Five Of These In Series?
Adjacent to large inverter terminals for short burst microwave or other load duty? Or do they need current limiting control. Just wondering...
Forum Discussion
You need a lot!
We can do this calculation. Let's see how many caps you need compared to a pair of Costco golf cart batteries.
GC2 = 200AH; but only 50% is usable (normal operation).
A string of 6 caps has the potential of 1.1 AH as previously calculated, but not all of that is usable.
Max cap voltage = 2.7V. We need to derate to 90%, or 2.43V. The max operating voltage for a string of 6 is: 6 * 2.43V = 14.58V.
We'll need a boost regulator to maintain a constant 14.6V output while the cap bank discharges towards 0V. The minimum cap voltage for the regulator to operate is 0.7V.
The caps will be discharged from 14.58V to 0.7V, with a delta V of 13.88V. Now we can calculate how many useful AH are contained in a string of 6 caps:
i * dt = C * dV
I * dt = (1500F/6) * 13.88V / 3600 s/H = 0.96 AH
You need 100 strings of 6 series caps, or 600 caps to get about 100 AH. At $25 per cap, that's $15,000!!!
We can do this calculation. Let's see how many caps you need compared to a pair of Costco golf cart batteries.
GC2 = 200AH; but only 50% is usable (normal operation).
A string of 6 caps has the potential of 1.1 AH as previously calculated, but not all of that is usable.
Max cap voltage = 2.7V. We need to derate to 90%, or 2.43V. The max operating voltage for a string of 6 is: 6 * 2.43V = 14.58V.
We'll need a boost regulator to maintain a constant 14.6V output while the cap bank discharges towards 0V. The minimum cap voltage for the regulator to operate is 0.7V.
The caps will be discharged from 14.58V to 0.7V, with a delta V of 13.88V. Now we can calculate how many useful AH are contained in a string of 6 caps:
i * dt = C * dV
I * dt = (1500F/6) * 13.88V / 3600 s/H = 0.96 AH
You need 100 strings of 6 series caps, or 600 caps to get about 100 AH. At $25 per cap, that's $15,000!!!
pnichols wrote:
A more interesting question would be: After you put five (or six) of these together in a series string ... how many of those string-sets would it take in parallel with each other so as to be able to use that bundle in an RV in place of batteries?
