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Capacitor Battery

  1. Mar 6, 2009 #1
    I am in the army and some friends and myself are doing some research for an experiment we are doing. None of know alot 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 lets 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.
  2. jcsd
  3. Mar 6, 2009 #2


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    You might want to rethink this statement.
  4. Mar 6, 2009 #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]
    Last edited by a moderator: May 4, 2017
  5. Mar 6, 2009 #4
    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:)
  6. Mar 6, 2009 #5

    hmmmm... thanks for the link, we dont 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?
    Last edited by a moderator: May 4, 2017
  7. Mar 6, 2009 #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.
  8. Mar 6, 2009 #7


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    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.
  9. Mar 6, 2009 #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:
  10. Mar 6, 2009 #9
    Fair enough, like i said we just dont want to give away too mcuh info because we dont 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 isnt 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 isnt 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
  11. Mar 6, 2009 #10


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    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.
  12. Mar 7, 2009 #11
    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.


    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)

    Last edited: Mar 7, 2009
  13. Mar 7, 2009 #12
    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.
  14. Mar 7, 2009 #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?
  15. Mar 7, 2009 #14
    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 dont 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:)
  16. Mar 7, 2009 #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:)
  17. Mar 8, 2009 #16


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    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?
    Last edited: Mar 8, 2009
  18. Mar 8, 2009 #17
    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
  19. Mar 8, 2009 #18


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    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).
  20. Mar 8, 2009 #19
    lol naw it aint but the drive shaft isnt 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 dont 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.
  21. Mar 9, 2009 #20


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    PMA is "permanent magnet alternator" right?
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