Lots of options for hydra motor control to conserve battery consumption.
Turn pump on/off via remote
http://www.robotmarketplace.com/prod...-BATTLSW1.html
This esc works great for tracked models, but you can also turn off the "mix" feature and run two motors seperately. I use this esc in my articulated dump trk to propel it for/rev and operate the hydra pump. If I were using a better radio I would "mix" the proportional channels of the valves with the hydra pump, but currently I'm using the ratchet stick to control hydra pump rpm manually.
http://www.robotmarketplace.com/prod...ER2X10-RC.html
This is the "auto sense" that Nathan refers to. The slightless bit of movement of the vlaves for oil flow and the hydra pump activates, but you have to have the valves perfectly centered or the pump will never shut off. If I recall correctly, it's about 2 or 3 second delay with no valve movement before the hydra pump turns off.
http://www.leimbach-modellbau.de/start.html
(scroll down left header to LKW Zubehor and click Pumpenbaustein)
Here's a handy translator to read foreign sites.
http://translate.google.com/#de|en|