Yeah, bubbles rising from a battery are hydrogen. Hydrogen is an explosive gas. You don't want to mess with that. You certainly don't want to look down a cell full of hydrogen gas and sulfuric acid while an ignition source is handy, like, say, an ignition system or exhaust or smoke or static electricity or.... The proper way to test for a dead cell is to use a hydrometer, which will tell you the specific gravity of the cell. Find one that is low, that cell is bad. However, with today's batteries, hydrometers are really a thing of the past. You can't get to the cells a lot of the time or it's difficult to and there are other tests for the whole battery, such as a load test that won't ruin your blue jeans in the process. A $10 Wal*Mart digital multi-meter will tell you more info about your charging system's condition than any other $10 you can spend.

 

Thanks Dr Hess, Now I understand why my battery blew up. Hydrogen.

Ever since my buddy told me what happened to him and his eyesight. I am very careful handling batteries. Eye glasses, and keeping back when the posibility ofsparks near the battery might happen are a good safety tip. Especiallywhen near a possible bomb.

 

A good 12 volt battery should read somewhere between 12 and 13 volts with no load. The charging system should be putting around 14 volts to the battery. Most newer batteries are sealed or sealed gel type. In my experience those puppies last a lot longer than the water/acid types. Yeah, I had an oldbattery blow when I hit the starter on an old Toyota truck. Buckled the hood a little and caused a hellova mess. Sediment built up in the bottom of the battery and created a dead short across the plates.