Granny Charging Advice Please

weedavemac

weedavemac

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Hi folks, I'm going away for the weekend and looking to use the granny charger for the first time.

Looking for help as to what to look for when buying an extension cable to use with the granny charger please?

How many amps does it need to be rated for? 10 amps? Or 13 amps? Does it need any overload protection? Does it need to be waterproof? The weather will be dry.

Thanks in advance.
 
Hi, definitely rated for 13A continuous waterproof socket and still put it under the car.
Make sure you fully unwind it to use and check it every now and then to see if anything gets hot.
I also got a cheap plug in tester to check the 13A socket you are going to use and an RCD unit.
 
Jomarkh said:
Hi, definitely rated for 13A continuous waterproof socket and still put it under the car.
Make sure you fully unwind it to use and check it every now and then to see if anything gets hot.
I also got a cheap plug in tester to check the 13A socket you are going to use and an RCD unit.
Click to expand...
Thank you.
 
I bough a dedicated lead for outside use

toughleads.co.uk

Tough Leads

Premium extension leads and adaptor made using H07RN-F rubber cable, built to withstand harsh commercial, stage, industrial and construction environments. Extension leads for electric vehicles (EV), stage or theatre lighting, construction sites, caravans and boats. European travel adaptors. 230v...
toughleads.co.uk toughleads.co.uk

Apart from having adequate power rating and waterproofing, it has the ability to padlock the sockets to stop theft.
 
You will absolutely need to fully unroll it to stop it overheating.

The issue is less the 'occasional' use more the duration of use and location / weather.

Try it and keep checking how warm the cable & plug/socket gets. As long as your house has a modern RCD/MCB fuse box you will be OK, otherwise add a RCD socket.
 
EVsince2016 said:
You will absolutely need to fully unroll it to stop it overheating.

The issue is less the 'occasional' use more the duration of use and location / weather.

Try it and keep checking how warm the cable & plug/socket gets. As long as your house has a modern RCD/MCB fuse box you will be OK, otherwise add a RCD socket.
Click to expand...
I will be fully uncoiling it... Don't want it getting hot. Staying at a lodge near St Andrews so will only be able to check the socket etc once I am there. It all looks very posh and modern so it would imagine the electrics will be up to scratch too. Will leave it in for a couple of hours, and check it. If all okay, then it will be on for the night. Cheers.
 
We got a cable from here and it is ruddy brilliant (expensive, but worth every penny for peace of mind imo).

toughleads.co.uk

EV granny charger 13A weatherproof extension lead

High quality 13A weatherproof outdoor waterproof extension leads heavy duty 1.5mm H07RN-F rubber cable. RCD option. IP66. Designed specifically to overcome the issue created by chunkier plugs on electric vehicles (EVs). 2m, 5m, 10m, 15m, 20m and 25m lengths.
toughleads.co.uk toughleads.co.uk

The outdoor cables you find on Amazon cannot close around the very thick granny charger cable, thus making the weather proofing compartment useless. Also a regular extension lead isn't that thick so isn't designed to carry a very high load for several hours. Finally, the garden extension cables re typically only rated to be splash proof but the cable from tough leafs is rated fully water proof.

Note. Your granny charger should be rated waterproof too, you will be able to find its IP rating on the case.

Edit: just noticed others in this thread have recommended the same company, so apologies for the repetition! I should have read all the posts first 🤦
 
weedavemac said:
Hi folks, I'm going away for the weekend and looking to use the granny charger for the first time.

Looking for help as to what to look for when buying an extension cable to use with the granny charger please?

How many amps does it need to be rated for? 10 amps? Or 13 amps? Does it need any overload protection? Does it need to be waterproof? The weather will be dry.

Thanks in advance.
Click to expand...
You might find this link useful.

toughleads.co.uk

EV granny charger 13A weatherproof extension lead

High quality 13A weatherproof outdoor waterproof extension leads heavy duty 1.5mm H07RN-F rubber cable. RCD option. IP66. Designed specifically to overcome the issue created by chunkier plugs on electric vehicles (EVs). 2m, 5m, 10m, 15m, 20m and 25m lengths.
toughleads.co.uk toughleads.co.uk

They do versions with/without RCD protection and are the only ones I found that are IP66 rated (ie. Fully waterproof).
 
weedavemac said:
Bought a fairly basic one from B and Q. 13 amps, 15 metres long, waterproof. It will be fine for occasional use. Thanks for all your help.
Click to expand...
What is the cross sectional size of the supply cable ?.
It needs to have a cross sectional dia of 1.5mm.
Larger ( 2.5mm ) is fine, but no lower than 1.5mm or the cable will get hot 🥵!.
 
Lovemyev said:
What is the cross sectional size of the supply cable ?.
It needs to have a cross sectional dia of 1.5mm.
Larger ( 2.5mm ) is fine, but no lower than 1.5mm or the cable will get hot 🥵!.
Click to expand...
I believe, but I am no expert, that 1.25mm cable is OK for up to 13amp/3kW so should cope quite OK with a 2.3 kW granny charger.
There are experts on here who may correct me.
 
Last edited:
Yes 1.25mm is rated at 13A but may get slightly warm compared to a 1.5mm cable after hours of use.
 
I made my own extension cable, because I already had a good length of 2.5mm multi strand three core spare in the garage.
I used a single weather resistant socket outlet and the best quality heavy duty three pin plug top I could find for sale, I think it’s a MK product.
The downside of using 2.5mm round flex cable, is making off the connections in the plug top accessory, is a bit of a tight fiddle but it’s doable.
The outside weather proof IP 65 rated socket is it Ted with a cable gland and the individual conductors have crimped ferrules.
I had the necessary items to hand, just had to buy the socket outlet and the three pin plug top.
It cost me about £20 for the bits and about half an hour to put together.
I have used it a couple of times, when visiting friends in mid Wales.
The charging infrastructure is poor at best !.
Our last visit was made in the ZS LR so I did not need the cable.
It hangs on the wall of the garage now.
I am not sure if it will get much use now 🤷‍♂️.
 
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