Di2 gears

Brainless

Member
Sep 14, 2018
74
32
Bradford
Quick one for guys using it, tried out the 900e today .. wow. I asked merida guy if gears would still work if battery power died, he said yes because the Di2 needs very little power to operate. So out I ride on demo bike, and I thought I would try gears with power switched off and found the gears would not shift ???? , the bike I must say was amazing I tried 8 bikesin total and I’m now back to square one ?
 

MattyB

E*POWAH Elite World Champion
Jul 11, 2018
1,266
1,279
Herts, UK
Would they change with the bike switched on and the assistance set to off? That behaviour would seem imply Merida have tapped a feed off the motor battery for the DI2, which I suppose makes sense in that it avoids the cost and complexity of a dedicated battery for the gears.
 

Brainless

Member
Sep 14, 2018
74
32
Bradford
Would they change with the bike switched on and the assistance set to off? That behaviour would seem imply Merida have tapped a feed off the motor battery for the DI2, which I suppose makes sense in that it avoids the cost and complexity of a dedicated battery for the gears.
Good question I never actually tried that dohh lol
 

mark.ai

E*POWAH Master
Patreon
Jul 10, 2018
828
593
Windermere
Yep they do work with assistance off so long as bike is switched on like MattyB suggests. The lowest I've run my battery so far is to 3% but what Kangr says gives me hope they would keep working when it runs out. I will have to try it someday just to find out :)
 

MattyB

E*POWAH Elite World Champion
Jul 11, 2018
1,266
1,279
Herts, UK
Looks like DI2 batteries are a two cell lithium ion of nominal voltage 7.4V...

Shimano BT-DN110 Di2 internal mount battery | BIKE SHIFTERS | Evans Cycles

Based on that price (~£125!) I think it is a very good idea they have tapped this off the main battery! I also agree that the tiny current needed to operate the gears and the fact that the BMS will not allow the battery to be discharged to a level where it could not supply that current means this would be a non-issue in practice; you’d probably have to be peddling multiple hundreds of miles unassisted before shifting would stop.
 

davowood

Member
Feb 14, 2019
5
3
Australia
Correct. I’ve run out of juice a couple of times now - it holds some charge in the ‘off’ mode to allow gear changes. This is different to when the battery is actually off, bear in mind.
 

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