# Possible EV Range Extension ???



## DavidDymaxion (Dec 1, 2008)

Batteries are nonlinear -- they'll last the longest, and give the best range, if you pull current from all of them, and charge all of them, rather than switching them in and out. If your generator runs once in a while you'd be ahead, but if it needs to run all the time you could well get worse gas mileage, and have far higher pollution, than a regular gas car.

Have you considered doing things this way: Start with a regular gas car (then it'll be low pollution, unlike a typical generator). Do a small battery pack to get regen, do 1st gear starts, power the accessories, etc.


Corky said:


> I am not sure this is the right spot to post this but I will start here and see. I have wanted to build a EV for more years then I like to think about and maybe now I can. What I need though is more range then it looks like I can get out of a standard plug-in EV. After thinking about for a while I thought of something that I am not sure will work and wanted someone else thoughts on the ideal I had. The car/trike I want to build would require a 72 or maybe a 96 volt motor and I could squeeze in say 10 batteries. That means I could not go far with battery power only. This got me thinking about a sort of hybrid unit. What I am thinking about is having a generator that has an output that would supply all the electrical requirements of the car. Then drive the generator with a smaller dc motor. Sense the generator motor would be smaller (say 24 to 36 volt) then I could have 2 or 3 battery packs. I would use one to power the generator motor and have the others on stand by for when the first pack starts getting low. Also sense the generator unit would be operating all the time (while at red lights - no load required) it could recharge one of the battery pack if one has been used. I am not sure that this will work and I do know that this does not give you unlimited range but maybe it could improve it to say 100 to 150 miles. Please let me know your thoughts.


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## Corky (Aug 11, 2009)

I guess I didn't state it well. I will not be using an ICE to power the generator. I was planing to use a smaller electric motor. My thought are that it takes a large motor to move a car (say 2000 lbs) then it would to run the generator. That means that I would be able to go for a longer time on what ever battery pack I use. This would then (I hope) extend the range of the car. It would be as if you could swith from a 72 volt motor to a 24 volt motor to drive the car. With the same battery pack you now have a longer span till you need to plug-in and recharge.


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## esoneson (Sep 1, 2008)

Let me see if I get this right.
You want to somehow charge battery pack A so that it has enough energy to power an electric motor that turns a generator, so that the generator can charge battery pack B. Battery pack B provides the energy to power an electric motor that drives the vehicle (puts it into motion).

When the power from battery pack A is applied to the electric motor (attached to the generator), you will incur energy losses.

When the motor turns the generator, you will incur energy losses.

When the generator produces electricitiy, you will incur energy losses.

When the electricity is stored into battery pack B, you will incur energy losses.

Why not simply join battery pack A with battery pack B, remove the electric motor connected to the generator, remove the generator and all the connecting components, and eliminate all those energy losses?

Think about it.

Energy in.............energy losses..........energy to move the vehicle.
OR
Energy in............................................energy to move the vehicle.

Energy losses AND heavier vehicle.
OR
No Energy losses AND lighter vehicle.

Think about it.

Which do you want?

I think you can answer your own question.


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## Jan (Oct 5, 2009)

Corky said:


> I guess I didn't state it well. I will not be using an ICE to power the generator. I was planing to use a smaller electric motor. My thought are that it takes a large motor to move a car (say 2000 lbs) then it would to run the generator. That means that I would be able to go for a longer time on what ever battery pack I use. This would then (I hope) extend the range of the car. It would be as if you could swith from a 72 volt motor to a 24 volt motor to drive the car. With the same battery pack you now have a longer span till you need to plug-in and recharge.


The efficience of a motor is not based upon the voltage or its size. It's based upon the type motor, the manufactorer, the RPM and the load to name a few. And non of those will be changed if you switch to another motor or drop the voltage.


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## Corky (Aug 11, 2009)

No that not what I mean. I will try to make it simple. Let say I have only one battery pack and that battery pack will only be connected to the motor that drives the generator. All of the power required to operate the car (drive motor) would come from the generator. My thought are that it would take a larger motor (more voltage) to operate the car then it would to drive the generator. There for you could extend the range of the EV because you would require less voltage/amp then if the battery was connected to the main drive motor. As I said in my last response it is if you switched the main drive motor from 96 volt to 24 volt. With the same battery pack (just rewired for 24 volts instead of 96 volts) you would be able to go longer before you need to be somewhere you could plug-in and recharge.


