edatoakrun
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The “range–extended” EV (BEVx) considered

Thu Nov 17, 2011 8:50 am

The ideas below have been posted on many threads, by many members. But now that many now have had more BEV experience and winter is here (I may get to try out my LEAF in the snow for the first time here in North California, tomorrow) I thought maybe there would be interest in a dedicated thread.

I’m still not so ready to totally write off the ICE, as many on this site seem to be.

In fact, a true ICE ”range extender” for a BEV is not a bad Idea, It's just that current designs are all abysmal failures, from the point of energy efficiency and driver utility. Putting an ICE drivetrain in an EV, whether in series, parallel, or any other hybrid configuration, is not advisable, IMO. Invariably, you will get an overweight, overpriced, underperforming vehicle, like the Volt. It seems almost as ridiculous, to install an extremely expensive and heavy large battery pack (like the Tesla S long-range options) which is only occasionally required by the BEV driver.

A functional range extender would consist of:

A small displacement (200-600 CC) ICE generator, run at highest-efficiency rpm, to recharge the battery pack. Generator output would not be sufficient to drive the vehicle, just enough to extend the battery pack range to the next convenient recharge location.

It would not run on gasoline, but a less polluting, and more stable fuel, such as propane (easier refueling) or CNG (lower cost). 5 gallons of Propane, for example, would probably offer about 200 miles of range extention for a LEAF-sized BEV.

The fuel would also be available to a combustion cabin heater, the one use for which battery energy storage is particularly inefficient.

I think this could be integrated into the design of BEVs (and maybe even as a portable unit, and available for rent, as many have fantasized) at lower cost, and lower weight, than the huge battery packs some BEV manufactures seem to think are advisable.

So, say you are a San Francisco Bay Area resident. You usually keep the heater set to propane by default in the winter, extending the range by about 10% and reducing battery cycling accordingly, without even using the ICE feature. You refill the 5 gallon propane tank once a month or so, just to supply the heater.

When you want to take the BEV on the occasional longer drive, say to Tahoe for a weekend of skiing, instead of making 3 or 4 stops (with a 20-30 available kWh battery pack) for DC charges, you just turn on the ICE generator during your trip, as soon as your battery capacity drops to a level to efficiently accept charge, while you and your passengers are kept toasty warm by the propane heater. You stop for one 30 minute 80% DC charge at Auburn (120 miles in 2 hours of driving, about 20 kWh consumed from the battery pack, and 16 kWh used from the generator) and top-off the propane tank (you only used a few gallons) at the adjacent minimart. This is just enough generator-assisted charge to get you the last 80 miles over Donner Summit to your destination, but you never get “range anxiety" (or BEV "freeze anxiety" about road closures or delays, due to weather) as you know that if you get the “very low battery” warning, you can just pull off the road, and if there is no charge station (or only a L2) nearby, you can always find a place to stop for a short break, while you self-recharge for the last few miles, using your generator. And if you get stuck behind a semi that jackknifed in a snowstorm, closing the road, you can watch the generator add bars to your battery, as the propane heater keeps you and your passenger comfortable, while you wait for the road to be cleared.

I believe BMW may be the only manufacture currently contemplating this true ICE “range extender” option, for its BEVs.

Personally, I believe that the several thousand dollars (?) of increased cost, and few dozen gallons of fossil fuel I would use per year, might be an acceptable price to pay for the increased functionality. I hope that, in the near future, there will be many production "EREVs" worth considering.
Last edited by edatoakrun on Tue Jan 31, 2012 1:21 pm, edited 1 time in total.
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mksE55
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Re: The “range–extended” EV considered

Thu Nov 17, 2011 10:35 am

interesting substitution that may be worth while, and options for buying now or getting later. how about portability as maybe it drops in the back trunk area. C an be removed when not needed. like a small portable Honda generator ( even better if you could use it as a free standing generator for emergency purposes. I guess it really all comes down to how many more miles a BEV would need to go on a charge not to really need a backup. I would say a true 120-150mile range would negate any need for ICE or other assist for a BEV.
Bye Bye Exxon , Shell, Mobil
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Herm
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Re: The “range–extended” EV considered

Thu Nov 17, 2011 11:53 am

You dont need a very big genset if you start it up right at the beginning of your trip.. it may not be enough to sustain a speed above 70mph once the battery is depleted but you can always slow down once that happens.

edatoakrun
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Re: The “range–extended” EV considered

Thu Nov 17, 2011 12:19 pm

Herm wrote:You dont need a very big genset if you start it up right at the beginning of your trip.. it may not be enough to sustain a speed above 70mph once the battery is depleted but you can always slow down once that happens.


