In other words, why haven’t we heard of the thousands of EV drivers over the last decade and a half complain about getting stuck with no charge because they didn’t plan properly. It’s because if you have half a brain, you won’t put yourself in that situation. You’ll use your secondary gas car or rent/borrow a gas car or take public transit to make that long trip. It becomes part of your routine mental process, just like you constantly monitoring your cell phone charge state.

Dr.A.Jagadeesh Nellore(AP),India
E-mail: anumakonda.jagadeesh@gmail.com

Size and I’m assuming weight would be big benefits to this system The Chevy Volts dua power plants (battery/generator) add weight and take up room that could otherwise be allotted to passengers or luggage.

The fact that this system is being considered is tribute to GM’s foresight in bringing the Volt to market. GM is in an ideal position to take advantage of advanced power generation technologies such as fuel cells. No other company has a production model that could take advantage of these.

600 vdc
335 amps (67kWh/600×3 – one third of an hour charge time)
5′ for cable length. Obviously could be much shorter with clever design. 2% acceptable loss.
Calculated size 9 AWG

1% acceptable loss = 6 AWG
5% acceptable loss = 13 AWG

As infrequently as most people would use a Level 3 charger (or should we call this a Level 4?) I would think a 5% loss would be acceptable. Charging up with $0.12/kWh power would make the total cost only ~ $0.40 higher.

You see a mistake I made? I’m not used to working with these sort of numbers. I’m sort of a 120vac guy.

And you’d need some honking big connectors.

Do the math with close to 20 minutes. Don’t distort the issue by using five.

0.35kWh/mile. 175 miles. Add in another 10% for charging inefficiency. 18 minutes. Say 67kWh.

(I tried with an online DC calculator and the size looked too small.)

Yes, there could easily be a need for buffering at the site. Some ultracapactors or batteries could do that part of the job as well as lowering peak needs.

Lets walk through this – 175 miles of highway range is about 350Wh for a Volt-style vehicle, or 61kWh. So at what rate do you have to recharge that battery to get 61kWh into the battery in 5 minutes? 1.28MW. How big of copper conductors do you need to push 1.28MW of 600V/2100A DC power back into the battery? The tables I have don’t go up that high – you’d need at least seven 4/0 AWG copper conductors in parallel to carry that much current.

How is the grid going to handle going from 0 to 1.28MW for 5 minutes then turning off? You’d need some sort of grid-side load balance to take some of the load.

What we need is around 175 miles of highway range. That would allow a 500 mile driving day with two short stops. About what people would do with ICEVs.

The question is whether range will increase or fuel cell price decrease fastest.

By the time this becomes commercially viable (5-10 years) batteries will be able to get us around town (100+ miles) no problem. But a four or five hour drive isn’t possible due to a number of issues (battery size, fast recharge, etc). Having a small fuel tank and this as a range extender (if its twice as efficient as ICE) would allow people to drive for 300-400 miles, along with being able to stop, refill the gas tank in five minutes, and be off for another 300 miles.

Range is not so much something to worry about, but it is a reality, an important nuance to bring up. In other words, why haven’t we heard of the thousands of EV drivers over the last decade and a half complain about getting stuck with no charge because they didn’t plan properly. It’s because if you have half a brain, you won’t put yourself in that situation. You’ll use your secondary gas car or rent/borrow a gas car or take public transit to make that long trip. It becomes part of your routine mental process, just like you constantly monitoring your cell phone charge state.

But range COUPLED WITH CHARGE TIMES means that EVs are only practical for certain types of transit. This is an important distinction from range anxiety. You can’t drive cross country very efficiently for example, but you COULD do it as shown by a number of cross country or around the world EV races.

Hopefully people will begin to understand EVs better than they currently do.