TPS ShopTalk: Battery Charging

Published by: Dave Schultz on 26th Mar 2013 | View all blogs by Dave Schultz

Cold cranking amps (CCA) is a measurement of the number of amps a battery can deliver at 0 ° F for 30 seconds and not drop below 7.2 volts.  So a high CCA battery rating is especially important in starting battery applications, and in cold weather.

Lead-Acid batteries when installed are actually charged by the alternator.  You probably knew this.  What you may not have known is that unless you are flying on long trips or for several hours at a time, the alternator due to size constraints is not quite strong enough to fully charge your lead-acid battery during occasional operating, especially if the battery has a low charge.  Therefore motorcycle batteries tend to get deep cycled faster than automotive batteries.  Cars have much stronger alternators and when regularly driven will easily keep the lead-acid batteries charged preventing them from getting deeply discharged.

 When a lead-acid battery is fully discharged, you risk reducing the calendar life of the battery.  Fully discharging, means taking a battery from a charged state to a discharged state where the individual cell voltage drops to 1.9v.  Since lead-acid batteries for motorcycles aren’t designed for deep cycling this will negatively impact the battery and reduce the life of the battery.

Under ideal operating temperatures and ideal voltage charge, a lead-acid battery will last according to manufacturer calendar life expectations.  In reality, we neglect our batteries.  Also, the conditions in which they operate in have many different variables.  So deep cycling will impact your motorcycle lead-acid battery life.  Temperature also plays a large role in battery life.  Lead-acid batteries work optimally under an operating temperature of 25 degrees Celsius (77 degrees Fahrenheit).  Higher operating temperatures will degrade battery life as can be measured by the Arrhenius Equation.  Many things can affect the operating temperature of a battery.  If you live in hot desert areas and drive a motorcycle, you may experience replacing the battery more than someone who drives the same motorcycle but lives in a more temperate climate like southern California.  This doesn’t mean you should move to a much colder climate to increase your battery life!  Extreme cold weather also affects lead-acid battery life.  Although the lead-acid chemistry type can withstand a range of temperature extremes, if a flooded lead-acid battery is allowed to discharge in extreme freezing weather, the water content is higher and more susceptible to freezing.  If this happens, the battery could actually experience cracking and leakage.  At which point you will need to replace the battery very soon.

Battery Charging

Remember you must put back the energy you use immediately.  If you don't the battery sulfates and that affects performance and longevity.  The alternator is a battery charger.  It works well if the battery is not deeply discharged.  The alternator tends to overcharge batteries that are very low and the overcharge can damage batteries.  In fact an engine starting battery on average has only about 10 deep cycles available when recharged by an alternator.  Batteries like to be charged in a certain way, especially when they have been deeply discharged.  This type of charging is called 3 step regulated charging.  Please note that only special SMART CHARGERS (Battery Tender Brand) using computer technology can perform 3 step charging techniques.  You don't find these types of chargers in parts stores and Wal-Marts.  The first step is bulk charging where up to 80% of the battery energy capacity is replaced by the charger at the maximum voltage and current amp rating of the charger.  When the battery voltage reaches 14.4 volts this begins the absorption charge step.  This is where the voltage is held at a constant 14.4 volts and the current (amps) declines until the battery is 98% charged.  Next comes the Float Step.  This is a regulated voltage of not more than 13.4 volts and usually less than 1 amp of current.  This in time will bring the battery to 100% charged or close to it.  The float charge will not boil or heat batteries but will maintain the batteries at 100% readiness and prevent cycling during long term inactivity.  Some Gel Cell and AGM batteries may require special settings or chargers.




1 Comment

  • Dave Schultz
    by Dave Schultz 4 years ago
    The Battery Tender® Junior is much more than a trickle charger. It has a brain. It's lightweight, compact, and fully automatic; very easy to use, especially in small spaces. It will keep your battery fully charged so that it is ready to go when you are!

    ■Perfect for all lead-acid, flooded or sealed maintenance free batteries (AGM and gel cell).
    ■Complete 4-step charging program (Initialization, Bulk Charge, Absorption Mode, Float Mode).
    ■Automatically switches to float / maintenance voltage after fully charging the battery.
    ■If the battery voltage drops too far under load, full charger output power resumes.
    ■Solid state two color LED indicates stage of charger.
    ■Spark proof.
    ■Reverse polarity protected.
    ■12' output cord.
    ■5 year warranty
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