Lead Acid Battery Maintenance

The key to happy and healthy batteries is understanding what you need to do to maintain them.  The pages below will help become a battery maintenance ninja.

Measuring State of Charge

If you want to know How to Check a Battery with a Hydrometer this is where you will want to go. It includes a step by step procedure and a link to a decent video.

Now if you have a sealed lead acid battery (SLA), this procedure will not work for you. You will have to test using a voltmeter.
The basic concepts behind using a hydrometer for lead acid battery state of charge measurements. If you want to get a sense for the capabilities and limitations of this test, this is the article to read.
The specific gravity of electrolyte changes with temperature. This Battery Hydrometer Temperature Correction article will help you to make that correction. It even includes a printable PDF.
The fundamental concepts with respect tomeasuring state of charge using a voltmeter . While measuring SOC using a meter is easy, knowing how to interpret the results is necessary to making a good decision about your batteries.
Battery Voltmeter SOC Temperature Correction is a MUST if you wish to make a state of charge measurement that approaches any sort of accuracy in cold or hot weather.