Replacing Car Batteries with Capacitors for EV - Answers Here!

In summary, the group is doing research for an experiment with an electric vehicle and is interested in using capacitors instead of batteries for faster charging and less storage. They are seeking advice on the most practical size and capabilities of capacitors, and whether an EV can be operated solely on capacitor power. They are also curious about the load a capacitor would have while charging. The group has designed a system that generates energy from forward motion, but is facing issues with battery recharge time. They are open to using supercapacitors despite their higher cost and potential for failure. The conversation also includes some skepticism about the feasibility of the group's project.
  • #1
trentr
13
0
I am in the army and some friends and myself are doing some research for an experiment we are doing. None of know a lot about capacitor capabilities and I have been looking for the last couple of days and found this forum. Here is my question, We discovered something interesting on an electric vehicle we made, that works but we read that capacitors charge faster then batteries but have around 25% less storage.

If I wanted to replace let's say 10 12v car battieries with capacitors.
What size would be most practical?
Can we operate an EV off the power of a capacitor?
What kind of load would charging a cap have?

Our design creates massive amounts of energy using forward motion, similar to regenerative braking. But ours constanly creates energy as long as the vehicle is in motion. The only problem we are having is the recharge time of the batteries. If we can cut the time by 25% then we will be out the army and chilling with Heff:)

Thanks for any help you all can provide.
 
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  • #2
trentr said:
But ours constanly creates energy as long as the vehicle is in motion.

You might want to rethink this statement.
 
  • #3
Supercaps are very expensive, about 100 times as expensive as lead-acid ones. The following link may help:
http://www.ika.rwth-aachen.de/r2h/index.php/Battery_and_Supercapacitor [Broken]
 
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  • #4
Averagesupernova said:
You might want to rethink this statement.

ok smart *** its transforms energy, because we all know that according to laws of thermo dynamics energy can not create energy only transform it. I was typing fast because I have a baby on my lap and that statement has nothing to do with the question I was asking. I wrote here for helpful info not someone trolling for something smart to say:)
 
  • #5
wywong said:
Supercaps are very expensive, about 100 times as expensive as lead-acid ones. The following link may help:
http://www.ika.rwth-aachen.de/r2h/index.php/Battery_and_Supercapacitor [Broken]


hmmmm... thanks for the link, we don't really care much about price, (within reason of course) the main thing is how much resistance they create. If caps charge faster and have produce less of a load that will be perfect.

Anyone had any xp with using caps in place of batts?
 
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  • #6
you're kind of on the bleeding edge here. chances are you will see a lot of failure. a company i worked for a few years ago was developing a hybrid vehicle, and used lithium batteries instead of lead-acid. better energy density per weight, but they tended to explode. supercapacitors are the "next big thing." they may or may not succeed.
 
  • #7
trentr said:
hmmmm... thanks for the link, we don't really care much about price, (within reason of course) the main thing is how much resistance they create. If caps charge faster and have produce less of a load that will be perfect.

Anyone had any xp with using caps in place of batts?


A capacitor is a capacitor and a battery is a battery. When it comes to power storage, they are not even in the same ball park. When it comes to memory backup and things of this nature, they are somewhat interchangable. A capacitor charges up fairly quickly compared to a battery at the expense of less available storage. Super caps are typically not designed for large current charing and discharging. They are more geared towards memory storage.
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As for my smart *** comment? I haven't been here since the beginning, but I have seen my share of people who come on here with ideas of perpetual motion and over unity and with a whopp'n 3 whole posts you fit the profile. I am sorry if I've confused you for something you are not. However, your ambitions still look suspicious considering you want to generate power based on forward motion and store this power in some way. My question to you is what is powering the forward motion? Regenerative braking is understandable and commendable, but that does not CONSTANTLY generate power as you have eluded to.
 
