[Source: Popular Mechanics]
14.1. Storing a battery on a concrete floor will discharge them.
14.2. Driving a car will fully recharge a battery.
14.3. A battery will not explode.
14.4. A battery will not lose its charge sitting in storage.
14.5. "Maintenance Free" (Ca/Ca) batteries never require maintenance.
14.6. Test the alternator by disconnecting the battery with the engine running.
14.7. Pulse chargers, desulfators, aspirins or additives will revive sulfated batteries.
14.9. Car batteries last longer in hot climates than in cold ones.
14.10. Charging cables or jump starters will start your car.
14.11. A larger capacity battery will damage my car.
14.12. Lead-acid batteries have memories.
14.13. Bad batteries will not harm the charging system or starter.
14.14. Once formed, batteries will not change polarity.
14.15. Use tap water to refill batteries.
14.1. Storing a battery on a concrete floor will discharge them.
All lead-acid batteries will naturally self discharge. The rate of self discharge is most influenced by the temperature of the battery's electrolyte and the chemistry of the plates. Some experts believe that storing car or deep cycle batteries on a colder concrete floor might actually slow down the leakage rate because the floor acts as a heat sink. (Please see Section 13.)
In the early 1900s, when battery cases were made of porous materials such as tar-lined wood boxes, storing batteries on concrete floor would accelerate their natural self discharge. Modern battery cases are made of polypropylene or hard rubber. These cases are sealed better, so external leakage-causing discharge is no longer a problem, provided the top of the battery is clean and free from wet or dried electrolyte and the same temperature as the floor.
Large differences in temperature could cause electrolyte stratification within very large batteries (>250 AH) which could accelerate it's internal "leakage" or self discharge if the battery is sitting on an extremely cold concrete, stone or steel floor in a warm room, boat or submarine. Stirrers or bubblers are often used on these types of batteries to keep the electrolyte from stratifying.
14.2. Driving a car will fully recharge a battery.
There are a number of factors affecting a vehicle charging system's ability to recharge a battery, such as how much power from the alternator is diverted to the battery, how long the power is available, and the temperature. Generally, idling the engine or short stop-and-go trips during bad weather or at night will not fully recharge a car battery. When a dead battery needs to be recharged, it is best to use an external battery charger because you could over heat and damage your vehicle's charging system. Please see Section 5.
14.3. A battery will not explode.
Charging a wet lead-acid battery naturally produces hydrogen and oxygen gasses as electrolysis of the water occurs. While spark retarding vent caps help prevent external battery explosions, sparks occur when jumping, connecting or disconnecting charger or battery cables and ignite the gas causing an explosion. Less common internal explosions usually occur while starting the engine or using the battery and normally just blow the filler caps or cover off the battery and splatter electrolyte all over the engine compartment or battery box.
The most probable cause of internal explosions are from a combination of low electrolyte levels below the plates in the battery and a low resistance bridge is formed between or across the top of the plates. This is called "treeing" between the positive and negative plates. When current flows in the battery, a spark occurs and ignites the residual gas in one or more of the cells. A second possible cause is a manufacturing defect in the weld of one of the plate connecting straps. The largest number of internal battery explosions occur in hot climates due to the loss of water while starting the engine. Most internal battery explosions could have been prevented if the plates were always covered with electrolyte. Please see Section 3.
[Source: Popular Mechanics]
Periodic preventive maintenance (Please see Section 3.), working on batteries in well-ventilated areas, or using sealed AGM or Gel Cell type batteries can significantly reduce the possibility of battery explosions. To neutralize residual battery acid, be sure to thoroughly wash the engine compartment and the back of the hood with a solution of one-pound baking soda (bicarbonate of soda) to one gallon of warm water and rinse thoroughly with water. While not fatal, each year battery explosions cause thousands of eye and burn injuries from the electrolyte (battery acid). Should a battery explosion occur and battery electrolyte (battery acid) gets in someone's eyes, flush them out with any drinkable liquid immediately because seconds count.
14.4. A battery will not lose its charge sitting in storage.
Depending on the type of battery and temperature, batteries have a natural self discharge or internal electro chemical "leakage" at a 1% to 60% rate per month. Over time the battery will become sulfated and fully discharged. Higher temperatures will significantly accelerate this process. A battery stored at 95° F (35° C) will self-discharge twice as fast than one stored at 75° F (23.9° C). (Please see Section 15. and Section 16.)
14.5. "Maintenance Free" (Ca/Ca) batteries never require maintenance.
In hot climates, the water in the electrolyte is lost due to the high under hood temperatures. Water can also be lost due to excessive charging voltage or charging currents. Non-sealed wet Low Maintenance (Sb/Ca) batteries (with filler caps) are encouraged in hot climates so distilled, deionized or demineralized water can be added when this occurs. (Please see Section 3. for other preventive maintenance procedures that should be performed on "Maintenance Free" (Ca/Ca) batteries.)
