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What Is Charging?

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physya

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I don't know why it charges for another half an hour, but I sure wouldn't try it too often cause if it's overcharging it could cause degrading of the battery, overheating, battery leaking and a lot of other unpleasant things

(see Battery University for more info on batteries)

greetings, Volta

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  The Low Volta said:
I don't know why it charges for another half an hour, but I sure wouldn't try it too often cause if it's overcharging it could cause degrading of the battery, overheating, battery leaking and a lot of other unpleasant things

(see Battery University for more info on batteries)

greetings, Volta

Well, I am a simple-minded technical person. I don't know what "overcharging" means. The chargers, in principle, should measure charging current and adjust voltage accordingly. Perhaps, I need to get my MD to the lab and measure these.

Anyway, battery university does provide some insight:

-----------------------

Charging nickel-metal-hydride

Nickel-metal-hydride chargers require more complex electronics than nickel-cadmium systems. To begin with, nickel-metal-hydride produces a very small voltage drop at full charge and the NDV is almost non-existent at charge rates below 0.5C and elevated temperatures. Aging and degenerating cell match diminish the already minute voltage delta further. This makes full charge detection difficult.

A nickel-metal-hydride charger must respond to a voltage drop of 8-16mV per cell. Making the charger too sensitive may terminate the fast charge halfway through the charge due to voltage fluctuations and electrical noise. Most of today's nickel-metal-hydride chargers use a combination of NDV, rate-of-temperature-increase (dT/dt), temperature sensing and timeout timers. The charger utilizes whatever comes first to terminate the fast-charge.

Lower-priced chargers may not apply a fully saturated charge. Some will indicate full-charge immediately after a voltage or temperature peak is reached. These chargers are commonly sold on the merit of short charge time and moderate price.

-----------------------

so, perhaps the batteries are just undercharged after the first run...

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  physya said:
so, perhaps the batteries are just undercharged after the first run...

I had been thinking that as well...but still, I wouldn't advise to use a second charging-round without previous testing whether this is actually the case...

(In my direct environmnt I have known one MD-battery to leak/'explode' because of charging to long...but the culprit wouldn't admit how much he had overcharged out of shame, so it could be an extreme case tongue.gif)

could be interesting to measure the battery right after the first full-indication with decent equipment... I don't trust the batt indicator on my NH900. I'm using a 1450mAh gumstick from GP powerbank right now, and the batt-indicator of my NH900 really doesn't know what to indicate with that battery (mostly drops quite fast, but lasts for another 14 hours playback on the last stripe and while blinking)

I'm actually thinking of buying a dedicated charger (but they mostly come with two additional gumsticks, which is a bit too much, especially price-wise)

Volta

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I notice the EXACT SAME THING... wtf sony. How long "should" it take to charge the 910 battery? Yeah, after a while, the "charging" disappears... but if I press "charge" again, it continues to charge... I'm not sure when the battery is fully charged. Can anyone else shed light?

Also, real-world battery life? How long do people get for:

- playback

- recording (e.g. a concert... using the standard BMC-3 mic)

?

Maybe if I record a concert, I should get out the AA battery extra thingie...

  physya said:
Has anyone noticed that after you charge a battery and press "charge" again (I use MZ-RH910), it starts charging again - for about 1/2 hour. The question is what is being charged (if the battery is already full)?

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Guest NRen2k5

Yeah, don't worry about it. I have the same thing with AA batteries and my Rayovac charger. On the charger, red LED's are lit when a battery is charging, and the LED's go out when the batteries are charged.

Well if you pull out a battery and put it back in, the LED will light up again for anything from 30 seconds to 30 minutes.

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  • 3 weeks later...

  NRen2k5 said:
Yeah, don't worry about it. I have the same thing with AA batteries and my Rayovac charger. On the charger, red LED's are lit when a battery is charging, and the LED's go out when the batteries are charged.

Well if you pull out a battery and put it back in, the LED will light up again for anything from 30 seconds to 30 minutes.

Most NiMH chargers need to charge the battery a bit to determine what state of charge it's in and if it needs any more charging - so even with a fully charged battery when you try and charge it again, the charger "has a go" for a while in order to monitor the change of voltage across the cell (sometimes referred to as delta V). Once it's detected that voltage change again, it stops charging - so once it has finished charging, it's best not to keep on trying again as you will eventually overcharge the cell and degrade its capacity - or worse cause it to leak, swell, or even burst.

Michael

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same thing I noticed with my NH700.

I laso have smart charger with 4 spots (AAA, AA, C/D, 9V) which does the job well and I would recommend it if you buy extra NiMh for use with MD and not charge it inside the MD unit.

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  • 1 month later...

  The Low Volta said:
I'm using a 1450mAh gumstick from GP powerbank right now, and the batt-indicator of my NH900 really doesn't know what to indicate with that battery (mostly drops quite fast, but lasts for another 14 hours playback on the last stripe and while blinking)

Volta

Volta,

Any impressions on the difference between the GP and the "dinky-di" Sony gumsticks? Have been thinking about a spare battery for a little while and the price differential here in AUS is significant if the quatlity is comparable.

Just don't want to buy a piece of crap which means I just end up buying twice anyway.

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  genghisbunny said:
Volta,

Any impressions on the difference between the GP and the "dinky-di" Sony gumsticks?  Have been thinking about a spare battery for a little while and the price differential here in AUS is significant if the quatlity is comparable.

Just don't want to buy a piece of crap which means I just end up buying twice anyway.

Well, if there is a difference in mAh, the difference should be just as it says, the same power for a longer time... but I've just upgraded from the low mAh included sony stick to a higher mAh GP.. so yes, I do notice a longer useage time. But if you really want more time, just get a rechargable 2500 mAh AA for the addon and you'll never run out of power unecpectedly

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  The Low Volta said:
Well, if there is a difference in mAh, the difference should be just as it says, the same power for a longer time... but I've just upgraded from the low mAh included sony stick to a higher mAh GP.. so yes, I do notice a longer useage time. But if you really want more time, just get a rechargable 2500 mAh AA for the addon and you'll never run out of power unecpectedly

Is there a way to connect the USB cable to SS without charging my RH910? unsure.gif

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  The Low Volta said:
welcome to MDCF ynos,

AFAIK, only way is to remove the battery while having it plugged in through USB

Thank you The Low Volta. I will try it since I spent bit more time of playing around with this new unit.

BTW my first upload was a disaster after around 30% of the transfer I've got a transfer error and tried again the same thing then now I can't play the track in my Hi-MD anymore. sad.gif

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