[ltp] how to trick a W540 or P70 into charging from a 90-110W power supply?

[Marc MERLIN]

Both those laptops use a 170W power supply which is freaking huge, and also
means that I can't use any of the 10+ regular 20V lenovo 90-110W power supplies
I have at work and at home (AC, DC 12V, and laptop battery packs)

When I plug any of them into my P70, it will not discharge, but it will not
charge either.
Even if I shut down the laptop, or put it to sleep, it will not charge.
Yet, when I plug it in to keep it alive, it only uses about 25W from my 110W
power supply, so there is plenty of room to charge the battery, even if not
at full speed.

I'm not sure how the laptop detects the fact that I don't have a 170W power
supply, but I'd love to know a way to trick it into charging from a smaller
power supply.

Does anyone know of a way?

Thanks,
Marc
-- 
"A mouse is a device used to point at the xterm you want to type in" - A.S.R.
Microsoft is to operating systems ....
                                      .... what McDonalds is to gourmet cooking
Home page: http://marc.merlins.org/