bullets getting hott!

[dana]

my wires are as long as they need to be and no more. prolly 1 1/2 on the motor, maybe 3 on the esc. motor wires are average and same on esc. i just soldered bullets onto everything they way it came. i really think my motor/esc connection has alot to do with my problem. i swapped em for some castle 5.5's. ill go to a 442 then see what my temps are after a run. its only been a problem recently. i ran that 445 on the boat several times before it went. the motor used to run alot cooler than it is recently. maybe because the weather is warming up? i dunno, the water isnt as cold as it was a month ago....

[lenny]

Ok wires sound good,
Check your flex shaft and tube, it may need to be aligned,
Water temps, may be has something to do with the temps but not a lot.

[bbill1]

Sounds like maybe a bad or cold solder joint that slowly got worse over time?

[sundog]

Dave,
I'm not saying there is anything WRONG with 8mm connectors, just completely unnecessary unless you are running EXTREME amp draws. If you were to run a poll of how many people are using them you would probably find not many. You are more than welcome to use whatever you want but trying to get people to switch just doesn't make a lot of sense when 5.5-6.0 work fine in 99% of the cases. JMHO

That is my whole point - I don't see why more people don't use them. Consider that a 5000mah 40C lipo (common battery) can deliver 200 amps when called for. Why would you go up in little increments of 1/2 mm? 5.5 - 6 - 6.5 etc. is weight the problem? Cost? What do you gain each time - 10-20a more capacity? I think it's more about what Tony referred to - it would take some folks a lot of time (not necessarily expense) to change everything over. Suggestion: make a couple of adapters to what you're now using, until you get things swapped over. I'm not of the opinion "5.5-6.0 work fine in 99% of the cases", as I see this subject come up time and time again, as with this thread! Please allow me to reiterate: If your connectors are hot - but the wires are not, get bigger connectors. Kinda catchy, ain't it?

[LarrysDrifter]

I would check every solder joint,shorten the motor/esc wires if possible,and upgrade the motor/esc connectors. Leave the prop you have been running on it and check the connectors again. If the bullets are still getting hot,I say it has to be the boats running attitude (just a guess really without seeing a video),or a lot of part throttle running. Ive had my motor/esc wires shrink tube stick together at the end of a run,but its a high rpm,hot set up with big props that I normally run untill LVC.

[dana]

I ran today on 442. Did ok. The boat seems not to like glass so much. I'm gonna try cleaning bullets with q tip and rubbing alcohol. Could be oily from fingers. Also I'm wondering if my timing is off. My card says 15 degrees but I'll reprogram

[dana]

That is my whole point - I don't see why more people don't use them. Consider that a 5000mah 40C lipo (common battery) can deliver 200 amps when called for. Why would you go up in little increments of 1/2 mm? 5.5 - 6 - 6.5 etc. is weight the problem? Cost? What do you gain each time - 10-20a more capacity? I think it's more about what Tony referred to - it would take some folks a lot of time (not necessarily expense) to change everything over. Suggestion: make a couple of adapters to what you're now using, until you get things swapped over. I'm not of the opinion "5.5-6.0 work fine in 99% of the cases", as I see this subject come up time and time again, as with this thread! Please allow me to reiterate: If your connectors are hot - but the wires are not, get bigger connectors. Kinda catchy, ain't it?

the wires are hott too... not just the connectors

[properchopper]

Oil is the last thing you want to add to make a connection better. Most oils are better insulators, with high dielectric strength, then conductors. Dont contaminate a connection. Clearance and mating surfaces cause enough problems. Dont add to them.

KEEP YOUR CONNECTORS CLEAN! AND CLEAN THEM OFTEN WHEN FREQUENTLY DISASSEMBLING SYSTEMS. A little alcohol and a q-tip make a big difference. Do not lubricate! Clean bullets are the key to reducing failures related to connectivity. Remember. Its all about circuit resistance. If mating the bullets together is an issue, take the time to size them to fit properly.

