@Abnalsid, Welcome to the Community. Ask away.
Update w/ Sleep:
Using Stop Mode (System.sleep( {}, {}, sleepTime); ) shows the same recharging performance as previous test in this thread, with both the API and PMIC modes.
I still prefer the new API (what I called mode 1 in the code snip), for the reasons mentioned previously.
Standby Sleep, or System.sleep(SLEEP_MODE_DEEP); will WAKE the Boron when the Solar Panel Output cycles. IE, when the Panel begins to provide a Voltage Source- the Boron will wake up from Deep Sleep.
A typical Solar Install will use a progressive timed sleep schedule depending on the Li-Po Voltage or SOC. It’s not too hard to size the Panel and Li-Po so the Boron can remain on 24/7 most of the time, if needed.
As a last resort- if the SOC drops below 40% for instance, it could go into Deep Sleep Instead of timed, knowing that the Boron will automatically wake from Deep Sleep once the Solar Panel gets sunshine.
Tests performed with a 2W Voltaic Solar Panel using the USB connector on a Boron LTE running 1.5.0-rc1.