  • #8
hey now, if the army is working on free energy, maybe we should keep him talking. if anybody out there has the secret diaries of Nikola Tesla and Alien Technology, it's Uncle Sam. :wink:
 
  • #9
Averagesupernova said:
A capacitor is a capacitor and a battery is a battery. When it comes to power storage, they are not even in the same ball park. When it comes to memory backup and things of this nature, they are somewhat interchangable. A capacitor charges up fairly quickly compared to a battery at the expense of less available storage. Super caps are typically not designed for large current charing and discharging. They are more geared towards memory storage.
-
As for my smart *** comment? I haven't been here since the beginning, but I have seen my share of people who come on here with ideas of perpetual motion and over unity and with a whopp'n 3 whole posts you fit the profile. I am sorry if I've confused you for something you are not. However, your ambitions still look suspicious considering you want to generate power based on forward motion and store this power in some way. My question to you is what is powering the forward motion? Regenerative braking is understandable and commendable, but that does not CONSTANTLY generate power as you have eluded to.

Fair enough, like i said we just don't want to give away too mcuh info because we don't want people to figure out what we did. I understand that a million people have made claims of perpetual motion and blah blah blah. But like i said this isn't we merely found a way to transfer some of the lost energy from forward motion into energy. The ability to store this energy a more effective manner will make this work. But like i stated before it all depends on if caps can store and transfer energy like i have been reading. If not even with regular batteries and tweaking to a engine control unit program that would allow the recovered power to be stored in Bank A and then when opt power is stored switch to bank B and rinse repeat. <---- reduces the hell out of the load, which in turn reduces resistance and ability to regen in a 15 hp eng. Because things like lights, radio blah blah blah are not drawing and creating more resistance. (All of this is common knowledge for EV theorizing) Tesla motors currently can reach and est 218 miles before recharge.
We are right behind them currently without the use of regen braking. Our design with regen braking would be insane and depending on how fast we can recharge the banks would say how long we can drive without recharge. We are comms specs in the army so this really isn't our field. But we got bored and found something that MIGHT work better then what is currently available and we are trying to find ways to make it better and prove it. So far driving 75 miles on 10 12v batts we have had almost NO batt loss that wasnt recovered. But the key is to keep the load as minimal as possible. That is why we got int in the caps discussion and why we began looking all over the internet for any educated info we could find.
Sorry for replying so late took my wife to see Watchmen:) Ty for the replies and ty ahead of time for any help and God Bless
 
  • #10
Those are some pretty extrordinary claims for someone who is asking such basic questions...

Sorry, no, you have not found anything particularly useful - you've made an error. "lost energy due to forward motion" is just gibberish. You'd be well advised to pick up an entry level physics book and start learning it rather than wasting any more time.

Averagesupernova is right: claims like yours are a dime a dozen and we're all still driving gas powered cars.
 
  • #11
Proton Soup said:
you're kind of on the bleeding edge here. chances are you will see a lot of failure. a company i worked for a few years ago was developing a hybrid vehicle, and used lithium batteries instead of lead-acid. better energy density per weight, but they tended to explode. supercapacitors are the "next big thing." they may or may not succeed.
Latest development in lithium are much safer; for example Lithium iron phosphate (LiFePO4) batteries themselves are very safe, I've seen people abuse the C size (LiFePO4)s, i.e recharge in ~80% in a few mins, and using a small fan to keep it cool. Though I'm sure it wasn't good for the battery Cycle life over all.

http://en.wikipedia.org/wiki/Lithium_iron_phosphate_battery

Energy density is a little less than normal lithium, but is safer and easier to manage (if your a battery pack designer.)

Regarding Super Caps, Maxwell are very nice, but still too expensive to be used as a battery replacement (ignoring the volume/space problem.) It would be better to integrate super caps in, if the main battery pack couldn't handle high C charge/discharge bursts (i.e. regenerative breaking, acceleration)

http://www.maxwell.com/ultracapacitors/products/large-cell/bcap0650.asp
 
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  • #12
trentr said:
...So far driving 75 miles on 10 12v batts we have had almost NO batt loss that wasnt recovered...
Calculate how much kWh your using up per mile, if it as good as you say it is, then publish the numbers and people will be throwing money at you. And then you could hire and EE to help you out on any details like Caps.

