# Ultracapacitor reseller site



## e-ghia (Mar 12, 2008)

Here's a link to a company that is selling a variety of these ultracapacitors (gotta love the group name! )

Here's the link

So looking at articles and things relating to their use it would seem they can compensate for the initial hit your batteries take when you press the gas pedal. I know in the car audio world stiffening capacitors allow the subwoofers to receive all the current they demand without weakening the current available to other electronics.

So using these in our conversions is a good thing, others seem to think so. Picking from the selection available on the linked page, which would be best suited for a lithium-based battery system comprised of thousands of cells? I am trying to see if the use of an ultracapacitor may meet acceleration needs since they are short in duration.

Phillip


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## Mastiff (Jan 11, 2008)

A good read on how the Farad Measurement for capacitors works:
http://electronics.howstuffworks.com/capacitor2.htm


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## e-ghia (Mar 12, 2008)

From what I have read tonight there is a considerable difference between the regular capacitor and a supercapacitor or an ultra. The power can be available for minutes...

nrel.gov/vehiclesandfuels/energystorage/ultracapacitors

popularmechanics.com/science/research/4252623

Phillip


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## AmpEater (Mar 10, 2008)

So a 144volt string of these would require 53.3 cells...at the max. volume discount of $111 each that is $5900...
As I understand it you could not just put the caps in parallel with the batteries and get much benefit...you need a buck/boost converter that will drain the cap bank down while keeping the output constant with your pack voltage...which would probably cost more than the capacitors themselves. This is starting to get expensive


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## AmpEater (Mar 10, 2008)

AmpEater said:


> So a 144volt string of these would require 53.3 cells...at the max. volume discount of $111 each that is $5900...
> As I understand it you could not just put the caps in parallel with the batteries and get much benefit...you need a buck/boost converter that will drain the cap bank down while keeping the output constant with your pack voltage...which would probably cost more than the capacitors themselves. This is starting to get expensive


I didn't understand you were talking about racing, they would make alot more sense for the application, no buck/boost required. Still, a 300F 144v pack could make 3000amp/seconds...or only 300 amps for 10 seconds...you'd need a considerable number of these things for enough juice. Lets say you go with the highest voltage practical, 348v, you'd need 129 cells. This would be 1,044,000 amp/volt/seconds, or about 1000amps for 10 seconds at 100v, just to put it in practical terms. At a cost of over $100,000....hardly seems like enough bang for your buck


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## e-ghia (Mar 12, 2008)

I wasn't thinking about racing necessarily, more along the lines of stop light acceleration or passing situations. Tasks which are quick and short lived.



AmpEater said:


> As I understand it you could not just put the caps in parallel with the batteries and get much benefit...you need a buck/boost converter that will drain the cap bank down while keeping the output constant with your pack voltage.


I was thinking the capacitors would sit between the batteries and the motor. The motor would draw its power from the batteries through the capacitors. The battery management system would keep everything leveled out amongst the batteries while they recharged the capacitors.

The burst from the capacitors would occur only a few times each trip for me. And the amount drawn at acceleration would not totally discharge the capacitors either.

But I may be totally off with this.  I am still learning about batteries and how to get the most out of the affordable technology available.

Phillip


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## AmpEater (Mar 10, 2008)

This seems like a reasonable application, almost like a "energy flywheel". If you had a battery with a very low sustained current, like certain lithium cells, this might be just the ticket. Perhaps even with floodeds that don't like high current, while maintaining your ability to crank it up for a few seconds when needed.

However, unless you fall into these categories the price is likely to be a major obstacle at these costs....
For a fraction of the price you could get a small AGM pack that could serve the same purpose (extremely high amp discharges for short duration with rapid recharge), but provide far more useable current and would even add to your total capacity, whereas a capacitor bank wouldn't. 1 million cycles is interesting....

I could see alot of promise at 1/10th this cost



e-ghia said:


> I wasn't thinking about racing necessarily, more along the lines of stop light acceleration or passing situations. Tasks which are quick and short lived.
> 
> 
> 
> ...


