Can I add electrolyte or Distilled water to Batt?

A while back I bought a new battery of the kind that needs to be filled & then charged for the first time. Unfortunatly I got stuck at work and it got charged a few hours longer then intended & boiled over a bit. Now I'm wondering should I top it off with distilled or de-ionized water or electrolyte? Any thoughts?? Thanks.

Depends on how much fluid phase spilled-boiled out as boiled evaporation only does not carry off the sulfuric acid so distilled water is used to top off again. Likely fine to just top off with H2O. Best way to know both state of charge and strength of electrolytic acid bath is by specific gravity tester. If boiled too dry then crud can fall down and short plates so can't fully charge again, if so oh well new battery time.
Over charging ain't as damaging as letting it go dead flat. Old fashioned gas stations and auto parts and battery shops had acid solutions to top off, now days only new batteries in boxes. Its actually healthy to over charge and boil a battery now and then, its called cell equalization phase, well know in solar power battery banks, they also add a generator too because solar alone usually ain't up to the maintenance task. So have gotten a dead battery to charge away from home by dumping upside down to get sediments out then cloth filter acid back inside.

In my experience, a battery that you constantly have to add electrolyte may be going bad and needs replacing.

gtsun, your over charging battery flashes me back to the night I returned from avatar X-mass tree light tire fold up wheelie throw down onto R knee that left if crushed and just dangling by skin alone, as I found out the hard way when first stood up found I could put some weight on it - so lifted thigh to hobble to the ambulance to tape it up, but from knee down just stayed down till skin stretched enough to bungee cord like smack lower leg into the upper for white lightened pains that crumpled me up in a heap again. Crowd was roaring in delight on my first standing, then went silent as I let or a squeal going down again. Got laughed at by the Harley guys that I'd ridden there with, while trying to figure out how to start Combat w/o R leg. 20-30 min. later found straddle faced backwards could hop up and come down with L leg to start so could shut down for gas on way home in a bit of crush injury shock. Got home after miles and miles of creeping speed on hi beam so hooked up charger and limped 70 yd to house. After some hours late at night I thought i'd better shut it off so hobbled off house deck steps while are about 20 ft from raw woods and steep Mt side...

At that instant I heard a large animal leap 3x's back up the Mt side which at first I though was just another damn deer, but something didn't feel right, the leaps air air time and distance were about 1/3 more than I'd ever seen/heard a deer do and the landings had more a thud like impact sound than light footed deer ... hm, a fear quiver went through me... so turned back inside and 30 second later opened back door to just shut off breaker to the shed... no sooner that i'd gotten off 3 steps to ground the big animal had moved back to within 30 ft of house I heard brush explode in parting and thumps of 3 landing impacts that sounded like 20 ft leaps each, to have the hair on neck and tops of big toes stand up involuntary like never experienced before as Mt Lion let out 3 loud screams that sounded like a woman's toes nails being pulled out! I hit breaker and got some shearing pains getting back inside with door shut tight.

It took 2+ years before I would venture to shed w/o packing a .357 or .45 not so much to shoot it but scare it off of me and last resort kill it. I like the danger of wild beast out here, don't want to remove them just not be a meal to em. I've since cleared the under growth and the amount of chickens and ducks tempting big cats is way reduced. Patients near by have told me of puppies being taken out barns the big cats broke into. ugh.