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So I found myself at an Ecotricity charger today, having just plugged in my Leaf, and an Audi e-tron driver pulled up, plugged in and tried to authenticate to start a session.

I thought of a rather good way of explaining the limitations of DBT chargers.

"They're rapid chargers, they can only fill one vehicle at once, a bit like a normal filling station pump can't dispense petrol and diesel at the same time, even though they've got hoses for each".

Which was my polite way of saying "that's an e-tron, it doesn't rapid charge".

And when I came back after my break, I found he'd left the AC connector in the raincatcher position.

Aside from rapid chargers, I'm only aware of the Source London IER charge points that have multiple outlets, but can only charge one vehicle at a time.
 

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Zoe Devotee
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Was it in the rain catcher position before the charge? My guess is not, can't say I'm surprised.
 

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TBH, I've not seen any public chargers, but it does sound like a totally stupid design. I can't see any good reason why the charger couldn't have been designed so that both outlets could be used at the same time, with both of them reduced down from their maximum power if both used, or operating at full power if only one is used.
 

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TBH, I've not seen any public chargers, but it does sound like a totally stupid design. I can't see any good reason why the charger couldn't have been designed so that both outlets could be used at the same time, with both of them reduced down from their maximum power if both used, or operating at full power if only one is used.
I'm not sure what is the advantage of having two vehicles charging at the same time but taking twice as long for each vehicle. The first one to start will be dalayed , whilst the second to start will not actually gain anything as the whole procedure will take longer. It would be similar to trying to run two shoppers through one till in a supermarket at the same time, possible but pointless.
 

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Well, it'd stop people moaning about people charging too long. If there were sufficient bays and the electricity was just shared amongst everyone plugged in, nobody loses.

For example with a single 32A 3-phase supply, you could charge 3 cars at 32A, 6 cars at 16A, 9 cars at 10A, 12 cars at 8A, 15 cars at 6A, etc... It'd be cheaper than fitting rapid chargers to every bay, but often people would still get 7kW, you'd be able to get a lot more people plugged in and getting some benefit rather than milling around hoping to get into the bay when the current person leaves, it could even by dynamic so you get more current for the first 30 minutes and less after that, and it'd be a perfect fit e.g. for the IKEA situation where the car park owner wants people to spend a reasonable time in the store.
 

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I'm not sure what is the advantage of having two vehicles charging at the same time but taking twice as long for each vehicle. The first one to start will be delayed , whilst the second to start will not actually gain anything as the whole procedure will take longer. It would be similar to trying to run two shoppers through one till in a supermarket at the same time, possible but pointless.
If the second car does not start charging until the first one has finished, the first driver is not delayed and there is the advantage is that the second driver can connect up, verify his charging method, and go and do something more interesting (such as have a cup of coffee) rather than having to hang around waiting for the first driver to return, with a second advantage that as soon as the first car stops charging, the second car will start charging without either driver having to be present. At the minimum, it will increase utilisation of the charger as the dead time while the first car is being disconnected and the second one is being connected and the second driver's charging method is verified. This is similar to having a separate pay point at a supermarket checkout, so that the checkout operator can start checking the second customer's purchases while the first customer is paying for and bagging the last of their purchases.

With a bit more engineering, if the first car is not taking the full capacity of the charger, then the second car can start charging at a controlled reduced rate (ie using the remaining capacity of the charger / electricity supply) and this will reduce the overall time for both cars to charge. [This is assuming the charger can run continuously at full power, and does not need the gaps (while one driver unplugs and the second driver plugs in) to cool off!!].
 

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Bloomin eck, to get a rapid to just pump electrons on one car at a time every time is proving troublesome.
Imagine adding those extras controls into a DBT charger. Good luck with achieving 30% network availability.
 

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I'm not sure what is the advantage of having two vehicles charging at the same time but taking twice as long for each vehicle. The first one to start will be dalayed , whilst the second to start will not actually gain anything as the whole procedure will take longer. It would be similar to trying to run two shoppers through one till in a supermarket at the same time, possible but pointless.
Charge rate tapering.

For most cars, for most of the duration of a rapid charge session, the charger is not actually running at full speed because the charging rate slows down. So there's unused capacity which could be more efficiently used if shared between two cars.

This is the Tesla Supercharger model - each charging unit feeds two supercharger bays which share the available power if two cars are connected at the same time.
 

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Bloomin eck, to get a rapid to just pump electrons on one car at a time every time is proving troublesome.
Imagine adding those extras controls into a DBT charger. Good luck with achieving 30% network availability.
You mean the availability will rise to 30% WOW:whistle:

Richard
 

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Charge rate tapering.

For most cars, for most of the duration of a rapid charge session, the charger is not actually running at full speed because the charging rate slows down. So there's unused capacity which could be more efficiently used if shared between two cars.

This is the Tesla Supercharger model - each charging unit feeds two supercharger bays which share the available power if two cars are connected at the same time.
There's another thread about how charging for rapids should be implemented - by kwh or by time.

With charge tapering that will mean both cars are slower to charge but would then be stung by a higher cost if charging (cost) is based on time.
 

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With charge tapering that will mean both cars are slower to charge but would then be stung by a higher cost if charging (cost) is based on time.
If the two cars share on a first come first served basis (ie the second car only gets any spare capacity until the first car has finished) the first car is not delayed, and the second car will finish its charging earlier than if its driver had had to wait for the first car to finish before connecting up. As charger hogging would be less of a problem, charging (cost) by the kWh would be more logical.
 
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