Common Battery TypesThere are three main common types of motorcycle batteries; these are Flooded, Gel-Cell and Absorbed Glass Mat (AGM). It is not necessary to choose the same type of battery that was originally came with your motorcycle. All three types have been supplied by BMW on oilhead and airhead bikes and each offer unique some advantages and disadvantages when chosen as a replacement. Researching your favorite BMW motorcycle forums is one of the best ways to find out which type of battery is best for you. People can be very opinionated on this topic, but ultimately, the decision is yours.
The following is a brief summary of each battery type:
Flooded (also called Wet-Cell):
Flooded batteries are filled with electrolyte (aka "battery acid") and generally require greater maintenance. Flooded batteries can sometimes be replenished by adding distilled water if they are overcharged. Generally, flooded batteries sold through our affiliates and other online stores arrive dry. In this case, you have to purchase the electrolyte from an automotive-store, add it to the cells of the battery and you should charge the battery before using it.
Sealed (aka Valve Regulated Lead Acid) Battery Types (Gel-Cell and AGM):
Sealed batteries offer several advantages over flooded types. The electrolyte in sealed batteries is suspended in either glass mat, or gel, making it virtually impossible to spill acid by inverting battery. This makes these types of batteries much safer and can prevent damage if you drop your bike or overcharge the battery; they are also less likely to produce caustic fumes during normal operation than wet-cells. Care should be taken not to overcharge sealed batteries as it is not possible to add distilled water to the cells if they become dehydrated.
Gel-Cell (GC) - Some BMWs came with Gel-Cells standard, for this and other reasons, some BMW owners prefer this type. While GC batteries offer a number of advantages over flooded types, it is debatable whether they also have any advantage over AGM types. It should be noted that GC batteries require a lower rate of charge than other types, so if you own a gel-cell charger it might not adequately charge other types. More importantly, if overcharged, fissures can develop in gel batteries, reducing capacity.
Absorbed Gas Mat (AGM) - AGM Batteries have their electrolyte absorbed into a "mat” of glass fibers and are generally considered to offer the most advantages of any type. AGM batteries self-discharge slower than flooded types. They are generally more tolerant to both extreme hot and cold weather conditions than other types and provide very good vibration resistance. Further, since AGM batteries can usually be discharged further than other types without damage.
