|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
Survey : Weight vs. battery life for bike computer?
"Cleanbean" wrote in message .. . I wouldn't use a computer with the weight of a AAA or AA. Consider using 2 large watch type batteries. John in Texas Why? You don't even know what features it would have. I suppose the original article should have at least hinted at what was on offer for the proposed costs. I did not answer because for me it would really depend on what I am getting. I would like to see a modular system. The disply could be designed like the SRM head unit and it could have some kind of open standards bus to add on peripherals. Let's say you have something comparable to the 710 but with a superior pixelated display. The add ons could incluse power from any of the systems currently available (or at least more than one). A GPS unit could be added for certain applications and otherwise left at home. "Reza Naima" wrote in message om... I'm working on designing a "next generation" bike computer. We're trying to figure out what would be the optimal tradeoffs for the batteries. We are looking at the following options (With non-rechargeable batteries you can get 2x the performance): 1 AAA NiMh Rechargeable Battery : 2 hours, 12 grams 2 AAA " : 5 hours, 24 grams 1 AA " : 4.5 hours, 27 grams 2 AA " : 10 hours, 34 grams Note that the product is designed to store ride information to be downloaded to a PC. Thus you would want the batteries to last the entire trip. However, you could always carry extra batteries with you in a separate pouch for extended trips. Let me know what you think... Reza |
Ads |
#2
|
|||
|
|||
Survey : Weight vs. battery life for bike computer?
Let's say you have a reasonable NiMh AA cell, say 1600 mah.
You have to draw 180 ma to run it down in 10 hours. That's a lot of current. 1600mah at 1.2volts. Most electronics want 3.3v, so you're looking at 581mah at 3.3v, which at a burn rate of 150ma comes to 3.8 hours based on our initial calculations. Since then, we've started doiong some measurements, and we're looking at a more reasonable 70-80mah including the LCD display. This doubles the expected time to ~8 hours which we think is sufficient for most riders. The big catch is that enthusiasts with high disposable income will view this as too heavy. An easy fix is to have an initial version with 2 D cells. Then switch to AA's and advertise "xx grams lighter." True Or, we can post the device weight w/o batteries and state it as such. Seriously, you need to budget power way better. Where is it all going? Are you using a linear regulator? Into the FLUX CAPACITOR!! I did mention the device is capable of time travel, right? We've made improvements from the 1.31 gigawatts required More seriously, a DC-DC voltage converter. Linear regulators can only reduce voltage. And finally, if you use USB for PC downloads you can sponge off of USB power and save or recharge the internal batteries. And that was the design before we consulted FCC regulations. Seems that it becomes much more complicated once it is attached to a PC. Having removable flash makes it save us lots of time and money in FCC testing. Plus, the smallest flash size is 32Megs!! That's a lot of data you can save! A future version might include a camera to snap a picture every so minutes. And the device is designed to be expandible via a multi-master bus system. So, who wants to buy some vapour-ware now? If not now, check back around xmass-time... Reza New Question : if the device could have any one "cool" feature, what would it be? |
#3
|
|||
|
|||
Survey : Weight vs. battery life for bike computer?
|
#4
|
|||
|
|||
Survey : Weight vs. battery life for bike computer?
On Mon, 14 Jul 2003 10:56:58 -0400, archer
wrote: In article , says... ... New Question : if the device could have any one "cool" feature, what would it be? The ability to import your ride data into one of those PC mapping programs, and plot your times and average speeds along the displayed map. And the ability to show you sprinting from the Yellow Jersey group at the end of the ride to leave them in your dust. Even though your ave MPH is only 18.5!! ;-) Lindsay ---------------------------- "One of the annoying things about believing in free will and individual responsibility is the difficulty of finding somebody to blame your problems on. And when you do find somebody, it's remarkable how often his picture turns up on your driver's license." P.J. O'Rourke |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
How to cycle for weight loss | Daniel Crispin | General | 163 | June 13th 04 11:15 AM |
bike computer wonkiness | Tanya Quinn | General | 7 | December 19th 03 06:46 AM |
Survey : Weight vs. battery life for bike computer? | Doug | General | 7 | July 14th 03 04:28 PM |
Survey : Weight vs. battery life for bike computer? | Doug | Racing | 1 | July 10th 03 01:05 PM |