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Supercapacitor Energy Harvesting - What You Need to Know - Workbench Wednesdays 74

Low-power IoT devices can harvest energy from Wind, Heat, or Solar sources. You can store that energy in a battery or a supercapacitor. With help from Eaton, James shows what Electric double-layer capacitors (EDLCs) are, considerations for when you want to use them, and a small demo where we harvest solar energy into a supercapacitor to drive a Pi Pico W.

Watch the Video:

                                                                                                                                                                                                                                                                                                                                                     Sponsored By:

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Bill of Material:

Product Name Manufacturer Quantity Buy Kit
Supercapacitor, 10 F, 2.7 V, PC Pin, -10%, +30%, 5 mm EATON ELECTRONICS 1 Buy Now
Supercapacitor, 5 F, 2.7 V, PC Pin, -10%, +30%, 5 mm EATON ELECTRONICS 1 Buy Now
Supercapacitor, 1 F, 2.7 V, PC Pin, -10%, +30%, 3.5 mm EATON ELECTRONICS 1 Buy Now
Solar Cell, 200mA, 5V OSEPP 1 Buy Now
Supercapacitor Charger, Fixed, 150 mA, 4.8V/5.3V Out Analog Devices 1 Buy Now
 

  • in reply to koudelad

    Assuming it is a somewhat dumb charging circuit (e.g., it just limits current and then shuts off when the voltage hits 4.2), it could probably work. However, it might detect the supercapacitors' very low impedance as a fault.

    The next issue is energy density. For a safe shutdown, you can probably build a reasonably sized supercapacitor. But a few measurements and some math will give you a better idea.

    Keep an eye on the temperature ratings of the EDLCs as well. They tend to be wider than batteries, but not by much. (But I think they would still have a longer operational life than a Lithium battery in similar conditions.

  • Great lead in to the super capacitor challenge.

  • Great video with explanations and demonstrations. Wow.

    I have a question. I have an Truecam dashcam, that uses a Li-Ion battery and uses it for powering while not driving (off board photos or video, probably for just a few minutes or a few pictures of an accident) and more important, when the car 12 V power rail is turned off (the ignition is turned off), it safely shuts down the camera - finishes the SD card write and shows a logo and shuts down in a few seconds. However, I have already replaced the Li-Ion cell 3 times - it always gets inflated, probably because of the temperature changes behind the winfdscreen.

    I know that newer models use supercapacitors. I am just wondering, if I might be able to measure the energy the camera needs to safely shutdown, find a proper supercapacitor and directly replace the Li-Ion accumulator. There must be some Li-Ion charger circuit inside, so it would limit the current as described and finish the charging at 4.2 V. Do you see any problems?

  • in reply to russoleum

    It depends on the ESR Meter. The Peak ESR70 (reviewed here) says it can measure up to 90F.

    And I don't see an obvious reason an in-circuit ESR measurement would be any different with an EDLC over other capacitors.

  • Can supercapacitors be checked with an ESR meter, like regular caps? Can they be checked in-circuit, or must they be removed?

    Thanks