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replacing batteries in Norelco shaver

D

Darmok

Jan 1, 1970
0
Hi,

I've got an older Norelco electric shaver, which has some kind of
'fast charge' ni-cads in it (haven't looked, but that's pretty much
what they had when it was made). Normally, it will recharge in about
20 minutes or so. Well, after all these years, one or both batteries
is dying, and I need to replace them. I was thinking of just putting
in a couple of Ni-MH cells (these are 'AA' size), because I know that
they can handle a higher charge rate than standard ni-cads. I've got
some extras of both, but no 'high charge rate' ni-cads (although, I'm
pretty sure I could get some at Tower Hobbies, or similar R/C model
shop).

Anyone ever replace batteries in a Norelco (or other brand) shaver?
Anything I should be aware of or watch out for? Seems like it should
be a pretty straight forward procedure.

TIA
 
J

Jim Yanik

Jan 1, 1970
0
Hi,

I've got an older Norelco electric shaver, which has some kind of
'fast charge' ni-cads in it (haven't looked, but that's pretty much
what they had when it was made). Normally, it will recharge in about
20 minutes or so. Well, after all these years, one or both batteries
is dying, and I need to replace them. I was thinking of just putting
in a couple of Ni-MH cells (these are 'AA' size), because I know that
they can handle a higher charge rate than standard ni-cads. I've got
some extras of both, but no 'high charge rate' ni-cads (although, I'm
pretty sure I could get some at Tower Hobbies, or similar R/C model
shop).

Anyone ever replace batteries in a Norelco (or other brand) shaver?
Anything I should be aware of or watch out for? Seems like it should
be a pretty straight forward procedure.

TIA

NiMH cells have a more complicated charge requirement than NiCd.
Unless you plan on designing a new charger,you should only replace with
NiCd cells similar to what you removed.
 
K

Ken Weitzel

Jan 1, 1970
0
Darmok said:
Hi,

I've got an older Norelco electric shaver, which has some kind of
'fast charge' ni-cads in it (haven't looked, but that's pretty much
what they had when it was made). Normally, it will recharge in about
20 minutes or so. Well, after all these years, one or both batteries
is dying, and I need to replace them. I was thinking of just putting
in a couple of Ni-MH cells (these are 'AA' size), because I know that
they can handle a higher charge rate than standard ni-cads. I've got
some extras of both, but no 'high charge rate' ni-cads (although, I'm
pretty sure I could get some at Tower Hobbies, or similar R/C model
shop).

Anyone ever replace batteries in a Norelco (or other brand) shaver?
Anything I should be aware of or watch out for? Seems like it should
be a pretty straight forward procedure.

TIA

Hi...

I'm in Canada, where Norelco is called Phillips, and I have
one (though there are so many models)

The heads-up I'd offer is to measure the cells carefully
before you get it too far apart at an inconvenient time...
mine has one of the sub-C variations, which is physically
just a little shorter than a AA. Shorter enough that you
can't get it in and still put it back together :)

Take care.

Ken
 
B

Bill Janssen

Jan 1, 1970
0
Darmok said:
Hi,

I've got an older Norelco electric shaver, which has some kind of
'fast charge' ni-cads in it (haven't looked, but that's pretty much
what they had when it was made). Normally, it will recharge in about
20 minutes or so. Well, after all these years, one or both batteries
is dying, and I need to replace them. I was thinking of just putting
in a couple of Ni-MH cells (these are 'AA' size), because I know that
they can handle a higher charge rate than standard ni-cads. I've got
some extras of both, but no 'high charge rate' ni-cads (although, I'm
pretty sure I could get some at Tower Hobbies, or similar R/C model
shop).

Anyone ever replace batteries in a Norelco (or other brand) shaver?
Anything I should be aware of or watch out for? Seems like it should
be a pretty straight forward procedure.

TIA
I replaced the NiCads with new NicCads. No problems after about a year.
Don't remember for sure what size they were but I think they were sub-C.

