pygmy_giant
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Re: using 4 AA batteries to power the Pi

Sun Mar 04, 2012 11:27 am

having looked at other posts and on the internet, the solution I intend to try is....

this:

http://www.7dayshop.com/catalo....._id=102083

plus this:

http://www.dealextreme.com/p/8.....ubec-45214

What could possibly go wrong?
Ostendo ignarus addo scientia.

Ren
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Re: using 4 AA batteries to power the Pi

Sun Mar 04, 2012 1:49 pm

I've been eyeing up one of these

http://www.suntekstore.co.uk/p.....0+Box.html

RogerJoensson
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Re: using 4 AA batteries to power the Pi

Wed Mar 07, 2012 8:44 am

There are emergency chargers with battery power and USB output.

I am thinking of trying this one, with 4xAAbatteries and 5V 1A USB output. Maybe with the right kind of batteries (with a "horizontal" discharge curve) it will work. I doubt this one is switched, so battery time may be short.

Sorry, only in Swedish (price in shop 12UD$ including 25% tax):

http://www.clasohlson.se/Produ.....=167105202

Looking on ebay i found these, not very cheap though:

http://www.ebay.com/itm/Extern.....868wt_1102

Capacity: 6600mAh (24.4Wh)  GBP 29.00 / US $45.64

This one should be good for 6-8 hours (my guess).

http://www.ebay.com/itm/Propor.....644wt_1102

Capacity : 5000 mAh, Output: [email protected] 1.5A (5500mAH) US $39.95

Doesn't say anything about the battery voltage, so wattage of the rechargeable battery is not told as far as I can tell…

I searched for "emergency battery charger usb"

Maybe there are lower priced battery powered USB chargers if one knows where to look...

drgeoff
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Re: using 4 AA batteries to power the Pi

Wed Mar 07, 2012 12:22 pm

RogerJoensson said:


There are emergency chargers with battery power and USB output.

I am thinking of trying this one, with 4xAAbatteries and 5V 1A USB output. Maybe with the right kind of batteries (with a "horizontal" discharge curve) it will work. I doubt this one is switched, so battery time may be short.

Sorry, only in Swedish (price in shop 12UD$ including 25% tax):

http://www.clasohlson.se/Produ.....=167105202


From the look and price (compared to the cables on the same page) of that one I'd guess it is only a battery box with a USB socket - no electronics in it.

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RaTTuS
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Re: using 4 AA batteries to power the Pi

Wed Mar 07, 2012 12:57 pm

http://www.amazon.co.uk/TeckNe.....pd_cp_ce_1

what about one of those instead
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RogerJoensson
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Re: using 4 AA batteries to power the Pi

Wed Mar 07, 2012 4:27 pm

drgeoff said:

From the look and price (compared to the cables on the same page) of that one I'd guess it is only a battery box with a USB socket - no electronics in it.


I sure hope there is a primitive analogue regulator/stabilizer. 6V+ with fresh batteries is way over the USB standard and risk frying some equipment. I don't think they would dare to sell it without regulated 5V output. -Also they do specify 5V output.

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sorinm
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Re: using 4 AA batteries to power the Pi

Wed Mar 07, 2012 4:42 pm

I have an APC Emergency Power Pack, I think it`s perfect for the Pi.

It takes 4xAAA.

http://www.apc.com/resource/in.....ku=UPBX-EC

Lauriz
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Re: using 4 AA batteries to power the Pi

Wed Mar 07, 2012 4:52 pm

Why buy all these overpriced usb boxes (some gives non-regulated output), when you can buy this http://www.ebay.com/itm/USB-DC.....256d8f22a6 cheap 3-5v booster with regulated output? Then you can connect 2,3 aa nimh batteries or a lion battery. I think it should work fine and efficiency is good. also.

drgeoff
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Re: using 4 AA batteries to power the Pi

Wed Mar 07, 2012 4:53 pm

RogerJoensson said:


drgeoff said:

From the look and price (compared to the cables on the same page) of that one I'd guess it is only a battery box with a USB socket - no electronics in it.


I sure hope there is a primitive analogue regulator/stabilizer. 6V+ with fresh batteries is way over the USB standard and risk frying some equipment. I don't think they would dare to sell it without regulated 5V output. -Also they do specify 5V output.


1.  Very little if any USB charged equipment will be fried by 6 volts.  Only the charger circuit is connected to the USB power pins.  The situation with the RP is rather different.

2.  A "primitive analogue regulator/stabiliser" will drop at least 0.5 to 1 volt from input to output.  So it wouldn't be able to deliver 5 volts from batteries that are not so far from new.

