New (I think) supercap..could be useful.

[x88x]

I was browsing Mouser's supercap selection today for an idea for an upcoming project and I ran across this little gem. Not much use for the project I researching, but I think I'm gonna get one or two anyway. Could be very useful.

The most interesting one is this, the Maxwell BCAP0310 P270 T10
2.7V
310F (yes, 310F)
2.2mOhm internal resistance
-40C to +65C operating range
33mm dia x 62mm length
~$20 each

There's also the BCAP0350 E270 T11, which is almost identical but is 350F and has an internal resistance of 4.2mOhm, and is ~$3 more each, but I think the T10 is better value. Yes, the T11 is 40F more and normally that is an absurdly huge amount, but in context...not so much.

Throw one or two of these on a little uC project, slap a solar panel on top, and you'll never have to worry about charging it again (even if you live at the north pole).

[BuzzKillington]

What's a uC?

[x88x]

What's a uC?

Microcontroller.

[mtekk]

Throw one or two of these on a little uC project, slap a solar panel on top, and you'll never have to worry about charging it again (even if you live at the north pole).

IIRC, supercaps will lose charge over time (self discharge), even if nothing is drawing from them. The self discharge may cause it to not be sufficient for running in the north pole when it has those few days of no sunlight . And, it could be quite easy to have the draw of the micro be less than the self discharge rate (what a fun situation to be in, we had a side discussion on this in one of my uC classes).

[x88x]

According to the datasheet the self discharge is only 0.45mA, so...maybe not several months worth...definitely would work through a normal night/rainstorm/etc.

I was talking to some people on another forum about its big brother (3kF!). Normally it goes for $90, but someone pointed out to me that Electronics Goldmine has some for $25. I'm definitely gonna be picking up a couple of those in a few days.

[Konrad]

310-350F???

Dare I ask what you're trying to build?

[x88x]

Nothing specific in mind atm. Oh, and the ones I'm gonna get (most recent post) are actually the first ones' big brother...3,000F.

[Kayin]

You could build a lightning gun with that...

[Konrad]

You could shoot down satellites with that. I imagine these caps either pack really low breakdown voltages or are the size of filing cabinets? Biggest I ever used were a handful of 10F/5V supercaps (each a bit bigger than my thumb) from SparkFun. Tried to build a railgun that could fire liquid mercury droplets, project was a rather unexciting failure.

[x88x]

Yeah, they're only 2.7V, so not much use for coil/railgun firing circuits or other fun HV stuff. Still though, 10kJ at 2.7V is nothing to laugh at. I'm thinking of testing these out as the charging source for my coilgun...not sure how well that'll work, but it'll be interesting no matter what happens. I wish I could get some high voltage, high capacity caps...unfortunately they tend to be absurdly expensive and actually not very high capacity. I might try and pick up some HV pulse caps at some point, but they're the other end of the spectrum than these..extremely high voltage, but very low capacity.