9xl w/ 6S LiPo and BK2099

[Wingdawg]

Hello,
I am running an e-maxx with the following specs:

Motor 9xl
esc BK 2099
Batts 6 Series LiPo (22.2 volts) 4.4 Ah Rated for 10C discharge
Spur 66T
Pinion 17T
Weight 10lbs 4oz.

So far I have had 2 esc go up in smoke! The batts don't even get warm and run times are around 30 min. I don't think that I am over current.... I have a fan on it.... Any thoughts?

I am thinking of upgrading to a 36120.

Thanks
Michael