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Hi there

Im currently trying to make a wirelessly controlled LED suit (with arduino + xbee + LED RGB Strip).
I would like some advice on how to power this. The LED strip is running 5V (just as the Arduino). And i'm using 5m of LED strip, in total if all white 10A of power! I would like to be able to have it on for maybe 15min or so, so its around 5Ah battery I'm looking for.
What technology of battery would you use? LiPo? And what what about if the battery is different voltage, is it a no-go to voltage regulate that many amps? I've never done stuff with this many amps before wirelessly.

Jonas Jongejan 
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I suppose it depends how many LEDs you want to be separately controlled. If you have a bunch of them that you want to be controlled together, it makes sense to power these in series to reduce the current requirements for the wiring harness and reduce the number of driver circuits needed. Of course you will need to provide a higher voltage, but as long as the voltage doesn't get high enough to be hazardous I don't see that as a problem. You need to work out how many watt-hours of power you need, and the minimum number of separate LED strands you can get away with, and hence the supply voltage and then the supply current. That will give you the information you need to specify the battery. You would power them via a driver circuit that was controlled by the Arduino but took its power from the battery. It would probably make sense to power the Arduino from the same battery, using a regulator/voltage converter.
« Last Edit: February 22, 2012, 07:19:50 pm by PeterH » Logged

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I know the amount of power used by the LED's. At max its going to use 10A at 5V. mY question is more about what battery technology is wise to use for this, and how bad is it if I use a different voltage battery and regulate it.

Jonas
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Thats a hella ton of battery power.  I would look into model RC car/airplane battery packs.  They are made to be as lightweight and compact as possible, and they're also able to release quick bursts of amps.  They're available in almost any power configuration, plus they're almost always rechargeable.  These days they're usually lithium polymer construction.  If you're REALLY concerned with the technology you'll also want to look into the battery's C rating - it has to do how fast you can demand amps from it.  I would get two batteries and mount one in each pants pocket or something to make up your needed amp hours.
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Thanks for that, i've ordered some RC batteries now to play with smiley
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Old thread, but same topic.  Anyone have any updates on battery power for arduino +  5V LED strip?

Ive had success running off 4xAA but LEDs are dim.  I had to bypass the 5v voltage regulator as the batteries died in order for the controller and lights to continue to work. 

Id like to use a better supply, but Im very concerned not to over load the controller or the LED strip.

Havent found much on this topic anywhere so far. 
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Ive had success running off 4xAA but LEDs are dim.  I had to bypass the 5v voltage regulator as the batteries died in order for the controller and lights to continue to work. 

Id like to use a better supply, but Im very concerned not to over load the controller or the LED strip.

Here's some food for thought...

If you are using the voltage regulator, add one or two more batteries in series.  An almost fully discharged alkaline AA will have a voltage of around 0.9 VDC.  Furthermore, though the actual voltage/service time curves vary by manufacturer (e.g. here's a link to a datasheet Rayovac's alkaline series if you are interested), they aren't linear and tend to flatten-out mid-service life.  So adding one or two more batteries to your power pack will mean being able to use the voltage regulator longer, even if you are wasting a bit more energy initially when the batteries are fresh.

Also, given the same cell chemistry, C & D batteries have the same nominal voltage per cell as AA & AAA, but the larger battery sizes do have larger charge capacities (i.e. a higher mAh rating).  For example, a standard alkaline AA is nominally 1.5VDC and could have 2200 to 2500 mAh, where as a C could have a capacity of 5400 to 7600 mAh and a D 10,000 to 16,000 mAh. 

Now I know what you might be thinking, "I worried about the output voltage decreasing too much, not capacity!"  However, with batteries the actual output voltage of the cell is roughly proportional to the amount of charge remaining in the cell.  So using four larger sized batteries will mean a longer period of time they can properly power the voltage regulator, because they will discharge at a slower rate compared to AAs.

With regards to the dimness of the strip, I'd look at your datasheet.  It could be the LEDs in the strip are intended to operate at a somewhat higher current than an Arduino can output.  In that case you'd want to power them directly from the batteries, with appropriate current limiting resistors and stepping down the voltage as necessary if you choose to add more battery cells, instead of from the Arduino board.
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Thanks for the quick reply!  That does help me sort out a bunch of the things Ive been reading about (I think ive been reading too much)

As for the setup, I have the power supply going into a proto board, and from there I power the controller and LED strip on different pins. They both draw from the same source, but the LED strip is not drawing from the controller directly. I may look into separating the power though.


Thanks again!

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As for the setup, I have the power supply going into a proto board, and from there I power the controller and LED strip on different pins. They both draw from the same source, but the LED strip is not drawing from the controller directly. I may look into separating the power though.

