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Discussion Starter #1
Ok let's say I have 48 2.5V ultra caps in my vehicle, wo would be the source
for the controller ?
Tony
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Discussion Starter #2
Don't need a controller, you'd have to get out and push. The energy
stored would be about 150Wh presuming 2500F caps.


Tony Wright <[email protected]> wrote:
> Ok let's say I have 48 2.5V ultra caps in my vehicle, wo would be the source
> for the controller ?
> Tony
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Discussion Starter #3
My impression was that most applications use the supercapacitors in parallel
with the battery pack to limit current spikes to/from (if have regen) the
pack. If you pull 400A at 115V for 20 seconds during acceleration, that is
about 920 kJ or about 0.26 kWh. The energy discharged from the caps is
0.5CV*V, so for a 5V change in voltage (120-115) that would be about 31.3 kJ
or about 0.009 kWh. If my numbers are correct, I don't see how this helps
reduce battery current spikes all that much. It seems more cost effective
to size your pack at larger Ah capacity to limit the current spikes to less
than 3C (for LiFePO4 cells), so they have a small effect on cycle life.
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View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/Who-sells-controllers-for-ulta-caps-tp3029625p3029965.html
Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com.

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Discussion Starter #4
tomw wrote:
> My impression was that most applications use the supercapacitors in
> parallel with the battery pack

This has been done for "quick and dirty" tests, but it is an ineffective
way to use them. A battery has a relatively constant voltage regardless
of current or state of charge. A 120v pack might actually swing from
100-144v.

A capacitor has huge voltage swings with state of charge; 0v when dead
and max voltage when full. To get a useful range of state of charge, the
voltage has to swing over a 3:1 or more range; like 50v to 200v.

If you connect a capacitor and battery in parallel, the capacitor stays
at essentially a constant state of charge, and only supplies brief peak
charge/discharge current. The capacitors in a controller are used this
way, to reduce the AC ripple current that the batteries see. But they
provide no net energy for range.

To use supercapacitors as a battery pack, you need a charger,
controller, and DC/DC converter that can work over at least a 3:1 range
of voltages. On charge, the charger brings the pack from 0v to (say)
200v. When driving, the controller needs to work as the pack goes from
200v down most of the way to 0v. The DC/DC converter that is supplying
12v power also has to work over this wide range.

--
Lee A. Hart | Ring the bells that still can ring
814 8th Ave N | Forget the perfect offering
Sartell MN 56377 | There is a crack in everything
leeahart earthlink.net | That's how the light gets in -- Leonard Cohen

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Discussion Starter #5
Some time ago, I contacted ESMA in Russia:

http://www.esma-cap.com/About/?lang=3DEnglish

Sometimes the above address may not run, so just leave every thing out afte=
r =

the com to get to the site.

They have super capacitors that are design for traction which are call =

traction super capacitors which have a conductive electrolyte instead of oi=
l =

or air. They also have ultra capacitors which are design as pulse =

capacitors for hybrids or starting large engines.

A large bank of super capacitors at 300 volts can run a city bus for up to =

10 miles and then can be recharge in with 10 to 15 minutes.

I gave them the specifications of my EV that weighs 4640 without the batter=
y =

pack, Caf=E9 Electric DC controller, a PFC-50 charger and a battery pack sp=
ace =

of 2200 square inches by 12 inches high. They came up with the following =

data.

Traction Super Capacitors

Thirteen 10-cell modules that are 21.5" long by 7.125" wide by 9.9" high. =

Weighs 75 lbs each for a total of 975 lbs.

Maximum Voltage per Module - 16 volts or 208 volts per pack
Minimum Voltage per Module - 9 volts or 117 volts per pack
Capacitance (AH) - 460
Maximum Power, KW - 420
Discharge Energy at 100 A - 7.5 MJ

Operating Temperature C. - -50/+70
Cycle Life - 500,000

Price per Module - $3000.00


You can use the existing controller and battery charger for a DC system.

Roland






----- Original Message ----- =

From: "tomw" <[email protected]>
To: <[email protected]>
Sent: Saturday, November 06, 2010 6:26 AM
Subject: Re: [EVDL] Who sells controllers for ulta-caps ?


