RE: Spektrum DX-7
Being a poor old country boy - I simply double up things (wires ) till the battery (a123) feeds everything all it wants . (yum yum)
No expanding devices (how do you expand power , short of a bomb?)
as noted, the weak link is simply supply --if you have proper battery.
I also use the A123, four of em in two 3.4 lb fully aerobatic electric models and pull over forty amps from em of for 8-10 min flights
The piddlin 6 amps I maybe pull at one instant as my rx pack is nothing to em.
apparantly the full sized car folks also have decided they work-------
not to mention a drag bike called killa cycle - 8.2 - 155mph