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## Corky (Aug 11, 2009)

I guess that I need to draw a picture about what I am thinking about. In a standard EV you have a Drive motor, electrical hook-ups and a battery pack. The drive motor size (voltage/amp) is determined by several things (EV weight, speed, CoD, Frontal area, ...). When you go through the numbers it will tell you what you need and you find a motor that fits those requirements. This the comes to the part that I am still working on but I feel that sense there are several generator units out there with say 10 to 20 kw powered by a 10 to 15 hp ICE. Then I know that ICE and electric motors are different in sizing their hp. ICE use peak hp and motors use constant hp, I saw somewhere a reference that it takes like 1/5 to 1/8 the hp for an electric motor to equal a ICE. Don't whole me to that because I question it myself. Anyway what it means is that I could use a smaller motor to drive the generator then to drive the car. Then with the same number of batteries but reconfigured to a lower voltage the battery pack should go for a longer period of time before you need to recharge it. An other way of thinking about it is, you have 8 - 12 volt batteries you can hook them up so that you get 96 volts with 100 to 200 Ah or 24 volt with 200 to 400 Ah. If both were hooked to the corresponding size motor (96 v motor to 96 v pack and 24v motor to 24 v pack) which would run out of energy first.


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## TigerNut (Dec 18, 2009)

Corky said:


> This the comes to the part that I am still working on but I feel that sense there are several generator units out there with say 10 to 20 kw powered by a 10 to 15 hp ICE. Then I know that ICE and electric motors are different in sizing their hp. ICE use peak hp and motors use constant hp, I saw somewhere a reference that it takes like 1/5 to 1/8 the hp for an electric motor to equal a ICE. Don't whole me to that because I question it myself. Anyway what it means is that I could use a smaller motor to drive the generator then to drive the car. Then with the same number of batteries but reconfigured to a lower voltage the battery pack should go for a longer period of time before you need to recharge it. An other way of thinking about it is, you have 8 - 12 volt batteries you can hook them up so that you get 96 volts with 100 to 200 Ah or 24 volt with 200 to 400 Ah. If both were hooked to the corresponding size motor (96 v motor to 96 v pack and 24v motor to 24 v pack) which would run out of energy first.


In order to get a certain amount of mechanical power out of your motor, you have to put in a greater amount of electrical power - the instantaneous or continuous rating doesn't matter. As an example, to get 10 HP (equivalent to 7460W) out of a motor, you might have to put in 8500 Watts. So in order to drive that motor to 10 HP output with a generator, you need to supply at least 8500W of electrical energy. But to get 8500W out of the generator, you will have to supply a greater amount of mechanical power - maybe as much as 10 kW. 10 kW is equivalent to about 13 or 14 HP. Now, your "smaller" motor needs to supply this 13 to 14 HP, which will in turn require a greater amount of electrical power, probably on the order of 16 HP.

So doing a two-step electrical-mechanical conversion process has cost you about 30% efficiency loss. The only way your process could be even slightly viable is if you have a high-voltage battery tied to the main drive motor, that you're recharging at a low (but continuous) rate - in this case your battery provides capacity to handle high peak loads while the generator recharges that battery. HOWEVER: That generator has to be driven by something. If it's driven from an electric source itself, then that electric source requires a substantially larger battery (in kW-h capacity) than the main drive pack, because of the sequential loss in efficiency due to the electrical/mechanical/electrical conversion. If the generator is driven by an ICE, then you basically have a series-hybrid configuration, which can be a viable way to go, as demonstrated on several railroads in North America. They're using genset switching engines and reportedly save a substantial amount of fuel over a conventional diesel-electric engine.

As to low vs. high voltage: The high voltage system will beat out the low-voltage system (at equal power levels) because the power loss in the system is proportional to the square of the current. And a 24 volt system would need to support four times the current of a 96 volt system at equal power levels, so you get 16 times the resistive heating loss.


