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More and more I'm seeing people quoting that you can charge at x miles an hour. More and more I'm thinking this is nothing more than a rough personal estimate at best and a dangerously misleading figure at worst.

Why?

People will regularly say to ignore the Nissan LEAF "guessometer" or GOM, because the car doesn't really know the range, it's just based on your consumption over the previous x amount of distance travelled. A very fair point.

Keeping that in mind, surely quoting you're charging at "100 miles an hour", or whatever, is even worse. I say this because it relies on knowing the actual charge being delivered (or an average/flat rate over your total plugged-in time) which is very rarely the number you'd expect. It also relies on knowing your consumption, which is a number open to many variations, past performance is no indication of future returns. So at best "charging at x miles an hour" is an assumption based on two figures that are estimates/averages.

Quoting that number at others could be even more misleading. In my LEAF I may average 3.6 miles per kWh, you may average 4.6, the official figures I don't even know. If I were to tell you, or you tell me, how many "miles per hour" a rapid charger, or even 6.6 kW charger would give me could be very misleading. This then could lead to a fair bit of confusion, disappointment, and even trouble if a journey was planned using those figures.

I know it sounds good, I know it can be a fairly simple expression of charge rates, but could "charging at 100 miles an hour" actually do more harm than good, ranking alongside official EV consumption figures as a handy number, but really of no use to anyone other than yourself in your own personal situation?
 

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People will regularly say to ignore the Nissan LEAF "guessometer" or GOM, because the car doesn't really know the range, it's just based on your consumption over the previous x amount of distance travelled. A very fair point.
I think this is a Leaf specific complaint - it really is a random number generator. The prediction in the i3 is much more accurate and it is much easier to have a handle on your consumption with the different driving modes.

I agree with you that it will never be accurate to measure charge/distance like this, but it isn't quite as bad in other cars.
 
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Charging a nearly empty battery would take about 6.5 hours, so our 3K system will only load about 20 km per hour (if I keep driving like i did in the past)
In my Kangoo ZE, the computer calculates the past consumption (after 12,000 km it is 17.2 KWh/100km) and I try to drive to keep the average on that figure... by driving like that, I get a range of about 130 km in our hilly Belgian Ardennes.
 

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Ian Sampson (rural leafer) quoted a trickle charge mile per hour figure in his latest video that I'd love to see when I plug in - alas my calculation is around nine miles of range added per hour and I drive with a light right foot to maximise economy.
 

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To me, miles per hour is a useful figure for charging (even if not that accurate). It means that if for example I am 35 miles from my destination, and have a range displayed of 10 miles, I need 25 miles of range. If I am at a charger that I know will charge my car at about 10 miles per hour, I can expect to need to wait for about two and a half hours.
 

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To me, miles per hour is a useful figure for charging (even if not that accurate). It means that if for example I am 35 miles from my destination, and have a range displayed of 10 miles, I need 25 miles of range. If I am at a charger that I know will charge my car at about 10 miles per hour, I can expect to need to wait for about two and a half hours.
If it's not accurate, how is it helping? Even if you can work out a rough figure for yourself based on a set of averages to give you some kind of personal ballpark, it surely wouldn't be helpful to a difference C-Zero driver with a different route and different driving style.

I'm also irked by the "rapid charge in 30 minutes" myth for LEAF, but this upcoming "miles per hour" charging rate seems even more of a minefield to me.
 

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I also find the Ampera estimated range to be pretty accurate. I'm not sure whether it's basing the estimates on lifetime history or not, but I find I can make working calculations on range and charging times. Of course, if I 'hoof it' I know that the figures are going to tumble.
 

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It can make sense if you use a fixed fuel efficiency number. If you use the Leaf as an example, and the EPA ratings of 84 miles for 100% charge on a 2013+ car, you have an actual realistic and fixed rate of 4 miles/kWh. That tells you that an hour of 3.3kw charging will give 13 miles of Rated range. Where the Leaf falls down is that it doesn't show you it's Rated range, (kWh in battery divided 4) it shows kWh in battery divided by an estimate of your economy.

Tesla have got this right, the car shows you Rated range, and gives an instant comparable for charge rates, and journeys. i.e. "When you go over the Pennines the distance is only 20 miles but it eats 30 miles of rated range".
 

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Tesla have got this right, the car shows you Rated range, and gives an instant comparable for charge rates, and journeys. i.e. "When you go over the Pennines the distance is only 20 miles but it eats 30 miles of rated range".
Agree the telsa is very good at this, it says I have 100 miles range,
I drive 50 miles and it says I have 50 left.

With regards to the charging at MPH, it has one fantastic use, I can tell my wife how long we need to stop for a charge. Instead of saying roughly 30 mins which we all know in the leaf means 45.
 

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I think giving a mileage figure per hour charging is very useful, albeit an approximation. Without getting too kWh technical with people, saying an xyz charger will give you about xx miles range in an hour is imo a sensible way to approach this.

For a LEAF these per hour figures are what I and other owners have achieved.
A 10 amp EVSE 3 pin plug will give approximately 8-10 miles range regardless of on-board charger fitted.
A 16 or 32 amp home or street unit will give approximately 12-14 miles range with the 3.3kW on-board charger.
A 16 amp home or street unit will give approximately 12-14 miles range with the 6.6kW on-board charger.
A 32 amp home or street unit will give approximately 24-26 miles range with the 6.6kW on-board charger.
 

