Maximum continuous current: 210A for 40°C temperature increase
Maximum peak current (1 sec): 2200A
Maximum leakage current: 5.2mA
Operating temperature range: -40°C to 65°C
Cycle life: 1000000
Life: 10 years at 25°C and rated voltage.
Shelf life: 2 years (Stored uncharged).
Supercaps are a alternative to batteries at least in some cases, but their abilities are very different. I have performed the test as a battery test, making it easy to compare to batteries.
Something to note:
Supercaps has a fairly low voltage rating, for higher voltage they must be used in series and this will require a balancing circuit.
This type of supercap can handle extremely high current both charging and discharging.
The discharge and charge curve is linear and the capacitor can be discharge to zero without damage.
The capacitor has a fairly high self discharge.
A size comparison to AA and 18650 cells. The AA cell contains about the same energy as the capacitor, the 18650 contains nearly four times the energy.
Note: The 20A and 30A discharge are not 20/30A all the way down. I can only maintain 30A down to 1.9 volt and 20A down to 1.2 volt.
The discharge is very linear and can go all the way to zero volts.
Charging is also linear.
Conclusion
This capacitor is fairly large and does not store more energy than a AA battery, it is not really a good replacement for most batteries.
This capacitor is designed to be used in cars or other transportation systems.
I have a 6x 350F module (http://www.ebay.com/itm/301128832966) and yes, all by itself it will start a Honda Civic. You only get one try though, it gives around 5 seconds of cranking time, max.
These supercaps can deliver crazy amounts of current.
There does also exist some types that can only deliver a very low current, they are often rated for a higher voltage (like 5.5 volt). They where the first type of supercaps made and where used for memory backup.
Solar would still take several hours to refill the bcaps. They're really better suited to a hybrid setup, using the bcaps as an accumulator/surge tank for the conventional (but possibly much smaller than original) battery. Small motorcycle-size battery or maybe even LiFePO4s for the low current/long duration stuff like running the trunk light while unloading groceries, and the ultra-high current parts supplied by the capacitors. A storage battery will recharge the bcaps in a matter of seconds after the cranking load is removed.
There is a guy that builds a solar jar [he calls it the infinity jar] (small glowing light like the walkway lights from wallmart) that use these, imagine instead of batteries going kaput in a year or two…they run for over 20 years!)
Either way INCREDIBLE to see the actual performance of these…thanks HKJ…excellent review!
Thanks for the review, i saw a youtube vid of a guy using caps as a starter battery, and it worked very well for him, i want to try building one for personal use.
I would love to build one of these (the first half of the vid) for my car, but how to charge it and does it need balancing circuitry are unanswered questions.
I think he was experimenting with balancing circuitry, some diodes and resistors and it balanced “fairly” well…cells withing .1 or .2vdc of each other
Would be cool to have one of these with a current limited LiFePo4 battery (and maybe a 20-30 amp charge controller), so if/when you sucked the caps dry trying to start the battery could then recharge it enough to give it one or two more tries, until it started and then recharged the caps and the LiFePo4 battery from the alternator
Just imagine being able to push full starting current to the starter in the freezing cold
Just like with lithium cells, if they are well matched to start with there's not much if any work for a balancing circuit to do. They all stay within tolerances. Only after wear sets in and they get more different with age do they start benefiting from the balancing stuff. These caps have such dramatically longer lifespans than just about anything else that it's not really necessary.
Like on the little module I have, six 2.7v caps (2.85v 'absolute max', which I assume means it's safe but will shorten lifespan) in series, the max total voltage is 16.2v, but the voltage regulator in the alternator won't put out more than 14.4v. That gives a lot of wiggle room for the caps to be unbalanced but still stay well within the safe voltage range. Mine has the balancing diodes built in but it never has anything to do, all the LEDs are always the same brightness (when one cap is out of line and balancing, it's LED shines brighter). The LEDs are only different if I connect straight to one cap and intentionally charge or discharge it alone to be out of line with the others. In normal charge/discharge of the whole module they all react the same so there's no balancing to be done.
Capacitors has something called leak current and it will not be the same for of them. A balancing circuit will compensate for that, without the balancing circuit they will drift apart over time and some of the capacitors will get into the over voltage range.
Small differences in capacity may also mean that the overhead on the voltage is not as large as the specifications says.
I have checked the individual voltages on my module and over many charge/discharge cycles they are always within a very narrow range, I don't think I have seen anything larger than 0.02v difference between them. When I intentionally unbalance one cap, the balance circuit takes a really long time to correct the difference (the bleed current is very low) so the balance diodes aren't fixing any differences before I have time to measure them. They really don't show any differences in actual use.
Maybe they would show more variation if the normal working voltage were closer to the 2.7v/16.2v limit? I dunno, I only know that after watching it closely that this one would work just the same without the balance diodes.
Yes, short circuit current on these is insane. 'Maximum peak current' is what they should be limited to for safety/longevity. The short circuit current is what it's capable of when abused, on the little D cell 350F ones that is 840 amps.