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## ruspert (Jun 16, 2008)

Hi Corky,
There are Dynamotors that preform the function that you are describing, basicly a mechanical voltage convertor (motor and generator combined into one unit.) There is a power loss when it is used. You would not gain any range this way and would actualy loose some range by using it.
Russ


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## icec0o1 (Sep 3, 2009)

You have to realize that in life there is no such thing as free lunch. If you use 10KW to run a generator, you can't get MORE energy out of the generator. You will always get less. 

There's a whole huge topic on free energy here:
http://www.diyelectriccar.com/forum...-free-energy-perpetual-motion-over-13449.html


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## jockepocke (Nov 24, 2009)

If you increase the voltage from 24 to say 96 there will be more Amps drawn at 24 volts than you get at 96 (yes, even without losses) as the Power=Voltage * Current.


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## Woodsmith (Jun 5, 2008)

This won't work.

Analogy:
Using my legs I can jump 2' off the ground.
If at the point I am 2' up in the air I grab my ankles and pull them 1' higher in the air using my arms does that mean I have increased the distance I can jump?
No, my feet may end up higher but the rest of me ends up lower and I land on my ass.

Your idea of driving using a pack to drive your main motor and then when you are moving you switch your pack to driving another motor that drives a generator that drives the main motor....

...Nah!


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## jockepocke (Nov 24, 2009)

If you are thinking about adding an additional 24 volt pack (but need 96) to your main pack to extend range, and thus you need 96 volt you could use a DC/DC instead of motor/alternator, with less losses and weight. Best thing though is using a 96 v additional pack to avoid losses.


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## Dave Koller (Nov 15, 2008)

Woodsmith said:


> Analogy:
> Using my legs I can jump 2' off the ground.
> If at the point I am 2' up in the air I grab my ankles and pull them 1' higher in the air using my arms does that mean I have increased the distance I can jump?
> No, my feet may end up higher but the rest of me ends up lower and I land on my ass.
> ...


And now you have done it Wood - as I fell off the chair laughing!!!


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## kek_63 (Apr 20, 2008)

I kinda like the wheel-barrow analogy I read here on the board.

When you get tired from pushing the wheel-barrow, you hop in and ride to rest (recharge your batteries) while you continue to push.

Keith


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## ga2500ev (Apr 20, 2008)

No one bothered to ask the most fundamental question:

Why do you need more range?

ga2500ev


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## Woodsmith (Jun 5, 2008)

ga2500ev said:


> No one bothered to ask the most fundamental question:
> 
> Why do you need more range?
> 
> ga2500ev


I think EV people crave range like ICE people crave horse power.

Seriously, it is s good question. Most, unlike me, can manage with quite a modest range and so when more is wanted the method for supplying it can depend on why it is needed.


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## icec0o1 (Sep 3, 2009)

ga2500ev said:


> No one bothered to ask the most fundamental question:
> 
> Why do you need more range?
> 
> ga2500ev


Because you never know when you're going to need to go further than you planned.


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## ga2500ev (Apr 20, 2008)

icec0o1 said:


> Because you never know when you're going to need to go further than you planned.


I think this is kind of a strawman for EVs. It's only based on the perception of how gas vehicles operate.

Let me try an example. I have an SUV. It's really good at towing and hauling stuff. The vast majority of the time when I don't plan to tow/haul stuff, I leave it at home and drive my Corolla.

Now if I happened to be in my Corolla and I "unexpectedly" needed to haul something, I'd drive the Corolla home, pick up the SUV and get do the task I need to get done. 

EVs' are the same. They are currently a limited range, specific purpose vehicle. BTW the limited range isn't because of the onboard power. The limited range is because there is currently no widespread infrastructure to support quick recharging of onboard power. It's just like being in a gas car with limited gas stations.

You build an EV with an expected range you plan to use it plus some margin. The margin covers limited unexpected side trips. Anything beyond that, go get a vehicle more suited for the task that needs to be done.

BTW when I get my Metro on the road, I do plan to keep the Corolla precisely because the EV is a limited range, special purpose vehicle that will serve well over 90% of my driving needs. The other 10% needs coverage. But building a hybrid for that 10% makes little sense.

ga2500ev


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## icec0o1 (Sep 3, 2009)

I think you're on the stawman argument if you can't envision plenty of scenarios where you'd be in your electric vehicle and would have to go further than your pack would allow. A few examples:

1.) Going to a football game at a stadium 30 miles away with your pack having 70 mile range. You unexpectedly meet some old friends at the game who invite you over their place for an afterparty and to catch up, 15 miles away the opposite direction. You either don't go or tell your friends you have to stay at their place for at least 5 hours to charge up enough for the trip back home. 