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## Dennis (Feb 25, 2008)

Capacitors discharge logarithmically so the benefits would quickly diminish as the capacitor discharges for a high current load. The energy is not free as the current to charge up the capacitors comes from the batteries. The motor controller already has capacitors inside to help prevent severe voltage sage on the rest on the electrical systems. So it's not really necessary to have these ultra expensive capacitors.....Now for drag racing if you can get enough farads such that the voltage dip at the end of the race is no more than 10% then you have a nice dragster setup that would kill battery powered dragsters. But remember the discharge of capacitors is logarithmically so it will takes LOTS of them connected in parallel just to keep the voltage from dipping no more than 10% versus what it takes in batteries connected in parallel to achieve the same...(caps also charge logarithmically...)


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## Madmac (Mar 14, 2008)

On an AC motor system with regen they can be used very easily to get a boost. As an example with a lithium ion battery pack of 340volts the max charging voltage is just over 400 volts. The super caps can capture that extra voltage and either use it as boost when the vehicle move off or if it remains stationary it will discharge into the battery pack. That 60 volts makes a large difference.

No more electronics is needed (other than resistors to balance the voltage across the caps) than used in the regen, monitor the generated voltage and limit to max charge voltage ( either DC injection into motor or load resistor).

Madmac


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## the slashmaster (Feb 24, 2008)

e-ghia said:


> Here's a link to a company that is selling a variety of these ultracapacitors (gotta love the group name! )
> 
> Here's the link
> 
> ...


I don't know much about capacitors but those don't even look that big. What happens if you try to use the ones you can grab for free at a recyling center? A lot of them are bigger.


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## e-ghia (Mar 12, 2008)

Madmac said:


> The super caps can capture that extra voltage and either use it as boost when the vehicle move off or if it remains stationary it will discharge into the battery pack.


I wondered about that. It would seem the batteries would not capture and store 100% of the voltage generated from the regen. But the capacitors would be able to hold and store this energy rapidly.


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## e-ghia (Mar 12, 2008)

the slashmaster said:


> I don't know much about capacitors but those don't even look that big. What happens if you try to use the ones you can grab for free at a recyling center? A lot of them are bigger.


Didn't know I could find capacitors at a recycling center. Hmmm...what type of recycling center are you thinking about, slashmaster?


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## e-ghia (Mar 12, 2008)

I sent the Tecate Group an email asking for more information on how they might help in my application. I will post their response here for you to read in case you are considering something like this for your project.


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## the slashmaster (Feb 24, 2008)

e-ghia said:


> Didn't know I could find capacitors at a recycling center. Hmmm...what type of recycling center are you thinking about, slashmaster?


 A metal recycling center. Maybe if you can find a number of something all being thrown away at the same time or something that is common thats known to have big capacitors you can take them if they are the same type. Maybe if it is common enough you can take what you can get for free and buy the rest you still need. Wish I could help you more but I'm no electronics expert. I would probably go and carefully open everything that may have a big cap and collect them all and once I had enough of a single type, bring all the other types back.


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## e-ghia (Mar 12, 2008)

With these ultracapacitors being different from regular capacitors I don't know that I would be able to distinguish between them. I like the idea and will look around and see what I can find available. Now what would have large capacitors in them and be available used....?

Phillip


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## 3dplane (Feb 27, 2008)

Just make sure you take a screwdriver with you to short across the terminals before touching them. They can zap pretty good


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## e-ghia (Mar 12, 2008)

I have always had a certain respect for capacitors. Part from their mystery to me in how they store their energy and the other part in not knowing how to prevent them from discharging into me! 

I heard back from the Tecate Group today and here's the reply:

I basically said, "I am looking to include them in an electric vehicle build using lithium battery cells. I plan to use 6768 3.7 volt cells giving me 348 volts and 194 amphours."

And they replied with: "Basically in order to combine the capacitors with batteries you will need to match their voltages. So for example if you have a 348 volt requirement then you will need to place 129 capacitors in series. Based on the energy you need out of the caps then you can determine which size capacitor to use or how many sets to place in parallel. I believe for your application if you have high peak load requirements then you can try and use the caps for handling them and size your batteries for the long term energy need."

Wow! 129 ultracapacitors?!? Out of my budget for sure. I was hoping I was following a good combination there to reduce the draw on the batteries but it is more expensive than simply adding more batteries. <sigh> Back to more digging...


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## Dennis (Feb 25, 2008)

One thing they did not tell you is that wiring capacitors in series reduces the overall capacitance. So to compensate you would have to make a series-parallel setup. The bad news is the required capacitors are a lot just to get any meaningful farad value with 348 volts...


