This thread is about the increasing number of ESP32 development boards with LiPo battery connectors, like the DFRobot Firebeetle range and Unexpected Maker boards.
This is not a thread about how to use a Solar Power Manager to provide 5V to other microcontroller boards - that has been covered elsewhere.
I like the idea of connecting LiPo direct to the dev board and reading the battery voltage … but what about charging the LiPo from a solar panel ?
My 5V solar panel is regulated, so it outputs a constant 5V - albeit at a ridiculously low current unless there’s strong sunlight directly on the panel - so can I connect it to the 5V IN pin ?
Or will I need an extra module ? I currently use a Sunflower: Solar Power Manager 5V (SKU: DFR0559) connected to USB of a regular ESP32-S3 board, and there’s no point changing if i will have to continue with the DFR0559.
What about the Solar Lipo Charger (3.7V) DFR0264 ?
Update: Unexpected Maker has confirmed that no solar panel (even one with a regulator) should be connected direct to the FeatherS3’s 5V pin … so an external solar power manager is still required. The SPM can be connected to the BAT connector … however the FeatherS3 will be reading the SPM’s regulated output, and not the Battery voltage.
FYI: I note that DFRobot’s Firebeetle 2 ESP32-C6 and ESP32-C5 boards do connect a 5V solar panel direct to the Firebeetle 2 board.
Generally, you are always going to need a SPM for solar power. Solar Panels are just way too inconsistent to output directly to a microcontroller without a lot of circuitry set up for it.
If DFRobot have designed one of their boards to have that circuitry to handle solar panel input, then perhaps it will work, but honestly I am skeptical about using it that way.
I do agree with your caution about connecting a solar panel … but it seems such an obvious use case.
FYI… according to DFRobot’s wiki, their ESP32 C5 and C6 Firebeetle 2 boards (which Core sells)(and as far as I can tell, only those 2 dev boards) include the solar management chip used in their Solar Power Management module.
The wiki for the C6 board mentions a CN3165: Solar management chip; and the C5 board wiki claims “Adopts the same solar power management chip as their Solar Power Management Module 5V@1A”.
Unfortunately (being a software person) I prefer to leave plenty of “wriggle room” by spending a few extra dollars to overkill the hardware and use the ESP32-S3 N16R8 - so I’ll give these particular boards a pass.
Hi, you’re right to be cautious. You should not connect your solar panel directly to the 5V IN pin, even if it’s regulated. Solar panels don’t supply constant current or voltage like a USB source, and that can confuse the dev board’s power and charging circuits. Using an external solar power manager (like your Sunflower SPM) or a dedicated solar LiPo charger ensures the battery is charged safely and the ESP32 doesn’t brown-out or get damaged. Connecting the SPM to the BAT pin will still charge the battery correctly, but you’ll be reading the SPM’s regulated output rather than the raw LiPo voltage, that’s just a limitation of measuring through the power manager. For a real-world reference on how people tackle solar-powered ESP32 systems with external charge management, check out this related PCBWay project: https://www.pcbway.com/project/shareproject/Esp32_Solar_Weather_Station_V1_4561b818.html, which uses a solar panel, LiPo, and proper power handling in an ESP32 weather node build.
Thank you Mark and Olivia for your contributions. Your information is correct and valuable … however you both seem to have missed that this thread is about those microcontroller development boards which have on-board LiPo BATTery connectors, such as the DFRobot Firebeetle range.
As Olivia points out, connecting the SPM’s output to the Firebeetle’s BATT connector means the firebeetle is measuring the regulated output - not the actual battery voltage … and therefore totally defeats the point. And worse, paying extra for functionality which cannot be used.
Jane, am I correct in assuming that VOUT of Solar Lipo Charger (3.7V) (DFR0264) would be ideal to connect to Firebeetle’s BATT connector ? DFRobot’s wiki states “VOUT: Lithium-ion battery output. Connect your electrical equipment to it”.
Hey Don, from what I’m reading of the wiki for DFR0264, that would work.
The phrasing of ‘Lithium-ion battery output’ leads me to think that you’d have no difficulties with this setup.
Obviously, you would not be able to charge the battery via the Firebeetle, but since it’s all trickling down from the Solar Panel in a closed system, that’s not going to be a problem.
The wiki does suggest not running an Arduino at the same time as the battery is charging and suggest this could cause factory resets and corruption on that microcontroller. But considering that the Firebeetle already claims that functionality, than this should work/
