The battery is 12.6v charged and 9.6 depleated. Having the ability to run 5v down to 3v would be great in order to keep the elecs working as long as poss in the event of a low battery. In the future a beacon will be aded to aid finding the model if lost. This would mean that the lithium cells would be destroyed due to overdischarge, but that is preferable to losing the modle..
http://www.ebay.co.uk/itm/3A-DC-DC-Step-down-Module-4-5-28V-To-0-8-20V-Voltage-Regulator-Adust-Over-LM2596-/251523752891?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item3a8ffbe3bb
That module is cheap enough to put on each servo, also small enough and can give 2a constant, apparently
It states a 30mv voltage ripple, that's not the spike it would give with a servo right?