Tip: Let battery go empty before reloading. Q: Why ?

[Skybuck Flying]

Hello,

The lady at the barber shop said the following:

She let the battery of the shaving device go completely empty before
reloading it with power. (she had a spare already loaded).

She said otherwise it doesn't load properly.

I think I am noticing the same effect on my own shaving device.

Right now I am completely letting it go empty, it's taking forever, this is
the second time in years that I am doing this.

It's like the battery never loaded properly because of all the quick loading
in between while it still had some power.

It's like the shaving device never had enough power to do a good shave after
only one maybe two times of usage.

Has anybody else noticed this effect ?

I believe the barbershop lady, she has many years of experience shaving lots
and lots of people.

Now comes the real question:

What's going on inside the battery during these quick loads ?

Why doesn't it load fully for good shaves many times ?

Why must it be drained completely first for good/full loading ?

After the shaving device is completely emptied and re-loaded I shall report
back on how many good shaves I could do !

Probably gonna take some weeks

Bye,
Skybuck.

 

[miso@sushi.com]

Hello,

The lady at the barber shop said the following:

She let the battery of the shaving device go completely empty before
reloading it with power. (she had a spare already loaded).

She said otherwise it doesn't load properly.

I think I am noticing the same effect on my own shaving device.

Right now I am completely letting it go empty, it's taking forever, this is
the second time in years that I am doing this.

It's like the battery never loaded properly because of all the quick loading
in between while it still had some power.

It's like the shaving device never had enough power to do a good shave after
only one maybe two times of usage.

Has anybody else noticed this effect ?

I believe the barbershop lady, she has many years of experience shaving lots
and lots of people.

Now comes the real question:

What's going on inside the battery during these quick loads ?

Why doesn't it load fully for good shaves many times ?

Why must it be drained completely first for good/full loading ?

After the shaving device is completely emptied and re-loaded I shall report
back on how many good shaves I could do !

Probably gonna take some weeks

Bye,
  Skybuck.

Assuming nicads/NiMH, the battery has a limited number of cycles. The
intent is to get full cycles, so drain the battery. Empty is a poor
term since you don't want to discharge the cells below say 0.9V per
cell.

Another advantage to fully draining the cell is it is less likely that
you will overcharge the battery if the charger is a simple timer.

For home use, just get a Philips shaver. They have great power
management.

 

[Martin Griffith]

Hello,

The lady at the barber shop said the following:

She let the battery of the shaving device go completely empty before
reloading it with power. (she had a spare already loaded).

She said otherwise it doesn't load properly.

I think I am noticing the same effect on my own shaving device.

Right now I am completely letting it go empty, it's taking forever, this is
the second time in years that I am doing this.

It's like the battery never loaded properly because of all the quick loading
in between while it still had some power.

It's like the shaving device never had enough power to do a good shave after
only one maybe two times of usage.

Has anybody else noticed this effect ?

I believe the barbershop lady, she has many years of experience shaving lots
and lots of people.

Now comes the real question:

What's going on inside the battery during these quick loads ?

Why doesn't it load fully for good shaves many times ?

Why must it be drained completely first for good/full loading ?

After the shaving device is completely emptied and re-loaded I shall report
back on how many good shaves I could do !

Probably gonna take some weeks

Bye,
Skybuck

Since you are the computer whizz kid around here
D/L GCC WinAVR and program an AVR micro to monitor the battery state
and plot it out, then stick it on your blog.

BTW nimh don't really have the memory effect that you speak about
http://www.farnell.com/datasheets/86372.pdf


martin

 

[Robert Roland]

It's like the shaving device never had enough power to do a good shave after
only one maybe two times of usage.

Has anybody else noticed this effect ?

It is called "Voltage depression". It is caused by overcharging the
battery over time. Many commercial products have no charge control at
all, and simply leave the charge on forever.

The effect is often confused with "memory effect", which has similar
symptoms, but a different cause.

 

[JosephKK]

The memory effect is only really applicable to NiCads. NiMH and Lithiums do
not have this phenomena.

It could also be the gas guage inside the shaver. Some gas guages need the
battery to be completely discharged so they can get a low reference point.
Frequent short charge discharge cycles allow the errors to build up. A good
discharge resets everything.

Bill Naylor
Electronworks.co.uk - electronic kits for education and fun

Just don't try full discharge with most lithium batteries, they tend
to get incendiary if you do.

 

[Skybuck Flying]

Well,

I had 3 shaves I think... and euhm..

The thing is still working.

But the RED LED is always burning ?!

I think that's just stupid Philips design.

The manual doesn't explain what the RED LIGHT means, it's always on because
I don't have power in the bathroom so I shave cordlessly.

The RED led probably means it doesn't have wall-socket-power.

I KNOW THAT. I DONT NEED A RED LED FOR THAT.

It would be more usefull if the RED led would indicate when the battery
power is too low for a good shave ?!

So I always thought RED led means lower power... (and then I would go charge
it up again ?!?) but I don't think it means that.

So that's bad.

It's spinning a little bit slower... but apperently it should be good enough
for shaving.

I think it might last a long time.

Also during the loading I am not sure when it's fully loaded.

First the green light is on... and then it starts blinking or something...

Or was it other way around ? Oh well.

Blinking probably means it's fully charged !

Bye,
Skybuck.

 

[Skybuck Flying]

Well,

The maximum was about 4 or 5... can't remember if it was 4 or 5.

But the battery is to weak to get a good shave.

I did use trimmer all 4 times...

Kinda sucks, now I have to reload it again.

I got this shaving device for free though...

If I ever buy a new one I will sure pay attention to battery life !

Bye,
Skybuck =D