I replaced batt. 9/21, ignored it for 19 mo.s. Bought a Romondes & de-sulfated first thing. I put it on a monthly charge program for 12 mo.s so far, Everything good for 2 years & 7 mo.s (took about .5 to 1 hr. to charge) THEN a week ago it charged to 95% & then refused to go to 100% charge even after another 1 & 1/2 hr. add. charge. What I'm thinking is NOW would be the proper time to de-sulfate. OPINIONS ? Thanks .