14.6. Test the alternator by disconnecting the battery with the engine running.
A battery acts like a voltage stabilizer or filter to the pulsating DC produced by the alternator. Disconnecting a battery while the engine is running can destroy the sensitive electronic components connected to the electrical system such as the emission computer, radio, audio system, cell phone, alarm system, etc., or the charging system because the peak voltage can rise to 40 volts or more. In the 1970s, removing a battery terminal was an accepted practice to test charging systems of that era. That is not the case today.
14.7. Pulse chargers, desulfators, aspirins or additives will revive sulfated batteries.
Using pulse chargers, desulfators or additives are very controversial subjects. Most battery experts agree that there is no conclusive proof that pulse chargers work any better than constant voltage chargers to remove sulfation. They also agree that there is no evidence that additives or aspirins provide any long-term benefits. Short term gains are achieved by increasing the acidity (Specific Gravity) of the battery.
14.8. On really cold days turn your headlights on to "warm up" the battery up before starting your engine.
While there is no doubt that turning on your headlights will increase the current flow in a car battery, it also consumes valuable capacity that could be used to start the cold engine. Therefore, this is not recommended. For cold temperatures, externally powered battery warmers or blankets and engine block heaters are highly recommended if the vehicle can not be parked in a heated garage. AGM and Ni-Cad batteries will perform better than wet lead-acid batteries in extremely cold temperatures and Ni-Cads is extremely hot temperatures.
14.9. Car batteries last longer in hot climates than in cold ones.
Car batteries last an average of two thirds as long in hot climates as cold ones. Heat kills car batteries, especially sealed Maintenance Free (Ca/Ca) batteries, and cold reduces the battery's starting capacity. (Please see Section 11.1.)
14.10. Charging cables or jump starters will start your car.
The cigarette lighter charging cable's advertising states "charges weak batteries in minutes." There is little doubt that charging cable products will certainly recharge your car battery if you have enough time and your battery is in good condition. Cigarette lighters are normally fused at 10 amps, so to be safe they probably limit current flow to 7.5 amps. Given the diameter of the wire used in the cable, the amount might be even less.
They work by applying higher voltage from the vehicle with the good battery to "charge" the bad one. In order to charge a battery the charging voltage need to be approximately two volts greater than the the battery voltage to overcome the internal resistance. Now let's assume it is a hot day and that you need just of 3% of the battery's capacity to start the engine from a 40 amp hour battery. This means you will need at least 7.5 amps for 10 minutes to flow from the good battery with the engine idling to the bad one. Now let's also assume that it is below freezing and you have left your lights on. You will need at least 50% capacity or 20 amp hours to start the vehicle. This will take over two hours to partially charge the dead battery. Using jumper cables with the engine running at high idle will partially charge a dead battery much faster. Please see Section 6., but be sure the battery is not frozen.
Some auto jump starter uses special high current batteries to provide up to 900 peak amps to start your engine. It can provide 200-300 amps for up to 8-10 seconds. Standard AA alkaline batteries are used to trickle charge the special batteries to maintain their charge. This type of emergency starter should start all but diesel engines up to six or eight times on one charge, depending on the capacity of the battery, condition of the engine and the temperature. After this, the jump starter should be recharged for 24 to 48 hours.
14.11. A larger capacity battery will damage my car.
A starter motor will only use a fixed amount of current from the battery, based on the resistance of the motor. A larger CCA, RC or AH capacity battery supplies only what is required. It will not damage your vehicle; however, using batteries with higher or lower voltage or physically too tall could potentially cause harm.
14.12. Lead-acid batteries have memories.
Lead-acid batteries do not have the "memory effect" mistakenly identified with first generation Ni-Cad batteries; however, continuous undercharging will lower the capacity of the battery over time. Deep discharges below twenty percent State-of-Charge (approximately 12.0 volts) can damage batteries and will shorten their service lives.
14.13. Bad batteries will not harm the charging system or starter.
A bad or weak starting battery causes additional stress on a charging system, starter motor or starter solenoid. It can cause premature failures due to compensating for the voltage or current. If you replace a battery, alternator, voltage regulator or starter, you should test the other components for damage and repair or replace them.
14.14. Once formed, batteries will not change polarity.
If a battery is fully discharged and continues to have a load, for example leaving the headlights on, it is possible for one or more cells to reverse polarity. When the battery has been recharged with reversed polarity the polarity can change. This is referred to as "cell reversal". To change polarity, fully discharge the battery and recharge it with the correct polarity.
14.15. Use tap water to refill batteries.
Use only distilled, deionized or demineralized water to replace the lost water in batteries because using tap or reverse osmosis water can produce calcium or magnesium sulfate crystals that can fill the pores and coat the plates. In an emergency, use rain water because rain water does not contain calcium or magnesium.
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