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## Mastiff (Jan 11, 2008)

e-ghia said:


> With these ultracapacitors being different from regular capacitors I don't know that I would be able to distinguish between them. I like the idea and will look around and see what I can find available. Now what would have large capacitors in them and be available used....?
> 
> Phillip


I doubt super capacitors will be available in most junkyards.

Here are a few places to look through for large capacitors:
Computer Power Supplies, or any equipment with a power supply.
CRT Televisions (tube televisions).
Stereos, Amplifiers, Subwoofers.

I can't think of anything else atm.


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## theboy16 (Feb 28, 2008)

aright, from highschool i remembered (with some refresher help from wikipedia) that F= (A*s)/V.

The examples used in the previous post refered to a 300F bank, however these are 3000F caps, pretty impressive if i may say so.

example: on a 240v bank,

3000 = (500*s)/240

3000*240 = 500*s

720 000 = 500*s

720 000/500 = s

1440 = seconds

1440/60 = 24 min

you could draw 500 amps from your 240 volt, 3000 farad cap. bank for a total of 24 minutes.

similarly, 

3000= (a*3600)/240

720000/3600= 200amps, that's 200AH (3600 seconds in one hour) of storage in the cap bank alone. why are we still using batteries then?

There must have been some wild breakthroughs in the last 5 years to have capacitors in the 3000 farad range, very impressive!! especially for their size.

I'm hoping that someone can confirm my result; intuitively, this seems like too much.


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## theboy16 (Feb 28, 2008)

Something stinks about that link to capacitors.

the following specs are giving (on the 1500F caps)

4.75wh/kg

.32kg/cap

with 89 caps (for a 240v bank) that's 89/4.75 = 135.28Wh or 135.25(V*A)h

135.25(V*A)h/240V = 0.5637Ah

F=(A*s)/V

F=(.05637*3600sec)/240

F= 8.455, a far cry from the stated 1500 farads. this answer makes more sense, intuitively, to me at least; recalling the size of ultracaps seen in the car audio world.

anyone else?


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## MrCrabs (Mar 7, 2008)

When you put caps in series the total capacitance of the string is less than the capacitance of the lowest cap.
See http://www.tpub.com/neets/book2/3e.htm
Ct = 1 / ( 1/C1 + 1/C2 + ... 1/Cn) 
I'm calculating ~33 F for 89 3000F caps in series.
Then you need to put strings in parallel if you want more capacitance.


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## e-ghia (Mar 12, 2008)

The last three posts have me wishing I had taken electronics in trade school instead of auto body! 

I was trying to understand theboy16's first post but the next to threw me.

Now I have no idea about these capacitors: the seller says it would need $14k worth of these (129*$111), theboy16 first says they look promising then sees a flaw, and MrCrabs goes back to serial and parallel configurations.

So one more time for me please, , is this worth looking into a little more and asking Tecate Group more questions? Or is it not worth the money in our application?

Remember. I only was thinking they could absorb the initial drain placed on my batteries during acceleration. Later we found out they can also recharge faster than batteries when the regen kicks in.

Seriously, guys, thanks for the hard numbers. Those are the little truths that I am trying to dig out. No sales pitches, no "my-best-friend's-cousin's-step sister's-uncle did this" stories, just the real numbers that show it like it really is.

Phillip


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## MrCrabs (Mar 7, 2008)

It depends on your definition of worth it. I would say no at that price, but if you could find a sale on some Maxwell Ultracaps it might be worth it. Maybe some discontinued models would be cheaper.

By my calculations, if you have 129 of these in series, for a total of 348 volts, you could draw 50 A for 10 seconds and the voltage would drop down to 312. or you could draw 50 A for 5 seconds, or 100 A for 2.5 seconds.
That seems like it might be a nice little boost, and if the controller can handle a larger voltage sag, you can draw current for longer.

Anyone have an idea on how they would connect these to the battery pack?
I would just go parallel to the batteries, so they can provide extra current when demand is high, but I'm not sure how the would interact with the batteries.

I did some more calcs on a 120 volt system, and 45 caps would be needed for a cost of $5,800.
They would put out 50 A for 10 sec and then the voltage would drop to 100.
What kind of current does a 120 volt motor draw at startup, and for how long?


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## theboy16 (Feb 28, 2008)

Thanks for the extra info on the caps... i knew it was too good to be true.


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## Bugzuki (Jan 15, 2008)

The capacitors would be fine in parallel with the battery pack. They would just act like a parallel battery that did not last as long. So it would give up its charge then get it back from the pack.

