does RTH use optimum battery life speed ?

[lesd]

When RTH is active, does the craft use a speed that will optimize battery life to get home if it's far ? If it's a fixed speed, is it fast ?

Also wondering if the 50 meter RTH height I have set is above and beyond the current altitude craft is at, or if it's referenced from the altitude at takeoff point?

 

[Meta4]

For some crazy reason no-one can figure out, the RTH speed is quite slow.
You don't want to use RTH against a strong wind.

RTH height set is above home point. If the Phantom is higher, it will return home from the altitude it is at.
If lower, it will rise to the RTH you have set and RTH from there.

 

[Dartmoor Dave]

RTH speed is close on 8 m/sec,( about 18 mph), I've used it often enough. If you want to return home more slowly and you are a NAZA user then try Home lock, that makes its way back home ( or 10 m from it) at just over 5 m/sec.