OT-Self-acharging electrical devices?

[Force_Feedback]

This may sound strange, but it's just an observation, maybe some chemistry involved.

Yesterday, I remember using 3 devices that hold a battery of some sort. My 4 years old wireless mouse (2xnimh, 650mah AAA), a Sansung cell phone, Li-ion, and an mp3 player with 1.8' tft screen (li-ion, presumably). The mp3 player was slightly less than halfway full, the cell phone was critically low (had 1 out of 3 bars the whole day long). My mouse, at the end of the evening was in need of charging too, according to a lighting up LED.

Now, the strange thing I noticed that this morning, mp cell phone had 2/3 charging bars, and still has them (~10 min talk time), the mouse was in no need of charging (it wouldn't charge) and my mp3 player's battery indicator gave an almost full indication (5/6, or 7/8, dunno) after having played music for ~20 minutes.

I got puzzled by this, since I didn't recharge those devices (the rechargers were entangled in lots of computer cables), so I can rule out sleep walking :p Maybe there was some EM-storm (solar flare?) yesterday, that charged up my accumulator-based devices?

 

I just discovered that my digital cam, working on two penlite ni-mh sticks is half through its charge, yet when I last used the damn thing it wouldn't even come on. Can ths be attributed to som sort of temperature differential, or is my CRT screen producing some interferrence?

 

I don't know where to post this, feel free to move it to the tech section.

[tflash]

The truth is out there.

[Ven]

This may not be the case but most devices such as cell phones and mp3 players give two different battery readings for standby mode and usage mode. When I use my cell phone and hang up, it gives me 2/4 bars... indicating how much battery is left if I keep yapping on the phone. Then after few minutes, it goes up to 3/4 bars indicating how much standby time is left. It may be this or you might've stumbled upon the elusive cold fusion!

[hitman]

You ate some russian glowcaps didnt you. They recharge your batteries in your NVG's, mine detectors, mp3 players, cell phones and all that other junk after you eat them.

[S77th-konkussion]

I always thought the heat might be porking the meter readings. Never thought much of their accuracy anyway. My Ipod nano does what you describe to a T. Runs down to RED while in use- turn it off and the meter climbs steadily as it cools. Cell phone- kind of the same thing, but not as noticeable. What Ven said makes perfect sense, too.

[Force_Feedback]

I'll go with hitman's explanation, maybe I did eat too much glowcaps :P, I'm a walking chemical-nukular power plant.

[spugnut]

This could be completely wrong, and dammit I'm not going to go on wikipedia or anything to check the facts - so if it's wrong, it's wrong.

 

As I remember though, Li+ and NiMh batteries have some odd properties when their charging regimes are a little off. Different charge and discharge rates can cause permanent physical changes within the battery, effectively forming a non-reactive chemical barrier to further charge/discharge above or below that point in the battery. While the potential across the cell will still be high the 'charged' status of the battery will read ok, but you won't actually be able to draw that much current. Or something like that. I need a mars bar. Or just a really big slab of chocolate.

[Kuky]

Batteries do not opperate well in low temperatures... it's as if they have no more charge, but they do, which is why you might be seing this. But then again this at least used to be with standard batteries like AA, AAA, C and D etc, I think this might have changed with new type charge cells used in newer devices like mobile phones.