Hi guys, I have a bank of 4 costco 6v batteries in my boat. I have had them for a year now and the water level still looks good but I was wondering if anyone knows specifically how high the water should be in them????

damn heavy batteries for a boat

I don’t know what the exact level should be, but the rule of thumb I always went by was to have
the water level well above the plates and not so full that the level is at the top of the fill.
If water is to low the plates will get sulfated, and if the level is to high when on charge and start to out gas they will spit out water instead of just gassing.

In my RV I switched to 6v batt’s long ago and always had trouble getting to all of them to keep the water level correct.
I had trouble getting to the back batt’s and seeing the water level.

I found this product that works great, the Pro fill by Flow-rite. You install them in place of your caps and pump in distilled water
and when water is at the correct level the valve closes and stops filling.

Great product, I pump in water every 6 to 8 weeks in the winter, and every 3- 4 weeks in the summer.
You can get a kit from camping world or on line, they make kits for 2-4, 12v and 2-4-6, 6v.
Low water is the major cause of batt failure, after putting on the pro fill my last set of batt’s lasted 5 years.

http://www.flow-rite.com/battery-watering/pro-fill-rv
http://www.campingworld.com/shopping/item/...ng-system/27035
http://www.rvpowersupply.com/pro_fill.htm

If you look down into the cell there''ll be a piece of plastic sleeve that starts from the top cap and goes into the cell area.

Fill with water until it reaches the top of the plastic sleeve.

If you buy a battery fill bottle(with the push down actuator), it's made to stop filling at the precise fill point.

You want to refill the batteries AFTER charging.

What is the reason for this?

If you fill while discharged, it will overflow after being charged...

During charging it causing "gassing" which causes some water loss. This is why most batter connections corrode. They're exposed to the gassing from the battery.

You also want to wipe down the tops of the batteries after charging to clean up any water/acid that has gassed off.

I second BPRacings motion "Damn heavy batteries for a boat"

They are for the stereo! (and add about 300lbs of ballast for a bigger wake)

PS....thanks for the replies guys. I have never added any water to them as they seem to be just fine still. Kinda surprised they are still filled since it gets pretty hot here over the summer.