Anyone powering a mysensor with solar plus supercapacitor?
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Below, "supercapacitor" could mean either ultracapacitor or supercapacitor. I don't know if there's any actual difference in meaning.
I'd like to get a ballpark notion as to how many Farads it would take, as well as the best configuration. If you don't have an actual example to report, then you could, for discussion purposes, assume a wireless mysensor temperature sensor that reports, say, once every minute.
In addition, which of the following is generally the best configuration (say, best tradeoff between efficiency and cost):
- use one supercapacitor (or more than one in parallel) and run it down from a fully charged high of 2.5-2.7v, while trying to stay above 1.8 volts (the minimum for an 8/12Mhz Arduino), or
- same as #1, but using a boost converter, so you can run the capacitor(s) voltage down as low as 0.5v (depending on the boost converter), or
- Put the supercapacitors in series and use a step down converter, or
- Put the supercapacitors in series and use a SEPIC (seamless step-up and step-down) converter?, or
- Other?
lastly, what are typical supercapacitor self discharge rates? I toyed very briefly with a Maxwell supercapacitor. If charged to 2.5v, then I seem to recollect it lost 10% or more (perhaps as much as 20%?) of its voltage overnight. Consequently, does anyone here have recommendations/suggestions for supercapacitors with low self discharge?
Any other gotcha's I should be aware of?
