Edge electric connections to Garmin Charge Power Pack

+1

I am also looking into custom uses for the bottom contacts on the Edge. According to a comment on a review website, "If you look at the Garmin from behind, it's 2 a.m. plus and 8 a.m. minus. The remaining contacts do not seem to be occupied. You can probably only charge the Garmin in one position"

My experimenting indicates that you can rotate the Edge 180 degrees around and still charge, which is what I expected. Many of the Garmin watches use a charger that can also be rotated 180 degrees around and they work (both charge and data) in both orientations.

I presume that one of the other three contacts on the bottom of the Edge reports battery voltage (edit: no, I think I'm wrong about that), and I hope that the other two would be USB data, but I haven't been able to get them to work yet.

Garmin-Matthew I don't suppose the pinout and signaling on the bottom connector of the Edge xx30 computers is something Garmin is willing to provide? Or does everyone need to reverse engineer it themselves?

Yup, a waterproof connector for charging edge computers is a must for bikepackers. 

As there are power on the pins, I would say there is a digital hand shake / communication between the devices other way would be very dangerous to carry the battery pack near other metallic objects like keys on your pocket. Electric car "chargers" works this way, they first hand shake before enable power on the pins other way would be to dangerous!!

This hand shake is probably some proprietary encrypted communication meaning no way to replicate it, so, no DIY for anyone.

Other advantage is that Garmin locks the users like us and so they protect their business, Garmin is a very closed company.

I developed what I is the very first OpenSource technology for Edge, I would like to share with you guys:

Give a look to the OpenSource Garmin Edge Remote Control I developed, costs only 18€ in materials, very easy to build DIY.

See all the information on the project page: https://github.com/OpenSource-EBike-firmware/ebike_wireless_remote

An idea is to use an original power pack and reuse the same electronics but exchange the lithium cell for a desired one. I have a friend that does this on electric cars because all the electronics are locked with proprietary encrypted communications from the battery pack to the car electronic control unit / main computer.

@lllllluuuu The handshake would only be needed to prevent the battery from discharging and maybe causing a fire. In this case, the Edge will accept a charge on its two contacts even without the proper handshake. It may just be a one way handshake: the battery provides high impedance voltage and once the Edge sees it, it sends a signal back and the battery goes low impedance.

As it is now, the Edge will take a charge on the two pins mentioned previously. I have tested it by appkying 5 volts and charged my unit.

Thank you for the wireless project. I may try that myself...

As it is now, the Edge will take a charge on the two pins mentioned previously. I have tested it by appkying 5 volts and charged my unit.

Good to know!! So I would say, for charging, it is ready for direct 5V connection from a USB cable.

I found an example of communication of a battery pack to a computer, this can help for any future understanding of this project. The guy had to understand the SMB communication between the computer main board and the battery pack BMS:

Open source Thinkpad T420 battery design

- https://beta.aceparent.me/#/battery

- github.com/.../ThinkpadBattery

Is this still relevant?

I have malfunctioning one. Will tear it down.

The answer above is correct.

Yes, all information that we can have is relevant.

You could also create a free repository on GitHub to put there any text notes and pictures. Thanks.