wierd solder joint melting problem

[audio131]

hi, i have a mini protos with a 4s motor(500watt max) on 1800 4s 25 gens packs. using the yge60 esc .. last week after a flight the esc was beeping as if it reset. after unplugging batted i noticed the the negitave wire in the esc side had came out of its solder(use ec3 conntector) its been soldered for a long time so didnt think much besides old.but looked weird. so resoldered a new bullet connector . this week after 2 flights heli in mid flight lost full power and crashed....THE NEGATIVE wire was un soldered as if the solder melted!! the motor and batteries have always been ice cold..I HAVE never seend this before in 8 yrs of flying.. ANYONE KNOW whats going on???? i am suspect to something wrong with esc.. i just dont know...

[desertstalker]

No-way the bullet unsoldered itself, if it go that hot it would have melted the connector.

[audio131]

the bullet is loose but not melted.. and yes the solder like cooked and melted out. twice. .been doing this for over 8 yrs. so id like to think i know how to solder.

[Mr dan]

Originally Posted by audio131

the bullet is loose but not melted.. and yes the solder like cooked and melted out. twice. .been doing this for over 8 yrs. so id like to think i know how to solder.

No one is questioning your knowlege. It sounds like a bad soldering connection, maybe you used a poor quality solder who knows? A signal pulse heating to the point that it would mealt cured solder is just hard to imagine, poor solder might be the culprit.
.. Again I dont mean your techniques, I mean the actual solder!
I alsway use a light coat of liquid flux prior to soldering, I never had a bullet fail to date.

[mattmezz]

Were the wires touching together maybe???

If there is a loose contact in the ec3 connector (or in any connector) the amount of metal making contact could be very small. Given the amount of current that is available in the packs we use. If all that current is going through a very small point in the connector. It would be like using a very small piece of wire to connect the battery. The small wire will burn like a fuse or in a loose connection will get hot enough to melt solder. Maybe that’s what happened in your case… My suggestion would be to cut the connectors off and put on new connectors. Then check all of the connections because it sounds like you could have more than one loose connection. Maybe a problem with the wires not being strapped down and moving too much during flight and causing connection to come loose… IMO, TOTALLY WIERD!
Matt

[audio131]

hi, thanks matt. ill try that