We have also been riding with long 12 awg to the motor without any issues. We soldered everything (no bullet connectors). We got 5.5mm bullets that are rated for 150A now, so should work I suppose.
I guess, those poor tiny Fets in the ESC just burned up cracking and spitting plasma as normal response to overheating and to high current, wonder they resisted repeated hammering with loaded startup current. Topology and packaging of those ESC does not allow any reasonable cooling due to lack of thermal mass and thermal path. They are extremely overrated in their current handling and usually have no protection mechanism against over current, like phase current limiting nor even parallel Fet current sharing or any advanced control algorithm. It is a good practice to at least divide the sticker rating of ESC by 2 and use it as maximum value for phase current. Then choose load value accordingly and you should have not reliable but at least mediocre system.
In short, if you need 150A, seek for 300A sticker.
I opened up today the ESC and some MOSFETs were burnt and cracked. But the cooling mechanism looks -for my understanding- pretty forward. I will post a picture tomorrow.
such a shame, all in the name of testing, we’ll get there 
@ tylerclark You mentioned you modified the SeaKing 130A HV ESC to 8AWG. Did you desolder the stock 12AWG wires off the board, solder on 8AWG and then re-pot the cables?
I’ll let @jclark chime in here, but we weren’t able to modify it down to the board. So instead we cut the wires down as much as possible and use bullet connectors to then switch to the 8AWG. If I see someone who has successfully done it, maybe we’ll do it too. Just seemed too risky.
We dissassembled the seaking and changed the wires. Not worth the trouble!! nearly killed the esc, but It works now (can’t get contact with the program card for some reason tho).
Better to take the wires down. Altho you might damage it by soldering close to the esc due to excessive heat from the solder.
This is critical (wiring size) Ill post it here agian for all to see… everyone really needs much larger wires than they think…
massive! The black cable (on the left) goes to the receiver?
Correct. The box act as a heatsink (aluminium) and is waterproof as well.
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Nice! Are you using water cooling also? Is the box custom made?
Standard box from RD components sanded flat. Will try without water cooling first (less parts that can break). but there is room to add it in later if needed.
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Well maybe… 2-3’ mast, 6-12" into motor tube, through board 3-6", across into ESC box 1-3’. is way more that 1m, but you are running small current your good, most ppl arnt they are tinkering running 100-130+A and melting down with 10awg.
Yes if you have things really tuned and short wires, but not sure why anyone would skimp out and do 10 or 11awg when its like $5 more to do 8awg and have things run cool and safe…
This might be a month too late but… why not fuse? If there is no over current protection in your system, you should throw one in there before you frag a battery and then you are in for a good fire…
The pulse rating of the ESC and the continuous current are different things. ESC vendors might quote pulse, but continuous will be way less. My esc will pulse 800A for <100us, but can only do 180A continuous. If you have a fuse for 2kW from 12S it will be ~40A, add +50%, so you get 60~70A. I’m fusing at 70A, but will run up to 100A as I unlock more power with development.
A fresh topped up set of 12S cells can be lethal because of pulse capability. To protect the fuse and batteries you need to make sure there is adequate capacitor banking on the esc side of the fuse. Current will ‘ripple’ from these banks, as it should, so that your battery current is nice and stable, and your fuse doesn’t die prematurely. This is much healthier for your cells, and can explain why they aren’t lasting as long as you’d like. Current ripple is bad. Big cap banks make a bit of a spark when you plug in, but they are lesser of two evils. You need big big caps and many, because each has a piddly current ripple - you want about 20A ripple capability in your bank, actual capacitance value matters far less than ripple rating.
When a fault happens, consider a hard short circuit on your esc output, will cause a massive pulse that won’t stop. It becomes the ‘steady state’ that drains the current smoothing banks, then they will replenish heavily from the battery and the fuse will blow. Sizing fuse to be small enough, so that the fuse blows before your esc catches fire is the trick. Preserving the esc, requires finding sweet spot between enough ripple capacity and so much energy in them that their discharge damages esc before fuse blows. If you don’t save it, at the very least you’ll stop a fire.
When wire burns it’ll desolder itself, melts insulation or just burn until gone and the fets would likely remain intact. Also, water isn’t that conductive, it’s more a nuisance. IMO your esc is driving at low frequency, no current limit, heavy demand looks like a short circuit essentially, tyour esc pwm keeps rising, he motor inductance saturates quickly, current shoots through, you get a busted low side from over current, then soon after a busted high side, crowbar because these fets always fail short circuit, heating in the pcb and packages, fire, magic smoke. This happened to me three times until I figured it out.
12AWG is easy to work with. 8AWG is a heavy bitch that is hard to terminate. 10AWG is a nice balance. None of them will give you a heating problem until you have a hard short circuit somewhere else.
I like to throw in my two cents here. I had an ESC once blow up underneath my feet. I built an e-longboard and the gearing wasn´t perfect yet. The motor tried to spin, but did not have enough torque. That caused the ESC to pull more and more current. It was rated for 120A, but who knows how much it pulled at the end. I was on low throttle, but suddenly there were sparks, fire and lightning. It was like fireworks, right underneath my feet. The ESC drew so much current that it burned up. The battery cables unsoldered and probably also shorted for a small moment. Luckily the LiPo did not get damaged. I was fine, but it was very very scarry!
What did I learn?
- Separate your ESC from your LiPo. Both can explode and its better if only one does.
- Use a 100A fuse for a 120A ESC. Costs 10€, but saves you a lot of money if it trips.
I ordered 8Awg silicone wires and XT90 plugs. Everyone happy with that?
Hey MaxMaker, be sure your silicone wires are not the cheap red wiring from eBay or Amazon that if you read the print it is CCA (Copper Coated Aluminum). I made that mistake and it’s not built for high continuous current. I did a lot of research on it only to find out it handles 20% less current and the silicone casing slices and breaks easily.
We also used XT90 Anti-Spark and XT90 plugs for everything on our first prototype they did get warm, and two melted. They are not really designed for high constant current either, and 8awg wires do not fit into them causing you to trim the wires and creating bottleneck/hot connections.
We have gone with all 6mm connectors that handle 150-200A continuous so our electrical system will be rock solid and safe. See these connectors and video:
7mm AntiSpark Bullets for 8awg wire: https://hobbyking.com/en_us/7mm-as150-anti-spark-self-insulating-gold-bullet-connector-2-pairs.html
6mm 150A Bullets for 8awg wire: https://hobbyking.com/en_us/xt150-battery-side-5-sets-bag.html
6mm 200A Bullets for 8awg wire: https://hobbyking.com/en_us/6mm-rcproplus-supra-x-gold-bullet-polarised-connectors-6-pairs.html
How To Solder Video: https://www.youtube.com/watch?v=hSuH0rjhVaA
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I can’t help feeling that ‘melting’ of anything is a symptom, not a cause. So stop the root cause.
If your wires are melting because of a short circuit somewhere, the problem is not that the wires can’t handle the current. The current is the problem. Fix the short circuit risk, then use the shitty wire from Amazon, it’s all good. Most current travels on the outside of the wire anyhow so CCA kinda makes sense.
Try to conformally coat. If you aren’t spraying your esc and battery contacts you’ll eventually lose your hole board because of all the shit floating around any enclosure. I like the coatings that you can solder through. I’ve bought some LET ‘liquid electrical tape’ recently and plan to spray over the XT90’s and terminals in my system. The stuff peels off when you need it to.
Don’t breath any of it in - it’ll give you cancer.
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