The PTO on my tractor will not stay engaged. I was knocking down some small cedars with the rotary cutter while feeding hay this weekend and the PTO started disengaging. It will start up and run for maybe 5-10 seconds and then just cut off. It is a model that uses electronic control to engage and disengage the PTO. Someone told me that a weak battery might cause this (the battery on the tractor does need to be changed). Do you think it is the battery or some other electronic problem?