Bill K7NOM
 
T

Tom S

Jan 1, 1970
0
Jim Yanik said:
NiMH cells have a more complicated charge requirement than NiCd.

Jim, could you be more specific? Not to hijack anyone's thread,
but we recently replaced a 3.6V NiCd cordless phone battery
pack (600mAh) with 1300mAh NiMH's, and plan to use the
phone's base (150mV input) to recharge it. If we're careful to
time the recharges properly, what other complications could
there be?
 
H

Hugh Prescott

Jan 1, 1970
0
Darmok said:
Hi,

I've got an older Norelco electric shaver, which has some kind of
'fast charge' ni-cads in it (haven't looked, but that's pretty much
what they had when it was made). Normally, it will recharge in about
20 minutes or so. Well, after all these years, one or both batteries
is dying, and I need to replace them. I was thinking of just putting
in a couple of Ni-MH cells (these are 'AA' size), because I know that
they can handle a higher charge rate than standard ni-cads. I've got
some extras of both, but no 'high charge rate' ni-cads (although, I'm
pretty sure I could get some at Tower Hobbies, or similar R/C model
shop).

Anyone ever replace batteries in a Norelco (or other brand) shaver?
Anything I should be aware of or watch out for? Seems like it should
be a pretty straight forward procedure.

TIA

Use nicads with solder tabs. Get then at a hobby shop that supports Radio
Control models.

Have changed mine several times no problems.

Hugh
 
J

Jim Yanik

Jan 1, 1970
0
Jim, could you be more specific? Not to hijack anyone's thread,
but we recently replaced a 3.6V NiCd cordless phone battery
pack (600mAh) with 1300mAh NiMH's, and plan to use the
phone's base (150mV input)

I hope you mean "mA".
to recharge it. If we're careful to
time the recharges properly, what other complications could
there be?

Well,your cells usually still have a partial charge of unknown amount,and
thus charging for the "standard time" will overcharge the cells.
A proper charger will monitor the charge voltage and look for the small V
drop as the cells reach full charge,regardless of the original charge left
on the cells,maximizing cell life.

That's why they are "smart" chargers.
And from what I've read,you can leave the pack on the charger even after it
is fully charged. No "forgetting" and overcharging.
 
K

Ken G.

Jan 1, 1970
0
Yes i have . I have an older 3 head shaver and removed the 2 old AA
batterys and soldered in 2 ordinary Hi-MH AA cells about a year or so
ago and the thing has worked just fine , it does not overheat or act
funny in any way .
 
M

mike

Jan 1, 1970
0
Darmok said:
Hi,

I've got an older Norelco electric shaver, which has some kind of
'fast charge' ni-cads in it (haven't looked, but that's pretty much
what they had when it was made). Normally, it will recharge in about
20 minutes or so. Well, after all these years, one or both batteries
is dying, and I need to replace them. I was thinking of just putting
in a couple of Ni-MH cells (these are 'AA' size), because I know that
they can handle a higher charge rate than standard ni-cads. I've got
some extras of both, but no 'high charge rate' ni-cads (although, I'm
pretty sure I could get some at Tower Hobbies, or similar R/C model
shop).

Anyone ever replace batteries in a Norelco (or other brand) shaver?
Anything I should be aware of or watch out for? Seems like it should
be a pretty straight forward procedure.

TIA

Call up a norelco shaver repair place. I don't remember the number,
but I do remember being amazed at how low their battery prices were.
I'd just been thru the hassle of replacing cells and would have just bought
them from Norelco had I realized they were affordable. YMMV
mike

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D

Darmok

Jan 1, 1970
0
Hi,

I've got an older Norelco electric shaver, which has some kind of
'fast charge' ni-cads in it (haven't looked, but that's pretty much
what they had when it was made). Normally, it will recharge in about
20 minutes or so. Well, after all these years, one or both batteries
is dying, and I need to replace them. I was thinking of just putting
in a couple of Ni-MH cells (these are 'AA' size), because I know that
they can handle a higher charge rate than standard ni-cads. I've got
some extras of both, but no 'high charge rate' ni-cads (although, I'm
pretty sure I could get some at Tower Hobbies, or similar R/C model
shop).

