This post is to address the issue of charging your Garmin Edge on the move. It’s been an ongoing problem for the long distance cyclist since the days of the 305. Battery life for an 800 is about 12 hours from 100% charge.
I resorted to trying to charge up my 305 in Audax control points with mixed results. As you can see an Edge 800 draws 440mA whilst charging a 50% discharged edge. You can’t get blood out of a stone and whatever system you use your biggest enemy is going to be time.
So for an Edge 800 it has to be the stem mount, conversely for an Edge 705 a bar mount may be the better option. On a 705 the charging port is on the bottom and an oversize stem may interfere with USB plug.
Do an Ebay or Amazon search for Power Bank or Power Monkey. There is a vast choice.
£70 is too much imho, bear in mind it has to charge on the move and the battery needs mounting somewhere. It needs to be robust.
Your Edge shutting down 100 miles is not something you want to see on a 120 mile ride.
The cheap emergency phone chargers are not up to the job for todays devices, like I said you cannot get blood out of a stone. They are designed for a Nokia and who uses them these days.
The same applies to smartphones perhaps to a greater degree as battery life is hopeless with all the bells and whistles on.
If your already using something that works let me know what it is
In the near future I will be making a charging regulator designed to make use of the MagicShine battery pack. The pack is rated at 8800mA/hr and will power the light for 3.5 hours. It will consist of a 7805 regulator and plug for the battery.