The original battery, again, was claiming to be fully-charged, but would only last maybe 20 minutes when unplugged... then when plugged back in, it'd immediately show ~60% charge, which used to be plenty for a couple hours. 

When it'd conk-out, there'd be no warning. Often, I'd be in the middle of taking pictures, the last would always be corrupt. But the videos that were cut short were the most frustrating... five minutes of footage lost, numerous times... 

one time there was a very thirsty deer trapped between I-5 at rush-hour, and a really long fence... was trying to help it get to the lake, and filming... and lost all the footage, a good half-hour, due to a no-warning battery-fail. I never did find a way for the deer to get through the fence, and while I was looking, he disappeared... Thankfully, I didn't hear any honking nor swerving, and traffic was pretty steady, so I guess he must've crossed back over safely.

Anyways, got to the point where I'd stop and restart my vids every couple minutes, so I'd only lose a couple minutes' footage, instead of the whole video... and that was doable for a while... frustrating, but apparently not frustrating enough to fix.

The Kicker, though, happened a few days after I got the old battery from storage... The plan was in the works, but implementation was on-hold. Until, a few days later it just wouldn't power-up, at all. Even when plugged in. There was no choice, at that point, but to try the older phone's battery, and boy-howdy it was a relief to see that home-screen again... but to be able to take videos without it dying and corrupting them...? WOW!

Later, I discovered something utterly-ridiculous about this phone: When it's plugged-in and powered-off, it takes more power to bring up the "charging" screen (and, stupidly, spin the vibrate motor) than a typical charger is able to supply to the battery before bringing up that screen. Thus, with a really-dead battery, it charges for a few seconds, brings up the screen, vibrates, then drops dead again before repeating.

Sometimes it'd do this twenty times before gaining just enough charge to sustain thereafter. BUT, only with a high-power charger. With a regular dumb 500mA charger, it'd sit in that loop overnight, or longer, maybe never gaining enough charge to bootstrap *charging*!

Then, to really top it off, the dang thing wont't function *at all* without a battery! So I couldn't even use it while sitting next to a power outlet! Talk about needing hackery just to use these things for the gazillion other purposes a tiny supercomputer could be used for!

I'd thought about putting a switch before the vibrate-motor as well as the backlight LED, that might've helped... thankfully I didn't have to go that far, as the combination of the old phone's battery and a 2.1A charger (and cable) eventually got it working.