One of the best products anyone can buy for their coach is the ProFill automatic battery watering system. Once installed (replace original caps and connect hose) all you do is drop a squeeze bulb into a bottle of distilled water and squeeze several times. The batteries will automatically fill to the correct level.
Many will balk at the price, about $150.00, but the main cause of batteries going bad is lack of care. Even if your batteries are easily accessed, it's still a pain and the job is often put off for another day. The battery watering system literally takes in five minutes and you never touch the batteries.