Anyone ever replace batteries in a Norelco (or other brand) shaver?
Anything I should be aware of or watch out for? Seems like it should
be a pretty straight forward procedure.

TIA

Thanks for all the input .. very helpful indeed!

Bill, KB8EB
 
H

H. Dziardziel

Jan 1, 1970
0
Charging in only 20 minutes is a 3C charge rate ie, three times
the cell mAh capacity. Shaver NiCads would be in the 500m-1000Ah
range. NiMh 2000-2600mAh AAs can handle that 1500-2000mA charge
rate but must not go over full charge or will be destroyed.

The question is: is that a timed 20 minutes or a "smart" 20
minutes? If timed and one starts with fully discharged cells
then all is well. NiMh have no memory effect so can be charged
and dicharged from-to any level But, if a smart charger is used,
it may not properly detect the NiMh charge state and keep charging
past fully charged.

For say, 1500mAh cells, that would take about one hour however so
manul timing would suffice. Monitoring the cell temperature is a
good idea. Some heating while charging is normal for NiMh but
after full charge is reached it quickly ruins the cells.
 
J

Jim Yanik

Jan 1, 1970
0
Charging in only 20 minutes is a 3C charge rate ie, three times
the cell mAh capacity. Shaver NiCads would be in the 500m-1000Ah
range. NiMh 2000-2600mAh AAs can handle that 1500-2000mA charge
rate but must not go over full charge or will be destroyed.

The question is: is that a timed 20 minutes or a "smart" 20
minutes? If timed and one starts with fully discharged cells
then all is well. NiMh have no memory effect so can be charged
and dicharged from-to any level But, if a smart charger is used,
it may not properly detect the NiMh charge state and keep charging
past fully charged.

For say, 1500mAh cells, that would take about one hour however so
manul timing would suffice. Monitoring the cell temperature is a
good idea. Some heating while charging is normal for NiMh but
after full charge is reached it quickly ruins the cells.

According to what I've read here and there,cell temperature is NOT a good
way to detect full charge for NiMH cells. For NiCd,its OK.
By the time the temp changes the NiMH cell is overcharged.
 
G

gb

Jan 1, 1970
0
mike said:
Call up a norelco shaver repair place. I don't remember the number,
but I do remember being amazed at how low their battery prices were.
I'd just been thru the hassle of replacing cells and would have just
bought
them from Norelco had I realized they were affordable. YMMV
mike

I have one (Norelco repair facility) here locally -- still repair very old
models and parts are very inexpensive (sometime cheaper than the department
store batteries).

gb
 
H

H. Dziardziel

Jan 1, 1970
0
A typo, "1500mAh cells" should read "1500mA."
, that would take about one hour however so

According to what I've read here and there,cell temperature is NOT a good
way to detect full charge for NiMH cells. For NiCd,its OK.
By the time the temp changes the NiMH cell is overcharged.

My post was poorly worded thanks. My "monitoring the cell
temperature" along with "some heating" was to imply hand sensing
as a very simple check of what's going on in the cells if they
have charged for more than 20 minutes or from an unknown charge
state..

The assumption was the shaver does not use temperature sensing
except for catastrophic shutoff and if a smart 20 minute charger
it is of course designed for NiCad characteristics so may not ever
shut off.

Unlike NiCads, NiMh are exothermic while charging so will get
warm, especially at this rather high charge rate.. Once fully
charged however the temperature (T) rises sharply after the very
small voltage drop that indicate full charge . The problem is
this short delay and the electronics and packaging usually getting
warm along with ambient variations. So, as you say, it's not
usually used since difficult to detect reliably.

