Hello, I have an SVD11215CAB Sony Laptop, at first Battery #1 and #2 were working fine, but after I installed Windows 10, upgrading from windows 8 that it originaly had, battery #2 stopped working, making the laptop a 4 hour battery life instead of the old 8 hours+, so it frustrated me, when I rolled back my windows upgrade to windows 8.1, battery #2 is still not present, and no matter what I do, nothing worked, I searched for solutions everywhere, nothing worked. Vaio care doesnt work like before (no updates no nothing), updates dont show like before, the official Sony website that shows the laptop downloads is not updated, I tried my best, how can I fix this? I know there are lots of posts about this but nothing helped....thank you. 
Basically:
1. When I bought it with Windows 8, I had full battery capabilities with at least 8 hours battery life with Battery #1 and #2 Working.
2. When upgraded from Windows 8 to 10, my battery #2 stopped working and it became 4 hours battery life at the most, and no good support from Sony on Windows 10.
3. Rolling Back to Windows 8.1 still did not return battery #2 to its original status, it still is "Battery #2: Not Present" with again, 4 hours battery life.
Laptop: Sony VAIO Duo 13 (SVD11215CA*B)
Specs:
Processor- Intel(R) Core(TM) i5-331U CPU @ 1.70GHz 1.70 GHz
RAM- 4.00GB
System type- 64-bit Operating System x64-based processor
Pen and Touch- Pen and FUll Windows Touch Support with 10 Touch Points
Operating System- Windows 8.1 Single Language (Was W10, rolled back to 8.1, originaly W8)
VAIO Care Version- 8.4.5.06026