I know we are talking about the Sphere on this thread but I wanted to share an email that I got from Charlie at Novak when I asked about the power cap and what was going to be used on their 4 cell version. Here is his reply:
I don’t think the 4 cell GTB uses a smaller cap. Who told you that? None of the one’s we’ve tested, or passed around the building for approvals have a different cap. We intend to use the same one as it simply provides added performance.
You probably could use a smaller cap, but you loose some performance and gain some heating.
The Power Cap is there to help the ESC cope with Ripple Current effects that are created by high speed ESC switching. Anytime the ESC is switching on and off, the power wants to keep flowing, the cap catches this and feeds it back to the motor when the mosfet turns on again. So it charges and discharges EVERYTIME the ESC switches. This is all the time with BL, so a good cap is very important.
The circuit board has what are called, “transorb” diodes. These items are like voltage “clamps” if you will. When a big spike comes through the system (usually from the motor), the transorb clamps on to prevent the spike from damaging the ESC and the cap. It kills the spike essentially. If you do go to a smaller cap, you have to KEEP the transorb board. Again, we don’t recommend smaller caps.