Batteries 101

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Batteries 101

Batteries are just batteries right? NO, Unfortunately I know too much about batteries and that is way wrong. To keep it simple were only going to talk about car batteries.

Most car batteries are rated at 12Volts, some race cars use 16Volt applications but let’s stick to 12Volts. 12Volts is the Nominal voltage, not the actual. The actual voltage on a car battery will range from 13-14.5 while charging via the alternator.

Car batteries use primarily flooded lead acid technology or sealed tinned lead acid batteries. Flooded or wet batteries are typically OEM type. They are filled with sulfuric acid, and can be topped off with distilled water. Sealed tinned lead acid batteries, aka non-spillable, aka gel batteries use a gelled acid that cannot be topped off. Both batteries in 12 volt form consist of six 2Volt nominal cells connect in series to make the sum of 12Volts.

What are cranking amps? Good question, they are a rating that is set by that manufacturer to identify discharge power. Each battery company sets its own formula to determine this rating so if you ask me its complete fiction. The real rating of a battery is in Ah Amp hours which are a calculation of current discharge over time. The other good rating is watts per cell. This is a power rating of the individual battery cell vs. time.

End Cell Voltage?All batteries have an end cell voltage rating. This rating is represented in voltage of a particular cell. If the battery voltage drops below this voltage while discharging damaging to the lead plates occur. Discharged under this also create more internal heat causing the plates to separate and crack. This can lead to shorted or open cells.

Thermal runaway and TemperaturePer Battcon the battery standard organization, batteries should be maintained at 77 degrees. This is the perfect temp for a battery, but lets face it doesn’t happen. Higher temps offer more battery capacity, but internally dry out the battery causing cell cracking and cell swelling. Colder temps prolong battery life, but limit the capacity of the battery. Too hot or too cold is bad so keep that in mind with battery location

What size battery to use Well bigger does not hurt IF it's the right type. However, using the wrong type of battery can strip the starter teeth tight off. I have seen it happen, my own fault.

Normal VS Deep Cycle and why not to use deep cycle in a carYour battery is meant to start the car and that’s it. The alternator is sized above the current draw to run the car and recharge the battery. Technically once the car is running you can disconnect the battery. A standard car battery is designed for these short, high current discharges such as starting the car. Deep cycle is designed for a small to medium discharge over a long period of time. A short high current draw on a deep cycle battery provides more power then needed and can burn up starter winding, and even over spin a starters teeth off. However with a proper set up, in audio applications deep cycle batteries are recommended.

Optima red/yellow tops, Odyssey spiral cell, Gel cell batteriesThese batteries are very similar to UPS batteries, but are designed for outdoor temperatures. They used a gel electrolyte and tinned lead acid technology. They offer greater starting power at lighter size and weight, but have negatives. These batteries are designed to be float charged. Our cars alternator does an okay job at that, but alternators have a lot of noise on them so they tend to wear these batteries down fasted then flooded type. The life cycle of these batteries is rated in 5 years but we only see 3, flooded are rated at 10 years and you can see up to 7 on those. Because these batteries are designed to be float charged you should never use an automotive battery charge on them. Those chargers don’t limit the voltage at the proper lever of under 14 volts for these batteries. They will ramp the voltage up to 19 volts and shut off when the current gets under a half an amp. A float charger will control the voltage and current charge of the battery a proper level, and then continually keep the battery on a stead float charge of 13.5 volts which is perfect for a 12V nominal battery.

Electrolyte aka AcidNever pour it out then fill the battery with water, its ruined if you do that. Test the acids specific gravity with a micrometer. The specific gravity should be 1.25 or the green ball on those floater types. Then fill the battery with distilled water to the fill line then charge the battery before use.

Clean spilled acid with ammonia and water 20% ammonia 80% water, or sprinkle baking soda on the spill to neutralize the acid. Then clean with water. Acid will eat metal and clothes. Always wash your hands and wear gloves, touching your eyes with acid on your finger can cause you to go blind.