DI2 External battery pack??

jonnywipeout

HI
I wanted to know if the Ultegra 6870 DI2 is able to be charged from an external battery pack? Like 1 I use for my GoPro for example?? Or does the DI have to be charged using a wall plug socket only?
Would be handy to take a small battery pack on long rides if the DI2 battery was only say half depleted? As its better to fully deplete then recharge these type of batteries isnt it?
Apologies if this has been threaded previously
Regards
Jon

964cup

Given that the battery lasts something like 50 hours of normal riding, how long are you planning to ride? And no, it's better NOT to fully deplete lithium-ion batteries. You're thinking of Nickel Metal Hydride, which is a much older technology.

father_jack

How about having this on the bike to charge the DI2?

http://www.ebay.co.uk/itm/Mighty-Max-12 ... 1548868980

ben@31

My external Di2 lasts a month between charges. Otherwise there's a fault somewhere that's draining the battery.
The way I see it is Di2 only makes an electrical circuit (switched "ON") when you press the gear change button and the dérailleur moves the chain. Then the rest of the time it's open circuit (switched "OFF" ) waiting.
This is the charger I have. Its very small, weighs nothing so you can take it away on cycling holidays. Uses that type of cable that my mum and dads tape player used to use. Like a 8 but on its side.

http://www.wiggle.co.uk/shimano-dura-ac ... y-charger/