Vincent
Posts: 11
Joined: Tue Mar 01, 2011 7:37 am

Re: Level 3 (public quick charge stations)

Tue Mar 01, 2011 7:13 pm

KeiJidosha wrote:Mobile L3 is cool and all. But EV charge capable emergency AAA trucks, roaming the freeway, are not a substitute for permanent QC installed in useful locations. The current lack of public charging infrastructure teaches new EV owners that the LEAF is less useful than it could be.
I agree that until a network of QC is widely available, consumers will be more hesitant to purchase an EV. Our mobile solution is not designed to be a replacement for public chargers but rather a complement as Level 3 charging will not be widely available for some time.

KeiJidosha
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Location: Simi Valley, CA

Re: Level 3 (public quick charge stations)

Tue Mar 01, 2011 7:58 pm

Vincent wrote:
KeiJidosha wrote:Mobile L3 is cool and all. But EV charge capable emergency AAA trucks, roaming the freeway, are not a substitute for permanent QC installed in useful locations. The current lack of public charging infrastructure teaches new EV owners that the LEAF is less useful than it could be.
I agree that until a network of QC is widely available, consumers will be more hesitant to purchase an EV. Our mobile solution is not designed to be a replacement for public chargers but rather a complement as Level 3 charging will not be widely available for some time.
Makes sense. Wish you were on the West Coast. Your rig would be a hit at our LEAF get-togethers. It would allow members with range or schedule issues to attend.

GroundLoop
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Re: Level 3 (public quick charge stations)

Wed Mar 02, 2011 1:31 am

If these are deployed before public L3 stations, I see a rash of AAA calls in our future.

"Hi AAA, my car is nearly dead and needs a QC boost. I'm at the HomeTown Buffet in Mira Mesa. See you soon."

Vincent
Posts: 11
Joined: Tue Mar 01, 2011 7:37 am

Re: Level 3 (public quick charge stations)

Wed Mar 02, 2011 7:35 am

drees wrote:
Vincent wrote:The generator that powers the Level 3 charger is 95% efficient. It is fully integrated into the truck and uses the truck's engine to act as the power source for the Level 3 charger. The generator is a 60kW 3-phase unit. Note that the vehicle used to test the mobile application of the DC charger was the Mitsubishi iMiev. Providing a full Level 3 charge (85% of full battery capacity) on the iMiev required 20 minutes and used one gallon of diesel.I know that the battery pack on the Leaf has a different capacity.
There is no way you are converting 95% of the energy of a gallon of diesel into electricity (~38 kWh -> ~36 kWh.) for one reason alone - the truck's engine from which your generator draw's it's kinetic energy to convert to electricity is no more than 45% efficient at it's optimal loading point and most likely less than that since it's not optimized for power generation.

But for the sake of the argument let's assume it's 45% efficient so it's able to convert a gallon of diesel (38 kWh equivalent) into 17 kWh equivalent of kinetic energy. Then your generator which is 95% efficient is able to covert the 17 kWh into 16 kWh of electricity. (This still ignores any conversion losses of the DC quick charger itself which must convert the 3-phase AC to DC for the car - this should be 5% or less, though)

Still quite a bit short of a full charge for the Leaf, but enough to drive it about 50 miles or so - basically equivalent to the appx 50 mpg a TDI gets on the highway. Can't complain about that if you are stranded and need a mobile quick charge to get you to the nearest fixed charging point, though.

It would be interesting to see the official specs, though.
Vincent wrote:*In the interest of full-disclosure, I work for Real Power, the company that created the Mobile DC Charging prototype vehicle.
Funny - your original post indicated that you were a third party. Might want to update that.

Note that this data was obtained while charging a Mitsubishi iMiev and, as I have mentioned earlier, we have not had a chance to charge a Leaf as of yet. The charging vehicle is equipped with a 6.6L Duramax Turbodiesel engine. The generator is a 60kW 3-phase unit and the EV Charging unit is an Eaton model with a 50kW capacity.