2.) You're out at work with 60% left in your batteries. Your wife calls and askes if you can pick up the kids after school because her car died. The school is 10 miles out of your way home and you can't do it. You have to go home first to switch cars and your kids will have to wait an hour or two to be picked up.

I can think of a lot more... I'm curious though, have any current electric car owners ran into a scenario like that where you couldn't go/do something because of range?


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## Woodsmith (Jun 5, 2008)

icec0o1 said:


> I think you're on the stawman argument if you can't envision plenty of scenarios where you'd be in your electric vehicle and would have to go further than your pack would allow. A few examples:
> 
> 1.) Going to a football game at a stadium 30 miles away with your pack having 70 mile range. You unexpectedly meet some old friends at the game who invite you over their place for an afterparty and to catch up, 15 miles away the opposite direction. You either don't go or tell your friends you have to stay at their place for at least 5 hours to charge up enough for the trip back home.
> 
> ...


I think for emergency situations you can always get 'a bit more range'.

You can always plug in at work for an hour or so when the wife calls. That may give you just enough to pick up the kids.
You can drive a bit slower after picking up the kids to extend the range a little.
Take the kids to McDs for a burger while the batteries recover a bit, maybe they would let you plug in for a while while eating.

If you are at the football game why not leave your car there and hitch a lift with your friends to the party, one of them can run you back to your car after. I have done that with friends who have cycled taking the bike with us and then dropping them off at cycling distance on the way home or taking them all the way if it isn't too far.


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## ga2500ev (Apr 20, 2008)

icec0o1 said:


> I think you're on the stawman argument if you can't envision plenty of scenarios where you'd be in your electric vehicle and would have to go further than your pack would allow. A few examples:
> 
> 1.) Going to a football game at a stadium 30 miles away with your pack having 70 mile range. You unexpectedly meet some old friends at the game who invite you over their place for an afterparty and to catch up, 15 miles away the opposite direction. You either don't go or tell your friends you have to stay at their place for at least 5 hours to charge up enough for the trip back home.
> 
> ...


It still looks like a man made of straw to me. You present these scenarios as if it's impossible to charge anywhere else other than at home. Last I checked, electricity is available almost anywhere. Ask a favor, use an extension cord (which should be part of your EV emergency kit), and both at your friends house or at work you can take the time to put some more juice into the vehicle.

Opportunity charging abounds. That's why it's almost an imperative to have the ability to onboard charge from 110V.

As for work, tell your boss it's an emergency (which it is) and leave work the hour or two early to get it done. Or take a cab. Or drive the EV to a rental car place. Or drive to your wife's work and fix her car. Or ask a friend for a ride. Or frankly the any number of other options that are available when your car isn't available.

What would you do if you had taken the train into work that morning and got the same call from your wife? Millions use public trans every day. None would if they were worried about exceptions to their routine.

Neither of these are everyday occurances. yet it's the mentality that drives the continual need to have a hybrid solution when in fact there's little need for one. Size your pack for your everyday commute plus a bit of slop, and have contingency plans available when you come across a need that is outside that range.

ga2500ev


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## Duxuk (Jul 11, 2009)

GM are proposing the Volt or Ampere (depending whether you're in the US or Europe). It will have an inbuilt range extender in the form of an ICE of about 1400cc. My thoughts are that it would be better to drop the ICE in favour of a double sized battery pack, thus increasing the range from 30 to 60 miles under battery power alone. I dont know if this would give a cost saving but lets face it, it is not just the motor you are leaving out. There is also the fueling, electics, generator and all ICE control requirements. I beleive that this vehicle will drive only through the electric motor, the ICE will only power a generator. Does this same logic not apply to other hybrids? I accept that the 60 mile range would be finite. BTW I am building my own EV to drive 27 miles to work where I will recharge for the return journey.


