Could you assist me in the purchase of a new battery for my electric fence please. I have the model SP-83-B solar electric fence . The batttery will not hold a charge. The unit will work with the sun shining on it ,barely.I mean you can hear it clicking as if it is working. The battery has this on top X11/96 model X6M12D 6 volt with low impedance.The solar collector is a Uni-Solar model # RM 603 made by United Solar Systems Corp serial #033673. I need your help to acquire another battery or to get a different model. Thank you ,Aubrey