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I think this is a Leaf specific complaint - it really is a random number generator. The prediction in the i3 is much more accurate and it is much easier to have a handle on your consumption with the different driving modes.

I agree with you that it will never be accurate to measure charge/distance like this, but it isn't quite as bad in other cars.
I actually find the range remaining figure in the Outlander worse than the GOM in the LEAF. I've seen it change its mind by as many as 50 miles during a 70mph motorway run and that's after the EV capability is exhausted.

TBH I don't understand the LEAF bashing re: the GOM. Accurate, of course not - but when your think about it that's an impossibility. I actually find it quite intuitive. Goes down a bit, goes up a bit, but generally seems in the ballpark as driving style changes. The Outlander just seems to punish massively for any motorway use, which probably suggests it's over optimistic in the first place.

Mph charging is almost as meaningless as coming up with a miles per second rate for ICE fuelling. You can't even tie the calc to a charge post type. Even on a CHAdeMO rapid the Outlander charges around half the rate of a LEAF.
 

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I've watched my Ampera charging, via my electricity monitor at home, and it draws a full 3.6kW the whole time it's charging, except about the last 5 minutes when it drops to about 1.5kW
 

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For a LEAF these per hour figures are what I and other owners have achieved.
A 10 amp EVSE 3 pin plug will give approximately 8-10 miles range regardless of on-board charger fitted.
A 16 or 32 amp home or street unit will give approximately 12-14 miles range with the 3.3kW on-board charger.
A 16 amp home or street unit will give approximately 12-14 miles range with the 6.6kW on-board charger.
A 32 amp home or street unit will give approximately 24-26 miles range with the 6.6kW on-board charger.


As a new Leaf owner I completely agree it is useful . But only if realistic figures are used like @Colin has given .
 

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TBH I don't understand the LEAF bashing re: the GOM. Accurate, of course not - but when your think about it that's an impossibility.
It's -completely- stupid. I can do a decent length drive on motorways/dual carriageway (dual carriageway ends less than a half mile from my house) and the GOM is giving me semi realistic number (about 60 miles for full charge). I plug it in at home, and once it's back to 100% it says 95miles, absolutely no chance.

If it either used the average of it's lifetime or a number you can set it would be great. I use the number of amp-hours left in the battery, being ~320wh per ah. So when I see 57ah left at 100% charge I know I can go 57 miles, at 70mph, with the heater on. If i drive slower, I go further, but all the time the number remaining tells me how far I can go at 70mph. This makes far more sense to me than a range number that can go up massively simply because I drive down a short hill. The most I want it to go up is 1 mile for each 320wh regenerated.
 

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The GOM has an impossible task. It can't predict the future. Only you know how your going to drive on your current trip and what elevation changes you will encounter.

I just look at the percentage gauge.

If your going to drive like a saint with very little elevation changes you will get 1 mile per 1% roughly.

If your going to do a mixture of driving it's 85 miles to 100%

If your going to drive like you have stolen it it's 60 miles to 100%

Just like any petrol/diesel car the miles remaining till tank empty is a guess.
 

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Like Dean Harmer, I just look at the percentage guage. The Leaf GOM fails to take account of changes in altitude (which it could get from the GPS system) which means that after a downhill run it will, for the same amount of remaining battery charge estimate a lot more range than after the same run in the opposite (uphill) direction. I calculate on a basis of about 1.2% battery capacity per mile + 3% battery capacity per 100m of climb between my starting point and my destination, remembering that if my starting point is higher than my destination then this latter figure will give a negative amount of consumption.
 

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I've watched my Ampera charging, via my electricity monitor at home, and it draws a full 3.6kW the whole time it's charging, except about the last 5 minutes when it drops to about 1.5kW
Really? What sort of monitor, and how long does it take? Mine charges at 3.0 to 3.1kW.
 

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I think it is a useful approximation and is in now way inferior to a guesstimate. If you charge at 3kW for 5 hours and you have a 24kWh battery to top up, how many miles will the charge you put in get you?

Answer, no idea, because
a) you've got no idea what the starting SOC is,
b) you've got the car's estimate of what the end SOC is,
c) you have no idea what the efficiency of the charging process is,
d) you've no idea of the tail-off in the charger power.

In short, knowing how many kW your charge point delivers, or even how many kWh have been consumed, will be no worse of an estimate than saying; 6mi/hr, 10mi/hr, 20mi/hr, 60mi/hr, which will be no less informative a figure than 2.2, 3.3, 7kw, and 'rapid-charge'.
 

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Really? What sort of monitor, and how long does it take? Mine charges at 3.0 to 3.1kW.
I have two of these in my dual-head charging station (where we charge two Volts):


The exact numbers dance around a little bit. But, having watched the dance long-enough I can say that 240V 14A is the absolute highest these 2012 Volts ever draw. That's 3.36kW. The low-end of the dance when it's not near the end of the charge is maybe around 3.1kW.

(The two EPCs in the charging station are tuned to max at 15A. The RCBO in the charging station is 32A. The breaker in the wall panel is 30A. The high-voltage wiring from the panel throughout the charging station is all 8 AWG. The J1772 cable from the charging station to the EV is rated 50A at 240V.)
 

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I can say that 240V 14A is the absolute highest these 2012 Volts ever draw. That's 3.36kW. The low-end of the dance when it's not near the end of the charge is maybe around 3.1kW.
I concur, these are exactly the figures I have for current drawn by my Ampera (that is, the charger operates on current, not on voltage, and we are therefore 240/230 different in power for the same current).
 
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