2010 FAT BOB OEM battery , still good always on Battery Tender brand charger when not riding. It is the large style Battery Tender.

 

Over more than forty years of riding Harley's with strictly stock batteries, I average 6-8 years of use. Trickled charged all winter and it fires right up when the snow melts.

 

( With a battery tender not trickle charger, wrong use of words.

 

Precisely.

 

A good analogy for me to understand the difference between the trickle charger and a tender was this

Trickle charger : imagine an empty bath tub with a trickle of water dripping into the tub after a while it will overflow.

Battery Tender: imagine the same scenario but with a float so it will never overflow and only add water if needed

 

Battery on my '08 Streetbob is the one that came with the bike in 11/08. On a tender jr whenever the bike is not ridden and over the winter. Tests 13.4 when taken off the tender. (Battery on '03 Sportster came with bike new in 9/03. Lasted till 11/16. Again always on. tender jr. Had to replace because tender wire clip to battery snapped and Was not discovered.)
Both batteries and the one bought for the Sportster are H-D batteries, no idea who makes them. Might be more expensive but they have served me well.

 

I had an airplane owner give me hell because one of two of an instrument's internal light bulbs, that were expensive to replace, went out on his next flight and it was my fault. I told him that when I can predict when a light bulb will go out then I would be an instant millionaire.

There is no specific answer to your question. A battery is good up until it reaches the chemical condition where it cannot store and deliver enough electromotive potential to crank your bike efficiently. Every rechargeable battery designed has a limited number of discharge/recharge cycles, no more, no less. That number is determined by a multitude of predictable and unpredictable factors and it can be a few months after a new install for a defective battery or even a few years past it's rated useful date for a good very well maintained and moderately used battery. Lots of folks here report 3-4 years or more past the 3 year useful date and some of us have experienced failures within a year of a new install.

And, it really doesn't matter what kind of battery you use as long as it is properly rated for your bike's electrical system and operating environment. The wrong battery or a cheap battery are inviting trouble.

You should expect at least 3 years with normal use, riding 3-5K miles per year, no tenders or serious discharges (left switch on) . However, the actual longevity is determined by many different factors ranging from how often you ride, manufacturing process, environment, application, care and maintenance, and just plain old Murphy gotcha.

When I can predict with certainty how long a battery will last and when a battery will fail, then I will be an instant millionaire.

 

I`m on my 5th year with the stock battery. During winter, it`s inside on the tender while the bike is in cold storage.

 

I burn through a battery about every 12 months. Its the winter temps here that ruin my Battery due to having to Park outside. I ride throughout winter, daytime temps are rarely above 5 deg C, but its the below freezing temps overnight that kill the battery, even if I attach a tender it cant keep up with the temperatures sucking the bag out of the battery.
Its gotten to the point where I literally take the battery indoors with me overnight now.

 

Make sure your battery is fully charged before you have it load tested.