I would imagine many mp3 players could run on 1mA. ....>
Unlikely! The audio amp alone would consume many times that, even for
a headphone amp.
Forestking wrote:
use ur solar cell to charge portables rechargeable batteries after the
battery is fully charged use it in use MP3 player u will save
electricity bill
I'm not so sure on balance this is technically "correct".
My experience with recharagable batteries is that you typically get no
more than a couple hundred, to perhaps a few hundred honest re-charge
cycles. And even then, many re-chargeable technologies DO NOT store
the same number of milliamp-hours as the typical primary alkyline cell
(which means you have to charge them more often.). Also, the chargers
are not 100% efficient.
Plus, you have to expend energy just building the batteries (toxic
stuff), which will on some level require environmental remediation
(more costs...); they also charge and re-charge with fairly low
efficiency, again requiring more cycles to obtain the equivalent mAh
capacities over time (averaging here). And, you still have to replace
the rechargeable batteries every so often (especially if they are
abused, overcharged, etc..) They are also much more expensive
initially, compared to a regular battery.
So while you may save a few pennies on the electric bill each month (if
that?), those savings will be completely swamped by the cost of the
rechargable batteries themselves, and probably by the utility bill
though I did not calculate that.
I suspect solar powered MP3 players don't exist because consumers don't
want them, the technology would be too bulky and cost effective to
implement, and frankly, "economics". There are much better
applications for solar power, and this is where you will find the
investment dollars driving solar technology development. Not in MP3
players.
