Putting a new battery in your motorcycle shouldn’t be a big deal. Depending on the make and model of your bike, it might be as easy as popping off the seat and undoing two bolts so you can slide the old one out and the new one in, then tightening two bolts and you’re done. On other bikes—I’m looking at you, R 1150 RT!—swapping out the battery could take an hour or more simply because of the sheer number of tiny bolts fitted through the plastic body panels.
No matter which bike you own, it pays to look at the papers in the box with your new battery, especially if you bought it online and had to have it shipped to your house. Because of the nature of lead-acid batteries, they can only be shipped via ground services, and to be perfectly honest, even though it’s new, you don’t know how long it may have sat on a shelf in the warehouse, waiting to be put into action.
Some batteries ship from the factory fully charged; others leave the manufacturer in an uncharged state, having only been subjected to routine testing to ensure proper functionality. Old-fashioned lead-acid batteries used to arrive with a package of distilled water the user had to put in the battery to activate the electrolyte and get the battery ready—then charge it fully to boot! Newer absorbed-glass mat (AGM) lead-acid and lithium-iron (LiFePO4) batteries don’t require that level of end-user intervention, but when you pull them out of their box, take a look at the papers included in the package.
The page neatly folded into the box with an AGM battery I recently purchased even said “IMPORTANT INSTRUCTIONS” on it, an obvious clue to its use. In included some safety instructions along the lines of “this is a sealed battery, please don’t try to un-seal it.” It also included an admonition to test the battery with a digital volt-ohm meter (DVOM), because they recognized the battery may have waited on a shelf for some period of weeks or months before finding its way into my hands. Since the problem with my motorcycle was already a dead battery, I guess they wanted to make sure I didn’t install this new battery, fail in firing up my bike, and engage them in what no doubt would be a customer service nightmare as they tried to explain to me why it was so important to make sure the battery was fully charged before trying to start the motorcycle the first time. Since my battery tested at 12.6 volts, they recommended I put it on an appropriate charger for up to six hours, which is happening as I write this so I can install the battery later today.
Any lead-acid battery will discharge slightly as it sits due to a process called sulfating, a buildup of sulfite crystals on the medium inside the battery that happens if a battery sits idle without its full charge. The whole point of a trickle-charger is to prevent the sulfating stemming from a lack of use.
Even without the presence of vampire draw—the electrical needs of the bike when you’re not riding it, which could be as simple as a digital clock—the typical lead-acid battery can self-discharge at a rate of upwards of 20% per month. Warm weather exacerbates the self-discharge rate possibly even beyond that, which is why it’s a great idea to keep your bike’s battery on a trickle charger unless you ride it regularly, say two or three times a week for a few hours each time. Most lithium-iron motorcycle batteries have a far lower self-discharge rate, typically from 3.5 to 5% per month, but as with lead-acid batteries, the self-discharge rate is affected by the weather. Important to note here is that LiFePO4 batteries require a different charging program than lead-acid batteries, so you may need to use separate chargers for the two types of batteries. Some chargers—such as the Optimate DUO line, $49.95 for the most basic model—have the ability to charge either type of battery (be sure to follow those instructions as well). I highly and regularly recommend Optimate chargers to anybody who asks, and you can get them on Amazon if your local car or motorcycle shops don’t carry them.
When disconnecting a motorcycle battery, always disconnect the negative ( – ) fitting first, then the positive ( + ). Disconnecting the negative side first avoids causing an electrical short, which can happen if you disconnect the positive first and accidentally touch something metal with the wrench you’re using. Installation is the reverse of removal, so when connecting the battery, start with the positive lead, then hook up the negative. Make sure the terminals and all fasteners are clean. Tighten the fittings snugly, and don’t be afraid to use a small amount of dielectric grease to help prevent corrosion.
It takes just a few seconds to read the instructions included with your new battery (or other part), and following those instructions can help give your new battery a full life. With the prices of seemingly everything increasing all the time, getting up to five years of use out of a motorcycle battery is all the reason I need to own a trickle charger and use it on my new battery—as instructed!