whats the best way to get them to take a charge, 3 out of 4 are dead and cant get them to stay charged even when theyre disconnected from the cables. 3 years old.

I was told you can take a set of jumper cables to a standard battery & put the charger on the standard battery. That will charge the optima slow like a trickle charger. Randy

Exactly. Most battery chargers won't charge anything below 10.5 volts. You can connect a battery as stated or get an oldschool "dumb charger" that will charge no matter what

Are you sure you don't need new batteries? If they are good they should be able to sit on the shelf for months and still be at 12.6v.

They probably got drained down. And yes, you will need to manually charge them, as the smart / automatic chargers work that way so as not to burst a cell if it is shorted. Optimas are extremely resilient, even with a dead cell and 10.8 volts it cranked my old car engine over like there wasn't even a problem. Ran it like that in the boat for about 2 months before I replaced it.

If your saying you FULLY charge them,,,,,then they discharge themselves disconnected from any draw ,,,, they are junk.

Agreed. OK, now that I've reread them I would say they are junk. That is assuming they are above 12.6 volts (should really be over 13 right off the charger) and then they drop below 12.6 volts in an hour day week. A good battery will maintain over 12.6 volts for quite a while unhooked.

Which optimas are they?

I've got a couple blue tops that have always been lazy, they are the dual starting/deep cycle. They are probably 6 years old at this point, but never seemed to really have the balls to turn the motor over.

I added a red top about 5 years ago strictly for starting, even used it in my truck for a year or so while the boat was torn apart (for 2 years) and that one is still going strong.

They were all ran down from the winter this spring, I charged them at 10 amps for a couple of hours, the red is back to normal, one of the blue's is lazy again, I haven't swapped it out for the other one yet. Give them a good cooking at 10 amps, provided they are above 10.5 volts when you start and see what happens. If they are below 10.5 volts you have to fake your charger using a regular battery, as has been mentioned.

#1 - don't let them run down.
#2 - always fully charge batteries after every use and store charged. If this means charging once over winter lay up do it.

Any battery can be ruined by storing at less than full charge.


CTEK 7002 is one of the best for accurate charging and does have a special desulfate mode that can revive/extend the life of weak batteries. (nothing will help if battery has a bad cell)
http://www.amazon.com/CTEK-Multi-700...attery+charger

Here is a good article on some methods to re-charge "dead" batteries. I had one that I brought back to life this way. I also had another that this did not work on.


http://www.optimabatteries.com/us/en...ip-articles/#3