Super Capacitor?



So what is a super capacitor doing in my solar power system? This video will try to explain its purpose.

In short, it helps to supply the bulk of the inverter surge current when it tries to start loads with high starting current, like refrigerators or freezers, or air conditioners or dehumidifiers. Basically anything with a motor that starts up under load. Adding a bigger inverter would not help, as it is the load’s starting current that is the root cause.

I used a 250 farad, 16.2 volt capacitor bank made up of 6 – 1500 farad, 2.7 volt caps in series:

In series, the voltage adds and the capacitance drops.

Guy Brown (channel link in the right sidebar) has a video on adding a capacitor to his solar power system:

Likewise, ElRazTheGreat1 has a video on charging/discharging capacitors on his channel:

I think I’ll add a 200 amp breaker before my capacitors so I can disconnect/charge/discharge them easier in my final setup.

Unlike lead-acid batteries which can take 500 or so charge-discharge cycles, a super capacitor can handle a million or more cycles. So I hope this capacitor bank will out live many sets of batteries.

For an in-depth discussion of inverter surge current, be sure to check out KnurlGnar24’s channel over under the Featured Channel list in the sidebar, or the link below:

Note that the surge current only lasts a second or two.

My 5.5 watt LED test seems to back up the capacitor bank rating. Using C/2 x V^2 = Joules, I get 32805 joules or 9.11 watt-hours to a full discharge. Discharging to half voltage yields 3/4 of the stored energy, or the 5.5 watt-hours I observed.

Anyway, I hope this explains what a super capacitor is doing in my solar power system. If you have an inverter struggling to start up a load, you might consider adding one to your system.

Thanks for watching.

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