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OK, my first post while waiting for my e Golf to arrive on Tuesday!

I want to keep a track of how much electricity I use while charging my car overnight. I've found something but I cannot add a link as a newbie. It's an Energenie ENER007 Energy Saving Power Meter Socket.

Has anyone any experience of these things? Or other options, I know there are many.

This one is rated to 3120W. Is that OK for the charger? Is the charger a component part of the cable or of the car?

So many questions, that will do for now.

Thanks in advance

Geoff
 

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OK, my first post while waiting for my e Golf to arrive on Tuesday!

I want to keep a track of how much electricity I use while charging my car overnight. I've found something but I cannot add a link as a newbie. It's an Energenie ENER007 Energy Saving Power Meter Socket.

Has anyone any experience of these things? Or other options, I know there are many.

This one is rated to 3120W. Is that OK for the charger? Is the charger a component part of the cable or of the car?

So many questions, that will do for now.

Thanks in advance

Geoff
Welcome to the world of EVs!

Sorry to answer with a question, but how are you going to charge? Via a 3 pin "granny" charger or will you be fitting a dedicated chargepoint to your property? If you don't own the property that may not be an option.

The Golf records how much energy is used to charge it, so you could rely on that. However, if you charge up elsewhere (work, rapids, etc.) it'll be hard to know how which charge is from home. Most dedicated chargepoints also record how much energy is passed to the car (to report back to the OLEV) and you can access this via an app (although not all will distinguish between more than one car using the chargepoint).

So only if you wish to use a "Granny" charger and don't trust the readings from the vehicle do you need to use a meter. Incidentally, "Granny" chargers run at most at 10 amps so you'll be using less than 2400W so the one that you suggest should be sufficiently rated. Beware about where you situate it and the effect of any water ingress.

Cheers

Duncan
 

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Discussion Starter #3
Welcome to the world of EVs!

Sorry to answer with a question, but how are you going to charge? Via a 3 pin "granny" charger or will you be fitting a dedicated chargepoint to your property? If you don't own the property that may not be an option.

The Golf records how much energy is used to charge it, so you could rely on that. However, if you charge up elsewhere (work, rapids, etc.) it'll be hard to know how which charge is from home. Most dedicated chargepoints also record how much energy is passed to the car (to report back to the OLEV) and you can access this via an app (although not all will distinguish between more than one car using the chargepoint).

So only if you wish to use a "Granny" charger and don't trust the readings from the vehicle do you need to use a meter. Incidentally, "Granny" chargers run at most at 10 amps so you'll be using less than 2400W so the one that you suggest should be sufficiently rated. Beware about where you situate it and the effect of any water ingress.

Cheers

Duncan
Thanks Duncan.

I had to check out what you meant by a "granny" charger 😀 and yes, I am going to use a "granny" charger.

I will only ever charge from home and no problems, I have a nice watertight garage. Will never need to thump charge into it quickly, so happy with the 3 pin domestic option for now.
 

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Just one word of caution. The 13A plugs and sockets for granny charging do get warm and can overheat because they are on continuously for very long periods of time.

So 1 - Make sure the socket in the garage is a good one and in good condition - if it's old it may be worth replacing it with a new MK or similar make.
And 2 - with that energy meter between the granny plug and the socket don't let the weight of the actual charger and cables hang on the plug. With the extra leverage it may bend the contacts in the socket and thus cause a poor connection which makes overheating more likely. If the charger has a loop or eye it'll just need a suitably placed hook on the wall, otherwise you'll have to be creative.
 

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So it seems that will be a suitable meter for you!

Just as a point of order, "Granny" chargers are Level 2 devices and marginally less safe than Level 3 devices such as dedicated chargepoints (due to the un-controlled section of cable between the plug and the "box").

You might want to consider a dedicated charger to charge at a higher rate to take advantage of lower tariff schemes such as OctopusGo (and others) where they have a limited time at the cheaper rate (4 hours at 1/3rd of the cost). This means that I choose to charge faster than is possible through a "Granny" lead to get all of my charge in that period. Clearly your circumstances might be different depending on your tariff, your efficiency in driving and the length of your journey. For the record my commute is 60 miles round trip, I average about 5 miles/KWh and hence need 12 KWh which in 4 hours is approx 3 KW/h - a "Granny" charger max's at 2.3 KW/h which would add nearly 50% to the overall cost of my charge (12KWh @ 5p = 60p or 9.2KWh @ 5p + 2.8 @ 15p = 88p) and any extra mileage would all be at the higher cost.

Cheers
 

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Also consider that granny chargers are known to degrade over time! Mine did 4 years hard work, and started tripping at 10A, so I reduced to using 8; then that started tripping, so I reduced to 6A. Then I stripped it & analysed the problem. They use chunky relays as the contactors, and over time these wear, and the resistance slowly increases as the points erode. Then the internal heat dissipation increases, to the point where the built-in temp sensor says "enough" and trips out. Time to replace the relays, which I did.

So if you're critically dependent on your granny charger for reliable commuting, what's your backup plan if it fails? It's really worthwhile to fit a proper wall charger if at all poss. At the very least, you might consider getting a spare granny from eBay/screwfix/wherever.
 

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Is the charger a component part of the cable or of the car?
Strictly speaking the 'granny' charger isn't actually a charger at all, and neither are the fixed home 'chargers' up to 7kW or so.
The actual charger is part of the car and the granny or wall mounted boxes are interfaces between the mains supply and the car. They communicate with the car and perform some basic safety and other checks before turning the power on, and also tell the car what is the maximum current it's allowed to draw from that supply (10A for most grannies).
 

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Just as a point of order, "Granny" chargers are Level 2 devices and marginally less safe than Level 3 devices such as dedicated chargepoints (due to the un-controlled section of cable between the plug and the "box").
Not quite:

Granny chargers are Level 1 EVSEs (portable AC supply equipment)
Wall boxes are Level 2 EVSEs (dedicated AC supply equipment) as are most AC public chargers.
DC chargers are Level 3 EVSEs (dedicated DC supply equipment.)

In European nomenclature these are Modes 1 - 4:

Mode 1 - Not used for most EVs (electric motorcycles, original i-MIEV and I think the Twizy use this; essentially direct mains to the vehicle)
Mode 2 - Granny cables that we are used to (protected portable AC supply equipment)
Mode 3 - AC charging stations
Mode 4 - DC charging stations
 
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