Download the ESC data log might help for debugging...

Regards,

Sean

Motor Bearing?
 I had exactly what you describe happen to me (Apart from I was inverted at the time). No warning the motor just stopped. When I checked everything immediately after switching off the motor was quite stiff although after I got home everything seemed normal. I decided it was a bearing so replaced them and no problems since. I think what happened was the bearing overheated and tightened up. The ESC kept pushing more amps into the motor to satisfy the governor until the ESC shutdown (I run on the very sensitive setting).

Might not be your problem but worth a look as bearings are only cheap.

TTFN
John.

Ron, were you doing 3 2 minute flights on the same battery? that could be putting you pretty close on capacity,,
It could be heat related, it could even be the ESC hitting the overheat cuttoff, which after it cooled it would work fine,,

What were your Speed control settings? Particularly the Low voltage cutoff setting and are you set for hard or soft cut off? How old are the batteries? Do you store them charged, discharged or in storage mode?
William

Ron,
 I don't see anything that would cause what you are seeing other than you possibly losing track of time and hitting the 2 minute mark without realizing it, but i bet I'm wrong there too. I feel your motor and battery are a bit oversized for that plane so if anything you should be more than fine there. I leave my current limiting on normal but I fly on blacktop 99% of the time. The soft cut off is what I use and I feel all cl fliers should use. There is NO need for a hard cut off in CL It will only lead to crashed planes if it kicks in. In RC uses you want a hard cutoff so if you hit LVC you have power to the servos so you can bring your plane down safely. I know some people will disagree with me on this next item, but Why do we as CL fliers need 3.2V as our LVC? Why not a custom 3 or 2.8 or even 2.5? I know very well that those settings can ruin a battery but a good battery should never ever hit those numbers, and I would rather have my motor sag in power and not shut off at a critical time and save my plane rather than crash my plane and probably lose both the plane and battery. I think that most people would rather keep their plane and lose just the battery. That would also provide some protection against the "oops I forgot that I used that battery already" line. I hope that this helps you. I'm sorry I couldn't pinpoint it down further. You are doing everything right as far as I can tell.
William

same thing happened to me a couple weeks ago - turns out a wire had become disconnected from the timer board......

Ron,
It sounds as though you have things pretty well sorted out. I'd imagine  quarters in your battery , ESC, Timer compartment are  pretty tight with the Vector. I  say that because I currently fly its bigger( read heavier , more  draggy ) brother,  the SV-11 and use an E-25 w a 4S 3900 pack. After 5 min & 30sec, I consume 2350-2418 maH, so there's plenty left over.

I think Will D. hit it right with your battery size being large. Being as you have a good # of flights on them, pick up  just one 4S 2700 or at most, one  4S 3300 pack to allow more space for air to circulate. Now, that might cause some cg issues, but you can improvise to regain the lost nose weight. I put stick on weights on  one  battery mount with a  4S 2700 maH to make it the equivalent weight of the 3900 packs. I adjust my timer down to 4 min. and 45 sec. and the big SV-11 lands with a nice safety margin of maH.
You'd be surprised how much more air will circulate that compartment when you don't have it filled as much on all sides.

Some guys will say- you can't complete a pattern in 4 min and 45 sec, but I skip some in between laps and steal a few from the initial level or inverted and it's a practice battery for the SV-11. My hunch is that a 4S 2700 should give you a 5min 30 sec flight and land with a good margin of safety.