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That’s good to know, thanks. 6A would have been better still but 8A will do.
Another question please. Can you turn the charging off/on remotely via the UVO app when using the granny lead for charging?

Cheers
Peter
You may like to note that you can reduce the rate of charge in the settings in the car - not very precisely but it is possible to specify a lower charge than the maximum possible with the charger. You can experiment to see how this works.

I think the UVO app works for the granny lead as well as 3.5 or 7kw charger.
 

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My granny lead offers 6A 8A and 10A. No 12A, which the documentation suggests is available only for 16A (Schuko) sockets so is presumably not available in the UK. On my edition at least.

Yes, you can switch granny charging on and off using UVO, though I find the UVO interface somewhat clunky.
 

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A lot of misinformation in this thread about extension leads, particularly incorrect statements about power loss and RCD protection. If you buy a flexible extension lead of 10 meters then 1.5 mm2 cable is perfectly adequate and has insignificant voltage drop and power loss. Always sensible to plug in with an RCD or buy one with integral RCD protection. If you are using it outdoors then make sure that you buy a weatherproof socket and be aware that some granny leads have oversized plugs so you may need a large weatherproof enclosure.

The warnings about not using extension leads really relate to additional hazards that may arise with careless use and the fact that you may have 10 amps continuous for several hours. Problems may include - using non-weatherproof equipment outdoors, not securing the plug properly in the socket (a problem with the large plugs on some granny leads), leaving the lead coiled and causing overheating, tripping over a badly located lead etc.

Obviously there have been problems with granny leads. BMW issued a safety recall simply to fit a warning label on the granny lead to be aware that the over-sized (non-standard) plug may not be fully inserted into some shrouded sockets.
 

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All good stuff. Thanks to everyone. Does the E Niro have an abnormally large 13A plug?
I'm pleased to hear it can be set as low as 6A too. Although I know it would be very slow, I can be confident that mostly through the daytime, my solar system can provide me with free energy.

Thanks.

Peter
 

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A lot of misinformation in this thread about extension leads, particularly incorrect statements about power loss and RCD protection.
I thought one problem of using an extension lead is that it will not monitor the temperature of the socket into which the extension lead is placed. If the granny lead is plugged directly into the socket then I think most granny leads will disconnect if the socket gets too hot. If you use an extension lead it is particularly important to check the socket into which it is plugged is in excellent condition.
 

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I thought one problem of using an extension lead is that it will not monitor the temperature of the socket into which the extension lead is placed. If the granny lead is plugged directly into the socket then I think most granny leads will disconnect if the socket gets too hot. If you use an extension lead it is particularly important to check the socket into which it is plugged is in excellent condition.
The thermistor (monitor), if there is one, is of course located in the granny plug and not the extension lead but, yes, at maximum charge rate you are taking 10 amps continuously for many hours and although this is well within the capability of house radial spurs or ring mains it will expose any weakness in wiring and sockets. It is wise to keep an eye on the plugs/sockets during charging (at least the first time) to make sure they are not overheating.

There are many electrical fatalities. People do silly things, that’s why extension leads are frowned on and manufacturers will not recommend. Clearly the fact that BMW have issued a recall indicates that there have been problems with granny leads where the plug is not fully inserted in the socket and an extension lead just adds another potential safety issue.
 

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Using my granny charger now, works fine, but be prepared its very slow. Took 12 hours last night to charge about 30ish %. That was at 10A.
 

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I've been using a 25m 1.5mm2 extension for about 9 months with the trickle charger. It drops 1 volt per amp at that length.
The EVSE allows the car to draw 7.1 amps.
The wall socket provides 240V at 7.1 amps, 1704 watts.
The EVSE receives 233V at 7.1 amps, 1654 watts.
The Kona gains exactly 2% per hour, so 0.02 x 64kWh/1h is 1280 watts.

So, the trickle charging itself is 1280/1654 = 77% efficient.
The extension wastes another 1704 - 1654 = 50 watts, or 2 watts per metre length.
 

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So for a 10 amp charge you would lose just under 5% volt drop for the 25 meters which is acceptable but near the limit of good practice. There is no need for a larger diameter cable which, as others have said, is a problem terminating in a standard 13 amp plug.
 

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I've been using a 25m 1.5mm2 extension for about 9 months with the trickle charger. It drops 1 volt per amp at that length.
The EVSE allows the car to draw 7.1 amps.
The wall socket provides 240V at 7.1 amps, 1704 watts.
The EVSE receives 233V at 7.1 amps, 1654 watts.
The Kona gains exactly 2% per hour, so 0.02 x 64kWh/1h is 1280 watts.

So, the trickle charging itself is 1280/1654 = 77% efficient.
The extension wastes another 1704 - 1654 = 50 watts, or 2 watts per metre length.
With respect, please note that you can only derive the actual power in an AC circuit from the product of Volts and Amps if the load is a purely resistive one (aka non reactive or linear) when the power factor will be unity or 1.

So your power and charging efficiency calculations are likely to be incorrect (pessimistic). They are not taking into account the power factor for the reactive load (the cars on board charger will likely be highly reactive so the Volts and Amps will not be completely in phase with each other).

This means that the actual Watts being consumed at the 13A socket will likely be somewhat less than the 1704 that you have assumed here. Therefore the charging efficiency will likely be better than 77%.

Nevertheless, your loss calculation for the extension lead will be realistic as the lead itself is a non reactive linear resistance.

To measure the true Watts being consumed at the 13A socket requires the use of a proper AC power analyser instrument that can read true RMS power and will take into account the power factor of a reactive load and the relative phase difference between current and Voltage waveforms.

Peter
 

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With respect, please note that you can only derive the actual power in an AC circuit from the product of Volts and Amps if the load is a purely resistive one (aka non reactive or linear) when the power factor will be unity or 1.

So your power and charging efficiency calculations are likely to be incorrect (pessimistic). They are not taking into account the power factor for the reactive load (the cars on board charger will likely be highly reactive so the Volts and Amps will not be completely in phase with each other).

This means that the actual Watts being consumed at the 13A socket will likely be somewhat less than the 1704 that you have assumed here. Therefore the charging efficiency will likely be better than 77%.

Nevertheless, your loss calculation for the extension lead will be realistic as the lead itself is a non reactive linear resistance.

To measure the true Watts being consumed at the 13A socket requires the use of a proper AC power analyser instrument that can read true RMS power and will take into account the power factor of a reactive load and the relative phase difference between current and Voltage waveforms.

Peter
Technically correct but in practice I believe the car transformer/rectifier will have high power factor, close to 1.0.
 

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You might be right, I’ve not analysed one (yet😉). Certainly there are lots of AC powered switching DC power supplies around which have notoriously bad PF. Hopefully, the on board car chargers won’t be quite so “made down to a price”, so maybe they are engineered to have a good power factor. It would add significant cost to the charger design I think.
Still contemplating ordering my first EV.

Peter
 

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You might be right, I’ve not analysed one (yet😉). Certainly there are lots of AC powered switching DC power supplies around which have notoriously bad PF. Hopefully, the on board car chargers won’t be quite so “made down to a price”, so maybe they are engineered to have a good power factor. It would add significant cost to the charger design I think.
Still contemplating ordering my first EV.

Peter
According to Charged EV, most on-board chargers have active (boost) power factor correction (PFC) where a switched series inductor charges a capacitor. All sounds a bit complicated and one thing is for sure, you won’t find any PF data in an EV sales brochure!
 
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