flanso 

The internal battery on my Di2 bike is almost 5 years old. It works fine and holds a charge. But I am wondering what is its life expectancy?

ft3safety

I think it depends on a lot of factors such as how hot it gets (do you ride in Phoenix with 110F weather)? Is it stored in a garage with sub zero temperatures? I have first gen Ultegra Di2 on my 2012 BMC and am still using the original battery. I never ride below freezing, it's stored at room temperature and rarely ride when it's over 90F. I put about 5k miles a year on it and charge it 4-5 times annually. So it probably only has 28-35 charge cycles. If batteries last 300 charge cycles I think it still has a bit of life left.

cutdbeard

In my case that was about 3,000km after I changed it.

Rogerogeroge

I got the first gen di2 (7900 series) in 2010. Rode it for seven years. The junction box went out so I didn't ride it for three years, but I replaced the junction box this year. I kept the bike the whole ten years in my garage which gets very hot in the summer and fairly cold in the winter (East TN winters are usually mild, but we have single digit temps sometimes). Battery life is good and it still holds a charge.

sch

My two Di2 systems are both external batteries, one dates from 2013 and the other from 2015. Both are doing fine though I probably didn't do either
any favors by charging once/month for 2-4 yrs. Now typically every 2.5-3 months when one bike with a battery readout falls to 40% charge, both are
charged. They are stored in a garage which goes to 90-100F in summer. Li battery failure is manifest by failure to hold a charge, ie a full charge only
lasts a few weeks or few hundred miles. Considering the significant price increases in Di2 batteries and chargers I would be in no hurry,
ie ext batteries were $45 in 2016, now $80. Considering price drops in Li flashlights over the same time frame......

TerryDi2C

Shimano claim that it'll last (at least) 300 (or was it 500?) full charge cycles.

(obviously some fail before then, but that's what Shimano say)

Polaris OBark

I have a similar question, so found this in a search. The difference is my battery is nearly 10 years old, but it works fine and holds a charge for 4-6 months, still.

(I finally developed upgrade-itis, but hate the idea of tossing/mothballing a perfectly good battery, unless it is near EOL.)

Apologies for the necro-post.

Steve B.

I recall reading about 3 years expectancy. Mine is now 5 or 6, still runs 6 mos. I did have a bunch of early fast drains on my mt bike with XT Di2, replaced the battery, had same issue, had a shop look at it, bad shifter. Replaced shifter for $90, all good. Put the extra battery in a drawer.

rm -rf

After 5-6 years, my original 2014 Di2 seatpost battery was getting to blinking green after 10-15 hours (around two weeks approx). So I replaced it. The new one is a newer model number, and so far, I'm not noticing shortened hours.

I shift "all the time" on the local rolling hills and variable headwinds. I charge when I notice blinking green (under 50% charge), and check every few rides of approx 3 hours each.

Polaris OBark

I have the same one, from 2014. It still holds a charge, but I am starting to think having the bluetooth features and syncro-shift might be nice.

veganbikes

Blueteeth felt nice the couple times it worked for me (though that could be my placement of the WU111) but the synchro-shfit blew up my front derailleur at the start of a long ride as it shifted me at the front while up a hill and really did me dirty (though Shimano replaced the derailleur no problems it just sucked at the start of a 160 mile ride and me not wanting to pay the difference to upgrade to Dura-Ace with my boss who had a derailleur but not Ultegra.

In the end I am sure synchro shift is probably great and I just had a bit of bad luck thanks to my generally poor shifting sometimes and having used E-tube on my phone for other bikes it is great. However I don't think in my position I was better off for them.

Polaris OBark

I was going to start off with a very conservative semi-syncro program, but you are making me think that if everything worked fine for 10 years, why change a winning game?

This was mostly motivated by my new AXS mountain bike that I have barely ridden. It is nice looking at the bluetooth display of gearing. But I can always look down to see what gear I am in, and I shift by feel anyway.

Thanks! You saved me $250 (or divorce court, if I swapped batteries with my wife).

phughes

Holy moly! That's a very expensive 3,000km! I honestly didn't think they were that short lived.

Polaris OBark

I've got about 55,000 km on mine (or about 35,000 miles, i.e., about 3,500 miles per year for 10 years), shift a lot (steep hills where I live), I use it off road frequently, etc. Mine still seems to work as it did new. It is the older, 2014 non-bluetooth version.

phughes

That's much better, but 3,000 km is seriously low mileage for the battery to be bad.

Polaris OBark

I wonder if he has gone through 3 or 4 more in the intervening 4 years since that post?

[The thread bump is my fault.]

flanso 

Almost 4 years after the original post, my Di2 internal battery from 2016 is still going strong. I plan to keep riding with it.

sch

4 yr update: the 2013 battery has 20k miles on it and still holds a charge for 3 mo and ~600-800 miles of riding. I rotate
between 3 bikes and get roughly equal mileage on them annually. The 2015 battery ditto at about the same total mileage.
Miles per charge at least 800.

Polaris OBark

Thanks for the update. I don't feel as guilty now for bumping this thread.

BTW flashing green means 75% to 50% charge, and then flashing red is 50% to 25% charge, and solid red is the last quarter. I charge mine only when it gets into the flashing red zone. I can't say that is why mine has lasted as long as it has, but it might be part of it. I suspect the other part is it is not got bluetooth capability, so potentially fewer demands are placed upon it.