I replaced the junction box with an internal wiring job, there's some pics in my Sig link, more specifically, here:- viewtopic.php?f=10&t=79248&hilit=archon+di2&start=30#p738930
" onclick="window.open(this.href);return false; and there's very useful wiring diagram here:- viewtopic.php?f=10&t=67791&start=285#p699718
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FYI, after about 6 months, vibration/water ect found its way in and degraded my efforts, resulting in a dead system one ride.
For my second attempt I left the external junction box alone under the bottom bracket and just hacked the power wire for an internal battery.
That part of the Di2 system may seem expensive but imo its not a trivial or simple thing to construct. They could have made it cheap, with smaller components screwed/plugged together, but that box, and the wires in/out are totally sealed unit, and probably more expensive to make that you think. I appreciate its construction anyway and can just about justify its cost. Unlike the cheaper Ui2 box/wires which have already proven (according to recent posts here) not as reliable under longer term/harsh conditions. Fingers crossed that DA 9070 follows the 7970 method and has a maximum amount of sealed parts and minimal number of seperated connections.