Booster Pack

If you are like me, the Edge is my favorite companion on the bike.  I can't imagine biking without her.  When I begin to think about doing a double century ride or 24 hour race, a tear wells up in my eye thinking she may abandon me in the middle of my bike... Her energy capacity isn't up to the task...  How can I give her an energy boost?  Lets create a booster pack for the Edge.

My first attempt involved a 9 volt battery, but it only gave me a few hours of runtime so I kept looking.  The final design of the booster pack is quite simple.  It uses 4 AA batteries wired up to a USB cable.  This setup gave me over 30 hours of runtime on one test using 2700 mAh Rechargeable Batteries.  You can just leave it plugged into your device and it will charge it as your battery goes down in your Edge.

If you want one too, you have a few options:

• Buy a charger unit that supplies 5 volts from 4 AA batteries.
• Build/Design one yourself

The Easy Way:

I found a device that is designed to charge an Apple Shuffle, which meets our needs.  If you want this exact model, search for BA-USB-W.  It is usually available on eBay for around $15 (not including batteries).  You can also look around for other USB charging devices.  They should all work about the same.

The one I got will use your sync/charging cable to plug into the Edge.

Lets Build It:

You can also build one pretty easily.  This is much better if there is a specific length of cable you want, or is you want the smallest possible form factor.  If you are not familiar with soldering or don't have a voltmeter, I would not venture into this area as you may fry your edge.

Parts List:

• USB A-B mini 5 pin cable.  $7 to $15
• 4 AA Battery Holder $2 @ Radio Shack
• 9V Battery Connector $2 @ Radio Shack
• 4 AA Rechargeable 1.25V Batteries with Charger
• Solder, Soldering Gun, Electrical Tape, Voltmeter

Instructions:

1. Mount your Edge on your bike and plug in the USB cable.  Decide where you will mount the booster pack and cut the cable to length.
2. There should be 4 wires in there.  The red wire is the +5V and the black is the ground.  Solder the red wire to the + wire on the 9V connector, and the rest of the wires in the USB cable to the ground on the 9V connector.
3. Wrap the connections with electrical tape.
4. Plug in 4 AA rechargeable batteries.  IMPORTANT: do not use 1.5V AA Batteries as this could  fry your edge with too much voltage.
5. Check the voltage by putting a voltmeter on the end of the usb cable.  The two outside pins should be reading 5V.  With the wide part down on the mini connection, the + is on the left, and the - is on the right.  The voltage should be under 6 Volts, but above 5 Volts.  If not, check your connections and try again
6. Attach the booster to your bike and have a great ride!

After you post your event done with a booster pack to Motionbased, send emails to booster@motionbased.com with the event.  We may choose to highlight your event!

Brad

Comments

[Chris O'Keefe]

Great stuff. Will be using one of these for the Devil Mountain Double on 4/29/06. My guess is that the next generation devices will have sufficient battery life for doubles and brevets, but this is a great stop gap method for getting us through these rides. Thanks for the thought and effort in this work around.

[Stephen Waits]

You really need to use a voltage regulator here, and also break the circuit if voltage drops too low.

--Steve

[Jason]

Specifically, you need to use a "+5V Fixed-Voltage Regulator 7805" from Radio Shack.

I put one together using a link from hackaday.com. Works like a charm in extending the life on longer rides. ...I'm also working on a solar charger to wrap around my top tube. --Geek on!

[Lisander]

Hello

I thought too about 7805 and breacking the circuit but the 7805 has a couple of drawbacks:

- requires min 8 V in input to work properly
- ripple in output (a capacitor would be required)

About breaking the circ: I thought about inserting a diode, so that the current flows only in the right way. But that would also mean loose ca. 0.7V in normal conditions and the resulting voltage would be too low, except using alkaline 1,5V batteries.

Maybe someone knows better, I´m no real expert.

[Mike]

I haven't tested this one yet, but a guy posted on MTBR forum saying he used it with an Edge 305 for the E100. After 14 hours of racing it tested with 30 plus hours left.
http://www.apc.com/resource/include/techspec_index.cfm?base_sku=UPB10&tab=models