maholli/ehb

Energy Harvester Board

🛰 Hi!

I build electronic systems for harsh environments (like space).

Everything is open source, so check out PyCubed, KickSat-2, V-R3X, or PY4 missions for more details!

🛠 Like prototyping electronics?

Check out my soldering tutorial used in Stanford's EE department, Or build a SAM32, a "swiss-army knife" for embedded projects

ehb's Issues

Comments and other boards

Not an issue, just food for thought.

Thanks for sharing.

TI also sells an eval board: https://www.ti.com/tool/BQ25570EVM-206

Mikroe sells a board: https://www.mikroe.com/solar-energy-click

I designed a really minimal board using the BQ25504: https://github.com/bootchk/BQStripped. The point of that project was to omit as many of the programming resistors as possible.

There is an interesting article by the designer of the BQ chips: https://www.edn.com/fast-charging-a-supercapacitor-from-energy-harvesters/
His point is that putting a supercapacitor on VBAT pin can take an extremely long time to come out of coldstart. So the design in the paper puts the supercapacitor on VOUT, and it coldstart charges more quickly.

I have designed another board, which does somewhat the opposite of your board.
I use a supercap only, without a battery. Uses the design cited above, with the supercapacitor on VOUT pin. Voltage on VOUT is programmed to the max the BQ will output, 5.5V, and the supercap is rated for that. This gives you more energy stored. Then I add a LDO voltage regulator to down convert to 3.6V, for an MCU.