Difference between 20120 and 12020??

[GriffinRU]

Originally Posted by BrianG

OK, 7xl and 9920 it is then!

I wish these BL motors would have more specs other than just the kv rating. At least power consumption would be nice. At least that way you can figure out the current draw for a particular number of cells to achieve 45-50k rpm.

You have Kv, I and R ...
You have all the parameters to calculate power...

And some manufactures even provide efficiency over RPM or load data...

Artur

[BrianG]

Originally Posted by GriffinRU

You have Kv, I and R ...
You have all the parameters to calculate power...

And some manufactures even provide efficiency over RPM or load data...

Artur

Where are the current and resistance (or impedance) ratings? All I see are the number of turns and the kv rating. Sepcifically, the BK Wanderers?

[GriffinRU]

Originally Posted by BrianG

Where are the current and resistance (or impedance) ratings? All I see are the number of turns and the kv rating. Sepcifically, the BK Wanderers?

For feigao motors are on the motor can. I hope you can get the same info from BK as well. If not then it is not difficult to get the trend from feigao/nemesis to BK...

Artur

[RC-Monster Mike]

For an xl motor and room to breathe, the 120 amp warrior is the one IMO. The 9920 can handle quite a bit, but the xl motors can also draw a lot of power. the 8xl or higher can get away with the 9920 more easily for sure, but a 7xl with some voltage is indeed pushing the 9920(it is proven to work, but the 12020 is better IMO).

[BrianG]

Thanks Mike. That's kinda what I was figuring, but without the amperage rating, or wattage rating to calculate amperage based on the number of cells used, on a specific motor, it's hard to guess what will work safely. At least the Lehner 19xx series does tell you max power it will handle, but those cost too much. I imagine a similarly sized non-Lehner can would dissipate approximately the same wattage, but the thickness of the can and how well the heat transfers from the coils to the can makes a difference. I suppose I could just get the largest amperage available to be safe, but that darn cost factor gets in the way. :)

BTW Mike, would increasing the size of the heatsink on any controller void its warranty? Of couse, if something went wrong as a direct result of the heatsink upgrade, I wouldn't expect to warranty it.

[RC-Monster Mike]

technically, removing the shrink wrap voids the warranty. BK is pretty fair when it comes to standing by their stuff, though. If the problem was a manufacturing problem, they would likely take care of it.

[squeeforever]

generally bk will warrant anything. i had one i got wet and they replaced it for free!!

[BrianG]

Yeah, I would never submit a warranty claim for something that was obviously my fault. A warranty is for defective products, not stupid users. :)

I have a little heatsink "box" that I was planning to use, properly insulated where applicable of course. That way, I can waterproof the ESC without affecting the heat dissipating properties. I'm not planning on going underwater, I just want to protect it against the occasional splash from a shallow puddle or something. Plus, all that extra surface area will keep it cooler, and that's always a good thing.