How long does a battery pack last for you?


#1

Hi All,
Before I do anything serious with the BrickPi, I am testing how long a battery pack of 8x AA lasts when running a fresh install of Dexter Industries’ Linux image, doing nothing.

My first take of the experiment is depressing and I thought it would be interesting to share, and perhaps find out about your measurements. Add your lines below!

  • BrickPi without “advanced power”, run by 4x 2000 mAh + 4x 1300 mAh and powering just Edimax EW-7811Un WiFi adapter, ~ 3hrs

G.


#2

Since you are using 1300 mAh cells, they are the “weakest link” so-to-speak.

1300 mAh / 3 hours = 433ma. The RPi model A is rated for 300-500ma, and model B is rated for 700ma. The WiFi dongle will certainly add to the current draw.

3 hours is about what I’d expect if you’re using a RPi model A, but if you’re using as RPi model B, I’d expect about 2 hours.

If you use 2000mAh cells, I’d expect roughly 5 hours with model A, or 3 hours with model B.

My time-frames are estimates, and certainly subject to RPi processing load, WiFi Dongle load, etc.


#3

Great matallen37, so my measurement is actually normal. I don’t know why I expected more when not using any motors or sensors.

It looks to me then that even a good set of batteries won’t last long after I actually built something with the BrickPi using motors etc…

I wonder if it is worth it at all to invest in good capacity batteries or I should rather look for a mains power supply, as you have been discussing at http://www.dexterindustries.com/forum/?topic=power-requirements .

Another interesting question is how come the BrickPi comes with 9V clip, when almost no mains power supplies come with one!!!

G.