Public Chargers - Blink and Chargepoint

[FreshAndClean]

What are the Level 2 charging rates of Blink and Chargepoint public chargers. I seem to be finding that Chargepoint chargers support only up to 7.7KW charging rate from some of the specs I see online. Is this correct?

 

[TonyWilliams]

What are the Level 2 charging rates of Blink and Chargepoint public chargers. I seem to be finding that Chargepoint chargers support only up to 7.7KW charging rate from some of the specs I see online. Is this correct?

Virtually all of them have 30 amp service, so the variable is the voltage. Most public charging is at commercial 208 volts, while at your house and most RV parks are 240 volts.

208v * 30 = 6.24kW

240v * 30 = 7.2kW

This is power from the wall, and with 87.5% charger efficiency, the actual energy into the battery is 5.46kW and 6.3kW respectively.

Typically economy of 2.7 miles/kWh around town will result in 14.742 and 17.01 miles per hour of charging respectively.

At your house at 240v and 40amp (or a typical RV park with "50 amp service" using a NEMA 14-50 plug), you will draw 9.6kW from the wall and 8.4kW into the battery, resulting in 22.68 miles per hour charging for the city. For freeway driving at 3.4 miles per kWh (65mph on level ground), that would be 28.6 miles per hour.


MILES GAINED PER HOUR CHARGING @ 70F+ Battery Temp
87.5% charger efficiency

--------------------- 2.7m/kWh --- 3.4m/kWh ---
----------------------- City -------- Freeway ---

6.2kW (208v*30a) ----- 14.7 miles --- 18.9 miles -- most public EVSEs

7.2kW (240v*30a) ----- 17.1 miles --- 21.4 miles -- some public EVSEs

9.6kW (240v*40a) ----- 22.7 miles --- 28.6 miles -- home and RV park


NOTE: Charger begins slowing above approximately 90% battery SOC.

 

[FreshAndClean]

Thanks Tony! This is very helpful. It's sad that despite having somewhat of a public EV charging infrastructure in California that most of it was put in with the charging rate of Leaf and the Volt in mind but not future faster charging EVs.

 

[TonyWilliams]

Thanks Tony! This is very helpful. It's sad that despite having somewhat of a public EV charging infrastructure in California that most of it was put in with the charging rate of Leaf and the Volt in mind but not future faster charging EVs.

Well, 30 amps is almost double the LEAF (2011, 2012 and 2013 "S") and the Volt at 16 amps.

 

[occ]

MILES GAINED PER HOUR CHARGING @ 70F+ Battery Temp
87.5% charger efficiency

--------------------- 2.7m/kWh --- 3.4m/kWh ---
----------------------- City -------- Freeway ---

6.2kW (208v*30a) ----- 14.7 miles --- 18.9 miles -- most public EVSEs

7.2kW (240v*30a) ----- 17.1 miles --- 21.4 miles -- some public EVSEs

9.6kW (240v*40a) ----- 22.7 miles --- 28.6 miles -- home and RV park

Very helpful Tony, thank-you!
Is there a way to know which rate you're getting from the Rav4's charge time estimates, or anything like that?

 

[Dsinned]

Like everything else with the RAV4 EV built-in charger management system, charge time "estimates" are very inaccurate, whether devrived from the instrument panel or from the Entunes smart phone apps (at least it is on the iPhone).

 

[occ]

You'd think it could measure the AC voltage coming in, and also get the Amp rate from J1772 EVSE communication, and get an accurate calculation to display somewhere.

 

[TonyWilliams]

You'd think it could measure the AC voltage coming in, and also get the Amp rate from J1772 EVSE communication, and get an accurate calculation to display somewhere.

Well, there's no way to measure voltage until it starts flowing juice. But, the EVSE does send the 1kHz square wave to let it know how many amps are available. The Pulse Wave Modulation % determines the amp setting (70% equals 42 amps available to the car).

