so by mistake, i filled my deep cycle battery with distilled water BEFORE charging.. i did not want it to overflow while charging so i took the vent caps off while charging my battery.. now my battery will not charge to full capacity..  does anyone know what happened or can help me fix it?  it is not the charger because i charged another battery with it and it worked fine.  please help if you can..

New one on me. I don't see a reason for it not charging up. Give us some details on your charger. How do you know it is not charging to full capacity?

How old is the battery?  

Was the electrolyte level below the plates before you added the water?

I just got a Schumaker fully automatic charger that is made for deep cycle batteries.

When a battery is fully charged, it will turn off.  A continuous trickle charge can damage a deep cycle battery.

In the trouble shooting section, under charger will not turn off:  Battery has problem and will not take full charge.

Solution:  Have battery checked.

You filled the battery before charging?

Just how low had the water level gotten?

electrolyte levels were ok before i charged.. a little low but nothing was exposed.. i just totally blanked and filled it before charging.. my charger turns off when it is fully charged and a green light will go on saying the battery is completely charged..  the green light hasnt come on for a couple days now and the tick says it is charging at 0-1 amp...  my battery is 3 months old!  

Seems odd to me that a battery at three months needed to have water added.

Is the battery connected to anything other than the charger?  If it is in your boat and connected to the trolling motor or other electronics, it's possible there is a draw on the battery.

If that's the case, the charger will never "see" the battery as being fully charged.

Let's back up a moment.  Pull the battery out of the boat and get it by itself.  NOW try charging it.  If it still doesn't charge, then it is indeed your battery. If it charges, then you have a wiring problem (a low voltage draw, short, or something along those lines).