>
> My impression was that most applications use the supercapacitors in =

> parallel
> with the battery pack to limit current spikes to/from (if have regen) the
> pack. If you pull 400A at 115V for 20 seconds during acceleration, that is
> about 920 kJ or about 0.26 kWh. The energy discharged from the caps is
> 0.5CV*V, so for a 5V change in voltage (120-115) that would be about 31.3 =

> kJ
> or about 0.009 kWh. If my numbers are correct, I don't see how this helps
> reduce battery current spikes all that much. It seems more cost effective
> to size your pack at larger Ah capacity to limit the current spikes to =

> less
> than 3C (for LiFePO4 cells), so they have a small effect on cycle life.
> -- =

> View this message in context: =

> http://electric-vehicle-discussion-list.413529.n4.nabble.com/Who-sells-co=
ntrollers-for-ulta-caps-tp3029625p3029965.html
> Sent from the Electric Vehicle Discussion List mailing list archive at =

> Nabble.com.
>
> _______________________________________________
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> =


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Discussion Starter #6
From: Tony Wright
Ok let's say I have 48 2.5V ultra caps in my vehicle, wo would be the source
for the controller ?
Tony

I'm not sure but I believe that it takes 3600 farads to make a 1 ah so
the gold mine batteries are not even 1 ah ,
Steve Clunn
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Visit our shop web page at: www.Greenshedconversions.com

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Discussion Starter #7
Steve Clunn <[email protected]> wrote:
> From: Tony Wright
> Ok let's say I have 48 2.5V ultra caps in my vehicle, wo would be the source
> for the controller ?
> Tony
>
> I'm not sure but I believe that it takes 3600 farads to make a 1 ah so
> the gold mine batteries are not even 1 ah ,
> Steve Clunn

It takes 3600 Coulombs to make 1 Ah. A Farad is one Coulomb per volt,
so a 3600 Farad 2.5V capacitor holds 9000 Coulombs, which is 2.5 Ah.

However, the voltage decreases as it discharges, so a 3600 Farad 2.5V
capacitor holds as much energy as a 2.5Ah 1.25V battery.

-Morgan LaMoore

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Discussion Starter #8
The difference between batteries and supercaps is after 1/2 the amp=hrs are
taken out the voltage is 1/2, with batteries it will be slightly lower than
the start voltage. I think it's better to work in Watt-hrs. A fully charged
2600F cap at 2.5V is 8125 watt seconds (joules), or 2.25 watt-hrs.
That is, if I have not made any mistakes!

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Morgan LaMoore
Sent: Thursday, 11 November 2010 3:37 p.m.
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Who sells controllers for ulta-caps ?

Steve Clunn <[email protected]> wrote:
> From: Tony Wright
> Ok let's say I have 48 2.5V ultra caps in my vehicle, wo would be the
source
> for the controller ?
> Tony
>
> I'm not sure but I believe that it takes 3600 farads to make a 1 ah so
> the gold mine batteries are not even 1 ah ,
> Steve Clunn

It takes 3600 Coulombs to make 1 Ah. A Farad is one Coulomb per volt,
so a 3600 Farad 2.5V capacitor holds 9000 Coulombs, which is 2.5 Ah.

However, the voltage decreases as it discharges, so a 3600 Farad 2.5V
capacitor holds as much energy as a 2.5Ah 1.25V battery.

-Morgan LaMoore

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Discussion Starter #9
Because the energy is proportional to V squared, so at 1.25V there is 1/4
the energy left.

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Morgan LaMoore
Sent: Thursday, 11 November 2010 3:37 p.m.
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Who sells controllers for ulta-caps ?

Steve Clunn <[email protected]> wrote:
> From: Tony Wright
> Ok let's say I have 48 2.5V ultra caps in my vehicle, wo would be the
source
> for the controller ?
> Tony
>
> I'm not sure but I believe that it takes 3600 farads to make a 1 ah so
> the gold mine batteries are not even 1 ah ,
> Steve Clunn

It takes 3600 Coulombs to make 1 Ah. A Farad is one Coulomb per volt,
so a 3600 Farad 2.5V capacitor holds 9000 Coulombs, which is 2.5 Ah.

However, the voltage decreases as it discharges, so a 3600 Farad 2.5V
capacitor holds as much energy as a 2.5Ah 1.25V battery.

-Morgan LaMoore

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No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 9.0.869 / Virus Database: 271.1.1/3245 - Release Date: 11/11/10
08:34:00

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