Disconnect the fully charged cap for 48 hours.
Then measure it's voltage again.
Leo..
Hi,
6V is without load, with super cap it goes to 5,6, so my plan is to add a Schottky diode. with 0,2 V drop.
Is that a solution you can agree about?
M
That is required anyway. The panel changes into a load after dark.
You don't want the cap to discharge into the panel.
Leo..
This I will try.
I would 'stay away' from the absolute maximum ratings of the super cap.
Moreover if you are using a linear regulator to power your esp32 you will not benefit from a higher vin ( you will only dissipate more heat on the regulator )
An easier solution could be using a solar panel with lower voltage ( but I know you already 'imagined' this ; - )
1 Like
Hi
Yes good point, but I use 5V to HX711, and 3.3 to the rest.
As far as I have calculated the system will have 18 runs on one charge 5.5V 10F. That is probably enough for me, I can extend sleep if low volt, and wait for a sunny day.
Another super cap question?
I can be charged down to ca. 1V, what is best option to boost it when power is under 3.3V?
M
Charged to 5,6
After 48
Farnell 4,9V
China 4,8V
Tested Farnell on my system, charged to 4.2V, runs for 2 sec then sleep 5 sec, runs 164 times, down to ca 2,6V.
China 94 cycles (look at form factor, half volume compared to those from Farnell)
All in all this is really good news for me! I can run the system 365 with solar.
afterall the chinese one have a max leakage current of 60uA ( as per table in post #8 ) that gives a max loss of 5 C/day or 0.5V/day