Electric cars, unclean at any speed

[redpoint5]

Originally Posted by P-hack

OB:unclean
If EV enthusiasts don't care that their range extender is fuel inefficient by design, then that kinda makes the point

What point?

30mpg is not inefficient by current averages. The fuel economy of a range extender becomes less important the less it is used. Put another way, the fuel economy of a range extender becomes more important the more it is used.

Since we are talking about very rare instances of use, and the inefficiency inherent in a device that only has a single application (pusher vehicle), it can actually be more efficient to run a series configuration generator. Efficiency is not relegated just to the realm of fuel economy; there is efficiency of one's time, efficiency of utility, efficiency of money... the consideration of all resources is important. For those who frequently need extended range, a pusher may very well be the perfect solution.

As IamIan pointed out, energy produced by a generator need not go through the losses associated with charging a battery if the motor is demanding the energy directly.

Originally Posted by P-hack

But I am terribly disappointed at the misinformation and almost religious devotion to series, and all the associated misinformation, special pleadings, and outright BS. It only reinforces the idea that EV'ers are completely indifferent to the upstream power source, and that driving the wheels directly is some sort of sin, even though it has far more potential, especially on long constant speed trips if you are carrying an engine.

I tend to be indifferent to the upstream power source, as my main consideration is cost per mile. My time and money is a primary concern as long as the environmental consequences of my choices appear to be relatively inconsequential. It turns out electric is cheaper per mile than fossil fuels, and when the vehicles themselves come down in price, this will make financial sense. It just happens that Oregon primarily generates RE.

There is no reason a microcontroller can't shift (including neutral/coast) and control throttle efficiently...

As I said, a pusher very likely makes the most sense for some people, but as you point out, perhaps they should have just bought a Gen 1 Insight. The complexity, safety issues, and single purpose nature of a pusher just makes it impractical and inefficient for most.

[IamIan]

Originally Posted by P-hack

For example, here is a page about the t-zero range extender: ACP AC Propulsion Series Range Extending Trailer prototype. Toyota Rav4-EV Hybrid prototype. Alan Cocconi. 2000 BEV (Battery Electric Vehicle). RXT-G. LongRanger. Hybrid Trailer. EV Range Extender. GenSet. "Stock configuration 42 MPG cross country series hybrid drive"?!? 42MPG, Really? with a picture of an SUV there? The thing is like $75k!!! and behind a small 1500lb car it only got 30-35. I call bullsh*t, major bullsh*t on these guys.

Blue Bold added ... Why?

YMMV ... Without knowing many details about the conditions of how the 42MPG vs 30-35MPG was achieved ... the MPG numbers are next to meaningless.

Example:
I can tell you nothing of the conditions ... and still 100% correctly and honestly tell you that I got 90MPG on one one tank (~10Gal) and 55MPG in the same car on another tank (~9Gal) ... without knowing many of the details of the conditions ... the MPG numbers are next to meaningless.

- - - - - -

If you want to knock a Generator trailer for the tiny % of trips is it used ... and for only getting a low ~19% efficiency from tank to road ... that's fine ... but I would expect you to equally knock just as hard ... any straight ICE vehicle any time it gets the same ~19% or less efficiency from tank to road... or harder when it gets 0% efficiency idling ... or knock harder any stationary generator for home use that gets less use and operates less efficiently than ~22% from fuel to outlet.

As has been said ... under some conditions the pusher trailer can be more efficient ... but in others ... it will not be.

And the generator trailer as more auxiliary useful utility than a pusher trailer does... electrical power on a work site ... power during a black out ... etc.

[oil pan 4]

Originally Posted by NachtRitter

Wish I could find it again, but I just recently read an article where some construction sites were using solar + battery power systems as an alternative to running generators (obviously in locations where the power companies hadn't run any power yet). Something along these lines: Mobile Solar Power: Diesel Generator Alternative

If it's going to be used only once a year or less, with no other usage at all, you're right... no point in owning it. But if it could be used for other things, it could be worth it... UPS for a portion of your house's power, construction power supply, camping power supply, portable power in case of disaster, etc.

