There are many things to consider as you wrap your bike up for winter such as ensuring your fuel does not go stale, but the electrical system needs attention too. One of the most common failures when placing your motorcycle in storage is the battery losing charge and eventually becoming damaged beyond repair.
Causes of battery failure
Most vehicles have a residual draw that slowly saps power from the battery even with the ignition switched off, but this is exacerbated by the fitment of alarms or other after market accessories. I highlighted this in an article I recently wrote for webBikeWorld reviewing the HealTech GIpro gear indicator, which was flattening my battery in about 3 weeks.
On top of this batteries also have a natural dissipation of the charge over time as well and require regular top up charges to remain in optimum shape. When a battery is left for a long time in state of discharge a reaction occurs between the lead and the acid that results in lead sulfate resulting in what is known as a sulfated battery. The longer the sulfation is allowed to progress the more permanent damage is done to the battery.
Another issue of long term storage of a lead acid battery is stratification, which is the separation of the electrolyte in the battery. The water and the acid will eventually begin to become distinct layers in the battery with the water forming on top of the acid, which can cause greater corrosion to the lead plates. Charging helps to mix the two again as does moving the battery. So riding your bike is one of the best cures for stratification!
Corrosion
In humid environments electrical systems often begin to corrode when they are left sitting for extended periods of time. This leads to poor operating performance, which can manifest itself as dim headlights or a dead horn. Sometimes the motorcycle will no longer be able to start as the earths have stopped passing current.
Problems with the wiring or electrical systems can be very hard to diagnose and may take hours of probing with a multimeter. In general the more modern the motorcycle is the more complex its electrical system will be.
Battery maintenance
To protect yourself from these problems there are a couple of simple defences you can employ. When placing a motorcycle into storage always ensure the battery charge is maintained. Preferably the battery should be removed from the bike and brought inside so that it is not exposed to extremes of temperature. Regular charging of at least once a fortnight is then required to keep the battery in top condition.
The best chargers for this duty are called battery tenders or trickle chargers, which as their name suggests gently ensure that the battery is always charged up. Some of the more expensive chargers are also smart enough to be able to recover partially damaged batteries and attempt to reverse the destructive sulfation process.
Wiring and general electrics
The wiring and electrical systems need to be protected from moisture so connections should be coated in a non-conductive hydrophobic material. Often this can be as simple as daubing the connectors in some grease such as the copper slip used behind brake pads or just about any anti-seize lubricant. This serves as a water repellent layer over the metal of connections and prevents corrosion.
When selecting the grease to you it is important that it does not conduct electricity if you plan to use it on connectors with many wires. Otherwise you may end up inadvertently shorting out some wiring or a connector, which could lead to expensive damage or a poorly running motorcycle.
As you bring the bike back out of storage in the spring it is a good idea to thoroughly check that all the electrical systems are operating as you would expect. You dont want a car missing that brake light!