Those are outrageously expensive. That is why we are still using batteries. Just think if you tried to put them in series to get the voltage up then the packs in parallel to get the capacitance back up. 89 caps in series = 240v @ 33F --- 91 packs in parallel = 240V @ 3000F --- equals 8099 caps * $125.00 = 1,012,375 for 24 minutes of run time.

This is all according to the previous posts - just for perspective.

Edit: I guess I was wrong if you buy more then 100 you get them for $111.00 each so the total price would come way down to $898,989.00 = much better.


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## Bugzuki (Jan 15, 2008)

Why would they make a capacitor with such a low voltage. 

They aren't that bad in size approximately 5.5" long and 2.5" in diameter, so you could probably fit a bunch in your car, maybe even 8099 of them.


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## MrCrabs (Mar 7, 2008)

Bugzuki said:


> Why would they make a capacitor with such a low voltage.


Because of physics. The charge a cap can hold is related to the area of the plates. The voltage a cap can withstand depends on the type of dielectric material between the plates, and the thickness of the dielectric material.

So to withstand a higher voltage, you need a thicker dielectric. If the dielectric material is thicker, you take away from the space inside the cap that can be used for the plates, reducing their area, and thus reducing the charge it can hold.

I've been doing so research, and people into building their own Tesla coils / rail guns, and other high voltage toys build their own caps. They build them to withstand 20 kV but the capacitance is down in the pico or nano farad range. I'm going to figure out if it would be possible to make a 1 F 300 V cap.


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## Bugzuki (Jan 15, 2008)

It seems like if you made the Cap bigger you could have a higher voltage and retain the Capacitance. Maybe it would take a capacitor the size of a car battery or bigger, but I am sure it could be done. I am not sure what other issues come into play when the capacitor grows in size. And I am sure that it is harder to roll up the thicker material enough to get the same capacitance.

Please correct me if I am wrong.


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## Da_Fish (Apr 28, 2008)

When you put caps in series the total capacitance of the string is less than the capacitance of the lowest cap.
See http://www.tpub.com/neets/book2/3e.htm
Ct = 1 / ( 1/C1 + 1/C2 + ... 1/Cn) 


Mr.Crabs is correct and its what we call FM logic (friggen Magic).

I also built some of my own Caps a few years ago as a project in school. Increasing the Voltage is what really increases the size of the Cap. The MFD does not increase it as much. Fair warning for anyone that is going to try and use caps in their system, when they go...they go hard!!! 

For the guy that suggested a screwdriver to discharge...shame on you hehe. You actually can damage the cap this way, cause blue spots in your vision, and knock your pee pee in the dirt if you do it wrong!!! Take a 1k ohm resistor and slowly discharge the cap. A short can actually cause a weak cap to explode...and like I said it aint pretty when they decide to vent.

They guy that was talking about using them for an AC system. This should be fine as this is what most inverters use for heavy initial loads but make sure you have the same caps on all 3 phases as caps will knock the Voltage out of phase 90 degrees. It would suck to have 1 phase 30 degrees off one phase and 180 off another hehe.

And buy the way, I too am starting to look into electrifying my Ghia. 68 vert. I am looking for similar performance and range and am thinking that AC and Li fe batts are going to be the only way to acheive this. Now I am looking at a 20k plus build. You have any luck with other options?


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## e-ghia (Mar 12, 2008)

Da_Fish said:


> And buy the way, I too am starting to look into electrifying my Ghia. 68 vert. I am looking for similar performance and range and am thinking that AC and Li fe batts are going to be the only way to acheive this. Now I am looking at a 20k plus build. You have any luck with other options?


More great info, Da Fish. Thanks

As for a better way on the Ghia? Nah

I have a long, long commute to work and it costs me around $450 each month just to drive to work. I thought I could spend $20-25K and offset my actual expenses (the loan would be cheaper than my current gas bill). But it ended up being too much of a pipe dream.

For the range, acceleration, and top speed I need (read want) it is going to cost much more considering battery costs. When the batteries come down a little more I pick up where I left off. For now I will work towards maximizing my MPG....


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## Da_Fish (Apr 28, 2008)

Hehe your in the same boat I am.


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## Wirecutter (Jul 26, 2007)

AmpEater said:


> __________________
> Project AmpEater
> Electron Powered 240z
> Reply With Quote


 Damn. Another good name for an EV taken...


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