Worried about ESCs and LiPo



Hello, I’m back

Recently I connected my LiPo to my PDB and ESCs. As soon as the male XT60 plug (on the battery) contacted the female side (on the PDB), a blue spark jumped out of the plugs! People say that’s normal, and I think if I had touched any connections on that board or the wires, I would have been dead. I had all four motor + ESC pairs connected on the board. Now I’m worried because I think I fried my ESCs, although I’m not too sure. The second time I attempted to plug in the battery (this time with only one of the motors and ESC), one of the bullet connectors on a wire on the board touched one other, and burnt each other! The motor didn’t even move nor did the ESC beep the way I think it should have.

My ideas about what the problem may be is that:

  • The solder joints on the PDB are shorting each other (not sure if flux conducts electricity)
  • The LiPo is shorted inside or the plugs are color insulated wrongly

Lastly, a LiPo should have NO current running at all, unless an ESC “asks” for it, right? And ESCs should beep when the battery is connected to the leads, or when the servo wire is connected to a 5v source (like Arduino), or both?

Sorry for lengthy words


Hi Jerome
Lets try and cover these points one at a time

Even without faults you will get a small spark/crack when connecting the LiPo battery, this is due to the capacitors in the ESC’s (and maybe other components) being at low resistance due to being discharged. They will draw a very high current for microseconds whilst they charge. If this concerns you somebody makes XT90 connectors which ‘suppress’ this surge, these are next size bigger than XT60’s though.

No, you would not die !! the lipo voltage is either 12v or 16v (3S or 4S fully charged. You need about 60volts DC to kill you. (trust me I’m an EV engineer :scream:)

Sounds like the bullet connectors shorted the LiPo + and -.
A LiPo battery can provide high currents very quickly and melt connectors, may even burn you if you are careless
Check your wiring and soldering very carefully for good bright joints, look for splashes of solder across connections where they should not be.
This hobby has the potential to do damage and cost money, ensure you have the basic skills, or a friend who can help.

No, when you connect the LiPo various components will put a load on the battery and draw current (about one amp total) i.e flight controller, camera, video transmitter, LED’s and the ESC’s will draw a little current for their logic circuits to work.
Only when the FC tries to power up the motors will the ESC’s draw (more than an amp or two) high current.

Yes, when powered ESC’s will beep, but this is low current for a few seconds, it could be as high as 2-3 amps.

Hope this clarifies
Steve :slight_smile:


Thank you for your help!

That’s a relief – I won’t die from touching the connectors, although there IS a great amount of amps coursing through the “circuit.”

Does this mean that my LiPo is OK? My battery meter is still reading 3 cells at about 12.3V.

And my ESCs. They should be fine, right?

As for my solder job on the PDB, no solder contact or shorts other joints (but some flux does; I’m worried about that)

I’ll try to post a picture of the PDB…

Thanks again; I really appreciate it!