THE sCHUMACHER BATTERY CHARGER IS THE 3rd ONE I PURCHASED AND I REALLY DO LIKE THEM BECAUSE I PUT THEM ON THREE CLASSICS CARS I HAVE.I SOME TIMES DO NOT START THEM FOR ATE LEAST 3 TO 5 MONTHS;BUT  WHEN I DO RUN THEM I HAVE NO PROBLEM STARTING THEM UP.THESE CHARGERS ARE VERY GOOD AND DEPENDABLE.I WOULS HAVE MORE IF I NEEDED THEM.