1 gallon of diesel = 130,500 BTU = 38.2 kWh

i-MiEV has a 16kW battery pack typical charge is around 12.8kWh (80% charge)

Assume the duramax is 40% efficient, our generator is 90% efficient and the charger is 95% efficient.

38.2 kWh * .4 = 15.28 kWh * .9 = 13.75kWh * .95 = 13.1 kWh or approximately 12.8 kWh


So that is why (and how) we only use 1 gallon of diesel to provide a full Level 3 charge on a Mitsubishi iMiev. It'll be really interesting to see how we perform when charging a Nissan Leaf.

Comments are always welcome!

Herm
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Delivery Date: 29 Aug 2012
Location: Timbuktu, Mali

Re: Level 3 (public quick charge stations)

Wed Mar 02, 2011 7:45 am

90% efficiency out of the generator is pretty good.. that and the Eaton L3 charger are the pricey units, probably a lot more than the truck itself :)

The problem is the lack of cars with L3 charging receptacles.

Vincent
Posts: 11
Joined: Tue Mar 01, 2011 7:37 am

Re: Level 3 (public quick charge stations)

Wed Mar 02, 2011 8:00 am

Herm wrote:90% efficiency out of the generator is pretty good.. that and the Eaton L3 charger are the pricey units, probably a lot more than the truck itself :)

The problem is the lack of cars with L3 charging receptacles.
Agreed.

The Leaf, iMiev (or i) and soon the Think are the only vehicles currently available with a Level 3 receptacle. However, the mobile/rescue charging vehicle also has a Level 2 on board for a "top up" in case of emergency. So it can support all other EV, with the proper charging adapter for the 240-plug.

Also, the generator is actually the least expensive piece of the puzzle. The L3 charger is the most, and the production truck will fall somewhere in between...

Herm
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Location: Timbuktu, Mali

Re: Level 3 (public quick charge stations)

Wed Mar 02, 2011 8:14 am

Hopefully more cars will come out with the chademo L3 charging receptacle, I would think its a way to future proof the car and is not expensive to implement.. basically the connector itself, a relay and some extra wiring.

The L3 chargers are overpriced now due to the uniqueness of their application, but that will come down. They are essentially 50kw variable DC power supplies, outputting 500V DC.

Your trucks could also act like portable generators in emergencies, if fitted with the proper inverter.. that may be an additional revenue stream if you are under contract to the fed, state and local governments.

Vincent
Posts: 11
Joined: Tue Mar 01, 2011 7:37 am

Re: Level 3 (public quick charge stations)

Wed Mar 02, 2011 9:03 am

Herm wrote:Hopefully more cars will come out with the chademo L3 charging receptacle, I would think its a way to future proof the car and is not expensive to implement.. basically the connector itself, a relay and some extra wiring.

The L3 chargers are overpriced now due to the uniqueness of their application, but that will come down. They are essentially 50kw variable DC power supplies, outputting 500V DC.

Your trucks could also act like portable generators in emergencies, if fitted with the proper inverter.. that may be an additional revenue stream if you are under contract to the fed, state and local governments.

Herm,

There's no need for an inverter as our systems produce pure AC from the get-go. Pure sine wave @ 60hz. That is our core business. We already count local, state and Federal government as our clients. Our generator outputs range from 12kW to 150kW, all driven from the truck's engine using a pto gear.

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planet4ever
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Leaf Number: 1537
Location: Morgan Hill, CA, south of San Jose

Re: Level 3 (public quick charge stations)

Thu Mar 03, 2011 12:18 am

Vincent wrote:There's no need for an inverter as our systems produce pure AC from the get-go.
But ... but ... L3 is DC, not AC.
End of April 2013: Traded my 2011 SL for a 2013 S with charge pkg.

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DaveEV
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Re: Level 3 (public quick charge stations)

Thu Mar 03, 2011 12:35 am

planet4ever wrote:
Vincent wrote:There's no need for an inverter as our systems produce pure AC from the get-go.
But ... but ... L3 is DC, not AC.
Yep. A truly integrated mobile quick charge station would integrate that huge L3 DC quick charge station into the area under the flatbed and get rid of the AC/DC conversion which saps an extra 5-10% efficiency out of the system.

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