging my i3 like this for the last 9 months. No issues and see no need to get a charger as never do more than 70 miles a day so only need to plug in overnight twice a week typically.
The i3 has an excellent battery management system. You can't overcharge and when it gets close to 100% (indicated not actual as it keeps some in reserve to protect battery) it starts cell balancing to improve performance. ABC - always be charging - is the i3 mantra And 3 pin v good way to do that as gentle - albeit slightly less efficient than faster charging.

[carl0]

Q1. I charge my 33kwh i3 on a 3pin overnight for a full charge.

[essayer]

3-pin charger limits to 10A, or about 8-10 miles per hour. So if you want to switch to a tariff like Octopus Go, you only have a limited time in the 'cheap' rate

Also need to think about the quality of the socket and the wiring behind it. It has to be safe to pull 10A for many hours at a time, which may reveal previously unknown faults or loose connections on a ring etc.

On the flipside a 7kW charger is likely to be £500ish installed and requires a 32A supply - easy if your garage has this available, otherwise you'll need to run cabling back to the house's main fuse

Edited by essayer on Tuesday 5th October 15:38

[WestyCarl]

I'm looking at getting one of these as an emergency back when away from home. Any recomendations for something cheap? or where to buy? (may only get used 3 or 4 times a year)

[andy43]

WestyCarl said:

I'm looking at getting one of these as an emergency back when away from home. Any recomendations for something cheap? or where to buy? (may only get used 3 or 4 times a year)

I've been using this screwfix 10m type 2 charger for 12 months - been fine. Dead useful as it's so long. Is recommend! Other option is checking ebay for used chargers - there are manufacturer-branded used ones that come up cheap quite often.

I've charged EVs on the same 13A MK Metalclad RCD socket in my garage for the past six years - no problems... yet.
Currently (see what I did there?) used for charging a Tesla at 10 amps for literally days on end - all ok.
Edited to add - charging at such a low speed must surely be the gentlest way to fill a battery up.

Things do get a bit warm to the touch with a constant 10 amps so if you needed an extension lead make sure it's a top quality reel capable of a full 13A and unwind it fully before using.

Edited by andy43 on Tuesday 5th October 17:51

[so called]

I used a granny charger on my i3 Rex 20kWh for about 9 months before getting a 7kW installed.
I charged every weekday night to full as my commute was 100 mile round trip would drain it every day..

Never a problem except when I forgot to plug in.

After installing the 7kW charger and switching to Octopus Go, I'd just set the car to charge at the low tariff rate and save even more money.

[audikentman]

10 metre lead from Screwfix, you won't buy cheaper

You could also get a we dedicated circuit and 3 pin socket installed just for recharging.

[off_again]

Ran a two pin charger for our i3 for over a year (so even slower) and in general it was OK. Just local driving and an occasional 15-25 mile drive. Just had to remember that if it was running low, you had to plug it in at night to make sure you had range. Over a year, there were maybe 5 times that we had an issue - as in the range was low and the time needed to charge it wasnt long enough. Just meant that worrying about the range was a bit more of an issue, since we just couldnt get enough charge in it!

Had a 7KW charger installed earlier this year and its a game changer. Suddenly its so much easier and we havent had any situations where we had range issues. Now charge less often but faster. Strongly recommend getting a good charger installed - it just makes things so much easier. Its not essential, and you absolutely can make it work without one, but just makes it a little easier to manage.

And to answer the OP on the use of the 3 pin charger - no issues. Just slow when you get to 80%+ charge. Charging slows as it gets close to complete, so getting a 100% charge will take longer. But if you can cope with 20% to 80% charge / range, it shouldnt be an issue. Just leave longer to go from 80% to 100%.

[FWIW]

I have a similar issue with a detached garage about 15m from the house.

The garage has power but is fed by a 14mm SWA cable (2.5mm2 conductor) so I'm also stuck with granny charging

I hate to think what it might cost to increase the cable to 18mm/6mm2

[aparna]

Is RCD important for a charging cable?

I picked up a EV granny charger 13A weatherproof extension lead with RCD plug, from a specialist website. But the plug gets pretty hot in one spot, as in uncomfortable to keep you hand on it. So I'm not using it at present, and just parking in a slightly less convenient place.

Any thoughts?

[JonnyVTEC]

Decent chargers like that should have a temp sensor in the plug as a safety feature.

[Frimley111R]

The future is EVs so you may as well do it properly now. As said above, long term use of an old circuit could be fine but if it's never been used much before, suddenly using it heavily could throw up issues.

Your big cost/challenge is replacing the cable to the garage. You need, probably a 10mm cable cable, armoured, and it need to be 30cm deep. That's quite a trench. (obviously I haven't seen the run etc.)

You're not alone in having this issue and almost all garages only have wiring for a light and a couple of sockets as they were built long before EVs were thought of.

You will get £350 off the cost of your charger via OZEV now but after March 22 the grant ceases for homes. Worth bearing in mind.

[off_again]

JonnyVTEC said:

Decent chargers like that should have a temp sensor in the plug as a safety feature.

Yup. And they are a box of electronics that negotiate with the car to deliver the right type of electricity. Plug and cable might get hot, but that should be about it.

They can go wrong and accidents have happened, but probably worth getting it checked out though. Socket and wiring needs to be able to cope with the continuous power. But if it’s correct the chances of anything going wrong is much reduced.

RCD is probably not a bad idea. But if that circuit is connected to a breaker, that’s the minimum that is needed. A breaker will cut the flow as needed.

[gmaz]

aparna said:

Is RCD important for a charging cable?

I picked up a EV granny charger 13A weatherproof extension lead with RCD plug, from a specialist website. But the plug gets pretty hot in one spot, as in uncomfortable to keep you hand on it. So I'm not using it at present, and just parking in a slightly less convenient place.

Any thoughts?

I bought one of these for charging, but the socket became warm and the cover would not clip over the chunky charger plug

https://www.amazon.co.uk/gp/product/B006X09WDC/ref...

So, returned it and did what I should have done in the first place, gone to toughleads

https://toughleads.co.uk/collections/ev-electric-v...

This works fine, and has a built in RCD, doesn't get warm at all even after several hours

[ruggedscotty]

aparna said:

Is RCD important for a charging cable?

I picked up a EV granny charger 13A weatherproof extension lead with RCD plug, from a specialist website. But the plug gets pretty hot in one spot, as in uncomfortable to keep you hand on it. So I'm not using it at present, and just parking in a slightly less convenient place.

Any thoughts?

If the plug is uncomfortable to hold - and thats just the outisde. imagine what its like inside and what it will be doing to the wiring. Its not good and needs to be investigated.

warmish is okay but uncomfortably hot is never good....

[Boxbrownie]

tallstevef said:

I just wondered if there were any long term effects of charging for that long / often via a 3 pin plug...

We have been using the granny charger with our 94REX since it was new in late 2016, the supply is a good one (it’s on our annexe which gets tested every year)……no issues whatsoever.

Edit to add……even after a full nights charge the plug doesn’t even get warm enough to genuinely tell it’s been on, if your 13 amp plug gets too hot to handle, or even uncomfortably hot as above it really needs checking out, and don’t use it again until you have.

Edited by Boxbrownie on Thursday 7th October 12:02

[aparna]

Cheers, raised it with shop support they are sending me another lead to try

as mentioned, they confirm it shouldn't be too hot to touch, so you may have a faulty plug if that's the case