This will be my first post on the forums, please go easy on me... I've got two old laptops running MSDOS that I want to convert to run on lithium ion cells, but I can't seem to understand how this charging stuff works. With this conversion project I would like to get to know more about this sorcery.
The first laptop doesn't have a PSU anymore (and the connector on the laptop is really something special...), so my thought was to trash the internals of the battery pack (6-7v NiMh cells) and add a barrel connector to the plastics for something like a more common 12v or modern 19v PSU with a lithium-ion cell charging circuit (and a few cells) behind it. The old battery pack gave about 6v (according to the label), but when my lab supply was on 6v, it didn't get it up properly. 7v works best, so I want the pack to deliver 7v. On my lab supply it tells me it needs around 2.2 Amps when doing read/write stuff on a 3,5" floppy drive, so I'm guessing 3A is enough?
I want the thing to function just like a normal (modern) laptop. I'm not afraid to use a soldering iron, I just cant seem to wrap my head around this charging (lithium ion) batteries stuff... I'm going to use the laptops for some packet radio projects (they'll mainly function as terminals for the TNC's), but for now I'm going to have my hands full on this first laptop. Who can help me understand what it takes to get this specific thing under control?
The second laptop still has the original PSU and the original battery (still working good enough), but as I try to understand the charging magic on the first one, the second one will hopefully be easily done on my own