Help with 100% to 7% battery

My board has extreme voltage sag. Is this a problem with the battery cells or bms? If it's the cells, I want to have a custom battery pack made. Evolve support wants me to send the board to them to diagnose, but that's expensive and they may say I need a new battery. I'm outside warranty on this board. I recorded a video of what I'm talking about.

 

Looks like that was a serious hill?

 

any further news on you situation jimmy?

 

I sent the video to evolve support. They are saying the voltage will drop based on weight, wheel size, temperature, etc. I'm aware of what causes voltage sag. The issue is the drastic change and degree it changes. Usually it will drop to a lower number and stay there, maybe dropping by a percentage or two as I continue up hill. Now it's just going from 100 to 1 percent at a constant rate. I just want to know what's causing this so I can make the best fix. If like to have a custom battery pack made, but that would not be wise if it's a bms problem.

 

so how much distance do you get in total from the board?

 

I went about 10 miles with abec 97's on a group ride where everyone else had bikes and went slow. I was going about 10-15 mph most the time. Usually I ride pretty aggressive if I'm on the street, and I like to full throttle up hills. I'm starting to think I put too many cycles through the battery and it's giving out (~ 200 full charges)

 

i get around 24k avg, all terrain wheels, on grass and street, with a few low hills to ride up, i.e. 300m