Battery Construction

 

Lead Acid Battery Construction

 Lead Acid Battery
     Invented in 1859 by French physicist Gaston Planté, are a type of galvanic cell and are the most commonly used rechargeable batteries today. They also represent the oldest design with one of the lowest energy-to-weight ratios. Also, the energy-to-volume ratio is low compared to other types of batteries. The power-to-weight ratio can be quite high, however. They are relatively low-cost and can supply high surge currents needed in starter motors. Every reasonably modern car uses a lead-acid battery for this purpose. They are also used in vehicles such as forklifts, in which the low energy-to-weight ratio may in fact be considered a benefit since the battery can be used as a counterweight.
     Lead-acid car and motorcycle batteries for a '12 volt' system consist of six cells of 2.1v nominal voltage. Each cell contains (in the charged state) electrodes of lead metal and lead oxide in an electrolyte of about 37 % sulfuric acid. Modern designs have gelified electrolytes. In the discharged state both electrodes turn into lead sulfate and the electrolyte turns into water. (This is why discharged lead-acid batteries can freeze.)

     Lead acid batteries for automotive use are not designed for deep discharge and should always be kept at maximum charge, using constant voltage at 13.8v (for six element car batteries). Their capacity will severely suffer from deep cycling, due to sulfation, or hardening of the lead sulfate. Specially designed deep-cycle cells are much less susceptible to this problem, and are required for applications where the batteries are regularly discharged such as motorcycles. Also, marine batteries are something of a compromise between the two, able to be discharged to a greater degree than automotive batteries, but less so than deep cycle batteries.

 

AGM Battery Construction

     Harley-Davidson AGM (Absorption Glass Mat) Battery
     Sealed battery technology was originally developed in 1985 for military aircraft where power, weight, safety, and reliability were paramount considerations. 
     AGM battery technology has continued to develop and offer improvements over other sealed battery technologies. AGM technology has become the next step in the evolution of both starting and deep cycle sealed batteries for motorcycle, marine, RV, and aviation applications. This "next generation" technology delivers increased safety, performance, and service life over all other existing sealed battery types, including gel technology. 
     In AGM sealed batteries, the acid is absorbed between the plates and immobilized by a very fine fiberglass mat. No silica gel is necessary. This glass mat absorbs and immobilizes the acid while still keeping the acid available to the plates. This allows a fast reaction between acid and plate material. 
     The AGM battery has an extremely low internal electrical resistance. This, combined with faster acid migration, allows the AGM batteries to deliver and absorb higher rates of amperage than other sealed batteries during discharging and charging. In addition, AGM technology batteries can be charged at normal lead-acid regulated charging voltages, therefore, it is not necessary to recalibrate charging systems or purchase special chargers.

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    A battery will most often fail in three different ways, won't take a charge, won't hold a charge, and won't release the charge under load (lights and electrical work but it won't crank the motor over).
Have the battery tested if you suspect it to be bad (insist on a "load test").