vincent asked 4 years ago
Hello
i have a “small” Powerproblem
i have some solarcelle which have up to 7V should be only 5V but it’s what my multimeter show.
I have a SparkFun LiPo Battery Manager – Battery Babysitter
where the PowerInput is between 4.3-6.4V so i got a stepdown and fixed the input to 6.3V and all works fine
https://learn.sparkfun.com/tutorials/battery-babysitter-hookup-guide
BUT,
Voutput is not fixed so if the power come from the lipo Battery it will be 3.7 and dropping and on a sunny day up to the 6V.
i would like to connect a ESP32 which have a 3.3V input. So i added a regulater too buth it is not working properly when the Powerdifference is only a littel bit above 3.3V.
so what should i do to not kill my ESP32 Board?
thanks for some smart help
have a nice day
vinc
Steve Mercer answered 4 years ago
I would recommend looking at the DFRobot Solar Power Management module series (There are quite a few different types depending on your needs). You connect your solar panel and 3.7V Lipo to the board and it provides regulated 3.3V to the ESP32. It handles all the different voltages that can come from a solar panel and keeps the battery charged.
For an actual project using this board check out the solar weather station using ESP32.
vincent answered 4 years ago
@Steve thanks for your feedback!
I also found this
TPS 79933 DDCT
LDO voltage regulator 3.3V, SOT-5
LP 3981 IMM-3.3
LDO voltage regulator 3.3V VSSOP-8
i hope it will work, and i find out how to use it 😉
have anice day
vinc
vincent answered 4 years ago
in my Box i just found
Solar Power Manager Micro V1.0 DFRobot (DFR0579)
but there is no Power going from the Battery to the v3.3 Out only from solarzelle to out is power flowing.
and the Boot button seems to have no effect
Steve Mercer answered 4 years ago
If you are using the micro, it may be fried if you’ve supplied more than 4V. Make sure to follow the circuits on that page.
vincent answered 4 years ago
@steve yes i did kill it i think, some parts looks strange
and about what i bought, don’t laugh!
having a look at the picture
https://secure.reichelt.com/ch/en/ldo-voltage-regulator-3-3v-sot-5-tps-79933-ddct-p189022.html?&nbc=1
i think this will work and i will solder direct the cable.
Got them today – hell this thing is only 3mm long with 3 Pins – i never will be able to solder something there ;-(
vincent answered 4 years ago
would i have been reading more carefully the ESP32 book i bought
After researching LDOs, the MCP1700-3320E is the best for what we want to do.
looks like big enough to solder a cable
have a nice day
vinc
Steve Mercer answered 4 years ago
If you look at the spec’s, the TPS 79933 has a max input voltage of 6.5V and the MCP1700-3320E has a max input voltage of 6V. You said your solar panel puts out up to 7V.
You may want to try a clamping circuit to protect the input.
I would still try one of the DFRobot boards as what you are trying to make will work in direct sunlight but what about a cloudy day? The output voltage may be too low to keep it running. That’s what the board does. It uses sunlight to keep the battery changed then uses battery voltage to supply the regulated 3.3V to your project board.
Anyway, good luck.