Apple Video Ipod – Battery Life analysis HDD vs. CF

Apple Video Ipod – Battery Life analysis HDD vs. CF


As promised I have been spending sleepless nights measuring and testing the battery life to bring you the ultimate and most comprehensive battery analysis for apples Video Ipod (5g & 5.5G) players ever!

My original intention was to just compare the run-time of the hard drive based iPod i.e. standard off the shelf video iPod with my compact flash based solution, but being slightly of the rails when it comes to things like this I really pushed the boat out and made some electrical Current measurements as well.

MethodNew Ipod CF Adaptor

First thing I needed to invent was a method of breaking out the battery supply, so I could insert my Current meter. The easiest solution I felt would be to make something which was similar to the battery fitting which I could then use to power up the iPod from my bench power supply.

So after some cutting and soldering I produced my own custom flexible PCB stick to fit in to the battery connector on iPod. I set my bench power supply to 3.7V the nominal voltage as supplied by the internal battery. In-line with the supply I attached my Current meter, which would show me current drawn from the power supply.

Playtime measuring was going to be a little more interesting as I was not about to stand around my iPod for 15 plus hours waiting for it to die while holding a stop watch. So after some racking of the brains, I came up with the simplest and most novel method you will ever witness.

I will record the audio output from the iPod using my computer and sound recorder software, till the player switches off from the low battery. I will then analyse the wave file to find when the music stopped to determine how long the playtime was. I said it was simple :)

Obviously I will record at the smallest bit length and sampling frequency as I don’t want to end up with a 20Gb wav file.

Ipod test lead with 47Ohm resistorsTo demonstrate my utter boredom, I even soldered in 47Ohm resistors to the output lead to mimic earphones!! (before the geeks amongst you starting commenting most earphones have lower DC resistance – around 30Ohms, but they are inductive loads, so resistance does change with frequency –  being on the safe side I settled on 47Ohms, plus I had the resistor lying here!)

To improve accuracy of the data, I have devised this charging and measuring cycle.

  • Charge battery till full
  • Play Music till it switches off
  • Charge for 6hours and start test

This will bring the battery up-to a known starting level, before the above is repeated while recording the output. This will be repeated twice and the average of the time will be used. I will also do these tests playing HQ Video files rather than MP3’s.

Once the timings have been noted the Hard drive will be removed and the Compact Flash adaptor and 8Gb card will be installed, and all the above testing will be repeated.

To maintain consistency, the 8gb CF card and HDD are loaded up with exactly the same MP3 and Video files, even the order of play will be the same – so don’t accuse me of not being meticulous.

Move on the next page to see the results.


12 thoughts on “Apple Video Ipod – Battery Life analysis HDD vs. CF

  1. Tarkan Post author

    There is another option – you can fit an extra battery/cell on top of the iFlash (still using the thin back). The maximum cell size that would fit is 50mm x 20mm x 3.5mm, in that size you should be able to get at least 500mAh, which will give you around 1000mAh in total.

  2. Tarkan Post author

    I don’t think there is anything off the shelf.

    If you don’t mind using the thick back on your iPod, you have a nice strip of space of approx 40mm x 90mm and in 3 to 3.5mm in height. I have seen Li-Ion battery cells approx 43mm x 73mm x 3mm thick 1200mAh capacity which would fit.

    It is an easy mod, just transplant the original battery connection from the old battery, and most Li-Ion cells will come builtin charge controller – and off you go…

    I don’t personally see the point, a 850mAh high capacity battery and CF card will take your iPod close to 48Hrs of continous music playback, the above 1200mAh will probably see you to 70Hrs maybe.

  3. Matthew

    Has anyone seen a modded battery anywhere? There is so much unused space thanks to this mod. Only seems logical to fill it with mAh’s…

  4. Tarkan Post author


    When you have the iPod in disk mode can you read and write to the iPod?

    The CF card is known to work – so have you checked that the ribbon is fully inserted in to the ZIF connector.

  5. Carlos

    i buyed the iflash adapter and i am using a kingston elite pro 16GB 133x flash card but itunes dont reconize the ipod just the computer in usb disk mode,what is the problem?

  6. jonas

    hi tarkan, i’m thinking about updating my 3d gen ipod to flash memory an wondered if the cache (i think its about 32 mb) thats normally filled from the harddrive decreases the battery life and could be deactivated?

  7. Tarkan Post author

    With a set of earphones plugged in and higher the volume level, more the current draw – but I would stress that runtime differences will be minimal, maybe 3 to 5%.

    My battery tests where carried out using 50 Ohms loads on the earphone output at quite a high volume level – I think my results probably represent worst case situation of someone listening to their earphones at the highest volume level.

    Most earphones DC resistance rest in the 20 to 32 Ohm range, but their AC resistance i.e. while music is being played can range from 30 to 2000 or 3000 Ohms. So you cannot just use the DC resistance to determine what kind of current will be drawn by the earphones.

  8. Dave

    What effects does the volume level have on the results? Does the a higher volume shorten the battery life?

  9. Pingback: The Apple diyMod: My Take on the Famous iMod [56k killer] Featuring 3G, 4G, 5G and nano 1G! - Page 93 - Head-Fi: Covering Headphones, Earphones and Portable Audio

  10. Pingback: iFlash Video Ipod Flash Adaptor - stop waiting get it now! > Tarkan Akdam’s BORED

Leave a Reply

Your email address will not be published. Required fields are marked *