Electron Solar Kit Charging Indicator?

[ScruffR]

@BDub

If you use Deep Sleep, the Electron will power up again from reset and re-handshake with the server. This will consume anywhere from 3KB to 6KB more data than if you were to use a STOP mode Sleep that effectively halts the processor and keeps the cellular modem on and connected to the cellular network. See example below.

Also to note, deep mode sleep does not turn off the modem, only the processor. You have to call Cellular.off() prior to sleeping for the lowest power consumption, at the expense of more data consumed on your next boot.

I'm not that deep involved into the interna of the Electon firmware but I think the docs are less likely up to date as @BDub is
So I just tried to reword what he said in the post you referenced (in parts).

While the quote above confused me a bit (first paragraph seems to advise agains DeepSleep, while the second seems to say it'll be fine to use without Cellular.off()), I just took the essence to answer this question:

@RWB

Maybe @Bdub can commend on why Deep Sleep does not turn off the cellular module.

So to answer this

@RWB

So the System.Sleep turns both the processor and modem off right?

And with the latest firmware the System.sleep will reconnect without needing to waste KB during the renegotiate and reconnect?

You can't have the modem off and save the extra KB cost - you have to find the compromise between power consumption and data usage and choose the best fitting sleep mode, with or without Cellular.off() in view of your desired wake frequency (wake often -> keep cellular on to save data usage at the cost of battery life, sleep long -> cellular off to save power at the cost of data usage).