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Old 07-17-2019, 12:59 PM   #9 (permalink)
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ChargE (not yet running) - '92 Mazda MX6 LX
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Originally Posted by oil pan 4 View Post
Most if not all of the public chademo units are 480v 3 phase powered in the US. 3 phase 240 and 208 are probably available for convenience. If you have 480 or whatever is common in Canada maybe 380v? Use that for rapid chargers.
575 VAC is the 'normal' industrial voltage in Canada

What's providing the power?
The feed is coming from a 1250 KVa transformer, through a load center. The load center breaker is rated for 600A continuous.

Probably start there. Mainly what's the voltage?
Then if it's not a big enough transformer, service feeder, or enough remaining capacity to tie into there may be no point in running an mcm size wire.
The cable is over-sized for voltage drop, nominally 3%. 2 runs of 350 MCM is easier to bend around the corners and route into the electrical equipment than a single run of ... 500 MCM maybe?

Depending on which area of the parking lot is dug up and whether they put the cable along a fence or some other area that does not see vehicles parked on top ... 600 - 800 feet from the load center to the common point of the chargers. Sorry for the wishy-washy numbers ... I'm on vacation ... I don't have my design notes handy.

I have learned more about the j1772 protocol. It appears that it can change on the fly in 1 or 2 amp steps from 6 to 70 amps. The pilot signal can chang and direct the car to draw less power. But I do not know of any j1772 setups that talk to each other like that to limit the amps on the feeder, but it appears possible and as if that were the intent of the design.
In a best-case future, where electric cars are purchased as quickly as people replace cars ... it is STILL *VERY* unlikely that we would ever see 600A used for charging electric cars and trip the load center breaker, at least for a long time to come. But due diligence dictates that it be looked into. If there are some vendors investigating how to do it ... that's one more column on my technical evaluation spreadsheet.
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