Give the battery a "shock". Connect (+) with (+) and (-) with (-) on a polling source larger than battery (up to 12V) for at least 1 min. I did it with a 12V one and it started charging again.
Give the battery a "shock". Connect (+) with (+) and (-) with (-) on a polling source larger than battery (up to 12V) for at least 1 min. I did it with a 12V one and it started charging again.