Hi Mike,
Thanks for getting back to me!
Yes, I plan on a custom Li-Ion pack for power. I really want to be able to run for over 8 hrs a day without recharging.
For that kind of power, Li-Ion is really the only answer.
Dan
----- Original Message ----
From: Mike Morley <
mjm80@cam.ac.uk>
To: Dan Brown <
dan@lantzer.org>
Cc:
balloon@balloonboard.org
Sent: Monday, August 21, 2006 5:05:30 PM
Subject: Re: [Balloon] Balloon 3 Questions
> 5. How are they looking as for as power usage is concerned? (My
> application is in wearable computing...)
I can only really answer question 5 from our experiences here at CUED.
Typical current draws are 100-200mA, and we're developing three
different battery technologies:
For robotics within the department, ~2.5AHr batteries at a nominal 12V:
- NiMH pack - lighter, but considerably more expensive. We're
currently experiencing problems with our charging circuits.
- Sealed Lead-Acid - heavier, but around 1/3 the price of the NiMH
packs. I've got a working demo sitting on my desk, and am currently
routing a small PCB.
For the PDA being developed, we obviously had to go with Li-Ion for the
weight saving, and - for convenience - I selected the Nokia BL-5C
battery - 900mAHr at 3.7V. The beauty of these are we can run them in
parallel to get almost 2Ahr, and they're easy to charge -- either in a
Nokia desk charger or a phone like the 6230i (Which both I and Chris
Jones have)
I hope that's of some help - I imagine for wearable computing you'd want
to save as much weight as possible and go with Li-Ion (even the NiMHs
weigh in excess of 0.4Kg
Mike Morley
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