If you are looking for a large, external battery which can power a Microsoft Surface Book, we have good news for you. After hours of searching Amazon and Google we came across the Crave PowerPack CRVPP101 50000 mAh,Dual USB and Dual Laptop Ports Ultra-High Density Portable Power Bank.
(Exact product names used for your information).
We also looked at the MAXOAK 50000mAh 5/12/20v Portable Charger External Battery Power Bank for Laptop & Notebook–Most of Sony Dell Hp Toshiba Samsung Lenovo Acer IBM NEC Mobile,Tablet(not for Apple Laptop) but it was heavier so we decided against it.
We then needed an adapter from the battery to the laptop. Amazon was unclear as to what adapter we needed so we purchased two. One was suggested by the ecommerce giant but mentioned various Surface models but not the Surface Book. We searched on our own for another adapter, hoping it would not only fit and work. It did. It is the BatPower ES4 Charging Cable for Surface Laptop Surface Book 2 / Book Surface Pro 4 / Pro 3, work with BatPower ProE 2 ES15 ES10 ES9 ES7 ES6 S90 S1798 and more (Connector 5.5×2.5mm to Surface).
We haven’t had a chance to do an extensive test but we plugged the first-generation Core i5 Surface Book into the battery and it works. When we use the other adapter, the laptop says “Plugged in, not charging.” We also found the 20V port in the battery didn’t work but the 12V did.
We hope this helps and you won’t need to do all the research we did. One last point, we intentionally did not purchase a battery with an AC port because of the potential power loss which takes place when converting from direct to alternating and back to direct current.
Also a disclosure, we may receive a commission if you purchase any of these products from Amazon.