Watering Your Lead Acid Battery: The Basics

Posted by Crown Battery on Jul 14, 2017 9:02:55 AM

Just like how you can't go without water, neither can your battery. Watering your lead acid battery is an essential maintenance step that can't be skipped. It  keeps your battery safe for use and in optimal condition. Not watering your lead acid battery at the right time can lead to serious damage, but knowing when is the right time to water your battery isn't always easy. Follow these steps on how to water your lead acid battery.


Why batteries need to be watered 

Lead acid batteries consist of flat lead plates immersed in a pool of electrolyte. The electrolyte consists of water and sulfuric acid. The size of the battery plates and amount of electrolyte determines the amount of charge lead acid batteries can store or how many hours of use. Water is key part of how a lead battery functions.

Additionally, during the recharging process as electricity flows through the water portion of the electrolyte,  water is converted into its original elements, hydrogen and oxygen. These gasses are very flammable and the reason your RV or marine batteries must be vented outside. Gassing causes water loss, which is why lead acid batteries need to have water added periodically. Low maintenance batteries like AGM batteries, are the exception because they have the ability to compensate for water loss.

Overwatering and under watering can both damage your battery. To keep your lead battery running at peak levels, follow these watering guidelines.


First – Start with Safety

To get started, make sure to wear personal protection equipment such as protective eyewear and gloves when working on batteries.  Also, it is very important to understand that some batteries require regular watering service – while other batteries deliver maintenance-free operation. 

Make sure to look for information on the battery labeling that indicate whether the battery can be opened and serviced.  Depending upon the battery type you are using, the warning labels on your battery should direct you to “DO NOT OPEN” the battery, or “KEEP VENT CAPS TIGHT FOLLOWING WATERING SERVICE.”  Make sure to follow the warning label instructions.


How to water a battery

While a battery should only be filled after it is completely charged, you should also check the water level before charging to make sure there is just enough water to cover any exposed plates. After charging, add enough water to bring the level to the bottom of the vent, about ¾ below the top of the cell. 

It’s important to note that battery owners should never add sulfuric acid to their battery.  During normal operation batteries will only consume water – and not sulfuric acid.  When your battery’s electrolyte is observed to be low, filling the battery with water will keep the battery healthy and safe for use. 


Don’t Over Water

While a battery is charging, the density of the electrolyte solution will increase. If too much water was added before charging, the electrolyte levels will expand and cause the battery to overflow and damage the battery. Additionally, excessive watering of a battery can result in additional dilution of the electrolyte, resulting in reduced battery performance.


When should you water a battery

How often you add water to your battery will depend on how often you use it. A golf cart battery that is only used on the weekends may only require once a month watering. A forklift used all day, every day, may need to have its battery watered every week. When the weather is hot, this will increase the need for watering. It’s important to check your battery’s fluid level regularly – and the best practice is to do so after the battery is finished charging.


What type of water should be used

Avoid using tap water. When filling your battery, regular tap water isn’t going to cut it. Tap water contains minerals that are harmful to batteries, even if added in small amounts. This is particularly true for water softened by water softeners which contain chlorides. To be safe, distilled water is your best bet and is a much smaller investment than a new battery.

Remember, that water will sit on top of the acid solution in your battery until it is mixed by the bubbling produced by charging. If you are taking hydrometer readings of the electrolyte, it’s best to take them after charging is complete.

Don’t let your battery get dehydrated. Keep it watered during hot months and all year long.


Tags: Battery Maintenance