In my experience, the biggest problem with the Optima's is that once they need a charge, they are a motha to get back up. I too own several, one in almost every car I own (which is a bunch). They are tough batteries. To charge them up properly, you must do it with a super beefy charger and on "slow". Even from 12.2 volts back up to 12.6 can take several days to do it properly. Sure on a fast charge the voltage will come up but it won't stay charged. I usually have to slow charge for about 2 hours, then fast charge for about 20 minutes to knock the gel(?) (they don't have plates) clean and then go bak to a 2 hour slow charge. The battery will stop taking a charge if one tries to charge them for a long period of time. I usually charge the battery up to a little over 13 volts and then let it sit overnight. If it stay close to 12.8 then you are done. If it drops to anything below 12.6, it needs a couple of more hours. Don't rely on the cars charging system to "bring up" an undercharged battery becasuse it won't. It will keep the car going just fine for many months but will never bring the battery back up to a proper static charge. Again, this is from experience dating back to about 1991. Results may vary but that is what I have learned and what works well for me.