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Nick,

I am new to Arduino but a BeagleBoard user, and radio amateur (KC4NYK). I recently read an article in Circuit Cellar on the power use of Arduino and how that facet is often overlooked and misunderstood by developers. My intention is to run an LCD on a FIO with an attached Xbee and wondered if you foresee any problems with current created by that combination while using the 850mAh battery that I got for that use. I am not so worried about how long the battery will last between charges as I am about damaging any of the components involved in that arrangement. I haven't been able to find what the maximum current allowances are on the Fio or LCD. I am using the Sparkfun LCD-09054 amber on black 2x16 display.

Thanks so much for you thoughts on that.

Regards, 73,

RT
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My intention is to run an LCD on a FIO with an attached Xbee and wondered if you foresee any problems with current created by that combination while using the 850mAh battery that I got for that use.
Current is created by the battery. It is consumed by the FIO (easy to measure), the XBee (known, if you know the ratio of receive and transmit time), and the LCD (measurable, but the data sheet will probably tell you).

The current consumption will tell you how long the battery will last (approximately).

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I am not so worried about how long the battery will last between charges as I am about damaging any of the components involved in that arrangement.
You can't damage a component by powering it from a source that can supply more current than it needs. If you could, the dash lights on your car would be in serious trouble, since there is no way that they draw as much current as the headlights. Or the starter.

You can't damage a component by supply less current than it needs. Your starter motor is not damaged by the battery on the car going dead in the winter. It simply fails to produce the desired affect.

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I haven't been able to find what the maximum current allowances are on the Fio or LCD.
What do you mean by allowances? The current that the FIO can supply to any given pins is documented. The current that the FIO can supply to all the pins is documented.

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I am using the Sparkfun LCD-09054 amber on black 2x16 display.
That "link" doesn't work.
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You can't damage a component by powering it from a source that can supply more current than it needs.

Strictly speaking that's true, but on another thread somebody (Nick Gammon, I think) pointed out that some laser pointers rely on the internal resistance of the battery to act as a crude voltage/current regulator. Not that any of the devices mentioned here are likely to be doing that.
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Thanks - Peter and Paul - still waiting on Mary . ..  ok old 60's flashback, heh!

Yeah it all makes logical sense - but experience is sometimes contrary so I always like to get a reality check from someone who is more fluent. Of course I just now find out that the FIO can only be programmed by the FTDI breakout board or and XBee Sereis 1 - and, of course I ordered the Series two when I was assembling the project. Oh well, when my Series 1's arrive tomorrow I will have 5 Xbees! 5 x the fun!

Thanks again and if you ever have any BeagleBoard questions just holler  - http://www.rarcpio.net/beaglebrick/

regards & 73,

RT
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