You could build a battery boost trailer and put say several 213 watt pannels on it.
Only problem is the battery boost trailer would very expensive and each 213w panel that only collects about 1kwh/day would add about $500 to the cost?
(I am not sure what they cost these days, not too long ago it was about 3 cents per watt)

Besides cost only other problem I see is if you use LiFePO4 batteries they do not like to be charged when they are around 20'F or cooler.
By don't like I mean the annode or cathode gets damaged during charging and up to 20% of capacity can be lost in one charging cycle.

[jakobnev]

How about the mowarm (motor-swingarm combo) from a salvaged scooter to push the car like an outboarder?

What can that set you back, $300 and a little fun building it perhaps?

[redpoint5]

Originally Posted by RedDevil

Even if the charging plug position or protocol prohibits charging while you drive, it could recharge the EV's batteries at any stop, anywhere, at the max rate both packs allow for. You'd have to stop after a few hours drive anyway, just to get some rest etc.

Having to stop to charge mostly defeats the purpose of having the generator in the first place. If I stop for any extended length of time, I'm plugging in. A generator capable of charging at max rates would be heavy.

I envision carrying a generator no more than 350lbs on something like this:



Eliminating the trailer makes the car a little easier to handle, and cuts down on the rolling resistance of having more tires. Plus having it immediately behind the vehicle mostly eliminates the aero drag.

[NachtRitter]

Originally Posted by oil pan 4

You could build a battery boost trailer and put say several 213 watt pannels on it.
Only problem is the battery boost trailer would very expensive and each 213w panel that only collects about 1kwh/day would add about $500 to the cost?
(I am not sure what they cost these days, not too long ago it was about 3 cents per watt)

Boy, I wish it was 3 cents / watt!!

Currently it's about $0.90 to $0.70 per watt (see the trend at Daily chart: Pricing sunshine | The Economist). It's projected to drop to $0.36 per watt by 2017 (see Forecast: Cost Of PV Panels To Drop To $0.36 Per Watt By 2017 | ThinkProgress)

So ya, today a 250W panel would run about $240 in single quantities, and closer to $200 if bought in a pallet of 26. For (roughly) $500 worth of 250W panels in my area (~4 to 6 sun hours per day) with 80% efficiency, it'd be possible to generate 500 * 5 * .8 = 2kWH a day. Hmmm... not gonna help all that much for charging up that EV if these figures are true:

EVs typically can travel 3-4 miles (or more) per kWh of electricity.

(from Can I charge a plug-in car with solar or wind power? | Plug In America)

So using solar panels to recharge the EV using a trailer probably wouldn't make sense unless you could get A LOT of panels on the trailer... or you get some high capacity ones (I've seen 400W panels, though the price per watt is higher)

[IamIan]

Originally Posted by NachtRitter

So ya, today a 250W panel would run about $240 in single quantities, and closer to $200 if bought in a pallet of 26.

A guy I met at one of the PV installer courses I took recommended this site for any bulk PV purchases ... Link ... I think their lowest right now for a full container is ~$0.57 / Watt ... I'm sure there are other similar bulk distributors out there too ... he said he always bought full pallet loads from them ... and then he would design individual customer's orders around the panels he had in stock at the time.

It's not something the average person can do ... outside of maybe some type of organized group buy ... Dropping ~$20k or so on a full pallet or container of PV panels ... but if you can afford the initial up front cost for buying full pallet loads at a time ... you can get the $/Watt significantly down.

[P-hack]

Originally Posted by IamIan

...
As has been said ... under some conditions the pusher trailer can be more efficient ... but in others ... it will not be...

Well not if I'm driving it

Also the pusher has all the same automation tools in theory as the generator (can drive by wire and automatically select the best ratio/throttle for conditions and load the battery if it actually helps efficiency while you are moving for peak bsfc, engine can downsize if in parallel w/electric motor) with the bonus of higher peak efficiency when it comes to actually moving the car.

So no, I cannot think of any situation where the pusher (parallel) inherently is not going to out-perform the generator(series) with the same diligence to optimization. Even using the bsfc rpm/ loading strategy is possible with a parallel.

If they start making superconducting batteries/generators/motors/cables/transistors then absolutely I would go with series (assuming it is cost effective), but not today, and we are talking about stopgaps till better batteries/infrastructure anyway (i.e. today).

