Comments on: How to Replace a Car Battery

on 9/8/2008 Note that either the old or new battery may have some battery acid on the outside. Even a very small amount of the acid will eat through pretty much any article of clothing.

Also, be sure to wear eye protection and don't smoke during the removal/installation process. A friend of mine had serious eye problems after an auto battery he was working on exploded.

on 6/27/2007 The comments submitted here are outstanding pieces of information but I'd like to ask for guidance about a comment made under "tips and warnings."

"Make sure the battery is fully charged before you buy it" is a great tip and I have thought about it for decades but never had a solution offered. I have bought batteries under two conditions: store installed and self installed. I have always suspected that the in-store installation was installing partially charged batteries even though they always told me it was charged. But every time I brought a new "fully charged" battery home, the specific gravity was never at the point of max charge. When I called the store they always said that's the way batteries are shipped and the car's system will bring it up to maximum after a week or so depending on use. I never had a battery that ever reached max specific gravity.

What gives?

on 5/22/2007 Very Important!
Always remove the Negative (Black) terminal first when removing the battery. After the negative terminal is completely removed and pulled away from the battery post, then remove the positive.
When installing a battery, install the positive cable first and tighten it up all the way. Then install the negative cable last.
The reason for doing this is to prevent you're wrench or other tools from Arcing and Sparking, while tightening the positive, when you're wrench accidentally touches the body or any ground point. If the negative is not connected when you're tightening or loosening the positive, you don't have as much risk of causing those mini lightening strikes, burns, fires, melting you're wrench, or any under the hood fireworks display.

on 7/18/2007 — some cars require that 12 volts be maintained on the electrical system during a battery change, as does my VW New Beetle. Check with your dealer or maintenance manual. Not to do so may mess up the car's computers, which will require a trip to the dealer for re-programming. A 12 volt battery or power supply plugged into a power outlet (cigar lighter) will do it.

on 11/17/2006 If you want a professional to help you with your battery--If you feel you are having problems with your battery, and for example, you can only drive your car after a jumpstart, I recommend trying to find an auto shop that offers free battery testing along with free battery installation. The only thing you would have to pay for is the battery. (Generally around 50-70 bucks.) There are a lot of locations where they do these testing and installation services for free, so do your self a money saving favor and locate one!

on 7/16/2006 Be very careful when tightening the screws, as my wrench hit a rubber pipe which had a small metal ring and when I was tightening the positive terminal my wrench hit the small metal ring and sparks flew!

on 7/2/2006 If your car has an anti-theft radio, be sure you know the code. When the battery is disconnected, the code is erased from the radio's memory, and the radio won't work until the code is re-entered.

on 3/13/2006 Make sure that the battery you buy have the positive and negative poles at the same locations as your old battery.

on 2/14/2006 You may find that when you try to unscrew the battery cables from side-terminal style batteries, the whole terminal piece will tear right out of the side of the battery. This isn't uncommon, especially if the battery is old. At this point, if you grab the battery chunk with something like a vise grips and try to turn the tightening nut out with a standard wrench or socket, most likely the nut will just round off and you'll have ruined it (and you won't get it out either). The nuts are deliberately made small and somewhat soft so you will round them off and ruin them if you lean on them too much (to discourage you from trying to tighten them too much when you put in a new battery, thus breaking off the battery terminal mount). For better results, use 2 vise grip pliers, one on the chunk that tore out of the battery, and one on the collar at the base of the tightening nut (not on the nut itself, or the you'll mess up the hex head). You should be able to screw the battery chunk off there and not ruin your battery cable in the process.

on 11/22/2005 Someone mentioned how to secure a battery that is too small. Personally, if the battery is too small, the question should be asked if this battery will perform to your requirements.

If you have aftermarket accessories, or factory options such as stereo, DVD, Engine Management, Sunrood, Electronic windows, etc., you should be looking for a larger capacity battery.

It's not always a true rule, but the bigger the battery, the more potential capacity it has.

Always check the discharge and amp ratings, and get the highest figure you can afford, that way when you turn your stereo up, you're not putting stress on your alternator to power your system, rather the alternator is charging the battery which is powering the system. An alternator can be a few hundred dollars + fitting, a battery is usually under $100, so I know which would be better to be putting stress onto.

on 11/22/2005 Put blocks of wood of the appropriate size between the battery fastener and the battery to secure a battery that is too small.

on 11/22/2005 Before changing a car battery, connect a third battery (possibly with jumper cables from another car) to your car. This will keep all of your on-board computer data and radio settings from being lost when the old car battery is disconnected.

on 11/22/2005 Before working on a battery, you may want to make a cup of base to have during the job. A bottle of water with a couple spoons of baking soda and a dab of soap will neutralize battery acid.

on 11/22/2005 Gloves are a good idea. Always wash your hands after handling the batteries. While handling batteries, be aware of what you touch until you clean up. Battery acid eats paint, concrete, rubber, clothing, some plastics, skin, etc.

on 11/22/2005 As batteries sit on the shelf the plates inside the battery sulphate, so it is important to get the newest battery possible. Most manufacturers use a date code that contains a single numeral representing the year and a letter that show the month (A=January, B=February etc). The letter I is skip/not used. Thus G9 would mean the battery was made in July, 1999.

Never buy a battery with a date code sticker older than six months.

FYI, neither AC Delco nor Interstate manufacture their own batteries. They are made by Exide, Johnson Controls etc. So show for CCA's and price, but keep an eye on the date code.