I'm encountering a power issue when using a single 26650 li-ion battery. Currently the circuit is an Uno, a Pam8304 audio amplifier and a passive notch filter. The program is a mozzi based sampler playing one sample.
I tested the circuit at lower than 5v with my bench power supply, and it works down to 3.7v. So I assumed that a battery with high peak amp draw like the 26650 I bought would behave the same.
Well, it doesn't: I'm assuming what is happening is the brown out detector is kicking in and the Arduino is stuck in a reset loop. When the battery is fully charged at 4.2v it works for a while.
Things I've thought of to try are running the mcu at 8mhz, which I tried earlier but didn't have much luck with, and editing the board text file to disable BOD.
My question is, will disabling BOD prevent the chip from resetting, and then work at a lower than optimal voltage?
Is there anything I can do to avoid this while still running the circuit off just one cell?
Do you have a capacitor in the circuit to hold up the voltage during the potential brown out? bigger is better, if you think that might be the issue. Try a 1000uF electrolytic cap.
Yes, I have a 2200uf and 470uf on the power lines(just had at hand). I'll try larger again. They do store enough voltage from usb power to run the circuit for a few seconds when I switch to battery power but when they discharge it goes into brown out reset loop.
Is the cell known to be good? I don't know of bogus 26650 batteries being a thing, like 18650's (some 18650's on the market are straight up fake, with a used and bad battery, or a much smaller battery + sometimes sand for weight). If it was suspiciously cheap, I would wonder about this.
What BOD voltage are you using?
What voltage do you measure on the cell when it's failing like that?
How much current does your circuit pull?
Wonder if that device you are controlling requires a higher voltage than the Arduino...
