Im not sure it's a battery problem now (it could be) I wonder if a few of the Tetra's pull just a bit more power than others?Based on your post using your Anker battery, I procured a battery providing 4.8 amps. I could stress out my Tetra no problems. With my limited testing (I'm very busy working also, work first play later) I have found different configurations, with my batteries (15,000's) show different results.
I really wish I had a Port Pilot,
I guess that's my next purchase.
Then maybe I could maybe pin it down.
shadowmmm, did you get a battery replacement? If so did it solve your problem?