John

This is the MOST IMPORTANT thing to consider. Right on, John

Given the variation in quality, size, and fitment of 5.5's, a well mated 5.5 isn't always the case. A little blueprinting and maintenence on these is a MUST to prevent high resistance (which results in elevated temperatures). It's better to have the battery convert it's energy into spinning the motor-thingy instead of heating up the conductors

OTOH the bigger sizes of connectors I've seen appear to be of higher quality and consistancy. While discussing this I just did a quick estimate of how many connectors I'd have to upgrade to a larger size ; roughly 75 connectors

[Jeff Wohlt]

dielectric grease is good stuff. Reduces wear and still ensures good contact. You only need very very little on the male tabs then insert and wipe them off.

Cheap connectors will scrape thru the gold and every use creates more resistance. Even Castles that I have were china versions but there quality might be better.

Also, this is why I use thrust bearings as well. Many motors have a rear shim..;put pressure on them and restance increases....and will eventually eat it up.

[6sHyper]

i run 8mm's on all my connections now, 5.5's were getting hot between my esc/motor, also my batt/esc connections would get hot on 6s1p, but switched to 6s2p and they dont even break 80 now, inadequate batteries will most definately cause the connections between the battery/esc to get hot, switching form 5.5 to 8 mm did the trick for me, of course the connections MUST be tight, if you can slide them apart effortlessly thats bad try spreading the males apart slightly to create a tighter connection.

[sundog]

Cheap connectors will scrape thru the gold and every use creates more resistance. Even Castles that I have were china versions but there quality might be better.

Jeff this is a misconception. The purpose for gold plating is to prevent corrosion. Metal to metal is not just skin deep. Scrape all the gold off and resistance is (about) the same - until they corrode. Corrosion creates more resistance. I said 'about' because if you test a new connector, it can show a slightly lower resistance because the gold plating has higher conductivity. But the bulk of the load will be through the brass base metal.

[785boats]

As work we use an electrical jointing compound on lugs when we are bolting cables up to transformers & switchboard busbars. This is to increase conductivity at the mating surfaces. These circuits are rated up to 2,500 Amps in some cases. I've often wondered if a smear of the compound on some bullets would do any good. I'll have to nick some & do a few tests. Good thread, this one.
Cheers.
Paul.

[Rich]

Dana, as you may recall, I ran that same motor on 5s2p (yes yes I know RPMs are too high). I got an amp draw that peaked at around 180. The connectors got to about 135-150f. I am using the castle 6.5mm. I would recommend going to bigger connectors just for added safety. I also looked back at some Eagle tree files I had when I ran the m445 on 3s2p. The amp draw was peaking at 150amps. I think that prop is just a tad to big for that motor, but there are others that recommend that prop for that setup. Try the larger connectors, use the m445 and see what temps you get. I have a feeling its the connectors.

[m4a1usr]

I'm not sure most if any of the cheap chi bullets have gold for plating. My guess is its a yellow colored "something" but not gold. At $1500 an ounce I doubt the cheap bullets have a molecule. But thats just my opinion. Now the Goldsteker's from Europe advertise as being gold plated and the guy I purchased my 5.5 bullets off ebay stated they were gold plated. And they were about 20% more expensive then a similar quantity of the same style/size bullets. I guess what I'm saying is if you dont see the word gold in the description its highly doubtfull your going to get any. The Chinese make things on the cheap and materials is one of those things.

John

[dana]

Dana, as you may recall, I ran that same motor on 5s2p (yes yes I know RPMs are too high). I got an amp draw that peaked at around 180. The connectors got to about 135-150f. I am using the castle 6.5mm. I would recommend going to bigger connectors just for added safety. I also looked back at some Eagle tree files I had when I ran the m445 on 3s2p. The amp draw was peaking at 150amps. I think that prop is just a tad to big for that motor, but there are others that recommend that prop for that setup. Try the larger connectors, use the m445 and see what temps you get. I have a feeling its the connectors.

rich, i just might change over, cause running the 442 after the 445 makes my mm seem like a tugboat lol