Community Alumni
Dec 15, 2016The problem with just disconnecting a battery is sulfation, something that slowly kills every lead acid battery over time. The natural byproduct of a discharging battery is the formation of lead sulfate. Once discharging beings so does sulfation. This sulfation sticks to the negative plates and, if left unattended, hardens onto the plate.
Batteries naturally discharge 1 to 15 percent per month with older batteries self discharging more than new. There's plenty of time for sulfation to take place in a battery that's resting and slowly discharging. The more a battery discharges, the more sulfation takes place.
Time between charges is really the enemy. Not charging a motorcycle battery for just 2 months is enough severely shorten its life and performance. Charging reverses the process of sulfation by causing the sulfate to reincorporate back into the electrolyte solution, however, this only works if the battery gets a charge soon after it's begun discharging. If not, the sulfation will begin to harden onto the negative plate and no amount of regular charging will reverse it. The battery starts a downward spiral of accumulated sulfate from normal discharges and self discharges. The harden sulfate reduces the surface area where chemical reactions can take place and you're left with a battery that struggles to hold a charge or won't take a charge at all. This is one of the reason why every lead acid battery will eventually fail.
The best way to reduce how much a battery sulfates is to keep the battery in a constant full charge state. This is how regulated trickle chargers help prolong the life of batteries. Since regulated trickle chargers are safely keeping the battery in a constant full state, the sulfate ions stay incorporated in the electrolyte solution and not sticking to the negative plates. It's also why our friend above has been able to get their battery to survive for 9 years as opposed to the typical 3-5 year life of a marine / deep cycle battery in trailer applications.
Most never give a second thought to replacing a failing battery once it's reached 5 years old. You constantly read comments to the effect of, "Once you're past 5 years then you're on borrowed time." But a battery that's been diligently maintained can easily last 10+ years.