I have had the P5 for year, riding it most days for ~2h – love the bike (after a few issues got corrected on warranty, 1) switching plastic bottom bracket cups to metal ones because of constant bottom bracket clicking noise, 2) switch out steering bearing because it broke).
However, charging the battery BTR1 every few weeks or so and having to remove the back wheel, fishing out the battery etc. became too much of a PITA so I finally switched to the internal battery BTR2. (Actually, why Cervelo didn’t ship the P5 with the BTR2 after it became available I can’t really understand – hope it ships with the BTR2 now). Anyway, after reading a few posts of people who have put the BTR2 battery into the seat post, which is fine of course, here is how I did it by just putting it into the original space where the BTR1 used to be. I thought it would be more difficult but it’s actually super-easy:
- Get the internal Shimano battery BTR2 and the charger BCR2 (doubling as firmware update device) – no additional cables needed.
- Take out the old battery BTR1 and also the battery holder that used to hold it, unplug the battery.
- Wrap the new BTR2 in bubble wrap (I used the stuff the battery came in), put some tape around it, connect it to the cable that the BTR1 was connected to, put the whole thing into the frame where the BTR1 used to be.
- After downloading Shimano’s E-Tube Project update the firmware of all the electronics by connecting it to the little connection box SM-EW90B (after making sure you switch to the TT shifters in E-Tube etc.).
- Voila, now you can charge the battery via the same plug and you can update the firmware yourself (and change details like speed of shifting etc.) because you have the BCR2.
Mike