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Free Destination Charging: 50x L2 80A Stations @ Caltech, Pasadena, CA

MITE46

Member
Aug 26, 2014
185
384
Los Altos / San Marino
We've been trying to increase EV adoption and transportation sustainability @ Caltech in Pasadena, CA. It took a couple months to get the design in place and things approved, but we have finally started construction. The system is designed to satisfy the needs of a substantial number of EVs, not just a couple of stations here and there.

The goal is to provide free 50x L2 80A stations in a single parking structure for the campus and visitors. Parking Spots are not time enforced, so there is no rush to come back to move your car when it is done.

We're doing 2x 150kva transformers(32inx27inx44in), these made the most sense for the wiring size, distance, expected demand, and parking geometry.

IMG_7247.JPG


They are quite heavy...800lbs, so floor mounting was the easiest method...We also needed 3ft clearance in front of the unit, so the easiest thing was to point them at each other.

IMG_7246.JPG


Stuck my hand in there...

IMG_7250.JPG


We also started mounting the actual stations...it's going to be 30x on one side and 20x on the other...should not have a problem finding an open station.

IMG_7257.JPG


We will have to relocate some of the existing 480v breakers to make space for larger breakers feeding new transformers...We had to take readings to prove we have excess capacity...lots of it.

IMG_7258.JPG


Anyway, the stations will go live in January, 2016. I'll more progress soon...
 

bredi

Member
Jun 9, 2014
294
168
San Francisco
All this work to accommodate your EV stable? :p

This is such great work and I hope other parking structures do EXACTLY this! Well done! PR the heck out of it please!
 

MITE46

Member
Aug 26, 2014
185
384
Los Altos / San Marino
@bredi: Yes..hoping there will be lots of EVs taking advantage of this. We do plan to replicate the this same setup in other garages on and off campus.

@Cosmacelf: OpenEVSE v4 + our own adaptive software and scheduling algorithms
 

swaltner

Active Member
Oct 13, 2012
1,602
1,614
Kansas, USA
Cool on deploying this with OpenEVSE installs that are tied together. Something like that would be required since you're putting equipment that could draw 416 kVA (25 units, 208 Volts, 80 Amps each) sustained on a 150 kVA transformer. Coordination between all the EVSEs would be required. As long as you're below the total power budget, feed an 80 Amp pilot signal to every car, but reserve the ability to ratchet the power available to each car down in the case of a peak demand situation.

Keep us updated, very slick.
 

Cottonwood

Roadster#433, Model S#S37
Feb 27, 2009
5,088
166
Colorado
Cool on deploying this with OpenEVSE installs that are tied together. Something like that would be required since you're putting equipment that could draw 416 kVA (25 units, 208 Volts, 80 Amps each) sustained on a 150 kVA transformer. Coordination between all the EVSEs would be required. As long as you're below the total power budget, feed an 80 Amp pilot signal to every car, but reserve the ability to ratchet the power available to each car down in the case of a peak demand situation.

I had the same concern. Glad that you worked out a great solution.

Great work, on an interesting scale.

For your next garage, consider using 3 each of 480V to 240V single phase transformers. Although not as common as the 3-phase, 480V to 208V transformers, they are available and would provide 15% more charging power to each car.
 

TTT

Member
Jul 10, 2014
359
14
San Diego
Mite46, this is great news, I've been traveling to Pasadena since Sept for a project and have been renting an ICE. Starting next week I'll be driving my MS, but was disappointed when I checked out the two chargers that Plugshare showed in the South Wilson parking structure and found Leafs plugged into both. Will the new stable of chargers be in the same structure? Would appreciate a heads up if they will be available before January
 

KJD

Supporting Member
Dec 14, 2013
1,331
992
SLC, UT
@bredi: Yes..hoping there will be lots of EVs taking advantage of this. We do plan to replicate the this same setup in other garages on and off campus.
@Cosmacelf: OpenEVSE v4 + our own adaptive software and scheduling algorithms
What a great project please keep us posted as it progresses. Would love to hear more details on your adaptive software and scheduling.
 

MITE46

Member
Aug 26, 2014
185
384
Los Altos / San Marino
@Cosmacelf: was able to lure unsuspecting family members during thanksgiving to assemble...got about 20 units done yesterday.

IMG_7333.JPG


Big contactors...

IMG_7336.JPG


@swaltner: Correct, adjustable pilot depending on available capacity and other variables. Have been testing the initial prototype for months now, originally in this thread: http://www.teslamotorsclub.com/showthread.php/45448-HPWC-Hacking/page2

smart-charger.png


Here's a sample of some of the aggregation charts: http://ev.caltech.edu/stations.html

@Cottonwood: had the same thought about 240V vs 208V, raised some concerns about phase imbalance, will take a closer look on the next garage.

@TTT: S Wilson garage will be looked at in the next phase...These stations will be a 5 minute walk away...will keep you updated on the completion date, we will probably have a soft opening in late December.
 

Vger

Active Member
Apr 10, 2009
1,781
210
Salt Spring Island, BC, Canada
Finally someone addressing EVentual charging needs in a strategic fashion. I hope you write this up when done and publish widely.

Lots of other institutions and businesses need to start thinking this way to break the persistent public (and media-hyped) perception that charging infrastructure is (and by implication always will be) insufficient.
 

Cottonwood

Roadster#433, Model S#S37
Feb 27, 2009
5,088
166
Colorado
@Cottonwood: had the same thought about 240V vs 208V, raised some concerns about phase imbalance, will take a closer look on the next garage.

Because the EVSE's in the U.S. are all single phase, as long as you distribute the EVSE's around all three phases and do your monitoring, pilot adjustment on each phase as its own resource/pool, you should not have any problems. In fact, 3, 100 kVA single phase transformers versus 2, 150 kVA 3-phase transformers would give you 3 100 kVA pools for allocation of power instead of 6 50 kVA pools.

Have you had any thoughts about demand charges and how that should factor into your allocation of power (current) to each unit?

Keep up the great work!
 
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Reactions: Big Earl

abasile

TSLA shareholder
Oct 21, 2012
1,630
3,411
San Bernardino Mountains, California
Very impressive project! Having 50 EVSEs in one location will, for some time to come, provide EV drivers with the assurance that there *will* be a place for them to charge, without contention issues.

My personal question is regarding acceptable use. Occasionally we spend the night in Pasadena, visiting at a residence that lacks a good place to charge our LEAF. While it's easiest to "just drive the Prius", we've in the past used our LEAF and hunted down charging locations. We could conceivably leave our 2011 LEAF (with its measly 3.3 kW onboard charger) parked overnight at Caltech and walk from there. Would that be frowned upon? We'd be willing to pay a reasonable fee, though it seems best to avoid charging a whole lot more than the cost of an equivalent amount of gasoline, and a full charge in the LEAF (in terms of drivable miles) is worth only a couple of gallons of gasoline or so.

Buying a Tesla should reduce our need to charge while in Pasadena, though even with a long range EV it's helpful to have destination charging. I also understand that many Caltech affiliates may not have access to residential charging. I hope that many other organizations choose to follow your lead.
 

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