Reprinted from the ACJ - January, 2002
It's January and if you live top side of the Mason-Dixon line you may be reading this while waiting for the goober in the back shop to install a battery in your cold, dead car. We take batteries for granted. At least most of the time. Last car in the mall parking lot. Turn the key, and get tat-tat-tat-tat. Turn on the cell phone, get the 'low bat' beep and it turns off. It's times like these we wish we would have pledged more money during the Ni-Cad telethon. Most of us consider ourselves to be somewhat handy under the hood of a car. Contrary to what the boss might say, we can still change our own car battery, right? As with many simple tasks, and all of these articles, there is a degree of danger lurking. Electrical shock, Lead, Sulfuric Acid, corroded hold-down brackets, all poised to cause trouble.
With any power source the major risk is the sudden release of energy in a direction we don't intend. This is most obvious when connecting the car battery cables; backwards. Power flows out of the battery in a spark that arcs like the Aurora Borealis. This pyrotechnic terminal causes your hand to recoil, which causes your body to involuntarily jerk backward, resulting in your head popping hard into the raised car hood. See, unintended, misdirected energy release. In ten years of installing batteries, I've seen them run dry, blow up, and melt. I've laughed hysterically as one coworker welded his wedding ring to a 1/2" open end wrench. I wasn't safety guy then, just another sadistic mechanic, so forgive me. Automotive batteries may be only 12 volts, but up to 100 amps. We learned as a group it's a good idea to remove jewelry so as not to bond, with a hand tool, until death do you part.
Batteries contain Lead. It is housed within a plastic box so not a big concern. When was the last time I told you lead was not a big concern? Wait there is a catch. In a car battery that lead is soaking in Sulfuric Acid. Also not a problem if it stays in the plastic case. But if you are filling a battery with electrolyte (the fancy 'charge you more' name for sulfuric acid), or if you are handling a cracked or leaky battery be sure to wear gloves, goggles and perhaps an plastic apron.
Previous thought patterns prohibiting contact lens use hinged on the perception that lenses would trap foreign bodies under the lens, that chemicals would melt the contact in the eye, or that eye muscle spasms, after getting splashed, would force the contact into the eye. For the vast majority of situations this has proven untrue. A 1967 report of a worker needing to have his contact lenses surgically removed after experiencing an arc flash at work is often cited as proof of increased danger for contact lens wearers. Review of the case shows the damage was actually caused by the man wearing his contacts for an extended period and causing an ulceration of his cornea. Similarly, an incident where a worker was splashed in the face with caustic was reviewed, revealing that although the man did wear contacts the damage was no more severe than if he hadn`t.
The reaction that gives a battery it's juice is known as oxidation/reduction . Lead, Zinc and Sulfuric Acid in a chemical dance that magically allows us to fly, 2 feet off the ground, while listening to oldies, and basking in the cool blue glow of dashboard lights. That anode/cathode tango generates Hydrogen (H2) gas, which is vented harmlessly through small holes in the battery. But, misconnect the cable ends, lean over with a cigarette glowing, or ground a wrench and, as anyone who has seen the news reel of the Hindenburg explosion (or the album cover of Led Zeppelin I) can tell you; H2 + spark = kaboom! This hazard is even more prevalent while charging a battery. So keep the area well ventilated, and pop the caps on the battery if possible while charging. A H2 hazard lurks even without thespark. If the vents are plugged by grease and grime the buildup of H2 during charging can bulge the battery case and in extreme cases split open it's sides. Releasing sulfuric acid to flow over the wiring harness and computer module the OEM engineers are so fond of putting below the battery tray. Moral of the story? It is always best to remove the battery from the car when recharging.
That puddle of acid under the car can be neutralized using baking soda or soda ash. The reaction from this neutralization will cause foaming and fizzing so put the goggles and gloves back on before the clean up. If you do this work in your shop; OSHA requires that an eyewash be present within a distance that can be traversed, screaming and temporarily blind, in less than 10 seconds. I think Michael Johnson took the gold in that event in Atlanta. If you are at home in the garage, keep a hose handy or make sure no one is in the bathroom during the repair time. In the interest of public safety, there are MSDS available for batteries and electrolyte. Yes, anyone who sells batteries should have one available on site. Ask for one and watch the kid behind the counter squirm.
My laptop battery is about to shut me down so, check your no-wind watch, jump in your car; battery providing the cough of life. Flip on the cell phone, hopefully there is enough juice to call the boss and tell him you are late because the power is off at your house and the battery backup on the alarm clock is dead. Of all the things in life that we take for granted, remember; batteries not included.
The above article was written by David M. Brown, Chief
Engineer of Johnson Manufacturing Company, Inc. and is published by
JOHNSON with the expressed approval of the National Automotive Radiator
Service Association and the Automotive Cooling Journal. Other reproduction
or distribution of this information is forbidden without the written
consent of JOHNSON and NARSA/ACJ. All rights reserved.
JOHNSON MANUFACTURING COMPANY
114 Lost Grove
Road / PO Box 96 / Princeton, Iowa 52768-0096
Phone 563-289-5123 or
Fax 563-289-3825