Feigao 7L, Warrior 9920 + 12 GP 3300 cells = hot?

Ok, seems like I've got the right jumper.

[Serum]

Yeah, you need to strip a rather large piece of the heatshrink..

Hi,
finally got to testing the car with a receiver pack (and the correct screws in the diff ;). I actually mixed some of them up and put longer ones in there which made it quite a bit harder to push the car. Seems like the motor didn't really notice though.

The controller overheated pretty much as fast as before, now I measured about 95C° on the heatsink.
As expected steering worked normal during the cool off time now. I think the warrior just puts out less BEC current while thermaled. The heatshrink didn't melt this time.

I'm going to try a 12t (smaller won't fit in the chassis easily) pinion and active cooling next.

12V CPU cooler & BEC unit are installed now:
http://cx4.de/rc/storm11.jpg
http://cx4.de/rc/storm12.jpg
http://cx4.de/rc/storm14.jpg

I'm not really happy with the additional cables. ;/

[RC-Monster Mike]

The UBEC is a "nice to have" more than a "need to have" on 12 cells. The real problem is that the motor is too hot for the application/gearing, as mentioned before. In order for the car to get to the speed it is geared for, it draws LOTS of amps! This heats things up a lot and will significantly reduce the amount of cycles you get on your batteries. If you want your car to go 60 mph, use more cells and a slower motor and you won't have nearly the trouble you are having now. You will also get a better runtime. You could even use smaller gp2200 cells (18 of these would only be a little heavier than 12 of the larger cells) and you would get cooler running, a longer runtime and more power(with a slower motor of course). Adding fans to your current setup is kind of a band aid. It will work, and may even prevent the thermalling, but it only covers the true problem (too hot of a motor/too tall gearing).

I know that but it's not that easy to switch if you already have the stuff.. ;)

More sub-c cells won't fit and I'm not sure about 4/5 cells.
My old 4/5 pack (8 cells) seems to be longer than a sub-c stick-pack, as one would expect.
The battery holder is really optimized for 6 sub-c cells side by side.

At the moment I want to get the setup to work and maybe later switch to LiPo. This would make quite a difference in weight and/or runtime. 6s and a slower motor would help with the heat.
Not cheap and as durable though.

[RC-Monster Mike]

just a motor isn't terribly expensive to work with the stuff you already have. I think you could might be able to squeeze 8 gp2200 cells into the 6 cell battery space. It would be tight, but I think it may just fit.

[Dafni]

Yeah, I think you should take Mikes advice and try a cooler motor. It will be worth it.

Just played around a bit and I think it will be really tight with a stickpack.
Maybe if I took off the end caps and resolderd the cables...

On the other hand a new motor + packs would easily get to 300€. I would rather use the 12 cell setup until the cells die and then buy lithium and a new motor.

Another option would be to go with less speed and put a 9L or something like that in there.
Do you have an Idea how much speed I would lose with a motor that's appropriate for 12 cells?

[RC-Monster Mike]

On paper, you would lose a bit of speed, but in real life,. you won't lose nearly as much, as the cells would hold higher voltage. The 9L or 10L would still get you over 40 mph (still handily beat a nitro buggy on a race track, and would be close in top speed). The 10L would get you near 40 mph, while the 9L would get you into the mid to upper 40s.

[RC-Monster Mike]

You may actually end up with the same or better speed, in reality, as I am sure your batteries are dropping serious voltage with the load you are putting on them. You may get better runtime and speed in the end simply by swapping motors.

Heh, well that would of course be perfect, better performance and more run time. ;)

Do you know which of the Wanderer 20s is best, 9L, 10L or even more winds?

[RC-Monster Mike]

10L would be my choice. The 9L would also work. I can get the wanderer motor direct shipped to you from BK, if you are interested (this way, you become one of my customers, but get your products shipped direct from BK and avoid the customs as if you bought direct from them - a rather nice arrangement I have with BK). I can quote you a price through e-mail or PM on any motor offered on the BK site.

What would be your prices for the 9L and 10L?
PM or email would both be fine.

[Serum]

80 dollars round..

Look here

I got a 9L today and it works fine so far. Had to put new plugs on the controller, which isn't fun if you have 2 cables from the controller to put into 1 4mm gold plug.

The strange thing was that everything went crazy when I tried to accellerate, steering started to act up and it accelerated and braked by itself. After quite some playing around I found out that it does this if the receiver is mounted on top of the Hitec servo (which worked for weeks) or if I touch a screw with the receiver.
For now I put a folded handkerchief between servo and receiver which seems to help. Only on fully throttle there's some wiggling of the front wheels (maybe normal?).