Hobbywing bec issue?
 

I have in my box a HW 120A V2.0 esc

The esc works well BUT when it (the buggy) is at speed there isn't enough power going to the servo and it doesn't turn nearly at all. When im not on the gas its fine or if I hold it off the ground and turn the wheels its fine. Only on power

Is there a fix or something I could do besides plugging in a life battery pack to the receiver?

Thanks

Trouble
 

Try connecting a capacitor into the spare socket on your receiver, 16v 4700uf might do the trick, this will help keep the voltage up when the servo is under load.

Give it a go.

Sorry to say it but don't think that will cure it, just out of interest is it a spektrum receiver?
Was advised on the cap for Savox servo on Spektrum receiver but no joy replaced the receiver and problem solved,
Same again different car/Esc replaced receiver and ok, fingers crossed been reliable for 12 months

My experience is the same as Beale - same problem, same cure. Savox servos on 1S and Spektrum receivers in general seem to be the cause of 95% of all the poor electronic performance I see.

Capacitors in the receiver will only offer minimal voltage storage, so they can help prevent receiver brownouts or transponder miss-counts. They cannot provide anything like the voltage or current needed to power a servo.

All the HW speedos I have had provided ample volts and amps from the BEC. They either work or they don't. Try Beale's suggestion first and see where you get to. HTH :)

FWIW I don't think OneKiwi is running either Savöx or Spektrum kit.

My Brushless 1c Ministock is running Spektrum receiver, Savox 1251MG servo and a power capacitor 16v 4700uf. It wont work without the capacitor and just goes into endless shutdown, restart, shutdown.
It's the initial voltage drop caused by high current demand of the servo that causes the problem, on standard servo's like a Fut 3003 its fine.