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## ga2500ev (Apr 20, 2008)

Duxuk said:


> GM are proposing the Volt or Ampere (depending whether you're in the US or Europe). It will have an inbuilt range extender in the form of an ICE of about 1400cc. My thoughts are that it would be better to drop the ICE in favour of a double sized battery pack, thus increasing the range from 30 to 60 miles under battery power alone. I dont know if this would give a cost saving but lets face it, it is not just the motor you are leaving out. There is also the fueling, electics, generator and all ICE control requirements. I beleive that this vehicle will drive only through the electric motor, the ICE will only power a generator. Does this same logic not apply to other hybrids? I accept that the 60 mile range would be finite. BTW I am building my own EV to drive 27 miles to work where I will recharge for the return journey.


The problem is that this solution is too logical. Oil companies don't want to give up gas, car makers don't want to give up the service of complex gas engines, and consumers don't want any compromise in the perceived freedom that gas gives them.

And that's the way it is...

ga2500ev


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## Duxuk (Jul 11, 2009)

I'm sure many of us would agree with this, ga2500ev. I think one of the biggest problems with a finite range (which won't affect me) is that people are not satisfied with a mere 99% of their needs being fulfilled. They want an effectively infinite range for the one time in a year when they will visit someone 150 miles away. They also want 5 or 7 seats but take a look at the cars you see on the road. Most in the UK have only one occupant, very few have more than two. The problem of limited range can be addressed with hire cars and recharging facilities, if only we have enough desire for these.


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## Voltswagen (Nov 13, 2008)

I have only driven my EV about 1500 miles. It has LA Batts and about a 38 mile max range. I don't drive it everyday as I am one of the few fortunates who are blessed with a home -based business. The only traffic I hit in the morning is outside the bathroom.

I have, however, had occasion to find myself short of sufficient amps to make it home. In one case I made a wrong turn and overshot my destination by about 4 miles which of course added another 8 miles to my trip. ( ya gotta turn around and go back ) I have since bought a Tom Tom.
What I did in that case was a self-inflicted "Limp Mode". I got off the main road (55mph) and took back roads at 25mph cringing everytime I looked at my Voltmeter. I made it home with about 5% left in the pack.

Two other times I used opportunity charging at friends houses which were near my route. Even with only a 120v on board charger you can put back quite a few amps in an hour or so. Where there is a will....there is a way.
Roy


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## Guest (Dec 27, 2009)

I like to read these threads and not get in evolved but sometimes I just can't help myself and have to chime in. Now I only had one semester of psychology in collage so don’t take this gospel. Our expectations for our ev’s are conditioned by the conventional gas powered car. I may be wrong but I gather that everyone on these threads are male. That being said range is a male thing. Lack of range can be compared to weakness. Example. If you are sitting at a light in your electric car and some dude pulls up next to you in a hotrod with a full house mill that can hardly idle under 1,000 rpm you are most likely going to wish you owned the White Zombie right then. The same applies to range. I will use myself as an example. I get 30 miles easy 40 if I really watch the gage and feather the peddle. Most of my round trips are under 20 miles. I have about 50,000 miles on my ev at 20 miles a shot. Of all that time I think I have had it in the red twice. Those were two of the most excruciating times in my ev driving life. But even when I make it out and back with 10 miles left and their is no one else around I still have a feeling of inadequacy through my vehicle because I wish it was a hundred. I bet a lot of you have had those thoughts too. You guys that do get 70 to 100 miles sometimes wish it was more too I‘ll bet. Driving an electric car is like leaving home with an empty gas tank and the only place to get more gas is at home. This is sounding like it belongs on chi chat so I’ll try to bring it back on subject. The rest of you have pretty much let it be known that an electric motor can’t power another electric motor. The fellow that suggested it is obviously on the low end of the learning curve at this time. But he is thinking and has not suggested anything that has not crossed our minds somewhere in our lives. Long range extension is going to have to rely the internal combustion engine for a little while longer. Gotta go now as my wife is rushing me up to go out. Unfortunately I will have to take the gasser as my ev is a two seater and there will be three of us but I will be wishing I was in the electric despite the so called draw backs.


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## Voltswagen (Nov 13, 2008)

Notmrwizard
As with any leading edge technology there are going to be drawbacks and hopefully imporvements.
The first Fords on the road were all hand crank starters and the literature is plentiful with stories of broken wrists and fingers, impossible starts in freezing weather etc.
It was not until the addition of a battery powered starter that the technology really caught on. 
There was in fact good reason for phrases like: "Get a horse!", "Tire Kicker!", "Back Fire!" etc.

