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ArcticMyst Security by Avery

Another one of my crazy projects :D

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You two crazy Aussies. You guys make the coolest stuff. :bowdown:
 





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Not really keen to push the thing to the limits until I've got my proper control board installed, would hate to cook $80 of ESC and $80 of motor! Or worse, start a $100 LiPo bonfire :D
 
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Holy Shit Dan. That thing is going to be a monster when you are able to go full throttle. Yea I have smoked a few motors and speedys plus a LiPo or 2 in my speed planes. And for the love of god wear a helmet and body armor:crackup:
 
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Oh and LiPOs are so safe. This is what we do when they are old and tired.........
 
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The scooter looks like its coming along great.

One of my favorites, fast forward to 0:32 to see it get really mad :evil:
The sound it makes is awesome

The worst scenaro ive had was a 3-cell that had one cell get very inflated and vent. I then turned into a 2 cell and it worked great for another year.
 
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Haha, thanks for the reminder of how my scooter could turn into a potential fireball :D

But naw, almost all LiPo fires are caused by punctures, over and under discharging. I've padded mt battery compartment in foam so the batteries don't bash around, and the circuit I'm designing should tare care of the under discharge. The charger is also one of the "smart" ones that should keep the packs nice and balanced, so really the risk is quite low if you look after them.

It's the under discharging that gets to them in use. For example when I first got these batts, I connected them up to 2 12V 12W lightbulbs in series. Accidentally forgot about them and came back to find 1 cell at 1.5V, and the pack was warm even with that tiny load. Lukcily I noticed it quickly and threw it on the charger, the cell seems to be back at full potential and staying nicely balanced luckily.

If it had've gone any lower I probably would have permanently damaged it. That's also the reason I'm hoping to pack a 3rd LiPo in here, not only for longer runtimes, but to make the discharge load a bit lighter. These packs are good for like 100A discharge safely though, so I doubt it's really an issue :)
 
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The batteries we do the nail trick to are all overcharged. If its a 3 cell we charge at 3 cell then to a 4 cell and that's when the fun begins.

Dan I am amazed that you revived that battery. Most if not all LiPos are done if discharge below 2.8-2.5 volts per cell. Also remember those cheap LiPos are over rated like Wicked Lasers.LOL
 

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Not actually so sure about that. This charger conveniently has the ability to show how much energy has been put into the pack, and I'm actually getting over 5000mAh, even when they're not fully discharged. Turnigy kind of have a decent reputation with LiPo's these days I've heard. Apparently they were a bit shaky in the start, but they seem to have their shit sorted out, especially for the price!
 
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Not actually so sure about that. This charger conveniently has the ability to show how much energy has been put into the pack, and I'm actually getting over 5000mAh, even when they're not fully discharged. Turnigy kind of have a decent reputation with LiPo's these days I've heard. Apparently they were a bit shaky in the start, but they seem to have their shit sorted out, especially for the price!

It's not the capacity it's the C rating. They are getting alot better but still under unlike a Thunder Power battery. Also the life cycles when pushed hard.
 
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Ah, OK. Well the LiPo's don't even get warm, so I think I'm pretty safe. The 10AWG wiring does get a little warm though, and my 12AWG motor wires get pretty toasty. Need to upgrade those I think.
 
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That is good news about the batteries. It sounds like you have enough headroom on those.
Now on to the wires. They may be big enough but if the connectors are not able to handle the currant the heat will transfer to the wires. How many amps are you pulling?
 

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No idea on the amps, but I'd take a guess at well over 150A peaks. The motor and ESC comes stock with 4mm bullets, which I'll probably end up upgrading to 6mm ones, because they do get hot. The motor winding wires also get hot too, but the insulation on those is rated to pretty damn high temps, so shouldn't really be any risk of melting them, especially with a fan on there. I've had them at about 130C, and they smelt really bad, but no discolouring or melting of insulation.
 
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You need to keep a eye on the motor temps. The magnets will demag at not much more than that. Even the best will demag at 160-165c I think some as high as 185c? You know the enamel wire on the windings will probably go first. You should be able to open the motor and change the input wire size. And yes change the bullet connectors to 6mm or 8mm.

Good luck and keep us posted.
 

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dont forget to derate the cables for the harsh australian climate....Straya Cvnt!
 

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Haha yeah, I bet if I was running this somewhere with sub 0 temps, nothing would get warm at all :p

34C outside at the moment doesn't help.

n2stuff, yeah, I've installed a fan and a shroud over the motor that helps drag air through the inside. The windings still get hot, but the rest of the motor stays cool-warm, so the only real worry is the wire insulation. Even that is a pain in the ass to melt with a soldering iron though, so I don't see it melting at anything below 180C at least.
 




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