80% in 30 minutes? Really?

Really you have to consider a few things:

Unit - some units are slower
Temperature - colder temps mean slower charging
SOC: post 80% the speed goes slowly; it scales too, so the higher your SOC is the slower it goes
Battery Degradation - the more degradation, the slower. At a 3 bar loss, it would take me 45 minutes on the faster QC units in the summer where it used to take me 20 minutes.

cgaydos said:

Starting metrics: 4 capacity bars, 5 temperature bars, 64F ambient temperature
Time to 10 bars: 27 minutes
Time to 11 bars: 32 minutes
Time to 12 bars: 51 minutes

Click to expand...

Another QC visit, different QC but same model (also 20 kW). Starting metrics: 4 capacity bars, 5 temperature bars, 54F ambient temperature
Time to 10 bars: 29 minutes
Time to 11 bars: 37 minutes

Concluding that the "80% to 30 minutes" is a bit of an exaggeration for the 20 kW units that we have in Colorado.

It's 0 to 80% in 30 mins, not +80% charge in 30 mins.

You almost never start your charge at 0%.
Use Leafspy to see exactly what charge you are really starting from.

johnrhansen said:

so if you owned a business and wanted to provide charging for your customers, what would you rather install. 2 chargers that are good for 20KW, or one good for 40 to 50 thinking the cost to install the 2 20s is nearly the same as the big boy.

Click to expand...

Part of the answer depends on the business and location. Are the customers passing through, staying for <1Hr, or staying for >1Hr?

Operating costs can be a big concern. Utilities often tack on a substantial demand charge for exceeding some threshold of demand. A 50kW charger used one time a month can double your electricity bill, even though the change to average monthly consumption may not be detectable. This alone suggests 20kW chargers cost less to operate than 50kW chargers. Start with a single 20kW, then add or upgrade to 50's if there is sufficient demand.

Install first L3 charger such that any of two (or more) parked cars could use the charger. This allows a second customer to arrive and unplug an unattended fully charged vehicle, and use the charger. Plan for a second charger (similar parking), but install later. Place chargers near entrance, but not in front (this leads to ICEd chargers = access to charger blocked by Internal Combustion Engine vehicles).

Expect that users may not be coming to your business. Treat the charger as a service to sell on it's own. Set billing rates that allow the charger to pay for itself.

Don't try to restrict use to only YOUR customers, or only during business hours. These chargers are considered undependable - and speak loudly towards your business. Word gets around (see plugshare.com). EV drivers will be going elsewhere to a charger they reasonably expect they can use when they need it.

You might offer free/reduced billing to your customers. Equivalents to carwash codes and loyalty card points come to mind. Easy to do since, on average, electricity is very low cost (subject to meeting demand charges.)

Find a management company that will operate and maintain the charger, but allow you to set terms (you get all the income, they get paid flat rate each month, you get billed for maint/repairs as required.)

Movie theater: L2
Nice restaurant: L2, 20kW
Fast food: 20kW
Shopping mall: L2, 20kW
Coffee shop: 20kW

Just off interstate freeway(s): 50kW (plan for multiple 50kW)
Truck stop: 50kW (plan for multiple 50kW)
Gas station: 50kW (billing like pay-at-pump with credit/debit or by cashier)
Convenience market (example 7-11): 50kW (billing like pay-at-pump with credit/debit or by cashier)

Slow1 said:

So can you provide some objective data? I.e. for a few sessions, can you provide start %, time spent, and end %? It may help us to understand what you are actually experiencing and relate to our own experiences. Charging rate is definitely a function of the car's level of charge and temp....

Click to expand...

Maximum current (Amps) is applied as long as the voltage is below about 393V (for Leaf). Once voltage reaches 393V, current is tapered down to maintain voltage. All this is controlled by the Leafs on-board charger which is managing the charge.

50kW chargers often reach 393V within 1-3 minutes at 125Amps. 20kW chargers reach 393V in 5-15 minutes at 50Amps (depending on the battery State Of Charge). Once either charger decreases power (Volt x Amp) to about 18kW, they perform the same, requiring the same time to reach 80% SOC (at about 10kW). At 90% SOC, power is <3kW.

Laptop computer batteries are charged the same way.

cgaydos said:

It's been a while since I quick charged, but yesterday I collected some charging stats. First I verified that the QC was in fact 20 kW. Then:

Starting metrics: 4 capacity bars, 5 temperature bars, 64F ambient temperature
Time to 10 bars: 27 minutes
Time to 11 bars: 32 minutes
Time to 12 bars: 51 minutes

It may have been that my perception of the time to charge to just 80% was distorted by the incredibly long time it takes to charge the final bar. But from this it does appear that "charge to 80% in 30 minutes" isn't *that* far off the mark - if the starting point had been 1 bar instead of 4 it probably would have hit 10 bars in 32-35 minutes.

On the other hand, this charging session might have been faster than previous ones for reasons unknown. I certainly was surprised when I did my first check with the Carwings app and saw how fast it had gotten to 9 bars. I'll continue to record the durations for future QC sessions.

Click to expand...

Temperature does play a role. Warmer temperatures allow faster charging. This seems to correlate with the amount of regeneration you get (also temperature dependent.)

Perhaps it only seemed to take longer - you may have been distracted by that potful of water you're trying to boil. Try reconnecting your internal chronometer.

cgaydos said:

cgaydos said:

Starting metrics: 4 capacity bars, 5 temperature bars, 64F ambient temperature
Time to 10 bars: 27 minutes
Time to 11 bars: 32 minutes
Time to 12 bars: 51 minutes

Click to expand...

Another QC visit, different QC but same model (also 20 kW). Starting metrics: 4 capacity bars, 5 temperature bars, 54F ambient temperature
Time to 10 bars: 29 minutes
Time to 11 bars: 37 minutes

Concluding that the "80% to 30 minutes" is a bit of an exaggeration for the 20 kW units that we have in Colorado.

Click to expand...

80% in 20 minutes applies to 50kW chargers.
80% in 60 minutes applies to 20kW chargers.

To my knowledge, the only non-Tesla 50kW DC chargers in Colorado are:
- 50kW AeroVironment CHAdeMO at the Fort Collins Museum of Discovery. This charger works but is very picky, and I have had to call AeroVironment every time that I have used it.
- 50kW efacec CHAdeMO/CCS at the Longmont Museum. I have had problems with this charger in the past but it seems to be reasonably reliable now. You need a smartphone app to use the charger (or you need to call), but otherwise it's pretty easy.
- 50kW ABB CHAdeMO at Canopy Airport Parking valet. This charger is free, but you may need to ask the valet to move a car and you should absolutely tip. This charger is invaluable if you are picking up someone at the airport and are far away - Canopy has let me charge for free on occasion. Canopy also has a number of L2 EVSEs in their covered parking and valet section, which I highly recommend.

Every other non-Tesla DC charger in Colorado is a 20kW ABB CHAdeMO unit to my knowledge. Other than the fact that they are only 20kW, the ABB units seem to work well.