Currently I have not seen enough facts or numbers given by you to really help.
 
  • #13
If I have this right, 1) speed of energy storage far outweighs cost.

2)Either the energy is coming from a source that is otherwise waste, or the increased load on the energy source is a never-mind.

How's that?
 
  • #14
russ_watters said:
Those are some pretty extrordinary claims for someone who is asking such basic questions...

Sorry, no, you have not found anything particularly useful - you've made an error. "lost energy due to forward motion" is just gibberish. You'd be well advised to pick up an entry level physics book and start learning it rather than wasting any more time.

Averagesupernova is right: claims like yours are a dime a dozen and we're all still driving gas powered cars.

Well honestly we just got bored and had an idea and it seems to work. Thats why we are trying to get more info without giving the design away. Just in case it does end up being able to work. Like i said we are not experts in physics that is why we are researching to get more info. I honestly don't care if you all believe me, if it works in the end the way its working now. Then awesome, if not then hell gave us a break from getting ready to go to iraq:)
 
  • #15
K I will get the numbers and post them and some of you smarter EE peeps can tell me what you think about what we are recovering and what we are using for ops of the vehicle. Thanks to all the peeps who have been posting and sending pms with ideas for storage:)
 
  • #16
trentr said:
K I will get the numbers and post them and some of you smarter EE peeps can tell me what you think about what we are recovering and what we are using for ops of the vehicle. Thanks to all the peeps who have been posting and sending pms with ideas for storage:)

Yes there is no reason why you can't post some quantitative performance figures without revealing the details of any "technical secrets".

So far you've basically told us that you have managed to get a vehicle of unspecified size and weight to travel a distance of 75km at unspecified speed over unspecified terrain using an unspecified amount of the charge of 10 batteries of unspecified amp-hour capacity.

Can you understand why everyone is so under whelmed?
 
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  • #17
uart said:
Yes there is no reason why you can't post some quantitative performance figures without revealing the details of any "technical secrets".

So far you've basically told us that you have managed to get a vehicle of unspecified size and weight to travel a distance of 75km at unspecified speed over unspecified terrain using an unspecified amount of the charge of 10 batteries of unspecified amp-hour capacity.

Can you understand why everyone is so under whelmed?

I aint trying to overwhelm anyone:) Just trying to figure out about a better storage system then regular batteries and if caps are actually viable. From the PMS I got, I understand what the point was for the tech data. Too easy, we should be able to get it together this coming week:) Thanks for the help guys
 
  • #18
Yep but could you at least just re-assure us that this isn't just one of those lame ideas like running an alternator or generator off the drive shaft of an EV and using it to "keep" the batteries charged. Because if it is please don't waste anymore of anyone’s time (including your own).
 
  • #19
uart said:
Yep but could you at least just re-assure us that this isn't just one of those lame ideas like running an alternator or generator off the drive shaft of an EV and using it to "keep" the batteries charged. Because if it is please don't waste anymore of anyone’s time (including your own).

lol naw it aint but the drive shaft isn't a bad idea. If you were to transform the entire drive shaft to a low rpm PMA that could recover some good energy with little resistance. But I don't know if like 10 pma assemblies would create enough to do anything. But would prolly look hella cool, kinda like some back to the future **** lol. Has that been tried? I think the load would rbring the vehicle to a winding stop if it even moved at all.
 
  • #20
PMA is "permanent magnet alternator" right?
 
  • #21
uart said:
PMA is "permanent magnet alternator" right?

yeah, I was you meant a low rpm disk PMA. I would assume that they were using a PMA instead of a normal electro magnetic alternator because the bearings in a standard alternator would create far too much resistance for let's say a 30hp ev engine to even spin and although i have never tested it don't think it would even move. So for that reason I would assume that the people who tested the drive train set up would of went with a pma set up because standard alternators would just be retarded.
 
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  • #22
Well actually I meant that no matter how you implement it that it's still a silly idea. I was hoping that you'd say that your idea is nothing even remotely similar to this idea.
 
