hi all...
i bought new lead acid battery 12 V. can any one tell me what is the best voltage value to charge it, and what about the time charging???
thank's...

 

You can charge it at 14V until the current tapers to very low, but it is OK to leave it at 14V for long periods of time.

 

Check out http://batteryuniversity.com/learn/article/do_and_dont_battery_table

 

This is the reference that did it for me.

http://www.engineersedge.com/battery/specific_gravity_battery.htm

That link to Battery University says, charge at 14.4 to 14.7 as a constant voltage, then float at 13.5V to 13.8V
The time to get a full charge depends on how much current the battery accepts and how many amp-hours it needs to arrive at "fully charged".

Bubbling is a sure sign the battery is "full". That's when you change to the float charge voltage.

On the other hand, I bought an AGM battery (absorbent glass mat) and the label on it convinced me to float it at 14.2V
If it has a label, follow the instructions.

 

For long term float charge, about 13.2V is good.

 

thank's to all, is there problem of use it to full discharge?

 

Yes. Lead acid batteries have shorter lifespan when deeply discharged.

I don't know the specifics but it comes down to, "How much sooner are you willing to buy another battery for the convenience of running it completely dead?"