15 km range on GTX AT

My new Evolve Bamboo GTX AT managed 15 kms before shifting to ECO mode.
I'm about 160 lbs (72 KG).
I rode it in FAST mode but only half throttle. A few stops and starts, a little bit of carving but not extreme. All wheels turn smoothly and freely.
I naively thought that the AT tyres would have come at the recommended pressure of 40 to 50 lbs psi. After my ride I saw that they were only 25 psi.
Would that have been enough to halve the advertised range?

 

I was riding my Carbon GT today, and it cut on me at my 5th mile. This was only ride number 3. Not too sure what happened.

 

Pumped the tyres to 55PSI, and did a 24 kilometer return trip in ECO mode with still some power left in the battery. Admittedly the ride was harder, but I'm pleased to have made the distance.

 

I'm 220pound, and after a year (close to 70 charges) I barely get 8km in fast mode, the battery sag is crazy bad on my AT wheel. they say 25km, but most roads are not flat surface making it unusable after ~10km to 13km. I'm on a GT Bamboo

 

After going through 2 evolve batteries. (Shame on me) on my carbon gt. I upgraded to LHB 30q 18650.

I ride gt mode on gravel trails AT setup. 50psi. I get no more than 20km on a charge. After 15km I take it really easy. The route I take is pretty flat terrain but all gravel.

I'm waiting to use my second crapped out evolve battery for new better longer lasting batteries. Tesla 18650's?

LG h2 always sold out but ive read they are pretty similar to the 30q Samsung's.

I WANT MORE RANGE!!!!!!!!!! SUGGESTIONS aside from riding like a 5 year old girl?