From Chris Howell's basics of the J1772:
http://code.google.com/p/open-evse/wiki/J1772Basics

Proximity Signal

This is a simple check of either 150 ohms (connected) or 150 + 330 ohms (button pushed to disconnect J1772 nozzle). If 150 ohms are present, the Pilot signal can move from State A to State B, for instance.

Pilot

The J1772 Pilot is a 1khz +12V to -12V square wave, the voltage defines the state and the duty cycle defines the current available to the EV. The EVSE sets the duty cycle and the EV adds resistance from the pilot the Ground to vary the voltage. The EVSE reads the voltage and changes state accordingly.

State -- Pilot Voltage High - Pilot Voltage Low - EV Resistance - Description ----- PWM
State A ---- +12v ------------ N/A --------- N/A ---- Not Connected --- DC
State B ---- +9v ------------ (-12v) ------- 2.74k ---- Connected ----- 1000 Hz
State C ---- +6v ------------ (-12v) -------- 882 ----- Charging ------ 1000 Hz
State D ---- +3v ------------ (-12v) -------- 246 - Ventilation Required - 1000 Hz
State E ------ 0 -------------- 0 ----------- N/A ----- No power ------- N/A
State F ----- N/A ----------- (-12v) --------- N/A ---- EVSE Error ------- DC


Max Current

Up to 51A Amps = Duty cycle x 0.6 Duty cycle = Amps / 0.6

51 - 80A Amps = (Duty Cycle - 64) 2.5

Duty - Max
Cycle - Current
< 3% -- (Error)
3% ---- 7% (Digitial Com Required)
10% --- 6A
20% --- 12A
30% --- 18A
40% --- 24A
50% --- 30A
60% --- 36A
70% --- 42A
80% --- 48A
86% --- 55A
88% --- 60A
90% --- 65A
92% --- 70A
94% --- 75A
96% --- 80A
>96% - (Error)

 

[TonyWilliams]

Very helpful Tony, thank-you!
Is there a way to know which rate you're getting from the Rav4's charge time estimates, or anything like that?

No, it's a mess it seems. After coming from the LEAF, I'm already jaded towards that kind of data from the car. You could certainly put a simple multimeter on it to measure volts and amps.

Here's a pic measuring amps on the Clipper Creek:

 

[TonyWilliams]

I've stolen these pictures from Phil S. at www.EVSEupgrade.com:



This one shows the rear of the J1772 inlet. This is where you'd want to connect a voltmeter:

Here's the rear of the inlet after the pin retention basket and pins have been removed. You can see the drain slots:

Here's the bare pins and basket:

 

[gary2020]

has anyone used the blink charge stations located publicly for a fee?

has anyone heard it doing any damage to the car like the pins overheating at these public stations?

also i was reading about the superchargers.
sounds like incompatible with the rav4 since those run on 480v?

thanks

 

[cwerdna]

also i was reading about the superchargers.
sounds like incompatible with the rav4 since those run on 480v?

The plugs are physically incompatible. And, IIRC, Tesla's Superchargers are DC fast chargers. No EVs other than a properly equipped Model S are compatible w/them.

The Rav4 EV has no capability for DC input.

 

[occ]

has anyone used the blink charge stations located publicly for a fee?

has anyone heard it doing any damage to the car like the pins overheating at these public stations?

thanks

I've been using the Blink to charge my LEAF and Rav4EV for a fee several times. I have Blink Network subscription , so I'm charged $1/hr instead of $2/hr or $1.50/hr.

Tony Williams' Rav4 was damaged by a Blink public charger:
http://www.mynissanleaf.com/viewtopic.php?f=26&t=10749&hilit=rav4+blink+damage

from badly crimped pins, causing heat.

The 2011-2012 LEAF only draws 3.3kw, so no problems because it's not drawing enough power through the bad pin to heat things up to failure. But the Rav4EV will, if it encounter a bad Blink. However, I've plugged in my Rav4EV to different Blinks several times without problems. I don't have a cut-off circuit that Tony put in his Rav (see post above), but I have gone back 5-10 min after plugging in and "feel" the nozzle for excessive heat. If it felt excessively warm, I would unplug and go to another. However, I haven't had to do that yet.