NiCads, being endothermic are more reliably temperature end of
charge detected since the T change is sharper. In either case,
_hot_ cells indicate overcharging

Regards..
 
D

Darmok

Jan 1, 1970
0
Charging in only 20 minutes is a 3C charge rate ie, three times
the cell mAh capacity. Shaver NiCads would be in the 500m-1000Ah
range. NiMh 2000-2600mAh AAs can handle that 1500-2000mA charge
rate but must not go over full charge or will be destroyed.

The question is: is that a timed 20 minutes or a "smart" 20
minutes? If timed and one starts with fully discharged cells
then all is well. NiMh have no memory effect so can be charged
and dicharged from-to any level But, if a smart charger is used,
it may not properly detect the NiMh charge state and keep charging
past fully charged.

For say, 1500mAh cells, that would take about one hour however so
manul timing would suffice. Monitoring the cell temperature is a
good idea. Some heating while charging is normal for NiMh but
after full charge is reached it quickly ruins the cells.

Well, I did as someone suggested, and "Googled" for "Norelco battery
replacements". I found a place that carries replacements for almost
all versions of the Norelco shavers. When I looked up my model number
(4845XL) it showed them as a pair of AA NiMH batteries! When I looked
at the actual cells in the shaver, they were a pair of 600mah Ni-Cds.
So, since I have a lot of NiMH cells around (for digital cameras and
hobby use), I decided to solder in a couple of them and see what
happens.

The first thing I noticed was that, for the first time in years, the
RED charge LED came on (for a few minutes) as well as the GREEN LED.
It then proceeded to charge for about 20 minutes, then the GREEN LED
began flashing, and I knew charging had stopped. The case of the
shaver felt warm, but not as warm as when there were Ni-Cds in there.
I've been using it now for a couple days, and it has plenty of zip,
and sounds real good (by the pitch of the motor). BTW, I assume that
there is some kind of "smart charging" going on, as if I were to plug
it in after only a couple days, it would shut off (green LED blinking)
after only a few minutes. Maybe its voltage based?

I guess I'll know how well, this works after some time has expired,
but for now, it appears to be working well. BTW, I have 2 Norelco
shavers, and this is the older of the 2. I use one until it runs
down, then grab the other one, and put the exhausted one on charge.

Thanks again ..

Bill, KB8EB
 
D

Doug McLaren

Jan 1, 1970
0
| The main complication would be very short battery life.

As you hinted at, that depends on the charger.

Most cheap rechargable appliances have a slow charger that charge the
battery at around C/10. If you replace 600 mAh AA NiCds with 2400 mAh
AA NiMH cells, the charger will work just fine, except that it's now
charging at a C/40 rate -- which is slow enough that the incresaed
self discharge of the NiMH cells will become an issue, but it'll
probably work just fine. (It might not ever fully charge the
batteries though. But it should be OK anyways.)

You really only have to worry about the charger if it 1) only charges
for X hours, which would mean that it won't fully charge the new,
larger battery unless you unplug it and plug it back in after X hours,
or 2) is a fast peak-detecting charger, as NiMH cells have a similar
peak to NiCds, but it's smaller.

In my experience, most cheap devices that have NiCd or NiMH cells have
slow chargers that will work fine with either. Only the higher
quality ones have things that actually detect when the battery is
actually fully charged -- things like better power tools and the like.
(And of course, anything with LiPo cells. Overcharging them is bad.
But LiPo cells don't fit within the `NiCd or NiMH' classification I
mentioned earlier.)
 
D

Doug McLaren

Jan 1, 1970
0
| Most cheap rechargable appliances have a slow charger that charge the
| battery at around C/10.

Of course, since the original poster says it charges the batteries in
20 minutes, obviously it doesn't fall into this category.

It would be best to replace those batteries with similar batteries.

Modern NiMH cells will tolerate overcharge almost as well as NiCd
cells, but they don't like being charged at over 1C rates, except for
the sub-C cells which can go a bit higher, probably 2C.

