tiger
+1y
If a battery is drained past 80% capacity, espically if it is drained all the way, it won't charge properly, or at all. So even though it was on charge all nite, it simply wasn't taking a charge. You can rescue a 'over-discharged' battery, but it takes time and more professional equipment, no just some ol' charger picked up at wal-mart. Oh, and you need a hydrometer and some other special tools and equipment. I used to be a forklift battery technician, so I'm a re-friggin-genious.
But I'm with ol' James, sounds like a parasitic power drain somewhere...somebody did something and didn't do it right, causing a drain on the battery....or a factory component has failed, maybe a voltage regulator or something.