So i ordered 2x 2.7 50F capacitors and began to upgrade.
With 100F, is the battery even necessary? Can it run all night on the super caps?
Perhaps pulling the battery out overnight might help show whether it can or not. It should be in the "worst case" which would be winter, which we are now past. (at least on this side of the Equator )
Greg H.
As an engineer, I view Davis' design as rather elegant.
Solar panel to provide environmentally-friendly free power most of the time.
Supercap, charged by the solar panel during the day, to provide power at night.
A dry battery to provide a bit of power if there was not sufficient stored energy in the supercap (cloudy, etc.)
AND that battery provides days of full-time power in the event the solar panel or supercap completely fails, thus providing time to diagnose and correct the failure without major loss of data. And of course the system monitors the battery voltage to provide several days of notification that there is a problem.
If the battery suddenly fails for some reason, the system will still continue to operate with perhaps some loss of before-daylight data. And, of course, will provide warning of the situation.
[Oh, and the option of providing external power through the included jack.]
Going to a system of just solar-panel-plus-rechargeable-battery would:
1. Require a substantially larger solar panel.
2. Complicate the ability to diagnose impending battery (or solar panel) failure. (Less reliable warning)
3. Cause total loss of data if, for some reason,
either the solar panel
or the battery suddenly fails.