I have Di2, but my Sram buddies talk about wanting to bring a spare battery along on non-epic rides as they aren’t confident in iron-clad reliability of the 2 on-board Sram batteries.
The only issue I’ve seen with Di2 batteries are from people forgetting to charge them because they need such infrequent charging.
Never had my SRAM battery die on me. Only take a spare for races, just as a precaution. Not from previous bad experiences.
Absolutely
Well to each their own I guess. Sounds like Shimano is going to a SRAM-style battery layout, so better stock up on current Di2.
Well I just sold my Di2 bike and my new ride has wired Campy EPS 12, so I’m set for the near future.
Put me in the camp of liking the current fully wired Di2 setup. I don’t get why people dislike this. It’s not like you are setting it up multiple times. Yes if takes more time to set it up the first time compared to SRAM, but after that the single, longer lasting battery is awesome
100% prefer the Di2 battery setup. Way bigger battery that lasts longer. And I never have to see it so it’s better looking. Two exposed batteries on SRAM is absolutely a drawback.
The exposure does not seem to be a problem, even in rougher environments (their MTB groupsets use the same battery).
In practice, it seems to be equivocal: Di2 has a longer-lasting battery, but it is harder to charge. With eTap batteries, you can always bring a spare with you. (One former team mate’s Di2 battery ran dry the day of a race even though he had charged it the night before. He fortunately found someone who brought the cable.)
There are some pretty obvious drawbacks. Ever wonder why there is no Shimano 12-speed Di2 mountain bike groupset? (I know DuraAce is a road groupset, but SRAM can use developments for eTap for both, dropbar (= road and gravel) and mountain bike groupsets. Here are a few more:
The last point will force Shimano to take one of three options:
This. I cycle my two eTap batteries (I have a 1x setup) so that both are always charged. It is simply peace of mind, and I know I am never left stranded in one gear.
I meant like exposed as in, I can see them. And there’s two of them. Both drawbacks in my eyes. Shimano Di2 just looks sleeker.
Harder to charge? I didn’t realize plugging a cable in was difficult. How is this harder than removing two batteries and having to put them on a charger. That seems harder to me.
Not really a plus to add weight. And Di2 lasts so long I’ve never worried about battery life across any of my bikes.
I get an alert in my Garmin. Low battery and Critical. With low I can still get 3-4 rides on it. So probably 8-10 hours when you hit low. I have Di2 on 3 bikes with around 12-14 total years of use of various Di2 iterations. I’ve only hit Critical one time and was still able to finish out a 2 hour ride. I’ve heard it will stop FD shifting to save battery life but I’ve never gone that far.
My peace of mind is knowing my battery is so much bigger that I never have to worry about it dying on a ride. 
I know people love the exposed batteries of SRAM. That’s all cool. I just don’t. I would 100% choose the hidden battery every day. I’m vain and think Shimano looks so much better than SRAM. I don’t like the look of the exposed batteries. Plus it’s just one (or really two) more things for me to lose. Di2 is always with the bike. People always talk about forgetting to charge their Di2 before a race or big ride. How about traveling to a race and realizing you forgot the batteries at home on the charger? I’ve seen that before. I’ve never forgotten my Di2 battery.
In the end it really comes down to personal preference. Some people prefer exposed batteries that can be removed. Some people prefer the single internal battery. And as we’ve seen, people will argue about which is better until they’re blue in the face. It’s a tale as old as time. Just pick the one you want and be happy.
It’s a problem to my eyeballs.
Yep, my thoughts exactly
I have had a sram battery die on a ride (why no battery warning at say 50% and 25% sram?). Swap front to back and keep going. I have had friends with Di2 have their batteries die. They get stuck in the small ring and have to spin spin spin home (maybe there’s a way to change this?). Oof.
How long will di2 batteries last and how much are they to change?
That said… I’m very close to pulling the trigger on a di2 bike. Pros and cons. Both systems are fine.
I’ve been a Shimano fan boy forever but I think my next bike will be SRAM. It just seems better in nearly every way, especially for offroad riding.
That would be a dealbreaker right there for me. No battery warning? Nope I’m out.
How long do AXS batteries last? Honet question, I never really looked into it. Do most people charge them every ride? Because again, having to charge them even weekly would be rather annoying.
I get your arguments about aesthetics, but I do think it’s far easier to just take off a SRAM battery and bring it to the charger than to try to find a place with the space and a wire long enough to charge a DI2 battery and angle everything where you can see the light to know when charging is complete. Plus, I hate their weird connection.
I charge mine maybe every 750 miles or so? I’ve never actually thought about it. I just charge them every month or two when it occurs to me.
So 4, maybe 5 times a year I have to put my bike next to an outlet and plug in a single cable. Compared to having to pull two batteries off the bike and place them on the charger, then pull them from the charger and put them back on the bike every 2 week?s How is that easier?
It’s easier because I don’t have to find a place in my house to put my dirty bike that it and the charger won’t get in the way and I don’t find it difficult to unclip a battery from a derailleur.
I don’t either? Do you not have plugs elsewhere? I mean, whatever works for you. I don’t even have to move my bike anywhere different than where I normally park it. So it’s 5 seconds every 3-4 months to plug in a cable. I don’t see how it could get any easier. But I guess it’s not for everybody.
Tell me how a single cable is harder to charge than a dock and 2 batteries