Hello.
Cant find answer anywhere else.
I have dewalt cordless drill with li ion battery without charger and i have charger from bosch.
Dewalt battery have 8 pins, bosh charger only 4.
Question is - can i charge battery with only + and - pins or it will harm the battery?
Battery is DCB141 and charger is AL1814CV.

 

Unless you know the details of the design of both the battery pack and the charger it is a good idea to only charge the battery pack with the charger designed to charge it, particularly in the case of Liion batteries in which case you can easily damage the battery or cause it to become dangerous to operate.

Most likely the other pins are there to sense battery temperature, something that chargers often need to know about. So no, don't try charging with only two pins connected. It the other two were not needed, they would not be there.