UPDATE: the report , all logs and analysis scripts are too long to be included.
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Long story short, I found out that the PMIC only allows battery packs being charged when battery temperature drops below 42.5. But Frame’s firmware is allowing charging when plugged in . So when you plug your Frame right after playing it, means the battery temperature can be above 50 degrees, then this is what gonna happen:
the Frame wants to be charged, pulling 1A from the charger to power the system and to charge the battery. PMIC found the battery temperature is too high to safely charge it, immediately cut the charging power, the current drops from 1A to 0A. Which means, you were expecting the battery to be saved from ~5% by the charger, but once you got the charger on, 9s after, it cuts off charging for 2s, it’s like 1A for 9s, then 0A for 2s, then repeat. But every that 2s your Frame has a chance of sudden death (by death I mean unexpected shutdown at low power and being flagged as SPML in system logs, but this doesn’t mean permanently damage or brick, it’s my bad using the word death, I’m sorry about this, but it’s still very not good for the Frame at that low battery level), the first 2s is the most deadly 2s (because it barely got charged but have to suffer a sudden voltage drop at the already super low battery level). That the reason why so many people found their Frames won’t charge when plugged it in after playing it for a while.
PS: when battery temperature is lower than 42.5, the Frame would start charging at 2.7A, so better give your Frame’s battery a good active air flow after finishing play it.
PS2: about playing with a power bank, idk, but I’ve played with a power bank when streaming and even with that damned loop, it works, but possibly because streaming only draws ~10W of power, which is still affordable for the 9s of 1A@15V charging status, but obviously the power bank and your (and mine) Frame’s battery was very HOT.
PS3 before I go to sleep:
let me be clear, the most clean way is do not play you Frame to lower than 10% battery left, therefore you can just plug it in and let the 9-2 loop starts until the battery temperature go under 42.5, and if you have ~10% of battery, I think it would be ok, because mine still died when I plugged it in at 7% battery, I plugged it in, heard the fan buzzing for several seconds, then fan went silent, not like the normal power off that would rise the rpm for 5s before shutting down but suddenly went silent, you won’t want that happen to your Frame.
And besides that, since I got so many people seeing this post, let me say another thing that really killed me for days: the mid-battery sudden death, it’s when you’re playing a standalone game then suddenly the Frame shuts down itself, just black screen and instantly power off, then you reboot it found there’s still ~half of the battery, and this happens and happens with basically nothing you can do to prevent it, reseat the gasket? done it multiple times, even brushed the connector with an eraser. and I’ve found and tested the solution: limit the CPU (X4 and A720, no A520) frequency by 15%, it worked and I’ve played games that had triggered the mid-battery sudden death several times in a row and with the implementation the game sessions were safely done from full charge to 5% battery. So in the end it’s not the connector, not the battery, not the thermal, but the X4 and A720s’ frequency-spike that triggers low VPH and BCL level 2 at half battery life which matches a lower battery voltage. The minus 15% of frequency of the implementation is just an initial conservative value, I may make another post once I finished the optimization and maybe make a little tool to help with quick multi-level frequency lock. Note that it seems only affects some people including me, if you haven’t met this problem and can always safely play a standalone game from full charge to 10% alert, congrats buddy. But if you have suffered this like me, this method is our cure.
