现在的车用12.6v电池一般是不需要加水的。有全封闭的，也有带密封很好的盖子的。后者可以看水位或加水。

Once upon a time all batteries required water to be added. In fact, checking the water level was a standard procedure during an oil change service. Today, most batteries are maintenance free. Some batteries are sealed and some have removable caps. During the life of the battery, most people will never add water. If your batteries have removable caps, there’s certainly no harm in removing them and adding water (distilled only) if the fluid level is low. If you are adding water periodically, suspect that the charging system is overcharging the battery and “boiling” off the water, which needs to be fixed.