Ultracapacitor project

Thread Starter

jacradn

Joined Jun 7, 2013
9
I have a battery of ultracapacitors 8.1V, 1000F.
I need to design a charger for rapid charging of battery.
To be fast charging current must be greater than 30A to max. 100A.

Does anyone have any idea how to do?
 

wayneh

Joined Sep 9, 2010
18,183
A high capacity battery charger could do the job if you could arrange your capacitors in two halves in series, to get half the charger's voltage (~7V) across them.
 

trader007

Joined Feb 27, 2010
249
since theyre capacitors, they shouldnt need a charging circuit. mcmelectronics has some 30a 12v power supplies that you can lower the voltage on.

this would work :D http://www.mcmelectronics.com/product/72-7685

or a cheaper way would be to get a 7.4v r/c car battery pack and wire it directly to the capacitors. they normally are about 8v charged. i think it would work with some of the better packs, be careful though.
 

Thread Starter

jacradn

Joined Jun 7, 2013
9
since theyre capacitors, they shouldnt need a charging circuit. mcmelectronics has some 30a 12v power supplies that you can lower the voltage on.

this would work :D http://www.mcmelectronics.com/product/72-7685

or a cheaper way would be to get a 7.4v r/c car battery pack and wire it directly to the capacitors. they normally are about 8v charged. i think it would work with some of the better packs, be careful though.
Thanks for the replies.

I have a new question.

need a load control with these sources?
supercapacitor battery needs to have a load control?
 

Thread Starter

jacradn

Joined Jun 7, 2013
9
They're your capacitors, you tell us. ;)

Do you think you need to limit the charging/discharging current? Otherwise I don't know what you mean by "load control".
Is need create some protection to disconnect the capacitor battery when fully charged? note: I use a current supply to charge the battery.

Thanks.
 

Shagas

Joined May 13, 2013
804
Since it's a capacitor then you just have to charge it with a voltage lower than the rated which is 8.1 V.
So if your supply is 7,5 V then the cap will charge up and stop at 7,5 by itself .

I'm just waiting for someone more experienced to drop in and say how many volts an 8.1V rated supercap can be charged up to without damaging its lifetime and ESR .
 

wayneh

Joined Sep 9, 2010
18,183
So if your supply is 7,5 V then the cap will charge up and stop at 7,5 by itself .
I agree. The only criterion you need to know when to stop charging is the voltage on the capacitor. You don't want to exceed the rating. If it was me, I wouldn't design it to exceed, say, 80% of the rated voltage.

I think you should also be certain of the charging and discharging rates, that they will not exceed the specifications and burn up your capacitors.
 

Thread Starter

jacradn

Joined Jun 7, 2013
9
the supercapacitor supports up to 130 A.
with a voltage source I know that there would be no problem with the load.
but this kind of load is slow, the supercapacitors support charges and discharges very fast, and typically are loaded through current sources with a constant current.

this battery of supercapacitors have 8.1 V, 1000F, 9.12Wh and fully charge in 80 seconds with a current source 100A constant.

But I need a protection to disconnect the battery when fully charged.

My question is how i can make this protection?

http://www.maxwell.com/products/ultracapacitors/docs/an-010_charging_ultracaps.pdf#search="charge"
 

Thread Starter

jacradn

Joined Jun 7, 2013
9
Since it's a capacitor then you just have to charge it with a voltage lower than the rated which is 8.1 V.
So if your supply is 7,5 V then the cap will charge up and stop at 7,5 by itself .

I'm just waiting for someone more experienced to drop in and say how many volts an 8.1V rated supercap can be charged up to without damaging its lifetime and ESR .

the supercapacitor supports up to 130 A.
with a voltage source I know that there would be no problem with the load.
but this kind of load is slow, the supercapacitors support charges and discharges very fast, and typically are loaded through current sources with a constant current.

this battery of supercapacitors have 8.1 V, 1000F, 9.12Wh and fully charge in 80 seconds with a current source 100A constant.

But I need a protection to disconnect the battery when fully charged.

My question is how i can make this protection?

http://www.maxwell.com/products/ultracapacitors/docs/an-010_charging_ultracaps.pdf#search="charge"
 

wayneh

Joined Sep 9, 2010
18,183
But I need a protection to disconnect the battery when fully charged.
Why? What are you protecting? Are you saying your charger will not stop at 8.1V on its own? Use a voltage cutoff. But you need to switch a large current, so that will not be simple.
 

Thread Starter

jacradn

Joined Jun 7, 2013
9

Thread Starter

jacradn

Joined Jun 7, 2013
9
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