Ryobi riding mower not charging or moving

[anstosa]

I have a RY48130 riding mower. Charge light does not come up when plugged in. Control panel turns on with key and reports low battery. Headlights work but can't move or mow. Have removed and tested all 4 batteries at auto shop and they're fine. Any help narrowing down which component(s) are the problem so I can replace them?

 

[sgkent]

define tested batteries. Under a load? Also have you checked all the grounds for corrosion?

 

[anstosa]

define tested batteries. Under a load? Also have you checked all the grounds for corrosion?

Yeah tested with a professional battery tester at an autoshop that included load

Where are the grounds?