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Discussion Starter · #1 ·
This is a long one, highlights in italic, tl;dr at end...

For a long time now I've had a niggle with EVs and the EV vernacular of "rapid charging".

You will often see claims that rapid chargers can charge an average EV to 80% in 20 minutes, or that they can charge an EV in 30 minutes.

In my experience owning a very "typical" EV (the gen 2 Nissan LEAF) this has never rung true, and the longer I've had it the more it bugs me.


Why?

Because it's leading to a widespread misunderstanding of EV capability and also potentially for rules and guidelines to be put in placed based on myth, not real-world data.

Personally I think this is at least as bad, if not worse, than the official mileage figures EVs are given. At least with careful planning and driving you can get at least close to the figures, but charging times and capabilities are totally beyond the control of the driver.

I know I can't get 80% charge in 20 minutes, or 30 minutes in my Nissan LEAF. The LEAF is NOT a big-battery EV, it's quite typical (perhaps conservative) in its size.

Today I managed to rapid charge at Ecotricity's charger at IKEA Milton Keynes and my experience was typical of my charging over the past 15 months and 11,000 miles or so.

I arrived at the rapid with 19% showing in the car and on the charger. Plugged it in and dashed off for some morning shopping. I arrived back and unplugged 29 minutes later.

Given the car was circa 20% at the start this seems to me a reasonable state of charge to expect people to arrive at a charger with, it's low, but not low enough the Low Battery Warning. This should also mean (from my experience) that the car would not be in the 80-100% charge capacity when we all know it can virtually grind to a halt on CHAdeMO DC charging.

So 30 minutes, on a "cool" charger (no other EV in sight, the fans not going) with a "coldish" battery and away from the notorious (but not commonly shared outside of EV owners) "slow zone". Given that rapid chargers are promoted as charging an EV in 30 minutes, or "80% in 20 minutes", where might you expect me to be when I returned? 100%? 90%?

The IKEA rapid has a habit that many seem to have, it flashes up the time connected and charge delivered VERY quickly. This time, I was armed with my iPhone and ready...

29 minutes of rapid charging. 13.1 kWh of charge delivered. Taking me from 19% to 80% indicated on both the car and charger (they are always within 1-2% accuracy).

That's an indicated charge increase of 60% of the total capacity, and should be closer to about 55% of the 24 kWh total.

This situation will only get worse as people want more range and battery packs increase in size and capacity, or when people's batteries degrade and their range drops (so rely on rapids more frequently). Rapid chargers will potentially have 30 minute charge limits (some people think they have already). This could severely limit the usefulness of rapid chargers (and therefore the EVs that use them) unless they can start pumping in more power more quickly.

And that's before we get to the point ("buffer") where they virtually grind to a halt delivering the final 20%,15%,10% or so.

In short, from my perspective and experience this charging an EV in 20 minutes (even 30) is nonsense and needs to stop being perpetuated by all concerned – at least without carrying very clear disclaimers about what it really means. It's just as bad as giving false impressions over range and just as much a potential let-down to the uninitiated.

2014-10-18 10.19.21.jpg
 

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I have always interpreted this claim that rapid charging charges from near empty to the 80% mark in 30 minutes and under the right conditions in 20. So in your example the claim held true. It's not that it will take you from 19% to 99% in 30 mins. The charge has to slow for the last 2 bars to protect the battery

20 mins is achievable when 7 or 8 temp bars are showing on the battery temp gauge as this is the optimum temperature for charging a Leaf. I've experienced this myself
 

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Discussion Starter · #6 ·
I have always interpreted this claim that rapid charging charges from near empty to the 80% mark in 30 minutes and under the right conditions in 20. So in your example the claim held true. It's not that it will take you from 19% to 99% in 30 mins. The charge has to slow for the last 2 bars to protect the battery

20 mins is achievable when 7 or 8 temp bars are showing on the battery temp gauge as this is the optimum temperature for charging a Leaf. I've experienced this myself
20% is not near empty IMHO, 5%, 10% maybe.

Battery temp was showing at 6 bars.

This rate of charge is very typical from my experience on both longer and shorter journeys.

Also if I had started with MORE charge it would have bumped me in to the really painfully slow 80+ percent charge zone which is even slower, painfully slow if you've something better to do

So even in what are fairly close to ideal test situations I gained about 55% of a full charge, or about 45, 50 miles range.

The oft-repeated headline claim is charging an EV in 30 minutes at these rapids, that just ain't happening.
 

