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Subaru
1-3-2-4
Premium
join:2001-05-31
Greenwich, CT
kudos:1

Electronics that stop working when cold

So it was my mistake for not reading most of the reviews since the new reviews started coming in during the colder months.. but anyways with new batteries and all this tire pressure gauge I has will not come on until it's warmed up above 20-26 F

So, I wonder what's keeping it from working under those temps.. I know most chips have operating limits as far as temperature but why?



alphapointe
Don't Touch Me
Premium,MVM
join:2002-02-10
Columbia, MO
kudos:2
Reviews:
·Socket Internet ..

More likely it's the battery not producing enough voltage when it's that cold... I know some of my radio batteries gripe when I walk to work and it's really cold, then be fine once they come back up to room temp...
(my scanner is REAL bad about this... I've come to accept the "low battery beep" as normal when walking to work when it's below freezing)
--
"When the hammer drops, the bullshit stops"



Subaru
1-3-2-4
Premium
join:2001-05-31
Greenwich, CT
kudos:1

Well they use CR2032's two of them.



aurgathor

join:2002-12-01
Lynnwood, WA
kudos:1
Reviews:
·Frontier Communi..
reply to Subaru

Just troubleshoot and figure it out.

Normally, batteries are more affected by cold than most other electronic parts, but it shouldn't be too difficult to figure out the culprit.
--
Wacky Races 2012!



tschmidt
Premium,MVM
join:2000-11-12
Milford, NH
kudos:9

1 recommendation

reply to Subaru

It is probably not the gauge electronics itself or the batteries but rather the LCD display. They don't like the cold.

/tom



SparkChaser
Premium
join:2000-06-06
Downingtown, PA
kudos:3
Reviews:
·Verizon FiOS
reply to Subaru

said by Subaru:

has will not come on until it's warmed up above 20-26 F

Got the same problem with my body.

Here's Maxell's battery, not too much variation with temp.




As Tom said it's a good chance it's the LCD
--
--
--
"Facts do not cease to exist because they are ignored." - Aldous Huxley

b10010011
Whats a Posting tag?

join:2004-09-07
Bellingham, WA
Reviews:
·Comcast Formerl..
reply to tschmidt

said by tschmidt:

It is probably not the gauge electronics itself or the batteries but rather the LCD display. They don't like the cold.

/tom

The L in LCD does stand for Liquid after all.
--
Bellingham Scanner Kicks Ass! »bhamscanner.kicks-ass.org/


alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1
reply to SparkChaser

said by SparkChaser:

Here's Maxell's battery, not too much variation with temp.

That chart is at 0c

0c is not an issue.

My iphone's battery went from 100% to 0% sometime during the 6 hours I left it in my car at -20C


cowboyro
Premium
join:2000-10-11
Shelton, CT

said by alkizmo:

That chart is at 0c

Goes to -10C (14F).
I'll do a test just because I can and I'll post the results.


Subaru
1-3-2-4
Premium
join:2001-05-31
Greenwich, CT
kudos:1
reply to Subaru

You can see it here

»www.amazon.com/gp/product/B000B6···_s00_i01



Subaru
1-3-2-4
Premium
join:2001-05-31
Greenwich, CT
kudos:1
reply to tschmidt

said by tschmidt:

It is probably not the gauge electronics itself or the batteries but rather the LCD display. They don't like the cold.

/tom

if my car's LCD display works in 12F then it should be no reason for this


Cho Baka
Premium,MVM
join:2000-11-23
there
kudos:2

I don't think that is a valid comparison.

The standards for automotive electronics are much higher than those for a throwaway tire pressure gauge.
--
The talented hawk speaks French.



JustBurnt

@rr.com
reply to Subaru

A battery operated tire pressure gauge? WHY?



Subaru
1-3-2-4
Premium
join:2001-05-31
Greenwich, CT
kudos:1

because it had a feature I wanted



cowboyro
Premium
join:2000-10-11
Shelton, CT
reply to cowboyro

Took a 2032 cell. From room temperature to -5F in the freezer and back to room temperature the voltage was between 3.33 and 3.34V (more precisely 3.332 and 3.342). There was an initial jump in voltage after putting the battery in the freezer that lasted about 10min, the the voltage decreased to 3.336-3.338V. After bringing it back to room temperature the voltage stabilized again to ~3.332V.
BORING....



Cho Baka
Premium,MVM
join:2000-11-23
there
kudos:2

That was an unloaded voltage?



cowboyro
Premium
join:2000-10-11
Shelton, CT

Yes, no load...


sergey3

join:2004-08-25

said by cowboyro:

Yes, no load...

Batteries produce electricity using a chemical reaction. When it is cold, the reaction slows down. This means that with no load the voltage will be mostly unchanged. But under load the battery will produce less power (fewer amps). I don't have enough experience to say how much less power to expect. But I have heard of cars in cold climates having an additional car battery because one battery might not be enough to start a car in very cold climates.

The same logic would say that adding an additional battery might be helpful. But realistically it might be easier to leave the electronic gauge at home and take it out for only a few minutes.

lutful
... of ideas
Premium
join:2005-06-16
Ottawa, ON
kudos:1
reply to Subaru

said by Subaru:

with new batteries ... will not come on until it's warmed up above 20-26 F

All batteries have internal resistance which goes up as temperature goes down. Above chart is for rechargeable batteries but gives you an idea of what happens to the power output below some threshold temperature.

said by Subaru:

I know most chips have operating limits as far as temperature but why?

Chips (digital or analog) are really a whole bunch of circuit elements. The behavior of each of those elements depends on temperature.


