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Topic: 150F caps vs 200F caps from china. (Read 1 time)previous topic - next topic

cjdelphi

Nov 29, 2012, 01:54 am
I bought 2 150F super caps from a local supplier in Aus, and really impressive but the 200F from coolshopper08 on ebay some other brand, the capacitor is 30% roughly larger in size and only 50 farads more, so I was not really expecting much difference..

But boy these caps suck 3 - 4x more juice! - after my wires started to smoke (I quickly touch the terminals on and off until i reach 2.7v) i soon realized how much power was being drawn from a 12v lead acid battery!

Since i already melted jumper wires to everything in sight, I decided to make a video and see how powerful this was, so to not damage the 200F cap I only made contact for a few seconds, watch the alligator clip! any longer and I'm sure it would begin to melt....

MarkT

#1
Nov 29, 2012, 02:05 am
You should limit the current on charge and discharge to prevent damage for a long capacitor life (and to prevent overheating).  For a 200F cap you can probably limit to 20A or something like that.  For supercaps a charge / discharge rate of 100mV/s is actually quite high!

The internal resistance of the caps will limit the current that can flow (and thus affect how hot the wires get).  This is not the same as the capacity itself.  Its the difference between specific power density and specific energy density.

PS Where's the vid?
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

#2

There

cjdelphi

#3
Nov 29, 2012, 02:20 am
The caps were empty fresh and brand new, I was curious - i never go over 2.8 (max overcharge voltage)

RoyK

#4
Nov 29, 2012, 01:59 pm
You do realize you are playing with a potential bomb?

#5
in this instance

Grumpy_Mike

#6
Nov 29, 2012, 02:19 pm
It is not only the heat that causes the problem. Too high an input current can cause physical distortion of the plates, you always need some sort of current limiting when charging them. Saying it is not connected for long does not cut it. At the very least you are damaging the storage capacity of your component.

cjdelphi

#7
Nov 29, 2012, 02:34 pm
I love the "future tense" statements here..

I did it, it's done, get over it, no more whinging, we all get it!, as pointed out i use a Regulator, I was more curious as to what it could do... the capacitors themselves barely even got warm, nor the battery, just the leads...

past tense, that was fun.

future tense, I'll continue using my switching regulator.

krupski

#8
Nov 30, 2012, 06:04 am

I bought 2 150F super caps from a local supplier in Aus, and really impressive but the 200F from coolshopper08 on ebay some other brand, the capacitor is 30% roughly larger in size and only 50 farads more, so I was not really expecting much difference..

But boy these caps suck 3 - 4x more juice! - after my wires started to smoke (I quickly touch the terminals on and off until i reach 2.7v) i soon realized how much power was being drawn from a 12v lead acid battery!

Since i already melted jumper wires to everything in sight, I decided to make a video and see how powerful this was, so to not damage the 200F cap I only made contact for a few seconds, watch the alligator clip! any longer and I'm sure it would begin to melt....

Gentlemen may prefer Blondes, but Real Men prefer Redheads!

retrolefty

#9
Nov 30, 2012, 06:06 am

I bought 2 150F super caps from a local supplier in Aus, and really impressive but the 200F from coolshopper08 on ebay some other brand, the capacitor is 30% roughly larger in size and only 50 farads more, so I was not really expecting much difference..

But boy these caps suck 3 - 4x more juice! - after my wires started to smoke (I quickly touch the terminals on and off until i reach 2.7v) i soon realized how much power was being drawn from a 12v lead acid battery!

Since i already melted jumper wires to everything in sight, I decided to make a video and see how powerful this was, so to not damage the 200F cap I only made contact for a few seconds, watch the alligator clip! any longer and I'm sure it would begin to melt....

http://stores.ebay.com/coolshopper08/Electronic-Parts-Instruments-/_i.html?_fsub=792766013&_sid=783436153&_trksid=p4634.c0.m322

krupski

#10
Nov 30, 2012, 06:11 am

http://stores.ebay.com/coolshopper08/Electronic-Parts-Instruments-/_i.html?_fsub=792766013&_sid=783436153&_trksid=p4634.c0.m322

Thanks. Are there any other places to get them (I don't do EBay - for personal reasons).
Gentlemen may prefer Blondes, but Real Men prefer Redheads!

retrolefty

#11
Nov 30, 2012, 06:16 am

http://stores.ebay.com/coolshopper08/Electronic-Parts-Instruments-/_i.html?_fsub=792766013&_sid=783436153&_trksid=p4634.c0.m322

Thanks. Are there any other places to get them (I don't do EBay - for personal reasons).

Even to just buy stuff? That's so sad, I would be a very unhappy camper if I couldn't buy stuff on ebay. Been buying stuff there for over 15 years with no complaints other then sometimes I buy stuff too impulsively.

Lefty

#12