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You got 60% in 30 minutes, however, it's probably not accurate to extrapolate that out to being 80% taking 40 minutes. Maybe 35 as the first 20% will rocket in at high speed, if going from 0%?

Probably not really that bad as marketing lies go though, given the way 0-60 mph times are usually quoted based on a car with semi-slick tyres by a race driver dumping the clutch from max revs on a sticky track ...

Given that even the CHaDEmos can have their charge rate doubled (not sure how complicated, but it was in the spec) there is probably some headroom. The Leaf is also particularly bad at long rapid charging with its lack of any battery cooling, so a properly cooled car on a doubled-up rapid could potentially suck in the same 13 kWh in 15 minutes.
 

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Discussion Starter · #9 ·
But you're not dealing in reality there, and that doesn't help anyone. And no, it doesn't tend to "rocket" from a low state of charge, I've been there before too. It's usually quicker, but it doesn't go much quicker or reverse time. ;)
 

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The claims I see everywhere are "80% in 30 mins". My experience is that it is never normally more than 30 mins to the cut-off point of 80%. I once did take 35 mins but I was almost empty.

Personally, and with over 400 rapid charges behind me, I can honestly say that the claim of "80% in 30 mins" is convincingly substantiated IMO.

Any claims that they charge "to full in 30 mins" are very much misleading but I haven't seen any of those claims anywhere. I have seen "charge in 30 mins" but that doesn't specificy how much so I take that to be the same as the 380% claim as you nearly always only charge to 80% except in special circumstances.

Don't forget that the vast majority of people charging will not be at 20% or below. The claims I see say "charge to 80%" they don't say that it will deliver 80% of the battery capacity in 30 mins... just that you will reach 80% inside 30 mins and that is nearly always true.

There is a degree if impreciseness in all those claims because no where do they say what your starting SOC is.

So whilst I do not see that the "80% in 30 mins" claim as misleading I do feel that the claim only really applies to cars with 20kWh batteries such as the Leaf, i-Miev etc. It doesn't apply at all to the Outlander, Model S or any car that has a wildly different battery capacity.

It does make for a snappy tag-line though.
 

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Below 55% I have always found it runs at full speed of 39 - 43kW. Above 55% it starts to ramp down.

So below 55% it is much faster than at any significant point over 55%.
 

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Discussion Starter · #12 ·
The claims I see everywhere are "80% in 30 mins". My experience is that it is never normally more than 30 mins to the cut-off point of 80%. I once did take 35 mins but I was almost empty.
From empty? Nope. So it's not 80% in 30 minutes. Plus you often tell me that when you see 80% it isn't really.
 

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The claims I have seen say that it charges to 80% in 30 mins and in all but the very rare situations it does just that. I agree, if you are dead empty it may take a little longer but it is a rare occasion when you are that low so the claim is accurate for the vast majority of the time.

I agree, it can sometimes take a little longer but it is very rare. The point I made that it is a tag-line is important here. We need a way to clearly and quickly say what rapid chargers mean. "80% in 30 mins" is a good, snappy way.

I see this as being similar to my reply when someone asks me how far the Leaf will go on a charge... I say "about 100 miles". That gets the message over and is all they need to hear until they want to look into it deeper. You could argue that I lie to them in saying that because it is only 100 miles under very specific circumstances and often less but to explain more you just look a geek. People want snappy, simple answers. "80% in 30 mins" and "range of about 100 miles" both do that. They are not lies but they give an accurate enough impression to get people's attention.

I would not argue the point that the "80% in 30 mins" claim is not completely accurate... but for a tag-line you don't need complete accuracy... just enough to get people's attention.

As for the 80% on car showing as 90% on charger... it still stops at 80% SOC even the charger say 90% for Mk1 cars. This has no bearing on this discussion as we are all talking about 80% SOC... not what it says on the charger :)
 

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Discussion Starter · #14 ·
So where have you seen this quoted?
Lots of places, but I'll just take a really quick google...

