Battery Low [Q] Battery recommendations lt30p and Power off charge fix?

Hello again guys, I know some of you if not all of you are aware with these problems. Is there a fix so that the phone can charged when switched off? This is my second phone now over the two years and they never charged whilst powered down.

Now the big one, am I right in saying my battery is a ba900? Can somebody recommend me a high capacity battery please?
I would like to keep this phone going for as long as possible

Cheers
R800i 2.3.3 Rooted BL untouched, bloat freezed