Cables and 5.5mm bullets very hot?

[paultbg]

Hello all
I am running my Osprey with Leo 4082 1600kv + T180 + 2*3S zippy 8Ah 30C (series),Octura M 445.
The problem is that if I am running the boat too aggressive (read : long full throttle) the cables from the esc and the connectors are so hot that solder is melting.I am using 5.5mm bullets.
Actually they become so hot that once even the plastic holder that keep the leads exiting the motor has melted and deformed, taking the form of the leads...
The motor and the esc are very cold, never above 40-45 degrees C.The batteries are also ok.
Now I do know that the this combination is slightly extreme (35k rpm) but I run a similar combination (with higher discharge rate,40C) in my Genesis and everything is normal.
Any ideas what could be the reason for this? Any solution will be appreciated.
Regards

[JimClark]

how long are you running it for? When you recharge how much is going back into the batteries? I would try going to bigger bullets

[MAMBA2200]

The first thing i would look into would be all the solder joints you could have a cold solder joint that appears to be good but is not. Second would be that 30c may not be high enough for this setup i have had issues with lower c rating's on big motor setups before. Third are your 5.5 connectors fitting tight when you plug them in or are they easy to plug you would want a good snug plug. Also check all your solder points on the esc to make sure theres not a bad solder joint from factory its happened before. I'm sure someone here will offer some better thoughts but this will get you started.

[Rumdog]

That motor is quite small for your boat. It's working real hard. Drawing a lot of amperage, therefore the hot connectors.

[paultbg]

Thanks guys for your answers.But if the motor is working that hard why the motor is cool and only the cables are very hot?
Regards

[dogg]

Hot cables is a result of resistance. They are the weakest link and therefore build up heat. The replies about poor connectors may well be true and cold/dry solder joints may be the problem. I would suggest you recheck every joint as suggested earlier as a poor (not tight enough) connector (or dry joint) will be a point of high resistance and build up heat.
If the motor temps are low, I honestly do not think that the motor is undersized as heavy load as a result of this would heat up the motor too, not just the cables.
The low (30c) batteries I cannot be sure of as noted in one reply. If the batteries are not supplying enough current for the motor, I would assume that the batteries AND leads would be too hot.

I'm no guru but am an automotive electrician. Just my 2 cents...

[jcald2000]

112 F is not that hot, My 8Ga. wires and 8mm bullets are 125F after a race drawing 5600 watts (7.50 HP).

[BHChieftain]

You also can try propping down. You are running a 6S config on 1600kv with a 45mm prop-- see what happens on a 42 or 40.

I have a mono with a 2200KV neu motor on 4S and a 240A ESC (a bit overkill on ESC), and when I ran anything over an X442 prop my bullets would get hot enough to split the shrinkwrap-- even though everything else was cool. I dropped to an x440/X442 everything was fine, plus my handling was better...

Chief

[dana]

I would beef up to larger connectors. Also make sure the connectors are clean and free of any oils or anything from your hands touching them. Clean clean clean

[keithbradley]

Poor soldering, period. I run over 300A through 5.5mm bullets at times and they don't get hotter than any of the other components.

[Fluid]

As others have stated, the problem is the wires/connectors. Long thin wires and small/poorly soldered connectors (or cheap solder) will heat up. If the motor is not hot then it is just drawing more than the wires/connectors can supply efficiently. While good 5.5mm bullets should be fine, going to 6mm, 6.5mm or even 8mm is not a bad idea. Use a chisel-tipped iron of at least 40W and good rosin core electrical solder. Power wires will always get hot in high-amp applications, but they should never get hot enough to melt good solder.

Going to higher discharge packs will only make things worse by supplying more curent through the wires - adding even more heat! I wish folks would think before they made such recomendations. :olleyes:

BTW, who descides that 105*F is "cold"? Does that mean that 130* is "warm" and 160* is "hot'? It only confuses readers to use relative terms like "hot" and "cold", especially if you have an IR gun anyway. Report the actual temperatues, and don't bother unless you take the reading within a minute or two of shutting down.






.

[paultbg]

Hello
Thanks all for your advices.
I will check the connectors/soldering, maybe I'll do them again.
Regards

[KartRacer]

Paultbg
I had a hot connector at one point and it was a tolerance issue on the connector. Only easy fit in the group and because of the looser fit it generated heat because of increased resistance. Replaced the connector pair with a tighter fitting pair and the problem went away. Connectors should require a effort to connect. JMO.