I have been very impressed with super capacitors in my electrical engineering experience. I would like to explore the cost effectiveness of building a super capacitor bank for energy storage to use at night time, especially considering the costs of these components from overseas is decreasing as time goes on and perhaps a high quality super capacitor bank could outlast conventional solar battery systems by even a decade or more. For my plan in mind, it would need to have enough energy for roughly 50 kWh.

Just had a quick look on ebay, found this:

https://www.ebay.com.au/itm/395144813886?hash=item5c00775d3e:g:ES0AAOSwqxZi~xy7&amdata=enc:AQAIAAAAwONgRXSwgpFtK2EuKOSAuriQz4F1BjyE+os6anqTFivxhbh2e3dUL8czZt9YoydhjvUBOhiiURujg2ASpWavC3UcVppdAigHa0gO6ITZRNW2ZEVjiF40qO2TEdzcT48qd9kS2qfVFahVv6QZsy7KPvMdqlYWCttrUmRtsNnfiPMmbnmK3A/m7C4908GdIQjwlEl/VjtDQacWVHU8Ct45ELpBuC8/8McAU5nIskkIylfx5dhV1+XG5twxiuMjT284hg==|tkp:Bk9SR-aNvOquYw
166 Farads at 48v roughly $1,000 for a

**USED** capacitor bank.

Charged up to 56v, stored energy = 1/2Cv squared.

166 divided by 2, multiplied by 56v x 56v = 260,288 Joules (watt seconds).

Discharged down to 40v, stored energy,

166 divided by 2, multiplied by 40v x 40v = 132,800 Joules.

Recoverable energy during discharge 260,288 - 132,800 = 127,488 Joules.

About half of the max initial stored energy, and you won't do much better than that.

127,488 watt seconds = 35.41 watt hours.

To get 50,000 watt hours we will need 50,000 divided by 35.41 = 1,449 of those thousand dollar batteries.

Do you have 1.5 million dollars to spend on a

**USED** capacitor bank ?