5/8 ton,
This is a little off-topic, but this is pertinent to Optima batteries (especially the 6v). When this battery is drained very low, it often does not recharge by following normal recharge procedures (using normal, older, chargers). Many owners and battery dealers attribute this inability-to-recharge as a defect in the battery (they think the Optima battery is dead - many say this is due to now being made in Mexico).
Here are recharge procedures for Optima AGM batteries. Option #1 and #2 have worked for me, even when shops and dealers have said my Optimas are dead (thus, Option #3 has been unreliable for me).
Last summer, Option #2 recuperated an 8-year-old Optima 6v that would not take a charge (it had been completely discharged due to a slow-drain-short over a 3-week period). Options #1 and #3 were fruitless.
If you have a 6v battery, obviously you adjust the voltage in the procedure by 1/2.
