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Newb Question - batteries and power


#1

Hi, I am new to the FEZ world and I had question.

I have written a small program for a FEZ Panda - a simple light display product, and it works just fine connected to my PC, but I want to install this into a piece of artwork. What battery source can I use? i.e Can I use 4 AA/AAA batteries? (6V) if so, short of connecting the batteries to the power +/- terminals, what else would I need to do?

Thanks


#2

You can power the device from 4AA batteries with no problems at all.
You might want to have a look at a larger battery for extended battery life.
The best battery would either be a LIPO (google it) battery (for embedding it into art) or a 12 lead acid (or similar) battery for large power and endurance.

Another possibility would be to use a solar cell with a small battery circuit.


#3

Robert,

Thanks for the quick response - for a LIPO, wouldn’t I have to charge it first?


#4

@ yonah - of course. I use single cell lipos with a step up circuit. You can get a charger for these for < $20 from several places like SparkFun. If you go with a 2 cell (or greater) lipo, you have to buy a special charger to balance the cells, and these run $35-$50. In general, I would recommend going with something rechargeable, as you will go through a lot of AA batteries otherwise.


#5

You can get 2-3 cell LiPo chargers at hobbyking.com for < $12. If you can wait for shipping from China this is the best place I’ve found for LiPos and chargers.


#6

The question really is how long do you need it to last?

Is it a once-off deal or do you need to recharge between displays?

The Panda can be powered through the DC socket (marked 9V) with anything from about 6V (a little low for the regulator) to 12V (high - might get hot).

It will draw about 100mA minimum with nothing else needing power - so 4 Alkaline AA cells should last about 20 hours.

I find that a 7.2V NiMH battery pack used in RC toys works great. Easy to find a charger too.

I’d stay away from Lipo for a once-off thing because you will need a decent charger and you need to balance the cells. Not very newb friendly :slight_smile:

Having said that, it is about time we got a nice design for a standalone Lipo battery system for the Fez’s that is easy to use from beginner to professional.


#7

There’s also another un-asked question that we need to know. What else are you powering via the Fez today? What exactly is your “light display” and is it powered separately or via Fez? That can have a huge difference in how long any battery will power the circuit for.

For instance, if you are powering one or two LEDs then that’s relatively small current consumption compared to the Fez itself, but if you’re powering something else that consumes as much or more power than the Fez then you may find you have minimal run-time unless you use something “large”