This is a consumer video I did for Kawasaki. Just a few simple pointers on the proper care of the powersports battery.
Batteries. They are the undersung heros of the motor vehicle world. Powersports batteries especially are under-appreciated. They're smaller than they have a right to be and thus work harder than they should have to. They are treated harshly, in the powersports realm in particular but especially in the more seasonal aspects of it, off-road vehicles, snowmobiles, and personal watercraft.
There are three kinds of powersports batteries in use by the OEMs. The basic flooded cell battery that has been around for nearly a hundred years and has all but disappeared from use as original equipment, the micron flooded cell battery that has more compact plates in its cells thus more power, and the so-called maintenance-free battery better known as the sealed battery which is the dominant type today and whose technical name is absorbed glass mat, or AGM, and substitutes dampened separator sheets for submerged ones and is therefore non-flooded cell type. The only thing you the consumer need to concern yourself with is the AGM battery does have some unique maintenance needs.
Several things kill batteries, but here are just four for your consideration. First, and the most common, is disuse. Battery plates grow sulfur deposits on their plates as a consequence of discharge, and these deposits are routinely "burned" back off and into solution again as the battery is systematically recharged by the vehicle. An unused battery is one that is not continuously receiving recharge input, thus these deposits have opportunity to increase, which electrically insulates the plates and dilutes the acid-based solution, both of which deaden the battery. At some point, even if recharge is resumed, the collection of sulfur is no longer reversible and the battery is history. The battery is, in the parlance of the trade, "sulftated." One difference between flooded cell batteries and AGM batteries is the AGM takes longer to get sulfated, but once it does is even harder to reverse, requiring some unique steps and a very high voltage bench charger.
The second hardship batteries face, and the next most serious burden, is cycles. A cycle is a discharge/recharge event. Optimally, cycles should be kept small, that is, shallow. The battery should be allowed to get only a tiny bit discharged before restoration of charge ensues. If the discharge is signifcant (headlight left on all night, starter cranked too long or too often), then the recharge will have to be commensurately heavy, and you have what is called a "deep" cycle. You have no doubt heard the term applied to marine batteries which are designed to accept unusually large discharge/charge events. Most batteries however are not, and the deeper the cycle, even for the marine battery, the shorter the battery's life will be. Deep cycles can happen from infrequent use, or by the use of electrical accessories that constitute an unusual drain on the battery, or by bad connections or faulty alternator regulation that can send electrical spikes into the battery. The frequency of the cycles is also important. Battery engineers design into batteries a known number of cycles, say 3500. Upon reaching that number, the battery is physically worn out. So both the depth of the cycle and the number of cycles determine battery life.
The third thing harmful to batteries is temperature changes. A battery's chemical construction makes it prefer a very narrow range of temperatures, ideally 68 to 75 degrees F. Below that the battery is sluggish and if made to work has to try harder to do work it could more easily do at a higher temp., and above that and the battery is a little hyper chemically and this hastens its deterioration.
Finally, the fourth thing that affects battery life is vibration. Excessive vibration loosens plate material which of course reduces plate efficiency but also allows the accumulation of material at the bottom of the cell that can interfere with proper plate electrical function. Most battery boxes on powersports vehicles have vibration and shock absorbing padding to limit the battery's exposure to vibration.
A few tips on battery maintenance. If you are going to do your own battery maintenance you need some tools. If a flooded cell battery, you need a hydrometer as it is most reliable way to measure the battery's state of charge after being bench charged. It does this by relying on the fact of that sulfur redistribution into the fluid I mentioned above. The more sulfur has been scoured from the plates and sent back into the fluid, the higher the tool's reading. It looks at battery charge from almost a physical, mechanical perspective. Very useful. If your battery is AGM, you will use instead a multimeter set for DC volts, and you will measure open circuit terminal voltage, that is, terminal to terminal voltage with nothing attached to the battery. Another mandatory tool is a load testet, and the only one properly matched to smaller powersports batteries is one you will make yourself. It's easy. Simply pick up a 2 ohm, 100 watt wire wound power resistor from Allied Electonics for about $25. This tool does the very same job as instruments costing up to $1000.
Flooded cell batteries have vent hoses. You don't want to pinch this hose, and if it falls off the acid solution will more easily get on the motorcycle or vehicle. Don't route the end of the hose carelessly near exhaust or chassis parts, especially the bike's drive chain. Keep chemicals away from the battery's case, keep terminal bolts tightened with a wrench, not simply a screwdrive (but not too tight), keep the terminals coated with grease to ward off corrosion, and if corrosion starts clean it off with a paste made from baking soda and water. Don't get any of that stuff on you though, it will burn you and your clothes.
Speaking of danger, batteries can not only chemically burn you, they can explode also. Remove watch and ring while working around your battery, and carefully avoid sparks and short circuits. One rule pro techs follow to minimize sparks is to remove the negative cable first and reattach it last, and they watch where their wrench or screwdriver is in proximity to the battery at all times.
Powersports batteries, even those well taken care of, are apt to not live as long as their automotive counterparts. The above reasons explain much of this, but consider also that their small size, necessary to fit into very compact vehicles, is against them as it requires them to be working at full capacity pretty much all the time. Add to this the relatively crude alternator systems found on most powersports vehicles, resulting in harsh, abrupt recharge scenarios, and you can see the powersports vehicle has a difficult time of it.