Your drop in voltage is totally abnormal and I agree you need to get it checked out ASAP, not only for warranty reasons but to make sure you don't get stranded, and/or do damage to the pack.
As to the second part (not to thread jack you!), my bike is 3 years old with 36K miles on it and I've noticed the "jump to zero charge" phenomenon is happening at higher levels, even when I don't make sudden demands of current.
Early on, it never happened: the gauge wouldl go down continuously until I hit zero percent SOC. I ran it down that far only twice, as I try to manage my range carefully.
Then, when the SOC had reached 10% or so, if I made a heavy current demand by twisting the throttle, it would jump to 0% and flash the charge battery warning, as has been written about on this forum.
Next, the 10% level gradually evolved into 20% for the current demand to trigger the jump to zero.
Last week I was at 28%, doing a constant 60 mph at 5000 rpm on the freeway and it jumped to 0%. I was about 3 miles from home and about 1/2 mile from my exit. I very carefully applied smooth throttle and proceeded at the lowest speeds I could safely run and made it home, still showing 0%.
I plugged in the charger and the SOC showed 7%.
I would like to know:
1) Is this a degradation of information monitoring only?
2) Is this a degradation of battery performance?
3) What are possible causes and possible remedies?
Not knowing my REAL state of charge at around 30% makes for lots of white knuckling!
