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Discussion Starter #1 (Edited)
So last night we did a charge on our Zoe R40. So it was reporting 26% full so I guested that it needed 3/4 of a full charge. So I assume this is somewhere around 30kWhrs. In the morning the Chargemaster reports that it used 39kWhr. Looks like about 9kWhr went missing somewhere.
Does anyone know a typical kWhr usage to fully charge the car?
I am guessing at this rate approx 50kWhr per full charge.
 

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Is it a Q model by chance? They aren't very efficient on lower charging rates so a lot of kWh is wasted as heat. I assume you have 7kW charger?
 

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had an R240, got an R90, might get a ZE50
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I have a Chargemaster and I wouldn't trust the data.
I would trust your electric meter, it is worth reading this before and after a charge. Obviously you need to allow for some domestic load.
The Q is less efficient at 7kW than the R according to Renault, they show this in increased time for charging the Q.
 

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Probably a bit of both factors.

Charging is only about 90% efficient so putting 30kWh into the battery requires about 33kWh from the socket.

But 39kWh is too high - the chargemaster unit may well be reading wrongly.

Is your supply voltage particularly low? Assuming the chargepoint just has a current clamp it might be assuming nominal voltage which will mean it overestimates energy delivered if supply voltage is low.
 

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90% efficiency on a 32A charger is probably about right for an R90 but user reports on the Q90 claim less. Also at 16A efficiency is far worse for both, hence my questions to OP.
 

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Better to check how many units used on the electric meter
The chargemaster always seams higher when i charge at home
 

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I wonder if you could use a cheap electric monitor from eBay*
The one that clamps on the mains cable but instead clamp it on the chargemaster cable to check usage only from the charger alone.
Would it work?

*Like the one below in the link

ONZO Smart Energy Electricity Monitor Starter Pack * Usage Meter * NEW Boxed | eBay
Problem with these clamp on meters is that they only measure current, not power. They take the current measurement and simply multiply it by a guesstimated constant derived from typical mains voltage, and typical power factor, to come up with a power figure.

This is fine if you want to get an idea of relative consumption of your appliances, or a sense of your energy usage from time to time, but no use at all if you are specifically trying to test the accuracy of another meter.
 

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This kind of micromanagement and checking of figures will drive most people mad, and waste a lot of time.

Do you work out how many kWh’s your fridge uses, or your kettle, or your television?
Your car uses as much as it uses, if you want to try and maximise your savings then drive more efficiently, but your time is worth more money than the cost of electricity.
 

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I hope that when I tell these people that their yearly petrol bill will go from £2000 to £400 ( for electricity) that they rush out and order a Zoe or indeed any electric car.
But having a detailed and precise knowledge of your own savings won't allow you to tell anyone what their fuel savings will be; you'll only be able to tell them yours. Since other people have different ICE cars, drive with differing levels of efficiency, take different types of journeys, pay different amounts for their home electricity, make differing attempts to find the cheapest petrol station etc etc etc the best you can ever offer someone is a rough estimate of what they might save anyway.

So just pick either 4x or 5x as your preferred factor and go with that.

(For me going from a gas guzzling car to E7 energy it's about 8x cheaper as it happens, whereas if you're comparing a Suzuki Ignis 1.2 SVHS to the average domestic standard energy tariff it's barely even 2x cheaper)
 

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Play by the king and love is all I bring
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My Q210 was recently flat-bedded home as she ran out of charge at the end of my street. She was completely and utterly dead at 0%. I checked the OLEV meter before and after charging to 100%. She consumed exactly 29.0 kWh to charge the battery to 22.0 kWh. The Zoe is rather ineffecient at charging. 5.0 kWh were lost.
 

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Play by the king and love is all I bring
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7kW 32A single phase.
 
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Play by the king and love is all I bring
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(Sarcasm) Seems she was very hungry and didn't eat in a lady-like manner; spilled some food on the table and floor.
Rather ironic, being that she's French. I expect nothing but impeccable table manners.
 

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I recently did a 7kW single phase charge for a couple of hours at a PodPoint, which claimed to have delivered 14.4 kWH. This took the ZE40 R90 from 25% to 56%, which equates to about 12.7 kWH or 88% charging efficiency.

That seems to be a pretty close match to Renault Zoe charging time and efficiency - Push EVs

A similar calculation at 22kW yields and 87.5% efficiency for 16.4kWH delivered from the pump, so it's perhaps not an exact science, at least not without CanZE

So it really depends on if you have the R90 or Q90, but the rates published above seem to match my experience in real life with the R90.
 

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Co-author of CanZE. Q210 nov 2013
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My Q210 was recently flat-bedded home as she ran out of charge at the end of my street. She was completely and utterly dead at 0%. I checked the OLEV meter before and after charging to 100%. She consumed exactly 29.0 kWh to charge the battery to 22.0 kWh. The Zoe is rather ineffecient at charging. 5.0 kWh were lost.
Speculation alert!
thought a bit more about this. As you completely drained the battery, including the reduced performance etc, I would think it is possible (but not a given!) that it used some of the "foot room" *) and therefor effectively took in somewhere between 22 and 24 kWh. It is also possible that the relatively deep discharge led to some extra balancing, which is a good thing, but it involves bleeding off energy to the cosmos **)

*) I have no better word for the other end of "head room". I am open too better suggestions. Important thing is we know what we're talking about, the bottom charge not available for normal use to avoid excessive battery strain (and possibly that last few bunch of electrons to just get home in turtle mode);

**) I don't think ZOE has the "creme-de-la-creme" balancer that uses charge transfer. The LBC is a pretty small box and I cannot imagine they could stuff that in there. I could be wrong of course.
 

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This kind of micromanagement and checking of figures will drive most people mad, and waste a lot of time.

Do you work out how many kWh’s your fridge uses, or your kettle, or your television?
Your car uses as much as it uses, if you want to try and maximise your savings then drive more efficiently, but your time is worth more money than the cost of electricity.
I do when i buy my appliances... Worked out my fridge paid for itself within 3 years when working out running costs to similar models...I've noticed the leaf is more more efficient with charging than the Volvo phev too, and that annoys me! I tend to work out running costs before I buy, I admit I've never met anyone else who does this...

weirdly this doesn't translate into my driving style!

i would love to know usage for charging different ev's from empty! to me its like comparing mpg, say 2 eve's have 30kwh batteries one takes 33 to charge and the other 38 if they are comparable cars I'd get the one that uses less energy to charge, assuming both use similar amounts when driving, we charge one phev and one Bev everyday, over a year that adds up, also eventually i want to get solar, knowing the amount the cars take will help decide on what kind of battery storage to buy, assuming i still have a job when the time comes!

pre ev we would use upto 3 kwh a day, now we use upto 35 a day.
 

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i would love to know usage for charging different ev's from empty! to me its like comparing mpg, say 2 eve's have 30kwh batteries one takes 33 to charge and the other 38 if they are comparable cars I'd get the one that uses less energy to charge, assuming both use similar amounts when driving, we charge one phev and one Bev everyday, over a year that adds up, also eventually i want to get solar, knowing the amount the cars take will help decide on what kind of battery storage to buy, assuming i still have a job when the time comes!
At least in the US the mpge figures quoted for EVs are based on wall-to-wheel usage i.e. they take account of charging efficiency, so buyers comparing vehicles there should be getting a reasonably fair comparison of efficiency.
 
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