I am trying to store small amounts of energy from a 12v motor with an ultracap. I'm thinking of a 3000F 2.7v cell from Maxwell. I am trying to find out info on charging ultracaps, specifically the current required/advisable, as in my situation it may fluctuate. I also need to boost the voltage to 12v on discharge, but with a motor stall current of 60A (although I do wish to put a PWM in to control it to about 30A), I fear that combined with the near 5x boost, I'm drawing some serious current (270A worse case without PWM) over the 30 seconds it's active. Will the ultracap take it? I read some can output up to 1000A safely, provided I make the wiring thick enough it doesn't melt. Or do I take the capacitance hit and put 2 in series?(For cost I don't really wish to buy 4 and put another 2 in parallel) Thanks,
It's easier to answer these kind of questions if you supply the components manufacturer part no. I assume you have Maxwell BCAP3000 P270 K04.
Reading the data sheet gives:
The absolute maximum current is 1900 A.
The maximum continuous current is 210 A with a ∆T=40 °C
The data sheet also tells us that the temperature rise at a given current is:
∆T=IRMS^2 x ESR x Rca
∆T=270^2 x 0.00029 x 3.2
The maximum operating temperature is 65 °C so you will be a bit over the specification if you start at room temperature. But doing this in short bursts and with sufficient cooling time, will probably not kill your capacitor but may affect its total lifespan.