12v car battery

11.3 sounds pretty low. There's ample discussion of lead-acid maintenance on the web. A start would be:

http://en.wikipedia.org/wiki/Float_voltage

DON'T forget to maintain electrolyte levels! I generally just return the floaties to a charger about once a month. I would check the open voltage of the battery a few hours after the charge cycle has completed, and re-charge if the open voltage drops more than .5 V.

Mark

I don't know what kind of application you are using a car / auto battery but mine is just using them just to have them. I have a few of them or really a lot of them and I use an Iota charger / converter with a plug in pendant to vary the state of charge to prevent stratification and keep it fully charged. Some of my 12 volt SLI batteries are 1997 date codes and can still crank over a car or generator. It even tests good on Schumacher Speed tester Battery analyzer SEC-100. I have a battery maintainer for my Honda gas scooter an Elite 125 and it too is bad for maintaining 12 volt batteries. My choke isn't working properly and not enough juice in little battery to get it started like it was summer time. one try and it died. So it is on my Iota till spring time. 13.2 is good for not cooking cells but 13.5 aint too bad either. Anything more than 14.3 and it will boil dry in short order.
I did take mine apart and it has an adjustment but I will do that another day. Just not worth the time right now for me to fool with. There are lots of cheaper battery maintainers other than using expensive regulated converters. BTW Iota is probably the most common charger converter for use on most EV's to power Lights and stuff.

what is the voltage I should keep a car battery on storage,I have a battery maintainer that has 5 output wires and its pushing 11.0v to 11.3v it brought my 3 batteries down too -

ALL CAR BATTERIES including wet, flooded, dry charged, Absorbed Glass Matt and Valve Regulated Lead Acid must be at least 13.2 volts at its lowest sitting voltage. 13.5 is actually lowest setting for any real length of time. Anything above 14.32 volts and gassing will occur. An automotive battery can not be used as DEEP discharge battery but if you want it just for "emergency" situation it is OK but a dozen charge discharge cycles and it is toast. A good Gel Cell can be charged maybe hundreds of times.
Set your float charger to 13.5 to 13.7 volts. Now that is for Lead types not the new Lithium Iron Ittrium Phosphate cells / batteries.