Correct. In the example I gave, the 8 kWh generator would only power the car, what, about 30-40 mph on a level drive?

It would be unable to climb any hill at that speed, and generally not be safe for highways, however. So the manufacture would probably prevent driving below battery capacity corresponding to "turtle" range, of a few percent, for long distances.

You could get a cup of coffee, while you wait for some charge to build up.

BTW, Herm, I actually started this post as a reply to your extended-range 400 lb. extra extended-range battery suggestion, on another thread, but it sort of grew on me...
Last edited by edatoakrun on Thu Nov 17, 2011 12:30 pm, edited 1 time in total.
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smkettner
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Re: The “range–extended” EV considered

Thu Nov 17, 2011 12:28 pm

The manufacturer will need to incorporate this in the original design.
Personally I prefer a rental trailer with either a battery or generator.

You can talk about it all day..... right now the only current option is a PHEV.
1 bar lost at 21,451 miles, 16 months.
2 bar lost at 35,339 miles, 25 months.
LEAF traded at 45,400 miles for a RAV4-EV

edatoakrun
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Re: The “range–extended” EV considered

Thu Nov 17, 2011 12:36 pm

"smkettner"]The manufacturer will need to incorporate this in the original design...


Of course, that's the idea.

A true range extending generator, with an ICE of only 200-600 CC capacity, should not be large enough to require a trailer.
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smkettner
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Re: The “range–extended” EV considered

Thu Nov 17, 2011 12:42 pm

Two reasons I prefer a trailer.

1) I prefer to have no emission control regulations and cost apply to the vehicle.
2) I have not needed a range extender in 8300 miles so a rental if ever needed seems better than adding all the permanent maintenance.
1 bar lost at 21,451 miles, 16 months.
2 bar lost at 35,339 miles, 25 months.
LEAF traded at 45,400 miles for a RAV4-EV

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davewill
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Re: The “range–extended” EV considered

Thu Nov 17, 2011 12:53 pm

If I'm going to the bother of renting a trailer, especially one that can't keep up with the energy expenditure and requires me to stop and recharge anyway, I'd rather just have it be an auxiliary battery than a generator. I can recharge it separately as I go, or trade it for a fresh one as needed. Besides, most small generators are HORRIBLE when it comes to emissions, something that I greatly care about. It would be better just to rent a Prius.
Last edited by davewill on Thu Nov 17, 2011 12:56 pm, edited 1 time in total.
2014 Rav4 EV, Blizzard Pearl White
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edatoakrun
Posts: 4298
Joined: Thu Nov 11, 2010 9:33 am
Delivery Date: 15 May 2011
Leaf Number: 2184
Location: Shasta County, North California

Re: The “range–extended” EV considered

Thu Nov 17, 2011 12:56 pm

smkettner wrote:Two reasons I prefer a trailer.

1) I prefer to have no emission control regulations and cost apply to the vehicle.
2) I have not needed a range extender in 8300 miles so a rental if ever needed seems better than adding all the permanent maintenance.



Well, I only suggest this could be an option for BEVs.

Don't want it, don't buy it.

I imagine the emission regulations and regulatory costs of a rental trailer (or even a portable in-car unit) would be just as onerous as for a permanent in-car installation.

You think the state and federal government won’t notice, and also won’t care about, that thing you are towing behind you on the freeway?
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DrInnovation
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Re: The “range–extended” EV considered

Thu Nov 17, 2011 12:57 pm

THe extender does not even need to really be a trailer, it could be a "hitch" attachement. Imagine a 1" square hitch (too small to abuse with a heavy trailer, but fine for a bike rack or a small flat pad for say a cooler or even a ER generator. Maybe even a really small haaul trailer (enough for plywood and timers and small amounts of slash/mulch for the yard).

The "coupler could both allow power to things coming out of the car (trailer lights for that small halling stuff trailer). The ER generator could then be direct connect (better areodymanics). Maybe even something you get at Uhall for a weekend rental.

And the manufacture only has to provide a rear-side charging and hitch, the rest can be all after market.

Still not replacing the AWD CUV need for snow driving, but would make the Leaf or other BEV far more viable.
Loving the Volt. I've saved 29 gallons compared to a BEV+CUV. From 10/29/11 to 12/29/12, went 11097 on 27.7 gallons of gas + 2742kWh Total fuel costs=$259.27, yielding: 0.25 gal./100mi, 400.5 MPG, 101.73MPGe, 166.5 MPG$ or $.0234/mi.

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