Car Batteries
Car batteries are different from your average CD player batteries. You knew that, or you wouldn't be looking here.
If you want to know all of the science behind a battery, click on the links at the bottom of this page. If you just want to know how to buy a good battery for your car, read on. While boats and RVs can use the same batteries as cars, there are different factors to take into account when buying those. This advice is not water-proof - don't use it for your boat.
Important Ratings
Your car will tell you what it needs based on three ratings. Check what you need and buy accordingly.
- Cold Cranking Power (CCA)
- How many amps the battery can give for 30 seconds and 0 degrees Fahrenheit while maintaining a minimum terminal voltage of 7.2 volts.
- If you live in a cold climate, it's even more important to have a high CCA.
- Reserve Capacity Rating (RC)
- According to Edmunds, "Weather rating (80 degrees Fahrenheit), which estimates the amount of time it takes the terminal voltage of a fully charged battery to dip below 10.2 (or 1.7 volts per cell) at a continuous discharge rate of 25 amps. The rating is expressed in minutes. For example, a rating of 120 means the battery will run for two hours (120 minutes) before ceasing to function."
- It tells you how long the battery can keep up the minimum voltage without help from the alternator.
- Battery Group Size
- Accounts for the physical dimensions of your battery.
- Cars are generally in one of four battery group sizes.
- 65 cars
- 24 (or 24F) cars
- 65s, 24s, and 24Fs take top terminal batteries.
- 75 cars
- 75 cars take side terminal batteries.
- 34/78 cars
- 34/78 cars take top and side terminal batteries.
Other Important Features
- Freshness of the battery. If it has been sitting on the shelf for a while, it can lose initial charge and will need a kick before getting up to its potential.
- Batteries should be no more than six months old when you buy them.
- The shipping date is marked by a letter and a number. The letter stands for the month (A for January and so on) and the number is the last digit in the year (5 for 2005, for example).
- A Good Warranty
- How long does the warranty last?
- Is it applicable across the country/world?
- How is the reimbursement calculated? Is it prorated for the amount you've used it? (That would be nice.)
Is This Battery Any Good?
- Perform a load test, putting a predetermined load on the battery for ten seconds. Then test its charge. If its over 11 volts, you're golden. 9-11 volts is not bad. If it's under 9 volts, dump that sucker.
- To test how charged it is, check its specific gravity with a hydrometer.
- Fully charged - 12.75
- Weak - 12.50-12.25
- Discharged - 12.00 and below.
- If your battery is discharged, trying charging it again. You may need a voltmeter
to get a more specific reading.
- About.com has a good description of how to check charge with a voltmeter.
BE SAFE
- You're working with sulfuric acid.
- Wear goggles.
- Take off your jewlery.
- Always disconnect the negative cable first.
- Never jump-start a frozen battery.
- Refill your battery with distilled water, not tap water.
Your Battery's Battery
|
Black & Decker Simple Start
It happens to everyone -- you get a dead battery exactly when it's least convenient. Why wait for AAA when you can jumpstart your battery with another battery that's been charging in your glove compartment? The Black & Decker Simple Start plugs into the cigarette lighter to charge up. When you need it, it discharges to get your battery going. - When you don't need it to power back up, you can use the Simple Start as a charging station for any gadget.
- Some models have built-in emergency lights.
- Different models deliver either 300 or 450 amps.
|
Major Manufacturers
Additional Links
