[Noumenon]

I'd debating whether to get a 3kW Granny cable or a 7kW charge point installed at home. I have a ZE20, so overnight charging is not an issue and it would be handy to throw the granny cable in the boot for short trips away. However, I was wondering what the charge efficiency of each solution is - presumably there is conversion efficiency to consider (which ultimately impacts the total amount of electricity used), but my google skills have failed me in finding what difference there might be!

 

[cah197]

A granny will charge at 10 amps, so 2.4 kW. This turns into around 1.7 kW into the battery due to ZOE charger losses. So a bad idea for regular charging.

Best to try and get a reliable charger.

We previously had an ABL charger which worked fine with a ZOE.

 

[555djx]

We used a Granny for 6 months on a 22kWh Zoe, and then for 9 months on a 40kWh Zoe without any issues whatsoever. If overnight charging works for you it’s ideal, and as you say, you can always take it with you on trips. I’d suggest trying the Granny first and see how you get on.

 

[555djx]

Deleted - duplicate due to website glitch at time of posting.

 

[mikeselectricstuff]

ISTR reading that the Zoe charger is rather inefficient at low current levels

 

[yoh-there]

I would advice to get a chargepoint. Not so much because of efficiency (that is basically your choice, though the difference in effectivity is quite substantial between 16A and 10A because of reactive load), but because the entire setup is much sturdier and much safer.

 

[80698]

As others have said, it's faster, more efficient, safer and more robust to have a home chargepoint installed. Even if you only went for 3kW (though I recommend going for 7 wherever possible for future cars with bigger batteries)

The granny cable is slower than 3kW and a full charge would take the entire night. If you were going to switch to a cheap electricity tariff for overnight charging, there's a good chance that you wouldn't have enough off peak time to charge fully for cheap, but you would with something faster.

As for trips away you're better off with a 3-Phase type 2 cable than you are with a granny cable. That's what almost all chargepoints now have, it will be way faster at up to 22kW and I just can't see it being useful to carry a 3-pin granny cable for anything but absolute emergencies anymore to be honest.

 

[Noumenon]

Many thanks. Home 7kW it is! =)

 

[cah197]

As for trips away you're better off with a 3-Phase type 2 cable than you are with a granny cable. That's what almost all chargepoints now have, it will be way faster at up to 22kW and I just can't see it being useful to carry a 3-pin granny cable for anything but absolute emergencies anymore to be honest.

Just to be clear for the OP - the Zoe normally comes with a 3-phase capable Type 2 cable.

 

[Noumenon]

Yes, that's what I have with the car. It did take a bit of research as the cable just says 32A 480V with no reference to how many phases, but I got there in the end. Thanks.