Idle drain power in battery operated devices

[2dye4]

I have several radios and at least one camera
that will consume their aa alkaline cells in 6 months with no usage.
This seems wasteful bordering on conspiracy. I have designed circuits to operate continuously on aa battery power for this time frame.
I can't help but think there are connections between the electronics manufacturers and the battery people.

All of my devices are of course made by Japanese companies, mainly because I want the best quality.
I am thinking of writing consumer reports with this issue because i think it can be improved.

What do you think?
Is there any legitimate reason idle devices should consume more than a couple of uA.

 

[MikeHalloran]

Self-discharge?

Real time clock chips?



Mike Halloran
Pembroke Pines, FL, USA

 

[jimkirk]

6 months is about 4320 hours. Wikipedia says AA alkaline batteries range from 1,700 to 3,000 mA-h, so we're taking around 400 to 700 uA. I agree, that sounds like quite a lot, depending on what the "off" is doing. Keeping the correct time should require a few microamps.

If it has a microprocessor, it may have many levels of doze, sleep and hibernate that take different amounts of time to wake up, sense different inputs and draw different amounts of current.

Years ago I had a little mp3 player (256MB) that would drain its AAA battery in about a week when "off". Ridiculous!

EnergyStar and other initiatives are publicizing the power drain for mains operated devices (my new TV has a standby drain of 0.3 Watts). It would be nice to have something similar for battery powered devices. Maybe a website where people could rate their gadgets. Does anyone know if something like this exists?

One reason I almost exclusively use rechargeable batteries.

 

[jimkirk]

Alkaline self discharge is on the order of a decade at room temperature.

 

[IRstuff]

mp3 players, "years ago" probably had active memory that needed to be powered, even when the player was not on.

Most cameras require battery power of some sort to maintain their datestamp clocks.

TTFN

FAQ731-376

 

[MikeHalloran]

Running a RTC and its associated crystal is not the same as sitting on a shelf. 32,768 times a second, something has to happen.



Mike Halloran
Pembroke Pines, FL, USA

 

[itsmoked]

Yes but it should still be pretty dang close. 1-5uA. We are talking self discharge rates of alkalies. Which means the RTC should run for years.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[MikeHalloran]

I know coin cells last for years in RTC service. I couldn't find appropriate data for alkalines, which have a different chemistry.

Regardless, I'm not inclined to support an assertion of conspiracy.





Mike Halloran
Pembroke Pines, FL, USA

 

[Skogsgurra]

We have designed gadgets that never sleep and still work for more than five years on AA cells. In our case, we used a cheapo PIC and a cheapo RTC crystal. The whole thing used about 12 uA. People used to phone us after five years asking where to send the thing 'cause it stopped working'.

-Did you change batteries?
-What? Are there batteries in it?

Instruction leaflet gone, or never read.

So, even if the device is active, keeping time, checking ring signals or whatever, it should be able to last a lot longer than six months.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[itsmoked]

It's because Gizmos these days have a halflife of about a year. Making complex designs that use little energy takes extra effort and $$. These junk purveyors logically have no interest in that. Besides about the time the device is going to self destruct they'll roll out an upgrade. Just look at Apple. Step and repeat. They come out with devices you can't even change the batteries on and fools buy it because it's a, "gotta have".

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[Skogsgurra]

I tend to agree there, Smoked.

What will Al Gore do to it?

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...