Build Your Own iPod Battery

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."

Comments

How about this?

[nametaken]

Wouldn't it be better to use the rechargable batteries you can buy at BestBuy or Target instead of burning up those AAs and 9vs for 10 hrs of play time?

Re:putting two batteries in parallel is not good

[neirboj]

Theoretically, if two batteries rated for the same voltage are connected positive-to-positive and negative-to-negative, no current will flow between them. In practice there may be a small difference in the potential at the positive terminal of one with respect to the other which would result in some current drain. At some point however the differential would vanish due to the discharging and current would cease to flow.

I propose that batteries in parallel are fine as long as you replace them simultaneously.

Re:Nice

[Bushcat]

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.

Re:10-8 hours of charge?

[Fulkkari]

What's the point of having 10,000 songs if you can only listen to 7 hours worth in a sitting?

I'm just curious; where do you listen to your iPod or any music player for that matter 7 hours a row? Traveling maybe? I'm quite sure you would able to use external power source part of that time.

Personally I can't get up to 7 hours a day even if I listen every moment I can.

And would people please stop to post these iPod battery stories? The whole is has become highly exaggerated.

Re:Nice

[dnoyeb]

IIRC, internally the CPUs and memory chips will operate at either ~3V or ~5.5V, so the voltage will be stepped down in either case.

two 9V batteries will not be discharging through one another. One of them can not go flat, they are in parallel, if one goes flat, THEN the other will discharge through it, in effect, charging it(if it were rechargeable). But the effect is negligable, they will reach equilibriun.

I would go personally with a bunch of AA batteries since they tend to have longer life under load. 9V seems to be passe for devices which have human interaction.

6 AA in series would do the trick, and you can likely get a package to hold them at Radio Shack.

And I would say he has passed EE101, it was a good freshman level attempt. On paper it works :D

Eight AAA cell would have been too easy?

[egork]

I know I am just a geeky physisist by education :-), can anybody tell me what in the world was the reason to use two 9V and two 1,5V cells and connect them in a funny way, when one could just take eight AAA cells. 8x1,5V=12V bingo!

That will be even cheaper. And would last longer. And will fit into cardbox as well. And ...

bad electronician, no donut

[TheSHAD0W]

Batteries in parallel (like those 9Vs) are bad, mixing battery types in series (such as AA and 9V in series), or even in brand (different brands of AA batteries) is very bad. If you're going to build this project, use 8 AA batteries in a simple series, unless you like having a pocket full of battery acid.

Re:10-8 hours of charge?

[Mononoke]

No, they fed me some absolute BS about a restocking fee or whatever, just so that they didn't have to look like they were giving in to me (i.e., make it look like I'm just an annoying person who changed his mind, not a customer with a legitimate complaint). So they knocked about $80 off the refund.

If you lived in the real world, you'd realize that restocking fees are not BS. It costs money to buy used equipment back (and return it to sellable condition) from people who can't read the specs before they buy the item.

I have since cost Apple several thousand dollars personally by advising technologically non-savvy people who ask my advice against buying Apple products. I know of at least 2 instances where this has been a determining factor in buying decisions. Ah, revenge. It's a shame, I kinda like Apple, too.

No, you don't. You do seem to like the ego boost that comes with thinking you are having some negative affect against "The Man."