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  • #23
trentr said:
yeah, I was you meant a low rpm disk PMA. I would assume that they were using a PMA instead of a normal electro magnetic alternator because the bearings in a standard alternator would create far too much resistance for let's say a 30hp ev engine to even spin and although i have never tested it don't think it would even move. So for that reason I would assume that the people who tested the drive train set up would of went with a pma set up because standard alternators would just be retarded.

please don't breed.
 
  • #24
Proton Soup said:
please don't breed.

HAHA first of all I didnt say that was a good idea! I said it would look cool and seeing how it was brought up just asked if it had been tried before. Its real cool to knock other people for trying stuff when you yourself haven't tried anything! Do I think it would work? No because I believe the load would cause the vehicle to not mvoe at all. An educated reply would of been well it was tried by university blah blah blah and found it to not be practical. I didnt bring it up, I just asked if it had been tested. Albert Einstein was basically kicked from his country because people said his ideas were crazy. No one bothered testing them or listening to what the benefits could be. Bell tried over 1000 ways till he found the proper comp to make the light bulb work. While his partners said he should give up and it was impossible, he kept trying different chemical make ups till he found what he was looking for. Then what did he say? I didnt have 1000 failures, I found 1000 ways not to make a light bulb. Regenerative braking was laughed at when it was first theorized. They said you can't used kinetic energy to stop! But now tesla automotives are extending EV drive times leaps and bounds because of this technology.
While I am not an EE major or a physics guru, I at least have the common sense not to knock any idea until it is proven wrong. The theory of thermo dynamics are just that a theory. They are just what humans thought up to explain their own limitations. We shouldn't knock people for trying new things or new set ups, in fact we should help them. Just because 1 person fails doesn't mean the next person won't come up with the needed chemical make up to make the experiment a success.
 
  • #25
trentr said:
HAHA first of all I didnt say that was a good idea! I said it would look cool and seeing how it was brought up just asked if it had been tried before. Its real cool to knock other people for trying stuff when you yourself haven't tried anything! Do I think it would work? No because I believe the load would cause the vehicle to not mvoe at all. An educated reply would of been well it was tried by university blah blah blah and found it to not be practical. I didnt bring it up, I just asked if it had been tested. Albert Einstein was basically kicked from his country because people said his ideas were crazy. No one bothered testing them or listening to what the benefits could be. Bell tried over 1000 ways till he found the proper comp to make the light bulb work. While his partners said he should give up and it was impossible, he kept trying different chemical make ups till he found what he was looking for. Then what did he say? I didnt have 1000 failures, I found 1000 ways not to make a light bulb. Regenerative braking was laughed at when it was first theorized. They said you can't used kinetic energy to stop! But now tesla automotives are extending EV drive times leaps and bounds because of this technology.
While I am not an EE major or a physics guru, I at least have the common sense not to knock any idea until it is proven wrong. The theory of thermo dynamics are just that a theory. They are just what humans thought up to explain their own limitations. We shouldn't knock people for trying new things or new set ups, in fact we should help them. Just because 1 person fails doesn't mean the next person won't come up with the needed chemical make up to make the experiment a success.

go educate yourself, then. have a nice day.
 
  • #26
Proton Soup said:
go educate yourself, then. have a nice day.
Good uneducated answer:) Just like i thought, god bless though
 
  • #27
trentr said:
Good uneducated answer:) Just like i thought, god bless though

you're just posting a bunch of crap. you really think it takes 30 hp to turn a rotor just to overcome bearing resistance? what do you think bearings are there for, to create resistance? seriously, go troll somewhere else. you're just spouting nonsense, and it doesn't deserve a bunch of anyone else's time. that's why you get such terse answers. bye.
 
  • #28
trentr said:
Bell tried over 1000 ways till he found the proper comp to make the light bulb work.

