10 August 2008: Scratch another 2nd year goal

Category: Photos
Posted by: mike
Friday, 8/1 - Hanger
Paul gave me some spare parts that might be useful in the quest to extend the time range away from an electrical outlet to 5 days.

Saturday, 8/2—Haaserpalooza
The 5th annual Haaserpalooza (family reunion) was fantastic again this year.
Because I intend to complete a four day, three night, full pack, mountain shake-down hike in early/mid September, extending the C-leg battery range has become a high priority. I took advantage of the combined electrical expertise of nephew, Judd (Marsha's son) and son-in-law Chris (Erin's husband) to complete the "5 day power supply" goal. We started late Friday evening with an intentionally close to dead C-leg battery. The C-leg was charged while tracking current consumption and time. Armed with enough information too be dangerous, Judd, Chris and I visited local hardware and electronics stores in pursuit of a light weight, prepackaged, 12 volt, lithium-ion (great energy to weight ratio) battery pack and charger. (The charger is too bulky but I won't have to carry on the shakedown hike. Chris is hoping to find a way to charge the portable batteries with the C-leg charger to minimize pack weight) I bought a rechargable drill that had every thing we needed. We had to make a short adaptor cord to transfer power from the portable drill batteries to C-leg - everything else is "off-the-shelf".

- drill/charger/2 battteries - - (above) - - spare battery -
- stripted down battery pack - (below) - Otto Bock car charger -

home made adaptor

It looks like each 5.7 oz battery pack will supply enough power to operate the C-leg for about 3 days. (Click read more for test data) That will be verified over the next couple of weeks. This system may not be optimized yet. I have been in contact with Scott Rogers (trail name One Leg Wonder) an AKA that hiked 2000 miles of the AT in 2004 & 2005. Meeting him on the trail in 04 has inspired my aspirations. Scott said he'd send his battery pack and there is good chance Otto-bock might even come up with something better.

Portable Power Supply Data

8/10 night - did not charge leg - charged porable battery packs "A" "B" & "C". Standing note: car charger is disconected from battery pack when in use.

8/11 morning - charged leg for 1 hr from fully charged pack "A" (8:30-9:30)
Milage = About 1 mile
8/11 night - did not charge leg or pack "A" (9:30)

8/12 morning - charged leg for 1 hr from pack "A" (6:15-7:15)
Milage = About 4.5 miles (7 io laps aroud the pond)
8/12 night - did not charge leg or pack "A" (9:00)

8/13 morning - charged leg for 1 hr from pack "A" (7:15-8:15)- (third day on the first battery pack)
Milage = About 1 mile
8/13 night - did not charge leg or pack "A" (9:00)

8/14 morning - charged leg for 1 hr from pack "A" (8:45-9:45)- battery charge LED was on (on=dead to 1/4, fast blink=1/4 to 1/2, slow blink 1/2 to 3/4, off=3/4 to full) Used the conventional 115ac wall charger for one hr just make sure the leg was ok - slow blink
Milage = About ? mile
8/13 night - did not charge leg recharged pack "A" (9:00)

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mike wrote:

Judd & Chris,
Great job on the power supply. I'm on the third day with the first battery pack; the blinking LED on the Otto Bock car charger showed the leg still carried significant battery life from yesterday and when I pluged Pack "A" into the drill - got all four status lights. It's acting like it has a full charge. HOME RUN!
Thanks again.
Now; how do we shrink the Milwaukee charger? Or; do I carry a couple more battery packs and leave the charger in the "bounce box"?
-- 13 August 2008 09:33:04

noel wrote:

congrats on your new geeked out leg! i have a huge nerd crush on chris and judd right now....it is pathertic how feats of engineering make my heart go pitter pat. HA!
-- 21 August 2008 17:52:36
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