Hobbyking A30 issues

The Hobbyking A30 is an economical power supply for LiPo chargers.

problems were noticed with a Turnigy Accel 8150 charger where the display became corrupted when the case was touched.


It turned out the output terminals of the A30 are isolated from chassis and power supply ground. Above is a scope capture of the voltage to chassis on the -ve output terminal, a common mode voltage of almost 300Vpk. Sure, it will not sustain much current, but it is potentially (pardon the pun) dangerous to any electronic equipment connected to the power supply.

In my case, I dismantled the case and bonded the -ve output terminals  to the mains connector earth terminal with a 2.5mm^2 insulated wire.

Whilst performing that work, I was concerned at the proximity of a large toroidal choke and the top cover with no intervening insulation. I applied some kapton tape to the lid to reduce the risk of problems.

Oh, and the power supply rattled when received. That was an extra case screw loose inside the power supply, and it had fortunately not yet caused apparent damage.

These power supplies are not intended as a general power supply for electronic equipment, and they do make a lot of radio frequency interference (RFI).

SAFETY WARNING: do not remove the covers or attempt such a modification unless you are competent to do so.