Lipo parallel setup smoking!

[cory lanahan]

hello I have two turnigy nano-tech 3000 mah 25-50c discharge, 2 cell 7.4v in a factory made harness for my hexacopter. Motors are DJI 2312/960kv and turnigy plush 30A esc. With Naza lite FC. It works fine with one battery just not enough power or flight time. Do I need to solder on some type of resistor or is my 16 awg wiring not thick enough? It also started to melt battery connection on PDB, do I need better quality board?? It got so hot with two lipos in parallel that it melted both bullet connectors off the wiring harness! What am I doing wrong please help! I've researched this quite a bit with no answer concerning this type of issue

 

[charleshidalgo]

Are you sure you're not in series?View attachment 27651

 

[cory lanahan]

yes, positive it was a factory made parallel harness. That's what I thought too but I triple checked and both positive red wires from lipo get fed into one single wire and the negative wires from lipo gets combined into another single separate black wire.

 

[charleshidalgo]

Have you used just a single 3s battery? If I'm not mistaken those motors are for 3s/4s? Something is way wrong. There's no way a battery be it single or parallel (if things are correct) pos/neg connections etc should be getting hot enough to burn and melt anything on that rig. Photos may help.

 

[Alwil]

I agree- If it flies fine with one battery but a parallel setup causes heating I would take a hard
look at some connections.

 

[duckduck]

Are the batteries at the same state of charge?

 

[cory lanahan]

View attachment 27670 View attachment 27671

 

[cory lanahan]

Fairly sure it's not anything on the hexacopter because one 3 cell 30-50c 3000 mah turnigy battery works fine ( just not enough power). Am I somehow changing the cell count or something? As you can tell I'm no expert on batteries but I'm trying to learn and have fun without blowing up my basement or me

 

[Alwil]

From your pictures I see two batteries but I see 3 red wires and 3 black wires going into
I red and 1 black. How did you get 3 red and 3 black from 2 batteries ??? Maybe I am
missing something- no coffee yet!

 

[Alwil]

Ok- Taking a second look- I see a third balance plug. You are running 3 batteries ?

 

[cory lanahan]

Yes I'm sorry I meant 3 batteries sorry!

 

[Alwil]

I would take a multimeter and read the voltage with one battery- then plug in the
second battery and read the voltage- should be the same. Also check each battery
to make sure the manufacturer has not crossed the wires up. The voltage should
be the same for each battery. Red= Plus Black= Minus Strange!

 

[charleshidalgo]

Three red and three black leads? There's a lot going on in that photo. I've seen where if all the packs are not charged and at the same level and you start plugging things in they will try and balance themselves out and things can get real hot real fast (though I'm not saying thats what's going on here). Here's a simple photo I took this morning of a parallel setup. You need to sit down and do some major reading. Like Alwil said put a meter on what's coming out of that setup (though using a meter requires some know how and if you're not sure have someone else look at things for you). Please be careful. Lipos will explode and they burn very hot!! Some reading: http://www.rchelicopterfun.com/rc-lipo-batteries.htmlView attachment 27677

 

[cory lanahan]

Wow stupid simple mistake on my part. Lesson learned. All harnesses are not universal in their polarity. Positive and negatives were opposite on harness vs the battery I've been using. Just failed to realize cuz majority of harness red wire is covered by black shrink tube. Issue fixed. Thanks for your help!

 

[Alwil]

Yes- This could have been costly in more ways than one. When working on electronics, it
pays to double check all connections with a meter before power is applied. This applies
to even prewired that were purchased. The little multimeter is invaluable.

 

[Efliernz]

Manufacturers can be very lazy... like a series of FPV cameras from Hobbyking that all had the power polarity leads reversed because they designed a plug that could be assembled in reverse by a child doing the assembly...

 

[Alwil]

Pete you are exactly right! I ordered some led lights that came with jst plugs installed.
They were installed backwards! Check and double check.