If you use 3volt CR2032 cell with the holder, do you still need a diode with it? I see some for sale with out it. Or if used a 3.6v phone battery, do you need a diode with that? lol or is it just easy enough to say use a diode with every battery but the barrel type. Sorry don't know much on this and rather ask looking stupid then pull a stupid and do it wrong.
lost
You need a diode if you will be using a non-rechargeble battery becouse the motherbaord will be trying to charge the battery when turned on. the phone battery can be recharged therefore you do not need the diode.
The diodes job is to let the current only move in one direction so the motherboard will not be able to deliver any to the battery, the battery will only be able to deliver to the motherboard.