Latest toys...

[CM800]

Managed to buy 4 of these maxwell boost caps 2.7v @ 3000F

Had a little play around, melted some copper wire.. but what to do with them now? any ideas? (or did i just waste £80)

[David Hess]

Find 4 or 6 more and build a replacement for the starter battery in your car.

[delmadord]

Find 4 or 6 more and build a replacement for the starter battery in your car.

Could you please explain what would be the benefits of suparcapacitor based car battery? Less self-discharge, greater longevity or better performance over temperature range? I am curious

[robrenz]

Make yourself a battery tab welder

[CM800]

Make yourself a battery tab welder

Could be a good idea, ive ordered some M12 lugs to put on it as i have some 50mm2 wire with no method to attach it.

[David Hess]

Find 4 or 6 more and build a replacement for the starter battery in your car.

Could you please explain what would be the benefits of suparcapacitor based car battery? Less self-discharge, greater longevity or better performance over temperature range? I am curious

Assuming the proper design with cell balancing, it will both perform better over temperature and last longer.  It would only be more economical if you could get the supercapacitors for cheap though and you lose the large reserve capacity that a starter battery provides.

[cybermaus]

Are those M12's?? What is the size of those things?
Just for fun, can you measure their resistance, or would that fall below the the 0.00 of a typical ESR meter?

[CM800]

Are those M12's?? What is the size of those things?
Just for fun, can you measure their resistance, or would that fall below the the 0.00 of a typical ESR meter?

Afraid i do not have a ESR meter.. yet.

[Artlav]

Nice. Got 12 of these too.
Haven't really found a good use for them either.

They are not that big, and surprisingly light:


Compared to BCAP0350 (D cell), a generic 100F cap and a 9V battery:


One thing they are good at is that they can give practically unlimited current for some while, without any danger.
Unlike batteries which will explode if short circuited, or capacitors which give high current for very short time.

I did all sorts of pulse power experiments with them, and occasionally use them when i need a portable super-low impedance power source.
I.e. induction heating:



Or lighting xenon arc lights:


And so on.
ESR meter does not read anything meaningful on them.

I also had a few dozen BCAP0350, D cell sized ones, which i put into a single 55V battery - now that is useful as a power source for linear magnetic accelerators.

[CM800]

Very nice, wouldnt mind getting some more to be honest.. but im kind of poor now.. spent way too much money. Need to sell more of my peltier units.
Where did you get those bolts for between the caps?

EDIT:

Nevermind, managed to find some bolts

[Frost]

Where did you get those bolts for between the caps?

At the hardware store?
The bolts seem to be normal M12 DIN 6334 extension/coupling nuts.

[Tinkerer]

So question, what do you need a portable induction heater for?'

As for the car battery replacement, that is indeed possible. It is not recommended if your car will be sitting for a several days at a time without use though as the voltage will drop alot because they naturally drain alot more quickly than batteries. Unless you dont mind giving them a jolt to charge them back up before you need to go somewhere after a longer period.
There is at least one guy on youtube that put up videos about replacing his car battery with supercaps.

[David Hess]

So question, what do you need a portable induction heater for?'

I have considered making one for annealing cartridge case necks.  I suspect it would be more consistent than using a torch.

As for the car battery replacement, that is indeed possible. It is not recommended if your car will be sitting for a several days at a time without use though as the voltage will drop alot because they naturally drain alot more quickly than batteries. Unless you dont mind giving them a jolt to charge them back up before you need to go somewhere after a longer period.
There is at least one guy on youtube that put up videos about replacing his car battery with supercaps.

One or two weeks appears to be feasible.  A small charging circuit and auxiliary battery would solve this problem.  If I did this as more than a test, I would add charge balancing anyway.