The only way i have found around it is to use bobs logistics mod, or another like it, which adds in extra tiers of robots with increased charge and decreased energy use. Steejo's bobs mods mega train series on YT uses both of these, eventually, so you can see how ridiculously fast the robots get.
Sorry i couldn't help you
![Sad :(](./images/smilies/icon_e_sad.gif)