Ok, this has been bugging me.

[Blurgas]

Charger output: 400mA @ 4.2v
eGo-T capacity: 650mAh

Now, I'm no electrical engineer, but shouldn't that charger finish recharging my eGo-T batts in just under an hour-forty?
As it stands, this thing can take 4+ hours to fully recharge my battery, so I'm guessing the 400mA output isn't "400mA pumped out per hour", or there's something else I'm missing



Also, please shut up Mr.Charger. It's bad enough that I can still hear into the 18kHz range, I don't need your semi-subtle 15kHz tone clawing at my eardrums

 

[Dreddsparc]

I believe the '400ma' is only what the charger is rated as being able to supply safely before it would be damaged, the battery will draw much less than that while charging.

 

[MorpheusPA]

I'm old enough that 15kHz is just a memory, so can't speak to that. I tend to mistrust electronics that sing, however.

Charging Lithium-Ion Batteries

During the bulk charge phase, your charger will be pouring in mAh pretty fast. Once the battery starts to get "full up," resistance rises. Dumping in power means you'd generate a lot of battery-killing and potentially dangerous heat. Nobody likes it when their lithium batteries jet flame.

So the charger drops the mAh flowing in back to keep the heat down. The battery charges, ever more slowly, until the charger detects that the cell is at the set voltage point (usually about 4.2 on cheap chargers, it can vary, though). Then it's done.

 

[Blurgas]

I'm close to 33 and I can still hear that high a tone. Especially fun since the girlfriend's dad has a "screecher" app on his phone that spews out a 18kHz tone. He can't hear it at all and likes to fire it off to see everyone else go "GAAAH! Dale! Turn it off!"

Found that Batt-U site while doing some googling, but didn't dig around much so I missed that exact page.
Makes sense about the bulk/saturation phases. The charger screeches the most at the start of the charge and drops off after a while.
If the LED on the charger didn't blink green once in a while, I'd start wondering if something was borked

 

[volume control]

I'm old enough that 15kHz is just a memory, so can't speak to that. I tend to mistrust electronics that sing, however.

Charging Lithium-Ion Batteries

During the bulk charge phase, your charger will be pouring in mAh pretty fast. Once the battery starts to get "full up," resistance rises. Dumping in power means you'd generate a lot of battery-killing and potentially dangerous heat. Nobody likes it when their lithium batteries jet flame.

So the charger drops the mAh flowing in back to keep the heat down. The battery charges, ever more slowly, until the charger detects that the cell is at the set voltage point (usually about 4.2 on cheap chargers, it can vary, though). Then it's done.

Nailed it!

 

[MorpheusPA]

I'm close to 33 and I can still hear that high a tone. Especially fun since the girlfriend's dad has a "screecher" app on his phone that spews out a 18kHz tone. He can't hear it at all and likes to fire it off to see everyone else go "GAAAH! Dale! Turn it off!"

OK, I'm not all THAT much older than 33...just a decade. And a little bit. I refer to myself as "forty-cough." The first time a young cousin of mine showed off her mosquito ring tone, I couldn't hear a thing. Everybody under 25 was covering their ears.

At that point, I knew it was probably time for Geritol and Centrum Silver.

Found that Batt-U site while doing some googling, but didn't dig around much so I missed that exact page.
Makes sense about the bulk/saturation phases. The charger screeches the most at the start of the charge and drops off after a while.
If the LED on the charger didn't blink green once in a while, I'd start wondering if something was borked

Most of the time, I'm over-reacting to that kind of stuff. A singing piece of electronics means that there's a resonance in there somewhere. It's entirely possible than an oscillator has a harmonic at around 15 kHz and that's what you're hearing.

I once built an LED lamp from scratch with a flyback oscillator that sang horribly right around 5 kHz. That was annoying in the extreme, but not indicative of any electronics errors or issues. A little hot glue fixed that puppy. It's never happened on any other one I built, using the identical design and (theoretically) identical parts.