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Build Your Own iPod Battery

Posted by michael on from the don't-come-crying-to-us-if-it-explodes dept.

OmniVector writes "With various complaints about the iPod battery's life, and its mere 10-8 hours of charge many of us are left looking for a way to keep the tunes kicking a little longer. Drew Perry has come up with a novel solution which can only run you a few bucks for an extra 10 hours of battery life out of a box of playing cards and a everyday batteries. Not bad for that long car trip where you just don't have a firewire charger handy."

1 of 318 comments (clear)

  1. Re:Nice by Bushcat · · Score: 5, Insightful
    No it's not, it's terrible. The running costs are immense, and it's unbalanced.

    In the first picture, there are a GP and a Varta 9V battery in parallel, with at least two cells, at least one of which is rechargable. So, 9 + (2 x 1.2) = 11.4 V.

    In the second picture, there are two Varta 9V primary batteries in parallel, placed in series with two 1.5V Duracell alkalines. So, 9 + (2 x 1.5) = 12 V.

    We can assume the difference in non-load voltage is not relevant. But when we consider the power available:

    The capacity of each PP9 Varta is at most 450 mAh. (Rechargables are 110 mAh to 150 mAh). Taking the best case in parallel, therefore, 900 mAh. The rechargable AA's are about 1350 to 2300 mAh. If primary AA's are used, then figure on 2400 mAh.

    So for an all-primary solution, the AA cells have 2.5 times the life of the PP9 cells. Basically, this design eats PP9 cells and there's no real way of telling which batteries/cells are running out at any given moment.

    If one's going to go for a primary cell solution, then it would be better to have, say, 3 x 2CR5 in series or 3 x CR-P2 in series. But obviously a rechargable pack is the optimal solution because it's way cheaper in the long run. Buy them all together, Use them together, recharge them together. Check out packs used for digital cameras.