As another poster suggested, if they're sub-C cells, get them at a
hobby store that sells R/C stuff. You can buy them online too easily
enough -- www.radicalrc.com is one of my favorite places.

Places like Batteries Plus probably have what you need too, but their
prices are generally quite high.
 
D

Doug McLaren

Jan 1, 1970
0
|
| >> For say, 1500mAh cells
|
| A typo, "1500mAh cells" should read "1500mA."

Are you sure? 1500 mAh seems right to me. You're talking about the
capacity of the cell itself, not the discharge rate, right?

Capacity is given in mAh. Charge/Discharge rates in mA.

| Unlike NiCads, NiMh are exothermic while charging so will get
| warm, especially at this rather high charge rate..

NiCds get warm during charging too. Just not as warm, due to their
generally lower internal resistance.

| Once fully charged however the temperature (T) rises sharply after
| the very small voltage drop that indicate full charge.

Same with NiCd and NiMH cells -- it's just that with NiMH cells, the
voltage drop is smaller.

| NiCads, being endothermic are more reliably temperature end of
| charge detected since the T change is sharper. In either case,
| _hot_ cells indicate overcharging

Endothermic? No way.

Apparantly there is an endothermic component to the chemical charging
process (and I see references to that in many places) but the current
going through the internal resistance will generate heat as well, and
from what I've seen, the overall temperature _increases_ as you
charge, even for NiCds, during the entire charge cycle, even when
you're not charging at an extremely high rate. (Of course, if you're
charging at a low rate, any temperature changes are hard to detect, at
least until the cell is fully charged, where it becomes much easier as
all energy is going into heat, not just some.)

Perhaps at low charge rates the endothermic component is slightly
stronger than the exothermic heating, but if you're charging a NiCd
battery in 20 minutes -- at a 3C rate -- no way. It's going to get
warm.
 
H

H. Dziardziel

Jan 1, 1970
0
|
| >> For say, 1500mAh cells
|
| A typo, "1500mAh cells" should read "1500mA."

Are you sure? 1500 mAh seems right to me. You're talking about the
capacity of the cell itself, not the discharge rate, right?

The 1500mA was an estimated 3C charge rate for the original
NiCads, hence the following words "..that would take about one
hour.." (to begin to fully charge the new high capacity NiMh etc).
Capacity is given in mAh. Charge/Discharge rates in mA.

Well, I do believe that strikes a note but thanks for the reminder
to be more alert. Sigh.
| Unlike NiCads, NiMh are exothermic while charging so will get
| warm, especially at this rather high charge rate..

NiCds get warm during charging too. Just not as warm, due to their
generally lower internal resistance.

| Once fully charged however the temperature (T) rises sharply after
| the very small voltage drop that indicate full charge.

Same with NiCd and NiMH cells -- it's just that with NiMH cells, the
voltage drop is smaller.

| NiCads, being endothermic are more reliably temperature end of
| charge detected since the T change is sharper. In either case,
| _hot_ cells indicate overcharging

Endothermic? No way.

Apparantly there is an endothermic component to the chemical charging
process (and I see references to that in many places)

Yes.and it's significant but I don't claim to understand the
electrochemical.theory behind it,. Good NiCads stay pretty cool
even at high rates. By the way, Li-ion are also somewhat
endothermic until nearly fully charged.
but the current
going through the internal resistance will generate heat as well, and
from what I've seen, the overall temperature _increases_ as you
charge, even for NiCds, during the entire charge cycle, even when
you're not charging at an extremely high rate. (Of course, if you're
charging at a low rate, any temperature changes are hard to detect, at
least until the cell is fully charged, where it becomes much easier as
all energy is going into heat, not just some.)

Perhaps at low charge rates the endothermic component is slightly
stronger than the exothermic heating, but if you're charging a NiCd
battery in 20 minutes -- at a 3C rate -- no way. It's going to get
warm

I'm warming to your point. Regards.



..
 
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