Feigao 10L/Warrior 7018 cutting out

I'm brand new to brushless. My son and I just finished converting an Ofna Hyper 7 to brushless. Here is the current setup:

Motor: Feigao 540 10L (61 amp)
ESC: Warrior 7018 (71 amp continous)
Batteries: 2 x 6 cell GP3700 matched zapped packs
Spur gear: stock
Pinion: 16 tooth Mod1

We basically copied this setup except for the ESC:
http://www.rcuniverse.com/magazine/a...article_id=467

Anyways, we just starting testing it today and what we are experiencing is cutting out. It will do a full speed run and then the next run, it will cut in and out or not run at all for a few seconds and then go or it will start to go and then cut out and then start and cut out and then run fine.

Are we experiencing thermalling? It is about 100 here today. The body still has all the holes cut out for the nitro motor so it should be getting a lot of ventilation. The motor and esc are rather warm, but not having used BL before, I'm not sure if this is normal heat.

We then, almost immediately, ran it up on the workbench inside (on a carstand with the tires off the ground) and experienced none of the problems.

I thought I did my research on the ESC but did I maybe choose the wrong one?

Ideas? Thanks.

Chris

One more thing. It is almost like it is not reciving a good signal from the radio. Could it be overamping the BEC of the speed control?

[coolhandcountry]

Did you try a battery pack on it? Some times they have problem with bec. I think it thremals about 180. Is the esc that warm do you know.

Yup, esc was warm. I just pulled it out and the shrinkwrap near the BEC (I think thats what that big square thing is for) is melted.

I'm thinking its one of 2 things.

1) I bought the wrong ESC - Maybe I need the Warrior 9920

2) gearing - maybe too tall - might try a 14t

[coolhandcountry]

Try it if you have one. You may want to try a lower one than that if you have one. If you melting the shrink it is getting right warm. Even a little hot. I would stick a 12 on it and try it first. I ran a 7xl for a little while. Draw of motor 95 amp. I had 18 cells as well. It survived but i got the best of it. Lasted about 6 weeks. Regular running as well. My brothe been running one for months on a 8L. I think the gearing is off some. The 3700 are heavier than the 3300.

Hi,

seems like I had the same problem with 9920 and a Wanderer 7L.
It probably thermals...

http://www.rc-monster.com/forum/show...=&threadid=764
Maybe you can find some answers there.

Update:

We switched to a 12t pinion gear. It ran pretty well and did not cut out as much or as early but it did thermal out. We then removed the BEC jumper and hooked up a 4 cell AA pack battery holder for the receiver. Now, it runs pretty fast and does not thermal out. This is with 103 degree outside temp, running on hot pavement, and several full speeed runs. The motor and ESC were pretty hot but did not melt any6thing this time. They cooled off pretty quickly after the run.

I think I'll order one of the motor heatsinks and maybe a 10t pinion to try also. I'm going to make a mount to get the esc higher up in the chassis for better airflow across it. Now I have to decide whether to go UBEC or reciver pack. I'll post up a seperate thread to ask opinions on that.

Chris

BTW - thanks Mike, that was very quick shipping. Ordered it Friday, got it yesterday (monday)

[coolhandcountry]

I say go with ubec. Less weight and no charging necessary. Just charge the batts for car and you ready. Just my opinion though. Not only that it is easier to mount. A ubec is not very big. just have to solder in the wires.

Here is the UBEC vs Receiver pack thread:

http://www.rc-monster.com/forum/show...&threadid=1037