Have you ever harvested and kept PJ working?

I have been reading up on this as I have one that my brother would like to use as a PJ and I'd like to extract more than 8 out of it.

I've already read about the resistor and diode method as well as some other ways to trick it into not error in and running.. just curious if any of you fellas have and if it works for a while. Don't want to give him a project or something real dangerous if you don't know what to look for, so only option may be 8 on this single unit.