3.  That item may have a fuse but I still think no active electronics.

I don't know for certain it is just a battery box.  It is your decision to buy or not.  :-)

drgeoff
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Re: using 4 AA batteries to power the Pi

Wed Mar 07, 2012 4:56 pm

Lauriz said:


Why buy all these overpriced usb boxes (some gives non-regulated output), when you can buy this http://www.ebay.com/itm/USB-DC.....256d8f22a6 cheap 3-5v booster with regulated output? Then you can connect 2,3 aa nimh batteries or a lion battery. I think it should work fine and efficiency is good. also.


Indeed.  Nice find.  Thank you!

kenco coffee bean
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Re: using 4 AA batteries to power the Pi

Tue Sep 04, 2012 5:33 pm

ive read alot of this stuff about 4x aa batteries and from what i gather its not going to power for very long - im busy in work but just come accross this VERY interesting article, now im an absolute beginner (learning fast) BUT this guy''s onto something im sure -

http://davidhunt.ie/?p=2641

copy'd and pasted the bit that caught my attention for you guys....

"I initially started by powering it externally, so then I tried the device shown on the left. It’s the guts of an iPhone car charger, which converts 12v to 5v, so I tried to see what it would put out if connected to 4xAA batteries, which is the end goal for power,as I want to be able to swap batteries during a shoot. Unfortunately, the DC-DC converter drops a volt from the 5.25v set of batteries I tried, giving me 4.25v. Not enough for the Pi. Putting it on a 12V supply gave me a nice 5.02v, but it’s more difficult to source a 12v battery that’s small enough for my purposes.

However, I then spotted the parts lying on my workbench, and as I sat there looking at the parts I’d already taken out of the battery grip, I realised it might be possible to use some of them to make a compartment for a Canon 5D Battery, which runs at 7.2 volts. A quick test with one of those batteries showed the output of the DC-DC converter at a steady 5.02 volts, so I then attempted to boot the Raspberry Pi. And up it came. I measured the current at 450-480ma, with a Microsoft wireless keyboard/mouse USB adapter in the USB port. I could ssh in, so the network port was fine with that PSU"

now doesn't that mean we could do a similar thing?!!!!!!!!!!!!!

regards
Chris

kenco coffee bean
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Re: using 4 AA batteries to power the Pi

Tue Sep 04, 2012 5:37 pm

ps that step up 3v to 5v is a nice find... does that mean using 4xaa batteries in series and this will work?!!

kenco coffee bean
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Re: using 4 AA batteries to power the Pi

Tue Sep 04, 2012 5:50 pm

*with usb to micro usb cable obviously...

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alexeames
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Re: using 4 AA batteries to power the Pi

Tue Sep 04, 2012 5:56 pm

kenco coffee bean wrote:now doesn't that mean we could do a similar thing?!!!!!!!!!!!!!
Absolutely. As long as the voltage you give the Pi is right and the cells are capable of delivering the required current, you can power it with any DC source you like.
Alex Eames RasPi.TV, RasP.iO

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redhawk
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Re: using 4 AA batteries to power the Pi

Tue Sep 04, 2012 6:40 pm

kenco coffee bean wrote:ps that step up 3v to 5v is a nice find... does that mean using 4xaa batteries in series and this will work?!!
I bought the following buck converter from eBay - http://www.ebay.co.uk/itm/DC-DC-3V-to-5 ... 0703100274
it provides a stable 5.1v - 5.2v output from an input of 1v - 5v as long as the power source meets the current demands.

I powered my PI for 1 hour with one of these boards and only 2 x AA 1300mAh Ni-MH batteries.
If I had 4 x AA (4.8v) or higher capacity 3000mAh Ni-NH the duration would had been a lot longer. :)
For testing purposes I had X-Windows running and I was streaming mp3 radio (digitally imported) with qmmp via a LAN connection.

Richard S.

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alexeames
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Re: using 4 AA batteries to power the Pi

Tue Sep 04, 2012 9:41 pm

Richard. Any idea of the efficiency wrt stepping up vs stepping down? I know with the common ebay switching regs I can get 85% stepping down from 12V to 5V. Would be really interesting to find out how stepping up compares? Obviously there's no free lunch here, but it would be interesting to know if one way is more efficient. :D
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Re: using 4 AA batteries to power the Pi

Tue Sep 04, 2012 10:12 pm

@redhawk - great info/link :0
Just ordered one :)
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0117blocky
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Re: using 4 AA batteries to power the Pi

Tue Sep 04, 2012 11:06 pm

I used a 3LR12 4.5 volt battery and a Max 757 max current 200mA @ 5V step up switching regulator to power a micro controller board which I made years ago. So I looked up Step up Switchers and the Max 8969 from Maxim may suit your needs http://www.maxim-ic.com/datasheet/index.mvp/id/7505