Despite the vagaries, I'm proud to be a member of this small community.
On day my Grandkids will be telling the story of how their Grandpa built and drove an electric car back in '08.


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## Guest (Dec 27, 2009)

I agree whole heartedly. I was trying to get across that range anxiety can be a good thing because it will give incentive to experiment and push on to newer a better things. Also the to bring up the topic of perpetual motion every once in a while is not bad either. Rather than immediately say no think about it and it might lead to a new idea that is feasible. I read somewhere about scientist asking 5 year olds about certain subjects in science. The Idea being they had no preconceived notions so their answer honest with out bias.


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## ga2500ev (Apr 20, 2008)

The issue as I see it is not the lack of range but moreso the lack of infrastructure to refuel.Voltswagon gave an example of taking a wrong turn and having to limp home. It's a non issue with a gas vehicle because the infrastructure to refuel is in place virtually everywhere.

I've spent quite a bit of time here talking about alternatives for refueling and I get a lot of flack about it. No one seems willing to talk about compromising the efficiency of batteries in order to get rapid refueling until such a time as a standardized and widespread infrastructure for supporting EVs can be put into place.

The one example of this is liquid nitrogen. As an energy carrier it certainly isn't the perfect solution. However LN2 can be generated anywhere, is quickly refillable and widepread processes for generating LN2 already exist. Also as has been pointed out in numerous documents, (for example: http://www.cryoelectric.info )freezing air to get LN2 actually cleans the air that is used to generate the LN2.

Use it as the hybrid fuel along with a traditional battery setup. An LN2 to air turbine can generate electricity to charge batteries. So use like a current plug in hybrid.

How are zinc air batteries as a backup? They are light and powerful. Unfortunately they cannot be recharged. 

Of course the best infrastructure development would be to have fast inductive charging stations everywhere.

More batteries are not the solution. More infrastructure is.

ga2500ev


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## Voltswagen (Nov 13, 2008)

ga2500ev
Here is a suggestion for Walmart which could begin the building of a nationwide infrastructure for EV recharging.
Most Walmarts permit free over-night parking for RV owners. Why not recharging for EV owners?
You pull in, insert your credit card, plug in and go shopping. 

Walmart offers free parking for RV owners knowing that many of them will make purchases while they are there. So would EV owners. If the supply could be 220v you could get a nice boost in an hour or so. Even 110 would be better than nothing.

Imagine if all Walmarts offered this, one could conceivably drive an EV coast to coast.


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## gor (Nov 25, 2009)

coud be fuel cells - MethanolFuelCell thread http://www.diyelectriccar.com/forums/showthread.php/efoy-direct-methanol-fuel-cell-40167.html


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## Jan (Oct 5, 2009)

gor said:


> coud be fuel cells - MethanolFuelCell thread http://www.diyelectriccar.com/forums/showthread.php/efoy-direct-methanol-fuel-cell-40167.html


The heaviest version delivers only 90 watts. OK, it only weights 8,8 kg. But still, that's 880 kg to get just 9 kW. I need more.

http://www.efoy.com/en/electric-scooters-efoy-pro.html


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## gor (Nov 25, 2009)

Jan said:


> The heaviest version delivers only 90 watts. OK, it only weights 8,8 kg. But still, that's 880 kg to get just 9 kW. I need more.
> 
> http://www.efoy.com/en/electric-scooters-efoy-pro.html


"2200 watt hours a day" http://www.efoy.com/en/efoy-pro-2200-elektroroller.html
any way to make it faster?


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## gor (Nov 25, 2009)

UltraCell XX55: 50w cont & 85 peak
10.7’’x8.2''x3.2’’[27.2x20.8x8.1cm] 
3.5lbs[1.6kg]

7.08a constant

10 x 7.08a = 70.8a ; 850w: 35lbs [16kg]
100 x 7.08a =708a ; 8500w: 350lbs [160kg]
------------

Cartridges:
XRT1000: _____40lb [18kg] 18.00x9.5x10’’ [45.0x23.75x25.0cm] 13750wh /14days at40w const

http://www.diyelectriccar.com/forums/showpost.php?p=159443&postcount=6

---


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