HELP!!! battery lead keep melting in flight

[jonchis]

Hi everybody,
i have freewing su-35 for almost 2 years. about 2 months ago i upgraded fan units to Extrême Alloy CS12 Blade combos with Typhoon 2w30 inrunner motors. Also upgraded ESC to Hobbywing 100A ones. using Pulse 5000 mah 65c battery. After that i had about 50 flights and crashed twice because leads from esc to battery becoming so hot that melted sattering material and wire come loose. after first crash i rewelded all connections to make sure there is no cold sattering. but this mourning it happened again and i dove from 150 ft straight down to runnaway.
where can be the problem? in both crash flights i was not pushing it to the limits ( wasn't try to hoover or smth.).
thanks a lot i advance.

[F106DeltaDart]

What gauge of wire and connectors are you using? I would use at least 10 gauge wires and EC5 connectors for that current load..

[jonchis]

that's the ones i am using. and the weird thing is that it is happening not every time.

[KJD]

Heating means you have a high resistance joint. The EC-5 in the last generation of the SU-35 really was a down grade from the XT-150 of the earlier version. The max wire you can fit to the EC-5 is 10 gauge. The bird cage style is rather weak and troublesome (resistance gets worse with each use). It takes a bit of skill soldering the power lead Y harness for larger gauge wire. But as you know about cold soldering joints you should know how to copper wire wrap and manufacture such an item. With the kind of power you are trying to move through a single connector you need to start to look at large bullet connectors. But if you still want parallel insertion connectors you need to upgrade to something like these 6.5mm Castle Creation.
http://www.castlecreations.com/produ...onnectors.html

[jonchis]

i thought about that. just a lot of sattering but its worth it. cheaper than new kit. I chose this upgrade from youtube where guy shows in 10 steps how he bilt his su-35. but he used ec-5 connectors ( actually i expected to be smth bigger). maybe he replaced them later on.

[KJD]

There are two styles of EC-5 the bird cage like those from Horizon and the solid finger type, like you see in the Castle Creation 6.5mm contacts.

Question; is sattering the same process as soldering?

[jonchis]

i use those words to describe the same process ( english is my third language - so sorry if i am confusing you).
i checked castle creation contacts. yes they look way more solid and have more contact surface than the bird cage style ones.

[KJD]

Not an issue, English is my second language. I just wanted to make sure we were talking about the same thing. "A rose by any other name would smell as sweet" - Shakespeare

[jonchis]

:) thank for help

[Flygirl]

Not an issue, English is my second language. I just wanted to make sure we were talking about the same thing. "A rose by any other name would smell as sweet" - Shakespeare

You would never know it is your second language KJD. Your grasp of english is awesome!

And you too Jonchis!

[KJD]

Thank you.

Now lets be honest my english sucks, but I try to compensate with a LARGE vocabulary.

Jonchis,
You have nothing to apologize for. You got your ideas across to us all. That is the point of writing! Great job doing in english!

[Flygirl]

Thank you.

Now lets be honest my english sucks, but I try to compensate with a LARGE vocabulary.

Jonchis,
You have nothing to apologize for. You got your ideas across to us all. That is the point of writing! Great job doing in english!

It really doesn't :) I had no idea you weren't a primary english speaker. Really :)

[jonchis]

ordered today a pile of connections from castle creation. will have to replace on charger and f-14 tomcat also cos i am usping same batteries.

[KJD]

Can I ask what is the current (AMP) you are drawing (pulling) from the battery?

[F106DeltaDart]

Considering he is running 2 of these fans http://www.extremerc.com.au/estore/i...oducts_id=1268 I would say it is at maximum around 150A. It seems odd to me that the battery connector would be the issue at this amperage. I have used EC5s up to 160A with no issues on my LX F-4. It is perhaps not the best choice, but not the most likely point of failure to me. It seems more likely to me that a thicker gage wire (roughly 10 AWG) is needed or perhaps higher quality wire. Was silicon insulated wire used? The normal types of wire you find at a hardware store will not stand up to high amperage and will get extremely hot very quickly. One of my friends made this mistake when he added an extension to one of his ESCs on his T-50, and the solder at the connection joint melted.

[KJD]

The bird cage (Assume this is the Horizon style) looses tension very easily as the connector gets hot, ALA Tamiya connectors. Like he said it worked for a while. So I suspect contact deterioration as a result of heat. The finger style contact are much more durable to repeated heating.

Not sure what silicone insulation has to do with anything. I assume you are associating silicone insulation with high strand count wire. High stand count wire will carry more current than solid (or low strand count) wire of the same gage. (Electrons are prone to travel along the surface of the wire).

I limit my EC-5 (Horizon bird cage) to 120 amps. Even at 2.4Kw you can feel a large temperature rise (voltage drop) across the connector. High power systems really need bullet type connectors. I really like the Jeti connectors, look at that 8mm one!
http://www.jetimodel.com/en/katalog/...es/Connectors/
But these are not parallel insertion type, so many sport of novice flier aren't comfortable with them. Nor are they with the ones from Neu and others.

The 6.5 Castle Creation connector works fine (actually great for the sport ships MotionRC sells).

[KJD]

Looking at my SU-35 I see that she has 10 gage wire at the start of the battery/ESC "Y". You might have noticed that the set up is showing the anti spark resistors and pig tail. I'm using EC-5 to have commonality with some of the guys I fly with. I use anti spark to extent the life of the contact and the ESC. I'm comfortable with the EC-5 as I'm only drawing 98 amps peak.

[F106DeltaDart]

Not sure what silicone insulation has to do with anything. I assume you are associating silicone insulation with high strand count wire. High stand count wire will carry more current than solid (or low strand count) wire of the same gage. (Electrons are prone to travel along the surface of the wire).

Yes, it is a combo of both qualities. The high strand count will have less resistance, and therefore produce less heat as current flows through it. I was simply referring to it as silicon wire since that is how it is referred to on Motion. And silicon is very resistant to higher temperatures compared to the typical pvc and rubbers used in household wiring insulation.

[KJD]

Yes, silicone has a very high melting temp like over 1K°F and is preferred over the less expensive PVC insulation. I don't think the issue that the OP (Jonchis) is having has anything to do with the insulation properties of the wire sheath.

I see, more imprecise nomenclature.

https://www.motionrc.com/collections/copper-and-silicone-wire

[jonchis]

wires i bought at hobby shop and pretty sure they are high quality and thick cilicone coating. when connecting battery i usually notice a spark which actually makes contact worse, and was thinking how to avoid that.
KJD : spark reducing resistor you added yourself of they came with plane? i need that too because i dont want start damage my new castle creation contacts.
about amperage i did not measured that. to be honest not sure how to do that. i know i need watt meter but maybe you guys can recommend one please?
by the way: yesterday picked up new arf kit at motion rc and today will start installing everything.