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Topic: How to limit solar panel voltage? (Read 1 time) previous topic - next topic

RudiAhlers

Sorry for the late response, it took some time to get all components for testing.

I've ordered a few solar panels:
53x30mm, 5V 0.15W (30 mA)
68x36mm, 5V, 0.3W (60 mA)
100x28mm, 5,5V, 0.22W (40 mA)

plenty of zener diodes for different voltage and BAT54 schottky diode.

After some testing I decided to use 5,5V, 0.22W solar panel, 1N4733A (5.1V) zenner diode to limit voltage and BAT54 schottky diode to prevent discharging.

With 1N4733A I got voltage drop ~0.1V (without load), it's appropriate as for me.
BAT54 has reverse leakage current 2μA at 25V, it also fits my requirements.

Thank you for help.
How long does it take to recharge the supercap, once discharged?

jremington

#31
Jun 29, 2018, 05:36 pm Last Edit: Jun 29, 2018, 05:37 pm by jremington
Quote
How long does it take to recharge the supercap, once discharged?
Depends on the illumination intensity, the capacity and the solar panel current.

From the capacitor equation Q = CV, it is approximately true that (delta t) = C*(delta V)/I.

RudiAhlers

Depends on the illumination intensity, the capacity and the solar panel current.

From the capacitor equation Q = CV, it is approximately true that (delta t) = C*(delta V)/I.
Yes, I know all of those factors play a role. I wanted to know from the OP, with the components he brought, how well it works.

jremington

#33
Jun 29, 2018, 06:44 pm Last Edit: Jun 29, 2018, 07:00 pm by jremington
If you bother to do the experiment yourself, you will discover that it works as well as it is predicted to work.

These devices obey the laws of physics, so you don't actually need to depend on someone else's results.

RudiAhlers

If you bother to do the experiment yourself, you will discover that it works as well as it is predicted to work.

These devices obey the laws of physics, so you don't actually need to depend on someone else's results.
seriously??? I am curious to find out how well the combination of components he brought worked. If you bother to give me the components he used, I will gladly experiment it myself. But I am mot interested in finding out if what he brought worked as well as he hoped it would.

strange_v

How long does it take to recharge the supercap, once discharged?
It depends on whether, but let say it takes less than an hour to charge a supercup on a sunny day.

I've bumped into another issue with this remote sensor. After some time (usually days) nrf24l01 starts to consume much more than it has to. I've found a few threads about such a behavior in other people.
So, for now, this project is postponed.

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