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redhawk
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Re: using 4 AA batteries to power the Pi

Tue Sep 04, 2012 11:22 pm

I'm still pretty new to these converters so I couldn't really quote you on efficiency but I have to say I was quite impressed with this little board.
I'm currently powering my home-made AM radio with LM386 speaker amplifier via a single AA battery. :lol:

As for step down converters I've only really experimented with one and that needed approximately 1.5v higher voltage at the input than the output for the regulator to work correctly.
This basically means your input voltage has to be 6.5v or higher which is perfect for a 12v car battery but wasteful when using AA battery packs.
I did find another interesting buck converter on eBay it steps up and steps down - http://www.ebay.co.uk/itm/300688084419? ... 1423.l2649
It runs from a wider voltage supply between 3.5v - 38v providing 5v output and while power efficiency at 86% is less than other step down regulators this should squeeze more juice out. :)

Richard S.

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alexeames
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Re: using 4 AA batteries to power the Pi

Wed Sep 05, 2012 7:40 am

redhawk wrote:This basically means your input voltage has to be 6.5v or higher which is perfect for a 12v car battery but wasteful when using AA battery packs.
Do you mean wasteful in the sense that you need more batteries to power it and hence it's heavier?
If the efficiency is better than stepping up, it can't be wasteful of power, just heavier. Obviously, the more serial cells you have, the longer you will power the pi when stepping down.

I wouldn't consider using AAs to power the Pi (routinely), but that's mainly because I have a stack of 3 cell lipos :lol: I normally use it plugged into the mains anyway.

I would consider using AAs to make a UPS for the Pi though. :D (A 2 cell A123 would probably be even better).
Alex Eames RasPi.TV, RasP.iO

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redhawk
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Re: using 4 AA batteries to power the Pi

Wed Sep 05, 2012 8:23 am

Wasteful in the sense that when a battery pack is providing 6.5v or lower this isn't enough to power a step down regulator but plenty for a step up regulator.

Richard S.

darkside40
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Re: using 4 AA batteries to power the Pi

Mon Sep 10, 2012 1:47 pm

Wonder a little bit that nobody seemed to come across the Lipo Rider Pro in this discussion.
http://www.seeedstudio.com/wiki/Lipo_Rider_Pro

Always wanted to purchase one of these for a few projects, but didnt have the chance till now.

Normally i use a pack of 4x AA Eneloops if i need to power a microcontroller board.

teeth_03
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Re: using 4 AA batteries to power the Pi

Tue Sep 11, 2012 2:18 am

Lots of interesting tidbits here

Just not much on actual battery life...

darkside40
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Re: using 4 AA batteries to power the Pi

Tue Sep 11, 2012 6:21 am

Just measrue the current your Pi need's on your specific setup and you can easily calculate yourself how long you Pi will run.

For example if it needs 700mA it will approx. run 3 hours on good Sanyo Eneloops (which have 2000 to 2100 mAh). You just have to make sure that there is no foulty Eneloop under it.

moony
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Re: using 4 AA batteries to power the Pi

Sun Aug 24, 2014 4:36 pm

4 NiMh batteries are possible (not alkaline 1.5V * 4 = 6V! As said before)

EDIT: my new 4 NiMh eneloop batteries didn't last longer (45 min.) than the old NiMh batteries - so really not a good idea. The voltage-drop comes too soon.
3 small, used Li-Ion batteries in parallel with converter are running for over 2 hours now


the specification of the RaspPi says, it needs a supply voltage between 5.25V and 4.75V, which is also the USB specification. But this is just the tested and guaranteed voltage it will run.

If you put 4 NiMh (or NiCd, but these are outdated) in series, you get a voltage range from 1.32V * 4 = 5.28V (maximum) to 1.1 * 4 = 4.4V (almost empty) through the the most of the time, which is very near to the specs. If voltage falls too low, then the RasPi will turn off, trying to boot again, but fails at too low voltage over and over, until the batteries are completely empty. So you should take care turning it off before that (better for the batteries).

My RaspPi ran well for 47 minutes using 4 old NiMh batteries (capacity about ~700mAh), all the time with the command "top" through ssh, and had attached a WLAN stick and a small USB keyboard to it, which also consume power.

Why this works so well: there are voltage regulators for the CPU and 3.3V supply parts. The critical things are USB devices connected to the Pi, which should get 4.75V to 5.25V - but: the WLAN stick also seems to have a regulator, and the keyboard isn't that critical. Most USB devices have a wider range, than exactly the USB specs.
Last edited by moony on Thu Oct 02, 2014 9:25 pm, edited 1 time in total.

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