Charging Optima Batteries

Left a switch on and drained the Optima battery in my XJS completely dead. Charger maxes out at 8 amps, but the battery does not seem to be charging. I read somewhere that Optima batteries can be hard to charge. Anyone have any experience charging one that can share a few secrets?

Optimas must be slow charged. Use a digital charger ( like battery tender ). They start charging at about 3 amps and go down to a 1.25 amp maintenance charge and automatically shut-down and start by the chargers system. I use a four bank charger and have all my boat and RV batteries on continuous charge (low amp) These chargers on an Optima can take 3 days to charge but will have it 100% afterwards. Not a solution to fast charge by no means. Optima Batterys are fiberglass celled batteries and will not charge by an alternator. I have my 03 Cooper S, I use occasionally for track an some driving wired so I plug in when I get in garage and unplug to use ( hard wired ) instructions are in box. I got mine for half price thru Amazon, but Advance, O'Reilly's, Autozone carry the single bank mini charger for $35-$45. Hope this helps.

You can use this method as well:

Good to know, never knew of the parallel charging. Have the AGM chargers, but now with time and extra batteries can parallel the charge. Thanks to Rick for posting.

That was a great!!! video. Got things charged. Thanks to all for the help

Michael J. said:

That was a great!!! video. Got things charged. Thanks to all for the help

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Glad it worked for you. I had the same problem with an Optima.