We recently purchased a few of these for a project and they do not seem to be working as intended for our usage. We’re using them to power some LoRa boards which appear to spike above 20mA which seems to prevent the battery from charging. As these devices are already installed onto bee hives, that we cannot really open due to cold weather, we are trying to think of remedy solutions that minimize soldering and disassembly. One of the ideas we have is attaching batteries directly to the Heltec LoRa 32 V3’s and leaving the solar connected to the SparkFun board. Will the SparkFun boards still output 5V when a 5V source is connected even if the battery is disconnected? If you have any other suggestions, we’d appreciate any insight you can provide.
Not of the SparkFun board but there’s a 5V solar panel soldered to the charger input next to the USB port, a 3.7V battery connected via JST (on the SparkFun board) with the wires matching the poles on the board, and the 5V out going to the 5V input on the Heltec LoRa V3.
The battery supply was working but we didn’t have time to test whether charging them via solar would work due to weather timeline. The solar panels are 5V/200mA with various reviews saying that even the not so good ones can output at least 100mA. The batteries should have been fully charged when installed and the Heltec board (with all its peripherals) draws at most 10mAh which spikes of up to ~100mA during LoRa broadcasts. I suspect that the current spikes are causing the the SparkFun board to not charge?
I think it’s your solar panels causing the troubles. Can you substitute a 5 volt 2 amp (or greater) power supply in place of your solar panel and see if that gets the battery charging?
There’s a note in the schematic that mentions lowering the load OR supplying more than 500mA to the charger/booster to be able to charge the battery. I think the board is detecting you don’t have enough energy available to charge and power the load so it just won’t charge.
If the 5V 2A power supply does the trick see if you can find a larger solar panel that can output lots more current than you need. This time of year and until at least mid spring, solar panels output a fraction of their rated output due to the sun being low on the horizon.
Whatever you do, don’t feed more than about 6.5 volts to the charger/booster, that will kill it.
Good observation. Unfortunately, I don’t think we have the ability to swap out the panels until spring. Going back to the original proposed idea, if the battery is unplugged, will 5V be outputted if 5V are coming in?
If not, would shorting the JST connector (or with a resistor) work to mimic a battery being there?