For this configuration, you won't need to have individual battery packs. 

Yet, it still might turn-out to be more convenient to have a separate battery pack for the Arduino.  That way you can have five or six AAs (or even just AAAs) to better handle the voltage regulator.  Then have perhaps four AA or C batteries just for the LED strip.  However, if you do have more than one battery pack you will either have to be sure the grounds of the Arduino and LED strip are tied together, or instead electrically isolate the control signals coming from the Arduino (e.g. using an optoisolator).  Connecting grounds will be the simpliest and cheapest way, but depending on the application it might not be the easiest or most prefered method for another reason.  For example, with a garment or other wearable project distributing the bulk and weight is usually a good idea and might make using optoisolated control signals the better option.
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You can get lipo battery packs that have 2 5 volt USB outputs or 1 each of 5/9/12 volts output.  These recharge from USB wall warts.  I picked up a battery that has 2 separate 5 volt terminals from Amazon for about $25, and I've seen the 5/9/12 volt batteries in the $35-60 range.  Typically these batteries have 5,000 maH or more when discharged at 5 volt.  I was curious and I could run an Arduino running blink continuously for about 3 days.  I would think it would be a lot more convenient to charge one battery (and change batteries if need be while you are wearing the suit) than a whole bunch of AA batteries.
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You can get lipo battery packs that have 2 5 volt USB outputs or 1 each of 5/9/12 volts output.  These recharge from USB wall warts.  I picked up a battery that has 2 separate 5 volt terminals from Amazon for about $25, and I've seen the 5/9/12 volt batteries in the $35-60 range.  Typically these batteries have 5,000 maH or more when discharged at 5 volt.  I was curious and I could run an Arduino running blink continuously for about 3 days.  I would think it would be a lot more convenient to charge one battery (and change batteries if need be while you are wearing the suit) than a whole bunch of AA batteries.

This is another viable option.  Although you do have to treat LiPos with a bit more care than most other battery chemistries, especially when charging them.  However, if you use a decently made commerically available charger, pay careful attention to the maximum current ratings, and don't try to operate separate LiPos in parallel (instead get pre-made LiPo packs with enough charge and current capacity for your application); you shouldn't run into major problems. 
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You can get lipo battery packs that have 2 5 volt USB outputs or 1 each of 5/9/12 volts output.  These recharge from USB wall warts.  I picked up a battery that has 2 separate 5 volt terminals from Amazon for about $25, and I've seen the 5/9/12 volt batteries in the $35-60 range.  Typically these batteries have 5,000 maH or more when discharged at 5 volt.  I was curious and I could run an Arduino running blink continuously for about 3 days.  I would think it would be a lot more convenient to charge one battery (and change batteries if need be while you are wearing the suit) than a whole bunch of AA batteries.

Would you mind linking to the one you've had success with?  I've been on the lookout for a lipo, but see so many varieties I haven't been able to hit the trigger on any just yet.  Plus I'm in Canada, and our Amazon selection (that's available to us) is quite dismal compared to the US.


Great info guys, and I plan to include all these findings in my project write up.


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Would you mind linking to the one you've had success with?  I've been on the lookout for a lipo, but see so many varieties I haven't been able to hit the trigger on any just yet.  Plus I'm in Canada, and our Amazon selection (that's available to us) is quite dismal compared to the US.
Here is the battery I bought (EZOPower 5000mAh 2-Port USB Universal External Rechargeable Backup Battery).  Note, the price seems to float around, it was $19.99 when I bought it, and now it is $25.99):
http://www.amazon.com/gp/product/B004I0H9MU/ref=oh_details_o02_s00_i00

Here is the description from Amazon.com.
EZOPower External Backup Battery is the perfect solution for emergency power and power on the go. It includes a built-in battery that can be recharged by provided USB cable. 2 USB output could charge 2 devices (Cellphone, Phone, iPod, MP3, NDS, GPS, etc) at the same time. This is the perfect unit for campers, travelers, gadget enthusiasts, hikers, and power hungry consumers.

  • Battery Type: Lithium-Polymer
  • Battery Capacity: 5000mAh
  • mini-USB Input: 5V 1000mA
  • USB Output 1: 1000mA
  • USB Output 2: 1000mA
  • Weight: 150g
  • Dimension: 106 x 57 x 15 mm
  • 2 LEDs with 3 color indicates battery capacity
  • 2 USB Port to charge up to 2 devices at the same time
  • Integrated microchip prevents overcharging
  • Recharge this battery by connecting mini-USB cable with PC/laptop
  • Package include battery, USB cable & adapters pin
  • Also works with original or generic USB cable.
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