Alert Code feedback

[ShawnKimble]

Adding some feedback on alert codes, and my understanding of what some of them mean:

BackfeedLimited - I believe this controls backfeed before PTO, under the "Permission to Operate" option under the settings menu. Prior to PTO the backfeed rate is limited, as the system needs to produce over the load, but by the minimum possible. The system seems to regulate this by switching MCI's open/closed, to minimize the overage that must be backfed, as the power has to go somewhere, and at this point the batteries are 100%. This seems to toggle that setting per inverter. I was told by Tesla that one of my two powerwalls were still stuck in this mode, post PTO, because of some software glitch that doesn't always toggle all devices to on, when selecting Yes to operate from the app.

RealPowerAvailableLimited - Seems related to the above

POD_w031_SW_Brick_OV
POD_w044_SW_Brick_UV_Warning
POD_w045_SW_Brick_OV_Warning
I believe all the Brick warnings are related to preventing the condition where the powerwall doesn't have the minimum amount of power it needs to turn back on. When this happens, a third party charger is needed to get the powerwall back to it's minimum operating battery requirement to turn back on, or it's "bricked". Solar cannot return it to this state, because it needs power to make power.

[ShawnKimble]

POD_w110_SW_EOC - This triggers when full backfeed starts and battery at 100%.

[jasonacox]

This is great, @ShawnKimble !!

I made some updates based on your notes in a pull request here: #43 - feel free to review and comment before I merge.