I installed an Antigravity lithium battery which has been working great until I left the parking lights on by accident last night. Completely drained the battery. Normally I put a bulk charger on the lead acid unit and in short order it's good. Been charging this battery since 11am with a Battery Tender charger and it's still completely dead. According to the description of the Tender it can bulk charge if it needs to but after 8 hours I would have expected at least the courtesy light working. Should I be charging it with a different charger? The Battery Tender functions as a trickle charger as well but I expected it to work faster.