Battery and Shifting ???? weird bike reactions

I really cant figure this one
I have a 98trx450es and sometimes when i turn the key on i have to push the gear buttons up and down a couple times to get it in N, but it always finish up working, but sometimes when in 1 when i push the DOWN buton to go in N
it shows 2....Also i noticed that the more i have to play with the buttons, you can clearly ear the gears engaging but has you go you can feel its running out of juice (with the engine not running), but when in N it seems to crank and starts perfectly and the lights are bright . Last night i gave it a good spin , went from 1 to 5 but got jamed in 5, turned the engine off and on again, and then when pushing the button DOWN to get back in N you could not ear nothing (no gear engaging noise) , it was just like playing with the buttons on a bike with the key off. Finnaly i waited 2 or 3 minutes ,turn it back on and it worked...??? until i redid a stretch from 1 to 5 downshift from 5 to 1 and got jamed in 1 this time.Shut the engine off and on again and it went in N, did crank up good and was shifting allright from 1 to 5.........
Does anyone have any idea at all any suggestion would be very appreciated
Thank you