 SparkChaser
Premium Member
join:2000-06-06
Downingtown, PA |
to Subaru
Re: Electronics that stop working when coldsaid 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
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 alkizmo
join:2007-06-25
Pierrefonds, QC |
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 |
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cowboyro
Premium Member
2013-Feb-1 7:47 pm
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. |
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cowboyro
Premium Member
2013-Feb-1 9:33 pm
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.... |
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That was an unloaded voltage? |
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cowboyro
Premium Member
2013-Feb-1 10:13 pm
Yes, no load... |
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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. |
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SparkChaser
Premium Member
join:2000-06-06
Downingtown, PA |
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. |
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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... |
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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 batteryOf 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. |
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cowboyro
Premium Member
2013-Feb-2 1:45 pm
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... |
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lutful... of ideas
Premium Member
join:2005-06-16
Ottawa, ON |
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. |
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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. |
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) where the battery played an important role. See: »