The battery incompatibility problem involving the i-Pilot remote has been discussed on several threads in this forum. The problem stems from the fact that there are at least two different designs for coin cells bearing the designation "CR2450." MK advises i-P owners to avoid Panasonic brand cells. Other brands have also proven to be incompatible. Both types of cells have identical voltage & polarity and both fit snugly in the i-P remote's battery holder. The difference is the profiles. The non-working cell has a thick top and the working cell's top is much thinner.

Quick solution
Bend the battery holders pins (green arrow) upward slightly so they contact the bases of all types of cells.


Complete explanation
Here is a closeup photo of the two types of cells. The one on the right works in the i-P remote and the other does not.


The image below shows the battery holder. When you place a cell in the holder, you can only press it down as far as the holder's "step" (yellow arrow) allows. When the top section of the cell hits the step, the cell will go no farther.


Working cells have a thinner top and can be pressed deeper in the holder where they will touch the negative contact pins. Cells with thicker tops will also work if you make a minor adjustment to the battery holder. Simply bend the battery holder pins (green arrow) upward slightly and they will make contact with the bases of all types of cells. Use a small screwdriver or knife blade to make the slight bend in the ends of the contact pins.

I've made this minor adjustment to my holder and it now uses both types of CR2450 batteries!