Five Of These In Series?

DIY project
The Forever Battery variable voltage 5~30v... this idea i like

videos
Super Cap "car start Booster"

Super Cap -Boost Pack..start battery replacement

Other than cost there are more problems with these caps.

They have a high leakage current. They won't hold a long term charge.

The caps may have a 20% tolerance. One cap in a string could have a capacitance 20% low. As a result of lower capacitance, this cap will have 20% higher voltage. It can now over voltage and explode. The fix is to add a parallel resistor to each cap. These resistors will also discharge the cap bank.

So you got leakage current and the resistor ladder that discharge the cap bank.

From the small amount that I've read, the initial charging of an empty depleted state takes special handling
After that the recharge from 11v to 14v is easily handled by any alternator or pure D.C. charger/power supply
You do not subject these to reverse polarity or high ripple
Should work well for high surge current needs
When paralleled with a battery bank they will be the same voltage as the batteries
If used as stand alone substitute for a 12v / battery, outside of a vehicle..
The use of a suitable D.C. to D.C. converter, that Will accept and use the tapering input voltage while outputting the needed voltage 12v or other voltage, will allow the use of almost all stored power
Drain it as low as you want while getting 12v out, say for a Cpap machine or a laptop
This is where you need the special recharge circuit, to limit the input current while bringing up the voltage
This is for protecting the input wiring and charger from high current over load demands, a totally deleted super cap bank, looks like a dead short to the avg power supply/charger

Hi Mex,

Don't the more expensive inverters already have decent capacitors on the input side?

Super Caps do exist. They are not affordable (yet).

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!!!

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?

Salvo wrote:
C = 1500 F, 2.7V

i = C * dV/dt

i * dt = C * dV

Six in series:

i * dt = (1500F / 6) * 2.7V * 6
i * dt = 4050 As

i * dt = 4050 As / 3600 s/H = 1.1 AH

Six in series gives you 1.1AH. Nothing to write home about. What do they cost; perhaps $200 for 6???

I agree...

If you take this analysis a step further, discharging the capacitor bank to 0 volts is really not a viable use.

So if you assume 10.5 VDC as being the cut-off point for most electronics, then you only get about 0.4 A-H of capacity.

However, the impulse current that can be produced, and also needed during charging, is incredible...

You know you'll just get a bunch of answers like:
'Why not just...........'

Or
"My inverter is so good I Don't see why........"

And soon it will turn into an AGM vs flooded war

One can not invite discussion anymore without somebody questioning your motives, your bank account, credit score and schooling.

Battery Council International used to offer this in a paper booklet form for free as a handout

https://batterycouncil.site-ym.com/store/ViewProduct.aspx?id=1298124

The idea was to stir up some comments about utilizing supercaps adjacent to an inverter.

It was intended to be a joke. Joules - Jewels. Some folks take themselves too seriously. I do not fall into that category. I am well aware of how capacitors and or passive components work. My weak area is digital and processing.

Years ago on this site I posted links to USN BuShips standards for lead acid battery design, construction, maintenance and testing. Photocopy web pages of the manual. That was WW II stuff. 7% antimony batteries built by Exide and Gould.

If someone has reference material for USN flooded LA battery design and maintenance criteria for this century I wouldn't mind reading it. The documents.

My stated maintenance protocols for flooded batteries agrees in most part with the Battery Council International. If an individual has issue with how or why the BCI has organized their maintenance data I suggest they take it up with BCI.

Produce data when stating a point. That is all I ask :)