参考这个视频。当心电池内的酸液! 保护好眼睛，皮肤。用蒸馏水，需要一个充电器（参考ebay 链接）...

https://www.youtube.com/watch?v=lZEzFP0RwOE  

ebay 充电器： https://www.ebay.com/itm/Car-Battery-Charger-12V-Portable-Auto-Trickle-Maintainer-Boat-Motorcycle-RV/273431216063?epid=22023152670&hash=item3fa9c53fbf:g:xm4AAOSwvWtbhZ6E:rk:41:pf:0

Overnight to charge。