620I i think isnt charging

I have a 620 I that I added a winch to and haven't used it much till I built a plow for it

the other day I went and cut wood with it then later that afternoon my wife wanted to take it out to plow snow and had the lights on and was usining the winch and parked it in front of the house and when I went to put it in it wouldn't hardly roll over so I boosted it and put it back in the shop. and while it was running I put the charger on it it has a battery tester built it and says the battery is good but not charging but I didn't know if it would pick up the charging system on something this small so I left it to charge for 2 hours on 2 amp went out the next day and the snow was blowing so I plowed a path from the house to the barn and used the winch maybe like 4 times (no lights) and the engine was wanting to die the battery was so low so put it in and charged it with the charger again

so im just not sure where to start with it is the winch just to much for the charging system? is the charging system or something in the system gone bad? could I have jammed some brush up under it cutting wood and ripped a wire out? cause I have never had a problem with it over the past year I have owned it with not starting

any help would be great thanks