Shimano ultegra Di2

[Iron]

oops my battery is external

so you would then need to try get your hands on DN-100 ( in sa i think not possible ) so considering the cost its best to then get a new Batt  DN-110 fit it internally , upgrade some wires and ew90 junction as well as firmware .

[splat]

so you would then need to try get your hands on DN-100 ( in sa i think not possible ) so considering the cost its best to then get a new Batt  DN-110 fit it internally , upgrade some wires and ew90 junction as well as firmware .

 

https://www.cwcycles.co.za/product/shimano-internal-di2-battery-bt-dn110-1

[DuncanCT]

oops my battery is external

For external battery you need a more recent battery mount.

 

'Shimano also tells us that the BM-DN100 external battery mount can activate Synchro Shift too.'

 

https://www.bikeradar.com/road/news/article/shimano-synchro-shifting-ultegra-6870-dura-ace-9070-49717/

[Iron]

https://www.cwcycles.co.za/product/shimano-internal-di2-battery-bt-dn110-1

dn-110 no problems , try find a DN-100 now that seems to be hard