Hi David,
An acquaintance of mine forwarded me your response about his
suggestion for adding EV fast-charging at RV parks. First off, I'd
like to thank you for responding. I agree with your points, but I'd
like to point out that there is no specific technical requirement for
480v or even 3-Phase on CHAdeMO type DC fast charging systems. (though
this could vary across different units) The one requirement that
cannot be avoided is the total power required, Most are rated at 50kW,
and thus require that service be adequate to handle that.
The very first CHAdeMO unit installed in the US (to my knowledge) is
located in Vacaville, CA at the Davis Street Park-and-Ride. It's a
unit made by Tepco imported from Japan. Sadly, although this unit is
fully functional, it's lack of a UL listing is preventing it's use by
the general public, and has been this way pretty much since it was
installed. (There is some fear of liability issues apparently) In
any event, this unit is made for the Japanese power system and so it
is designed for 200v 3-phase. It's presently hooked up to 208v
3-phase on a 200A circuit, and it works properly. In fact, I
personally have charged my Leaf from it on several occasions. This
model can apparently also be set up to run off of single phase
service, obviously requiring substantially higher amperage.
The other thing not commonly understood is that the CHAdeMO system can
be made to operate at lower power levels. For instance, you could
install a standard 50kW unit somewhere that only has 20kW available
(or wants to avoid demand charges), and the charger could be limited
to only provide up to 20kW.
I have designed an add-on module that can be installed in any existing
CHAdeMO QC to limit the power output to a user desired level, and in
addition, it could be connected such that the power limit would be
dynamically adjusted in response to local electrical system demands,
smart grid commands, etc. This is intended to allow installation of a
CHAdeMO QC where it would otherwise be impossible due to power
limitations.
Obviously the down side is that cars charging on these Level 3
chargers would suffer longer recharge times than if the power was not
limited. Still, this is a significant improvement over the J1772
Level 2 charge for vehicles such as the Leaf and the iMiEV. Both
vehicles will gain about a highway mile (more in the city) for each
minute charging at a 20kW reduced CHAdeMO station, which is about a
600% improvement!
This means that a suitably reduced CHAdeMO charger, such as
Nissan/Sumitomo's upcoming >$8k solution could even be installed on a
residential power system, or that of a small business. It would only
require about 85-90 amps single phase 240v, which a common 200A
residential electrical system could likely handle.
Please feel free to share this information where it may be of benefit
to the improvement of our EV charging infrastructure and it's
planning.
Thanks!
-Phil