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jjrr007

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Ideal Battery Hardware For Project

I am developing a remote module (not wired to a computer) that has an Arduino Uno board, 5 volt hall effect sensor, xbee radio and data logger connected together.   On this remote module,the data from the sensor will be recorded to my data logger every 15 or 30 minutes.  The xbee radio though would need to be available the vast majority of the times.

For the xbee, I will configure the sleep mode the best I can to preserve battery.  Ideally, I would like this to last a couple of years (as long as possible ) without changing/charging the battery. For now, I am purchasing the hardware.

I wanted to ask what is the best battery I can purchase for this (i.e lithium, how many volts etc)?     For this much time, I am thinking that I should use a few batteries and have something autotmatically switch or share power among batteries.  Which switching regulator and battery would be good for this project? If need be, I can purchase a voltage regulator if it's needed.
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Andy Bogus
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would this unit be outside? Have you considered a solar recharger?

Lithium would be a great start, but I would go as low in voltage as you can, because the more voltage, the faster the charge will drop.

Take a look at Radio Control car batteries, they are LiPo and are rather immune to abuse.

There are tons of options and you can then test the best one for your needs.

If anything, a couple of those in parallel might just do the trick... You will have to test your discharge rates to get an idea of the mAh you will need. But some of these RC batteries are now into the 8000 mAh range, ahead of many laptop batteries and easier to deal with.

Another option is a laptop battery booster... these pads or chunks of batteries that are designed to plug into the power port and drive the laptop when there isn't a power source. These things are pretty intense. I know Targus and Belkin made some, and another company, Electro-something made them... The last company had good batteries, but sketch customer service. The only downside, they might be too large.
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How big will this completed project be?  if there is plenty of room then a battery is no problem but I suspect you have a space limitation.
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Andy Bogus
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I am doing some rough math... the board looks to draw about 40mW @ 7v ? the radio, another 50mW @3.3v... let's be safe to assume that the unit, at full load, is drawing 200 mW.

7.2v is more than enough it appears.

I am ending up with .02 amps for the radio, and .005 amps for the board... two of those 7.2v packs = 11AH.

I am just adding the two amps together and getting:

11/.0025 = 440 hours of usage. Or, 18 straight days.

If this goes off for 1 minute at a time, it would have 26,400 hits.

Assuming that this happens every 30 minutes, you would get 48 hits a day, it would last 550 days. That's not quite 2 years.

My math is sloppy cause there are variables I don't know... so some are swags... but I don't think I am really all that far off.
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jjrr007

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sorry for the tardy reply. Thanks