It is largely a less glorious mechanical engineering problem for a max efficiency pusher, but that angle really deserves more consideration where an ICE is concerned because of the efficiency gains (and real world examples of efficient ICE vehicles), and there is still room for efficiency improvements in a mechanical driveline too.

The series advantage is that it can "easily" charge the battery when sitting still, but that is not much of an efficiency advantage as you should be using the wall for that, just an "emergency" thing, and a larger alternator on the pusher can mitigate that or just help with lights/fans/whatnot in the EV.

Does that make sense?

[IamIan]

Originally Posted by P-hack

Also the pusher has all the same automation tools in theory as the generator

Nope.

It is mechanically connected to the road ... at 1 MPH , 5 MPH or 50 MPH ... etc ... there is a finite limit to what the transmission can convert that to for what the ICE sees ... and the transmission is not a 100% efficient thing either... the connection to the road is itself a limitation that the generator option as a tool does not share.

And least we forget ... the Generator can have the automation option to power my house in the event of a black out ... the pusher trailer can not.

So no... the pusher trailer does not have all the same automation options.

Originally Posted by P-hack

The series advantage is that it can "easily" charge the battery when sitting still, but that is not much of an efficiency advantage as you should be using the wall for that, just an "emergency" thing, and a larger alternator on the pusher can mitigate that or just help with lights/fans/whatnot in the EV.

It is an advantage when one stops at a rest stop that doesn't have a EV charging plug ... the pusher can't help you when the vehicle is stationary ... the generator can... saying you don't want to do that stationary generator function ... does not remove it as a pro that the generator can do that the pusher can not.

A bigger alternator ... or any alternator at all for that matter ... on the pusher ... just turns it into a combination of both a pusher and a generator ... as long as you are anti-generator ... the alternator is not an option.

Originally Posted by P-hack

Does that make sense?

It makes sense ... It is just too heavily one sided / biased in favor of the Pusher for my tastes ... To me ... I see pros and cons to both ... trying to pretend the pusher wins in all categories ... as if their is no situation where the generator isto me seems like ... just turning a blind eye to the actual pros and cons of the two... and I see it as just incorrect.

I don't see it as simple as A = always better than B ... for either the Pusher or the generator.

Originally Posted by P-hack

So no, I cannot think of any situation where the pusher (parallel) inherently is not going to out-perform the generator(series) with the same diligence to optimization.

Here I'll show you a few ... but there are others as well.

#1> Generator out-performs pusher.
Low SoC ... pull into rest stop to pee and eat ... this rest stop does not have a EV charge port ... Pusher gives you ZERO ... while you are there for 30 minutes to an hour ... but the Generator could have given you more than the ZERO ... More than Zero is better than Zero.

#2> Generator out-performs pusher.
Many Hours of Grid lock traffic on a 120+ degree day ... your EV as Air conditioning so you don't have a heat stroke ... but the pusher trailer just doesn't seem to be able to help the electric AC in the BEV with your stop and go grid lock traffic ... as you spend far more time stopped than moving ... but a generator option would still work fine ... and power and charge things fine.

#3> Generator out-performs pusher.
House generator during a black out.

- - - -

Those are the easy three situations ... that are just an inherent con of the pusher trailer system , compared to a generator style system.

We can get into other as well if you like.

- - - - -

Both systems have pros and cons ... neither is the best option for all situations ... pretending or claiming otherwise ... to me ... is just incorrect and too biased on one side.

The pusher trailer will likely have lower bottom efficiencies than the generator trailer ... and the generator trailer will likely have lower peak top end efficiencies ... And the Generator trailer has some function the pusher does not ... which one will give you better net average efficiency ... or utility ... will very much depend on the specifics of the context of usage.

[NachtRitter]

Originally Posted by IamIan

A guy I met at one of the PV installer courses I took recommended this site for any bulk PV purchases ... Link ... I think their lowest right now for a full container is ~$0.57 / Watt ... I'm sure there are other similar bulk distributors out there too ... he said he always bought full pallet loads from them ... and then he would design individual customer's orders around the panels he had in stock at the time.

Dang, that's an amazing per Watt price! Thanks for the link!