Auto and Truck Repair and Advice
Serving the Gainesville and Hawthorne Florida Area
About Your Car's Battery
If your car starts and runs, or if the engine turns over normally when you try to start it but it won't actually run, there is probably nothing wrong with your alternator, starter, or battery.
There are three things which give about the same symptoms on your car:
The Battery
The Starter
The Alternator or Generator
You get in your car to start it. You turn the key . Either nothing happens, a clicking noise happpens, or it turns over really slowly and won't start.
DIAGNOSIS
Turn on your lights. Look at them. If they're bright, the problem is probably not your battery. Get a friend to try starting the car. If the lights stay bright, the problem is probably not with your battery. On the other hand, if the lights are dim or go dim while trying to start the car, the problem is low voltage at the battery. THIS DOES NOT MEAN YOUR BATTERY IS BAD! IT MAY NOT BE GETTING CHARGED BY THE ALTERNATOR. DIRTY TERMINALS CAN ALSO DO THIS!
Feel the battery terminals. If one of them is getting hot or looks nasty, you may just need to clean or replace the terminals. NOTE: A DIRTY TERMINAL DOES NOT ALWAYS "LOOK" DIRTY!!
Here's a battery that just needed terminals. Notice that this terminal has been replaced by a clamp on replacement terminal. These terminals are not as good as the original factory terminals. The factory terminals are either soldered to the cable, molded onto the cable out of lead, or very securely mechanically crimped onto the cable end.
The clamp on replacement terminal cannot equal the durability provided by the factory style terminal. It is an easy fix for a bad terminal, though, and is commonly used.
When cleaning or replacing clamp on terminals, make sure to clean the place where the cable clamps into the terminal as well as the place where the terminal end clamps onto the battery terminals. Notice that the battery terminals don't "look dirty". A terminal can have a bad electric connection and look fairly clean.
Try charging the battery, or using jumper cables (WARNING!!!!!! MANY CARMAKERS SAY DO NOT JUMP THEIR CARS OFF!!! JUMP AT YOUR OWN RISK: CONNECT THE POSITIVES OF BOTH CARS TOGETHER, THEN CONNECT TO THE NEGATIVE OF THE DEAD BATTERY, THEN LASTLY CONNECT THE NEGATIVE CABLE END TO A GOOD CHASSIS GROUND ON THE VEHICLE HAVING THE GOOD BATTERY. (NOT TO THE NEG TERMINAL ITSELF!!)
If the car starts and runs normally with a charge or jump, get a voltmeter. (or come by and we'll check this for free) While running the battery should have 14.2 volts or so. If the charging voltage is good, the battery is probably not holding a charge and needs replacing. If the charging voltage is low, you have a charging system problem.
If your headlights are bright when not starting, but are dim while the starter is engaged, OR you put in a new battery and the car still turns over slowly, OR the battery cables themselves (not just the terminals) are getting hot, you probably need a starter. As usual, our ASE certified mechanics can test and repair all of your car's electric system.
HOW A LEAD ACID BATTERY WORKS:
A lead acid battery has a series of lead plates sitting in an electrolyte bath of sulfuric acid mixed with water. These lead plates are separated by insulating material, separating them from each other but not separating them from the electrolyte. I won't go into the physics of the reaction here, but basically when you get electricity out of the battery the lead plates "dissolve" in the electrolyte solution. When the battery is charged again, the lead is "built up or re-plated" onto the lead plates in the battery. A lead acid cell produces approximately 2 volts, so a 12 volt car battery has 6 cells which are joined together inside the battery, each with its own separated "bath" of electrolyte. That's why a 12 volt battery has 6 holes for adding to the electrolyte, should it run low.
HOW BATTERIES FAIL
By far the most common cause of battery failure is deterioration of these lead plates, usually from repeated deep discharge of the battery. In addition, deposits from these chemical reactions can accumulate on the bottom of the battery, shorting out one or more cells. The lead plates can warp and contact each other, shorting out the battery internally.
NEWER AUTO LEAD ACID BATTERIES: AMAZING TECHNOLOGY OR PIECES OF JUNK?
Batteries have gotten smaller and smaller, while touting larger and larger amperage outputs and so on. Are these better batteries than their larger and heavier ancestors?
It depends on how you define "better". Smaller and lighter means economy, but ther is a downside. To make these batteries smaller, the manufacturers have reduced the thickness of the lead plates and put them closer together. Thus these smaller batteries are less forgiving and more prone to failure in a deep discharge situation. When I have a choice of a battery with large physical dimensions and another that is smaller, I pick the large sized one. Hopefully the plates are a bit further apart!
BUYING A BATTERY
Remember the J.C. Penny battery? It had an unlimited lifetime warrenty. One of my customers had one of these: he got a new battery from them free of charge every 5 years for at least 20 years. J.C.Penny finally abandoned the warranty (as well as their automotive department) and refunded my customer the original purchase price of the battery.
The moral of the story? LEAD ACID BATTERIES LAST ABOUT 5 YEARS!
You might get more, but don't count on it! So how do you pick the best value in a battery? Do you always get what you pay for?
BATTERY WARRANTIES
Batteries come with a bewildering arrray of warranties and guarantees. In fact, most are rated as "2, 3, or 5 year" batteries. Is there a difference? Sometimes, although often not as much as you would think!