SparkChaser
Premium
join:2000-06-06
Downingtown, PA
kudos:3
Reviews:
·Verizon FiOS
reply to alkizmo

said by alkizmo:

That chart is at 0c

The chart is from 60 to -10C @ 15K load LiMnO2 chemistry

I have a LiPo cell sending me temp data from the front of the house and it's -8C outside. I've had it in the freezer for over 24 hrs @ -16C and sending data.

I have no experience with iPhones.
--
--
--
"Facts do not cease to exist because they are ignored." - Aldous Huxley


DKS
Damn Kidney Stones
Premium,ExMod 2002
join:2001-03-22
Owen Sound, ON
kudos:2

1 recommendation

reply to JustBurnt

said by JustBurnt :

A battery operated tire pressure gauge? WHY?

Exactly. Other than a bunch of silly convenience features, using a battery is a huge INconvenience. Give me a quality dial or pencil type any day.
--
Need-based health care not greed-based health care.


SparkChaser
Premium
join:2000-06-06
Downingtown, PA
kudos:3
Reviews:
·Verizon FiOS
reply to Subaru

said by Subaru:

if my car's LCD display works in 12F then it should be no reason for this

My car's TPMS works while I'm driving in the snow. Go figure.


DKS
Damn Kidney Stones
Premium,ExMod 2002
join:2001-03-22
Owen Sound, ON
kudos:2

said by SparkChaser:

said by Subaru:

if my car's LCD display works in 12F then it should be no reason for this

My car's TPMS works while I'm driving in the snow. Go figure.

Likewise. Mine works at -30C.
--
Need-based health care not greed-based health care.

lutful
... of ideas
Premium
join:2005-06-16
Ottawa, ON
kudos:1

said by DKS:

said by SparkChaser:

My car's TPMS works while I'm driving in the snow. Go figure.

Likewise. Mine works at -30C.

TPMS systems use specially designed Lithium Thionyl Cholride cells which are rated for -40C to +125C.

Nobody has managed to bring the low temp spec down to -55C (yet) so overnight in some Canadian towns, the TPMS could actually fail until tire warms up to -40C due to friction. Meanwhile in Arizona in the summer, some TPMS could fail because the air inside the tire got a bit hotter than +125C.

Now regarding the CR2032 of Subaru See Profile's tire gauge ... typical Lithium Manganese Dioxide coin cells are not meant to be used in very cold weather because internal resistance goes from already high 10 ohm at +20C to terrible 40 ohm at -10C. So the current and voltage both drops and maybe it is not enough to power the circuit.

P.S. Lithium Iron Disulphide cells also work down to -40C. These are 1.5V/cell and commonly sold as "lithium" AA replacement.


cowboyro
Premium
join:2000-10-11
Shelton, CT
reply to sergey3

said by sergey3:

But under load the battery will produce less power (fewer amps).

That without doubt. But then the power requirement of a pressure gauge isn't that big to start with...


aurgathor

join:2002-12-01
Lynnwood, WA
kudos:1
Reviews:
·Frontier Communi..

said by cowboyro:

said by sergey3:

But under load the battery will produce less power (fewer amps).

That without doubt. But then the power requirement of a pressure gauge isn't that big to start with...

But that extra resistance may decrease the output voltage enough to cause the gauge to malfunction. I had a similar issue (and I did my own troubleshooting to find the culprit -- Subaru, that's a hint for you ) where the battery played an important role. See: »Highest voltage 2032 battery

Of course in my case the root cause was an improperly designed circuit that required 3+ volts to function properly instead of going down to 2.6 - 2.7V.
--
Wacky Races 2012!


cowboyro
Premium
join:2000-10-11
Shelton, CT

said by aurgathor:

But that extra resistance may decrease the output voltage enough to cause the gauge to malfunction.

I'm still willing to bet on either LCD or the gauge refusing to work outside a temperature calibration range.
But I guess the voltage drop is something that I can easily test...

lutful
... of ideas
Premium
join:2005-06-16
Ottawa, ON
kudos:1
reply to aurgathor

said by aurgathor:

Of course in my case the root cause was an improperly designed circuit that required 3+ volts to function properly instead of going down to 2.6 - 2.7V.

Typical "3V" CMOS chips are actually designed to accept VCC = 3.3V +/- 0.3V. So the lower end of acceptable VCC is actually 3V which may be higher than a partially discharged CR2032 battery.

Now, the current drawn by all CMOS chips increase with lower temperature, so VCC could go down even more than acceptable range.

Solution is a buck-boost DC-DC converter IC to supply stable 3.3V from a single CR2032 cell. But that of course will cost an extra buck or two.


cowboyro
Premium
join:2000-10-11
Shelton, CT
reply to Subaru

Repeated the test with a 2032 cell. After a shock discharge @100mA for about 10 sec the voltage stabilized at ~3.16V
2032 cells have a maximum pulse discharge current of 15mA; I used a 2.2k resistor as load.
At room temperature the voltage dropped from 3.16 to 3.13V after 10 sec. After being kept in the freezer for 15+ min, the voltage dropped from 3.17 to 3.01V with the same load.



aurgathor

join:2002-12-01
Lynnwood, WA
kudos:1
Reviews:
·Frontier Communi..
reply to lutful

said by lutful:

Typical "3V" CMOS chips are actually designed to accept VCC = 3.3V +/- 0.3V. So the lower end of acceptable VCC is actually 3V which may be higher than a partially discharged CR2032 battery.

So in this particular use, they should be using a custom CMOS circuit designed to work with 3.0V +/- 0.3V, which more closely matches the CR2032.

I guess I need to take apart my gauge to see what's in it.

Solution is a buck-boost DC-DC converter IC to supply stable 3.3V from a single CR2032 cell. But that of course will cost an extra buck or two.

And would also decrease efficiency.
--
Wacky Races 2012!