Di2 new charger style?

[redfalcon]

So Calfee has a new charger that lets you charge your internal battery by plugin into the harness at a derailluer point.
are they using some magic or can this trick be used with other batt conversions?

"We are very excited to introduce the Calfee Inline Charger for Dura Ace Di2. Simply unplug either your front or rear DA Di2 derailleur and plug our charger into the wiring harness. Our charger returns power to our battery through the DA internal wiring harness. You no longer need to remove the seat post to recharge our battery. This product in immediately available and is compatible with any Calfee DA Di2 installs, past or present."

[toiyuet]

I think it's not that difficult?

[pritchet74]

Pretty sure that's the wiring diagram for the original Di2 and not the new style.

[Jeffr]

You can't just hook power and ground to a battery to charge it. You need a charging circuit. I don't think there is one in the battery pack. It's in the charging stand.

Please keep that in mind before ruining any expensive lipo or lion batteries.

[di2diy]

So Calfee has a new charger that lets you charge your internal battery by plugin into the harness at a derailluer point.
are they using some magic or can this trick be used with other batt conversions?

"We are very excited to introduce the Calfee Inline Charger for Dura Ace Di2. Simply unplug either your front or rear DA Di2 derailleur and plug our charger into the wiring harness. Our charger returns power to our battery through the DA internal wiring harness. You no longer need to remove the seat post to recharge our battery. This product in immediately available and is compatible with any Calfee DA Di2 installs, past or present."

The only issue I have with this charger is that its only a charger, and will not balance the cells, and can actually damage the battery, or possibly cause the battery to catch on fire, as is not uncommon with LIPO cells, but it is a clever idea. since Calfee has a sealed case battery I would predict an explosion worst case. I have tested this type of charger, in fact I believe the same unit... from china <$10, and 2 out of 10 times, it did not turn off (not all that smart), and over charged one of the (2) LIPO cells. I unplugged it before it caused a fire, but it could if left on.

[Jeffr]

calfee presumably includes the charging circuit with the battery and detects external power.