i got my boost caps

[willib]

They are 350 Farads 2.5V ultracaps

internal resistance is 3.2 milliOhms

Isc is 1500 A

i bet i could spot weld with these caps

i am going to see whether they will start my car or not.

i charged one up with the excercize bike-gen , the amount of time it took was impressive , as was the pedaling required to charge it up

as ya can see they are about the size of a D cell battery

[willib]

BTW it took 2min 50 seconds to go from 30mV to 2.5V at a constant current of about 5A .

as close to 5 A as i could keep it.

[Nando]

V= C * dI/ dT

C= V / ( dI/ dT) = ( 2.5 - 0.03) / ( dI/ dT) = 2.47 v * 170 sec / 5 amps = 83.98 Farads

What is the size value of the capacitor.

Nando

[willib]

amanda gave me this equation

CV=IT

350F(2.5V)/5A= 175 seconds

which is very close

[Slingshot]

That's pretty impressive for a capacitor.  It stores over a thousand watt-seconds of energy.  But that's still only about 11% of what you can store in a AA NiMH battery.  The difference, of course, is frequency response - the capacitor can store and release the energy in a much shorter time.

[willib]

i got one string done , i drilled into the tabs and tapped one end and used a machine nut

[windstuffnow]

  Pretty cool willib !  I never did order any because of all the other stuff I had going at the time... Still tossing around the idea of the 2600's for some play time as well as the 350's.

  It will be fun hearing about your adventures with them though! Keep us (me) informed !

.

[willib]

the 8 week wait is nonexistant as far as i can tell

it only took 4 days for them to get here

been reading about balancing them to prevent one cap ( in a string)from being overcharged

http://www.ewh.ieee.org/soc/pes/switchgear/Presentations/Maxwell_Switchgear_Galveston.pdf

below is their paper on starting an internal combustion engine with boost Caps

they ( students)did two tests ,one on the bench and one with a real car

they got me beat with the caps they used 1400F , but they only used five in one string. for a total of 280F

with two strings of five  350s i can get 140F total.

should be interesting , and touchy ..

because if i do get it started i'm gonna have to shut it off immediatly , before the alternator starts overcharging them.

http://www.maxwell.com/pdf/uc/BOOSTCAPs_Start_ICE-1007240.pdf

the paper gives a value of 12 mOhms for a 12V 'starter' battery , i was wondering about that.

[coldspot]

Well

After reading that paper about starting an ICE with them and I bit of thinking,......&@*^$%@

With enough Super Caps and using NiMH battery packs

A scooter with a motor and the super caps charging from the electronic brakes and then being used for the high drain starting from dead stop to assist the motor up to better RPM's for power used would be great.!!

LOL

:

   

[Nando]

Heck I miss placed the formula.

I = constant therefore

I = C * dV/Dt :

C = I *dt/dV = 5 * 170/2.5 = 340 F

[tecker]

These show some impressive load handling promise .I have also been playing with caps  ( and 7ah batts)integrated several Audio caps parallel to My 12 volt transfer lines from the charging stations Where line loss is a problem  . It works  I'm hoping to switch to ultracaps to make one large cap bank circuit instead of a centralized battery bank and load circuits .

[tecker]

A good example . The optimum transfer distance for my solar panels is 25 feet .There's a voltage drop to my battery bank at 80 feet of 3 volts .With the caps set in ajbox every 10 feet the voltage drop is not there and the control bank ( 3 ea 6v golfcart batts ) stays around 19.5 to 20  volts during the day rather than 18.5 .The charge rate set to  8 amp .

[willib]

If i use two strings of six caps 350/6*2= 116 F

then i wont have to worry about them overcharging, i think, because 6* 2.5 = 15V

can anyone see any problems i might run into if i try to start a saturn ion with caps ,because i would really really hate to F up the electronics on a three year old car..if it doesnt start and just clicks the starter relay i would be somewhat relieved because i'm not sure how the alternator will react with the caps.

i could measure the current needed turn the starter and see if my setup could supply that much current for the duration of the starting process.

i think thats what i will do , measure the current first .

very interested in your responses

[RP]

Willib,

I'm not sure about the Saturn but a lot of cars use two postive battery cable.  One is for the electronics, etc. and the other goes to the starter solenoid.  If the Saturn is set up like this perhaps you could connect the cap bank to the starter only.

[willib]

I spent the day cleaning out the trunk where the battery is...

and started up the mustang after years of sitting,a little engine fog ( thats foamy oil stuff )and a very little gas down the carb and she started up fine :-)

so i may just use the mustang as a test car  if i can get the mustang to start every time , although the saturn shurely takes less power to crank the engine

i'm undecided as of yet

i didnt have time to find out the cranking amps needed to start either car

looks like tomorrow is going to be nice also , today was beautiful !

[RP]

The Ford will be even easier.  

The starter solenoid is located on the fenderwell next to the battery.  Just connect your boost cap bank to a set of jumper cables and then clamp it right to big cable that runs to the starter motor.  As long as you don't actually rotate the key to the "start" position, you won't make any connection to the cars' electronics (except for sharing a ground).

[willib]

i'm not as worried abot frying anything on the mustang as i am about the car i drive everyday.

i have to make up a couple of cables to go from the caps to the car

if i do what you said about the mustang , about rotating the key ? what did you mean by that ?

key on ? or off?

i dont want to just crank the motor , i want to start it.

[willib]

ohhh  i see what you ment..

[willib]

ok , i've got about 7 feet of 10 gauge (~ 0.001 ohms per foot)

and did some testing with the excer-bike

at 5A it reads 34mV

at 6A it reads 42mV across the shunt.

the connection to the battery is a 3/8 bolt

so at 100A it should read about .7V across the shunt.

we'll see!

[willib]

this is my shunt , it may look like a coil ,and you would be right!





acording to my calculations

1.305V across a .007 Ohm resistor is a lot of amps

this is the shunt installed and almost ready for testing.

i thought i had everything worked out !

i used the min/max button on the meter after selecting Voltage , BUT the friggin meter would only read the correct max value after i went back inside to get a voltage divider that put the voltage in the correct RANGE !!( without going over) because apparently it will not read the correct  voltage if the voltage when you press the min/max button is in the millivolt range...

 i did notice with the key on it was drawing .957 A , and after a few starts it was charging the batt at 3.9A which quickly dropped to 3.2A