So let me guess... In your world Thomas Edison invented the telephone right? Samual F. B. Morse invented the morse code, Plato invented the plate, and now I, Holly, have invented the Holly Hop Drive. (For those of you who are not familiar with Red Dwarf, don't even question it.)
-
Seriously though, you can argue all you want about people not having the right to knock an idea if they haven't tried it but that only holds water in some cases. If I come up with a theory that no previous theory contradicts then I can say "Don't knock it if you haven't tried it." But so far your claims are contradicting known and established scientific facts that have been tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried.
 
  • #29
Proton Soup said:
you're just posting a bunch of crap. you really think it takes 30 hp to turn a rotor just to overcome bearing resistance? what do you think bearings are there for, to create resistance? seriously, go troll somewhere else. you're just spouting nonsense, and it doesn't deserve a bunch of anyone else's time. that's why you get such terse answers. bye.

Actually the reason that EM alternators were not put into production is that because the more of a load= more resistance. The vehicles would not even move or running the standard alternator with the use of the motor created such a drag that it used more power then it would of it the alternator was not on the car. So really get an education on a subject before you try to put other people down. Because honestly your history of this subject is a bit messed up. This is the reason that regen braking is working so well. Its is basically alternators attached to the non driving wheels that tighten when the brakes are applied tighten up tighter and tighter creating more and more energy as more resistance is applied. Transforming the vehicle's kinetic energy back into electricity by storing it in soem form of bank or cap.

I already got the info i needed from the people that actually know what they are talking about from PMs. So like i said take care and read a book:)
 
  • #30
Averagesupernova said:
So let me guess... In your world Thomas Edison invented the telephone right? Samual F. B. Morse invented the morse code, Plato invented the plate, and now I, Holly, have invented the Holly Hop Drive. (For those of you who are not familiar with Red Dwarf, don't even question it.)
-
Seriously though, you can argue all you want about people not having the right to knock an idea if they haven't tried it but that only holds water in some cases. If I come up with a theory that no previous theory contradicts then I can say "Don't knock it if you haven't tried it." But so far your claims are contradicting known and established scientific facts that have been tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried and tried.

My theory has not been said here, I never thought the PMA would work. I just simply asked if it had been tried because someone had brought it up before. I did some light research on it and didnt find anything on the net about it or attempted configs. I was only saying that you shouldn't knock other people if they are trying something IF you don't know for a fact it won't work. I don't know if a PMA would work and I haven't seen anything to say it wouldnt. But in my opinion I said I didnt think it would work, but I thought it would LOOK cool:) Not that everyone should go out and transform their drive shafts to massive PMAs to drive around town.
 
  • #31
trentr said:
take care and read a book:)

what books do you suggest?
 
  • #32
Ok. Fine. Let's start over. Exactly what is it you are trying to do? Don't sidetrack this thing again by saying that something would 'look cool' which has nothing to do with the discussion at hand.
 
  • #33
Like uart said, you haven't specified the amount of power needed to operate or the current in one hour that you need in order to find the amount of charge before going to calculate the capacitance for the capacitor that you need. Voltage is one piece of the puzzle to find out the capacitor that you need.

When you know the current in one hour, you just do this equation to find the charge which is:
Q = I * t

Q = charge in coulombs
I = current in amperes
t = 3600 seconds or 1 hour

Then to find the capacitance you use this formula:

C = [tex]\frac{Q}{V}[/tex]

C = capacitance which is measured in farad (F)
Q = charge in coulombs (C)
V = voltage
 
  • #34
trentr said:
lol naw it aint but the drive shaft isn't a bad idea. If you were to transform the entire drive shaft to a low rpm PMA that could recover some good energy with little resistance. But I don't know if like 10 pma assemblies would create enough to do anything. But would prolly look hella cool, kinda like some back to the future **** lol. Has that been tried? I think the load would rbring the vehicle to a winding stop if it even moved at all.

Generator creates resistance when it generates energy.

I'm not too clear on your idea but from what I've read, it's not going to work. Try it if you think it is going to work. If you fail, you'll still learn something new.
 
  • #35
The March 12, 2009 issue of Nature has an article about lithium batteries which purportedly achieve ultrahigh charge and discharge rates (comparable to those of supercapacitors, according to the authors). They use LiFePO4.
 

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