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Discussion Starter · #1 ·
We all know the blurb, 'it only takes x minutes to charge to 80%'.
If the BMS instead made 80% the new 100%, how many times would you get stuck behind someone charging for 30 minutes at 3kW to get enough charge to exit out of the service station?

That way, the sales blurb would say 'only x minutes to full charge!!'. Then if you want to use the extra 20% 'reserve' it only works via the AC input. The general public are happy to get 100%, and think it is normal.

OK, now list all the problems with this.....
 

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2021 Hyundai Kona Ultimate 64kWh
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This is something along the lines of what Mercedes did with their original B250e and the ability to boost your range. You could charge to 100% (28kWh), or you could push the 'Range Plus' button and charge up to 36kWh, using more or less the entire capacity of the battery including the buffer for occasional use where you need to go further.

The problem is, putting such limits on the cars would likely affect the range numbers that the manufacturers are allowed to quote. Additionally, not every car slows rapid charging speeds at 80%. Some do it much earlier at around 60, meanwhile others can keep going at high speed up to the mid-90's. Finally, your suggestion of making this AC only would just make people abuse the AC Connectors on rapid chargers to keep going all the way, so still blocking them from others who need a charge.

EV Rapid chargers are fully capable of stopping a charge at 80% (on DC Connections only). In fact it used to be a really common feature in the early days. I'm not actually sure why this fell out of fashion.
 

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This is something along the lines of what Mercedes did with their original B250e and the ability to boost your range. You could charge to 100% (28kWh), or you could push the 'Range Plus' button and charge up to 36kWh, using more or less the entire capacity of the battery including the buffer for occasional use where you need to go further.

The problem is, putting such limits on the cars would likely affect the range numbers that the manufacturers are allowed to quote. Additionally, not every car slows rapid charging speeds at 80%. Some do it much earlier at around 60, meanwhile others can keep going at high speed up to the mid-90's. Finally, your suggestion of making this AC only would just make people abuse the AC Connectors on rapid chargers to keep going all the way, so still blocking them from others who need a charge.

EV Rapid chargers are fully capable of stopping a charge at 80% (on DC Connections only). In fact it used to be a really common feature in the early days. I'm not actually sure why this fell out of fashion.
Because the chargers were so shoddy and spaced so far apart, and the gen 1 vehicles range was so low, that you needed 90% or more sometimes to get to the next working charger! And in reality all you had to do was disconnect and reconnect once you hit 80 and it would carry on.
 

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VW ID.3 Worst Edition & Tesla M3 LR
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On my car, even 100% is only 93.5%.

Where does it end?! 🤷

I think the 80% idea for on the road rapid charging is a good one, gives you some idea how long it will take to continue your journey.
 

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Sometimes you may want (or need) to charge higher on a rapid. I needed to get to > 87% in the Leaf 40 at Birchanger in order to collect someone from Stansted and get back to Norwich. It's all very well deciding that 80% is the maximum, but you have to allow for a reasonable amount of discretion around individual circumstances.

The main issue is around information. Most new EV drivers don't have a clue how the rate of rapid charging curves off and many people hate being told what to do, especially by some knowall rocking up and telling them to move. But once they realise they are wasting their own time by charging slowly when they could charge faster by stopping again later then most people would move on.

The rule should be "don't charge over 80% if someone is waiting unless you really need to".
 

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Discussion Starter · #7 ·
Sometimes you may want (or need) to charge higher on a rapid. I needed to get to > 87% in the Leaf 40 at Birchanger in order to collect someone from Stansted and get back to Norwich. It's all very well deciding that 80% is the maximum, but you have to allow for a reasonable amount of discretion around individual circumstances.

The main issue is around information. Most new EV drivers don't have a clue how the rate of rapid charging curves off and many people hate being told what to do, especially by some knowall rocking up and telling them to move. But once they realise they are wasting their own time by charging slowly when they could charge faster by stopping again later then most people would move on.

The rule should be "don't charge over 80% if someone is waiting unless you really need to".
What: there was a working charger at Birchanger?! now I know this is a Christmas fairy tale....
 

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The rule should be "don't charge over 80% if someone is waiting unless you really need to".
Which is exactly what Tesla do - if you plug in at a Supercharger which they know to be busy (and tesla know not only how busy a supercharger currently is, but also how many low-charge teslas are sitting nearby and a reasonable idea of how many are en-route) then the car will pop a message up on screen telling you that max charge is limited to 80% because of this. You can manually override it in some cases, but they can force it if necessary (for example when cars are queuing). If you do not move the car away you rapidly get into significant idle fees (70p/minute if no other bays are free, idle fees are waived if you move the car away within 5 minutes of your charge completing).

On one of the tesla facebook groups someone recently had a £112 supercharger idle bill when their wife went christmas shopping at bluewater and left the car plugged in for 3 hours. No sympathy was forthcoming, as the proof they posted showed that they'd previously had a £70 idle bill waived (tesla tend to waive a first offence in case users were unaware of idle fees).

This kind of system tends to mean that superchargers are very rarely left blocked, relative to other chargers.
 

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80% on Ioniq 38 will see you drawing 14 kW ! You've probably shot off far sooner, as it drops from about 42 to 32 once it hits 50% ...
 

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What: there was a working charger at Birchanger?! now I know this is a Christmas fairy tale....
It was ChaDeMo so slightly more reliable than the Ecotricity CCS offerings. Luckily I never had an issue with that particular charger and I only had to wait one time while an Ipace driver tried to get his head round why he couldn't get 43kW out of the type 2.
 

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Which is exactly what Tesla do - if you plug in at a Supercharger which they know to be busy (and tesla know not only how busy a supercharger currently is, but also how many low-charge teslas are sitting nearby and a reasonable idea of how many are en-route) then the car will pop a message up on screen telling you that max charge is limited to 80% because of this. You can manually override it in some cases, but they can force it if necessary (for example when cars are queuing). If you do not move the car away you rapidly get into significant idle fees (70p/minute if no other bays are free, idle fees are waived if you move the car away within 5 minutes of your charge completing).

On one of the tesla facebook groups someone recently had a £112 supercharger idle bill when their wife went christmas shopping at bluewater and left the car plugged in for 3 hours. No sympathy was forthcoming, as the proof they posted showed that they'd previously had a £70 idle bill waived (tesla tend to waive a first offence in case users were unaware of idle fees).

This kind of system tends to mean that superchargers are very rarely left blocked, relative to other chargers.
As a Tesla shareholder, but not yet a Tesla owner, i wholeheartedly approve of this. (y)
 

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80% on Ioniq 38 will see you drawing 14 kW ! You've probably shot off far sooner, as it drops from about 42 to 32 once it hits 50% ...
yeah but we are also lucky to get 24kW at around 60%!
The new Ioniq with its rather low voltage battery pack isnt exactly best of breed when it comes to charging speed ;-)
 
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