Developed by Nissan, the rapid charger units can recharge an electric vehicle, such as the 100% electric Nissan LEAF, from empty to 80% full in just thirty minutes and IKEA will be the first major retailer in the UK to make them available to its customers.
http://www.ikea.com/gb/en/about_ikea/newsitem/electric_vehicle_charging

These units will charge the Nissan Leaf, or other cars using the CHAdeMo protocol, at a rate of 50kW allowing the cars to be charged to 80% of their capacity in just 25 minutes.
http://www.chargemasterplc.com/index.php/applications-rapid/

Rapid Charging allows a LEAF to charge from 0% to 80% in approximately 30 minutes.
The fastest way to charge your LEAF however is by using a Rapid Charger which can charge from 0% to 80% in under 30 minutes.
http://www.nissan.co.uk/GB/en/vehic...battery/charging-nissan-leaf-and-battery.html

A rapid charger, delivering a 80 per cent battery capacity charge in just 30 minutes costs £7.50 per half hour.
http://www.thegreencarwebsite.co.uk...k-launches-new-app-as-charges-are-introduced/

Rapid chargers allow electric vehicles to be charged in 20-30 minutes
http://www.essexhighways.org/Transport-and-Roads/Getting-Around/Driving/Electric-car.aspx

Rapid Chargers (50kW DC/ 43kW AC) - Capable of delivering an 80% charge in around 30 minutes
http://www.aberdeencity.gov.uk/plan...g/transport/pla_electric_vehicle_charging.asp

Rapid chargers, capable of charging an electric vehicle in just 20 minutes, will be installed in Milton Keynes
http://www.milton-keynes.gov.uk/streets-transport-and-parking/parking/electric-vehicle-charge-points

The rapid chargers, supplied and operated by Chargemaster, are some of the first 'tri-standard' units in the UK, allowing EV drivers to charge their cars in approximately 20 minutes.
http://www.fleetnews.co.uk/news/2014/3/12/cross-country-ev-charging-network-launched/49860/

Electric vehicle users will soon are soon to benefit from the introduction of 50 new charging units – which can charge a car in 20 minutes.
http://www.miltonkeynes.co.uk/news/...d-for-faster-charge-points-for-cars-1-5949128

"In the past 12 months we've gone from 8 hours to charge a car to 20 minutes," says Dale Vince, the founder and chief executive of Ecotricity.
Over the past year, Ecotricity say they have installed around 170 of these units, covering 90% of the network.
These allow you to charge your car battery up 80% in 20-30 minutes.
http://www.bbc.co.uk/news/science-environment-29034483

That's just a quick search and there's many more examples day-to-day that absolutely give the impression (as stated by Nissan above) you can charge from 0-80% in or under 30%, and this is with current capacity BEVs, so it will only get less accurate over time.

None of which gives me the impression that I, in my average EV, will get about 55-60% charge in half an hour, and that's the reality that many of us are faced with.
 

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But I still say that you are expecting total accuracy from these statements. They all give a reasonable impression even though they are mostly not 100% accurate.

What would you say then... bearing in mind you need to get over the idea of what a rapid charger does... not the details... just the impression? It must be easy to explain without complexity as all those are.

Remember... it is not a lesson... it is PR. You can have a degree of inaccuracy to get the message over.

EDIT: I don't have an issue with any of those. They give the right impression and all are within a reasonable scope of what happens in real-life IMO.
 

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You "can" charge from 0 to 80 percent in 30 minutes. But the battery has to be at the right temperature and the charger has to be a fully amped up charger. It doesn't mean you can always do it though.
 

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As others have said, I haven't seen too many claims of 20 minutes (I know that was on those MK council tweets recently, but that's the only time I can recall).
My experience is that it pretty much always gets me to 80% in 30 minutes regardless of what level I start at, so the claims are about right, I feel.

Yesterday I rapid charged while grabbing food. I started at 20%, was charging for 14 minutes, and left with 65% showing. I'd say that's pretty decent.
 

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Discussion Starter · #19 ·
But I still say that you are expecting total accuracy from these statements. They all give a reasonable impression even though they are mostly not 100% accurate.
Nissan UK says:

Rapid Charging allows a LEAF to charge from 0% to 80% in approximately 30 minutes.

The fastest way to charge your LEAF however is by using a Rapid Charger which can charge from 0% to 80% in under 30 minutes.
As someone uneducated and looking to learn, should I not be able to trust "the source"? It's just not true.

If we were talking a few minutes, a couple of miles or similar it wouldn't matter so much, but most EVs have short range (shorter than manufacturers given numbers) and take longer to charge than they're saying.

I'm singling out Nissan and the LEAF because I have one, and I know what I've got and I don't want to give false impressions – under sell and over deliver, not the opposite.
 

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Discussion Starter · #20 ·
Yes. So most mention charging TO 80% in 30 mins which is what you are experiencing but complaining about.
Read them again, they're not saying a 55-60% charge in 30 minutes. Which is what I got.

The Nissan quotes in particular are very clear.

To me it's about managing expectations and not making false promises. In 11,000 miles, many rapid charges and 15 months I've never seen 80% of my battery filled in 30 minutes at a rapid charger.
 
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