Most batteries are rated in "years". The "year" rating is how long a "pro-rated" guarantee is in effect. Pro-rating works like this:
You buy a 5 year battery for $50. (Good luck!!)
It therefore would cost you $10 per year, providing it lasts the full 5 years. Suppose it then fails after 2 years. The warranty will pay you $30, usually only appicable to the purchase of a new battery from them. (That's $10 per year for the 3 years remaining.) Like I say, this is normally NOT a cash thing, it's a discount on buying another battery from them. Suppose the battery now costs $75. They'll still only give you $30 off. This means you will have spent $95 in 2 years for a 5 year battery!
SO WHAT SHOULD YOU DO?
I normally go by specifications rather than "years". Although the best battery will always have better specs than the bottom line model (by the same manufacturer), the actual specifications may be fairly close. Check the old battery in your car. All batteries have specifications on the top, such as "cold cranking amps" and "reserve capacity" . The higher these numbers, the more powerful the battery. If your car's battery has lasted for 4 plus years with no trouble, I'd replace it with the cheapest name brand battery with equal or greater specifications.
A NAME BRAND BATTERY
In reality there are only a few people actually making batteries. Most of the brands are just marketing systems who have batteries made for them by one of a very few manufacturers.
For the longest time most all batteries in the US were made by either Globe Union (Sears Die-hard, J.C. Penny battery, Interstate, etc.), Exide (Own brand, Wal Mart, K-mart) , and Delco (own brand). Nowadays there are a few more players: Globe Union has sold out to Johnson Controls, and there are a few overseas manufacturers in the mix. All of these guys make good battery, but they make some of their batteries better than others. The battery retailers order a battery to their specifications and the manufacturers make it. Thus one retailer's "best 5 year" battery may be exactly the same as another retailer's "3 year battery": made by the same company, identical specs, just a different label and warranty!
SO HOW CAN YOU TELL?
1) First, ask. The people selling the battery may know who actually made it. An internet search will reveal who makes various batteries.
2) If the battery is at a major part store or department store chain, it is probably made by one of the big manufacturers. As with a lot of things, a reputable seller means a good part.
3) Go by specifications, not warranty!!! Many times the difference in price between a 5 year and 2 or 3 year battery is not worth the extra bucks!
MORE ABOUT BATTERIES:
I have gotten a lot of questions recently about car batteries in other applications, like wind and solar power. A lot of folks ask me about the optimal charging voltage for a battery.
Although the 14.2 to 13.6 rule applies to auto systems, somewhat different rules apply to battery chargers. If you were to apply 14.2 volts constantly to a lead acid 12 volt battery with no load on it, the battery would "boil out" all of its electrolyte and become useless in a few weeks. Thus "smart" battery chargers (sometimes called marine chargers) use the following charge strategy:
HEAVILY DISCHARGED BATTERY: CHARGES AT 14.4 to 15 volts to bring the battery up to 90% of full charge as rapidly as possible.
MODERATELY DISCHARGED BATTERY: Charges at 13.6 volts
FULLY CHARGED BATTERY: MAINTENANCE CHARGE: 12.5-13.2 VOLTS
At the maintenance charge voltage you can leave a battery on charge "forever" without damage to the battery. Many boat owners keep their boat battery on charge like this, hence the naming of "smart" chargers "marine chargers"
Does this mean you have to buy a sophisticated "smart" charger for your battery?
Not necessarily. If you can check up on your charger every couple of hours and remove it when the battery is charged, you can provide the "smarts" for your charger by just removing it from the battery when the battery is charged. Even the cheapest of chargers usually have has an ammeter indicating the charge rate. When the ammeter goes down close to zero, remove the charger. The battery is fully charged, and you haven't damaged it by charging it.
IMPORTANT NOTE:
Charging your battery will not damage it, but FULLY DISCHARGING IT WILL!!!
The effective operating range of a lead acid battery is between 12.5 and 11 volts. If you discharge a battery past this 11 volt minimum, you may damage it, especially the newer batteries. By my experience, if you "deep discharge" a battery, it will fail within a year or two, even if it takes a full charge.
The Economechanix Cyber Mall
We also serve the surrounding communities of Alachua, High Springs, Hawthorne, and Newberry!
Thank you for visiting the ECONOMECHANIX WEB SITE. Please feel free to comment. We also serve the surrounding communities of Alachua, High Springs, Hawthorne, and Newberry! Gainesville has been my home since 1974, and I've loved Gvl and the Gators since I came here in the fall of 1974 to attend the University of Florida. I loved it so much I stayed and opened my car repair business. Originally it was out of the back of a 1963 Chevrolet wagon, but in 1977 a fellow mechanic and I opened an auto repair shop with actual walls, etc. I stayed in the same location for 26 years, and recently moved my operation to property I bought 15 miles east of Gainesville. I am doing most all the repairs myself now, having reduced my overhead from $1500 per month to practically nothing. I do work by appointment only. I mostly work only on my established customers cars, but I will occasionally take on new clients. E-mail me and I will either make arrangements to look at your car, or I will recommend you to someone who will.
George G. Scott, Jr.