I have an Interstate deep cycle marine/RV battery that doesn't seem to hold a charge. There are a few numbers on the top of the battery - SRM-27 600CCA 750MCA.<br /><br />It doesn't seem to want to hold a charge and takes a really long time to charge.<br /><br />Anything I can do to overcome this problem?<br /><br />I don't know if the cells are low, call me crazy for not wanting to mess around with acid, but I heard you have to add distilled water to the cells when they are low - where can you get it?
<br /><br />Heres some info:<br /><br />- Battery should be on a level surface when you are checking it.<br /><br />- Wear eye protection!!!<br /><br />- That battery has two caps; there are 3 fill holes under each cap. Each hole is for one of the six cells that make up the battery. Each cap has a slot, usually low on the broad side of the cap. Slide a screwdriver into that hole/slot, and carefully pry the cap off. If you can get a good grip on the cap you may be able to pry it off with just your fingers. Any of the drippy, watery stuff under it is battery acid, a mild sulfuric acid. It wont kill you but it will be more than happy to eat away at your favorite jeans or canvas sneakers.<br /><br />- This is a good time to wipe around the fill holes, but be careful not to allow anything to fall into the battery. It would only be contamination in your battery. I use paper towels to wipe around the fill holes then toss them.<br /><br />- When you look down into any hole, you should see liquid. If you see something that looks like the edge of a plate or squiggly metal, the cell is low on soup. Each fill hole is a tube that extends into the cells. There are one or two slits on the sides of the tube. Lower down on the inside of the tube is a raised ring molded into the plastic, all the way around. That ring is the fill level. Anything below that, add water. if there is soup in the fill tube and you dont see the ring, youre ok. As was mentioned above, only distilled water goes in there when you are adding water.<br /><br />- If you need to add water, pour some into a smaller, clean container. I use a yogurt cup. Then, using your pipette, (that would be a clean turkey baster for normal folk) slowly add water to the cell until the soup comes up to that ring at the bottom of the fill hole. A little over or under, doesnt matter.<br /><br />- When you have all the cells filled to the proper level, carefully press the caps back into place. DO NOT shake your battery to mix it up in there. That happens automatically when you are charging the battery.<br />