Used my Z122R to cut grass two weeks ago. I had to use a jump box to get it started as it’s been sitting since September, but it fired right up and did fine. Went to use it yesterday and nothing when I turned the key. Hooked up jump box and it fire right off. When I went to unclip from jumbos, it started dying. I clip it back and it runs fine, I unclip and nothing. I increased the throttle and was able to unhook the jumpbox and drive it out of shed. 3-5 minutes of sitting and it starts the same thing at higher throttle. Hook jumbos up and it smooths out. Went to full throttle and was able to remove jump box,but couldn’t get blades to engage and it started acting like it was being choked down. I’m thinking bad battery…any other thoughts?