Unusual battery use, or is it?

[Andy Wood]

I was tinkering with a cheap universal remote control. Before spending
a lot of time trying to program it I decided to test if the code
memory was non-volatile.

Thinking that the four AAA cells would be connected in series, I
pulled one of them out and waited. And waited... but the display (LCD)
stayed on with the clock running. I found that the whole thing,
including the LED back lighting was still working just fine.

A bit of investigation reveals that two of the AAAs are connected in
series, and the other two AAAs are also connected in series, then the
two sets of series connected cells are connected in parallel. Net
result is that the remote can work with only two of the cells in
place.

Opinion about parallel connected cells seems to range from "don't do
it" to "no worries as long as the cells are matched". I tend to go
along with the latter.

I have encountered devices where cells were not all in series, but
this is the first thing I have seen with parallel connected cells.
What I am wondering is, how common is it to use cells in this way?
Andy Wood
woodag@trap.ozemail.com.au

 

[Jon]

"Andy Wood" <woodag@trap.ozemail.com.au> wrote in message
news:GLmdnWQKStRopfbWnZ2dnUVZ_sydnZ2d@westnet.com.au...
<snip>

A bit of investigation reveals that two of the AAAs are connected in
series, and the other two AAAs are also connected in series, then the
two sets of series connected cells are connected in parallel. Net
result is that the remote can work with only two of the cells in
place.

snip

I have encountered devices where cells were not all in series, but
this is the first thing I have seen with parallel connected cells.
What I am wondering is, how common is it to use cells in this way?
Andy Wood
woodag@trap.ozemail.com.au

The Microsoft wireless mouse cells are in parallel as well.




--- news://freenews.netfront.net/ - complaints: news@netfront.net ---

 

[Mr.T]

"Andy Wood" <woodag@trap.ozemail.com.au> wrote in message
news:GLmdnWQKStRopfbWnZ2dnUVZ_sydnZ2d@westnet.com.au...

A bit of investigation reveals that two of the AAAs are connected in
series, and the other two AAAs are also connected in series, then the
two sets of series connected cells are connected in parallel. Net
result is that the remote can work with only two of the cells in
place.

How annoying, it's far cheaper to use two AA cells rather than four AAA
cells if they only need 3V.
Must have been designed by a battery manufacturer!
Or use 2 AAA cells, save size and weight, and just replace/recharge them
more often.

MrT.

 

[Mickel]

"Andy Wood" <woodag@trap.ozemail.com.au> wrote in message
news:GLmdnWQKStRopfbWnZ2dnUVZ_sydnZ2d@westnet.com.au...

I was tinkering with a cheap universal remote control. Before spending
a lot of time trying to program it I decided to test if the code
memory was non-volatile.

Thinking that the four AAA cells would be connected in series, I
pulled one of them out and waited. And waited... but the display (LCD)
stayed on with the clock running. I found that the whole thing,
including the LED back lighting was still working just fine.

A bit of investigation reveals that two of the AAAs are connected in
series, and the other two AAAs are also connected in series, then the
two sets of series connected cells are connected in parallel. Net
result is that the remote can work with only two of the cells in
place.

Opinion about parallel connected cells seems to range from "don't do
it" to "no worries as long as the cells are matched". I tend to go
along with the latter.

I have encountered devices where cells were not all in series, but
this is the first thing I have seen with parallel connected cells.
What I am wondering is, how common is it to use cells in this way?
Andy Wood
woodag@trap.ozemail.com.au

Isn't it only a problem for charging?

 

[geoff]

Andy Wood wrote:

I was tinkering with a cheap universal remote control. Before spending
a lot of time trying to program it I decided to test if the code
memory was non-volatile.

Thinking that the four AAA cells would be connected in series, I
pulled one of them out and waited. And waited... but the display (LCD)
stayed on with the clock running. I found that the whole thing,
including the LED back lighting was still working just fine.

A bit of investigation reveals that two of the AAAs are connected in
series, and the other two AAAs are also connected in series, then the
two sets of series connected cells are connected in parallel. \

The parallel pair possibly are dedicated for the backlight, if applicable.

geoff

 

[Andy Wood]

"geoff" <geoff@nospam-paf.co.nz> wrote:

Andy Wood wrote:
I was tinkering with a cheap universal remote control. Before spending
a lot of time trying to program it I decided to test if the code
memory was non-volatile.

Thinking that the four AAA cells would be connected in series, I
pulled one of them out and waited. And waited... but the display (LCD)
stayed on with the clock running. I found that the whole thing,
including the LED back lighting was still working just fine.

A bit of investigation reveals that two of the AAAs are connected in
series, and the other two AAAs are also connected in series, then the
two sets of series connected cells are connected in parallel. \

The parallel pair possibly are dedicated for the backlight, if applicable.

geoff

No, that is not the way it is. If I label the cells A B C and D, then
(A and B) are in series, and (C and D) are in series. I can remove
both A and B and everything, including the display and key back
lighting works. Everything also works if I put A and B back in and
remove C and D.

It won't work on any old combination of two of the cells, of course.
If I remove either one of (A or B) AND either one of (C or D) then it
is dead.


Andy Wood
woodag@trap.ozemail.com.au