"Never needs calibrating"

[Jbhunter223]

Hey everyone,

I've been playing around with hygrometers moving them all around my wineador seeing the differences throughout. I have 2 xikar "never needs calibrating" hygrometers. This is them sitting 3" apart on the same shelf. Both got brand new batteries and still read differently. I know it's not a big difference and I'm not freaking out about it. Im just curious if it's possible to have this kind of variablity on the same shelf 3" apart?

thanks,

Jayme

[BuzzArd]

Probably within the +/- you'll see between any instruments that measure humidity.  For instance, if the real humidity is 64.5 % and the manufacuturer claims accurate +/- 3% they consider it good.   Do they always stay 3 % apart?  

[Jbhunter223]

6 minutes ago, BuzzArd said:

Probably within the +/- you'll see between any instruments that measure humidity.  For instance, if the real humidity is 64.5 % and the manufacuturer claims accurate +/- 3% they consider it good.   Do they always stay 3 % apart?  

Ahhh this is true, I didn't think of this.  It varies a little, but pretty close to 3% most of the time. 

[btort910]

The variance is more likely due to the hygrometers than the actual difference in humidity on that 3" shelf space.

[shall]

Xikar site guarantees 2%, so you might send them a note.  Also, if you aren't happy, they will swap them out for you regardless.  Stellar customers service, although I only have use their cutters.

If the cigars are smoking to your liking, I wouldn't fret too much. 

[Jbhunter223]

25 minutes ago, Weaponiz'd1 said:

I have the Xikar with 3 different channels, 3 sensors. 

I switch mine fairly often to check them against each other and rarely see more than 1 point of difference. 

Does "Never needs calibrating" mean no way to calibrate?

Yea, no way to calibrate. 

[Jbhunter223]

16 minutes ago, shall said:

Xikar site guarantees 2%, so you might send them a note.  Also, if you aren't happy, they will swap them out for you regardless.  Stellar customers service, although I only have use their cutters.

If the cigars are smoking to your liking, I wouldn't fret too much. 

I'll shoot them an email. Again not the end of the world here. Was just curious, maybe I should do the salt test and see which one if either Is correct. Thanks!

[CrankYanker]

@BellevilleMXZ showed me these and I am using one currently.  I've had no problems with them and I don't need to open anything up to check on them. 

https://www.amazon.com/SensorPush-Wireless-Thermometer-Hygrometer-Android/dp/B01AEQ9X9I

[PigFish]

2% on each instrument means that these are still within tolerance potentially.

You will find that hygrometers set next to each other can have different values. This is more prevalent when there is a temperature difference. The aH in this small space is likely the same. I find temperature more the cause of rH variation especially at different elevations. I cannot read the temp on both instruments so it is impossible for me to tell.

Remember that calibration does not imply any linear relationship in errors. Get an instrument calibrated at several points and you will find this out. Sensors that are out at one rH at a given temp might be right on at another. That is just the way it goes.

All sensors drift over time. Tying to stay ahead of the accuracy game is pretty much a losing game. The point is, both are probably wrong, and it just depends on how far!!!

Cheers! -Piggy

[Jbhunter223]

1 hour ago, PigFish said:

2% on each instrument means that these are still within tolerance potentially.

You will find that hygrometers set next to each other can have different values. This is more prevalent when there is a temperature difference. The aH in this small space is likely the same. I find temperature more the cause of rH variation especially at different elevations. I cannot read the temp on both instruments so it is impossible for me to tell.

Remember that calibration does not imply any linear relationship in errors. Get an instrument calibrated at several points and you will find this out. Sensors that are out at one rH at a given temp might be right on at another. That is just the way it goes.

All sensors drift over time. Tying to stay ahead of the accuracy game is pretty much a losing game. The point is, both are probably wrong, and it just depends on how far!!!

Cheers! -Piggy

The temp. Is 2 degrees higher on the right. But this makes sense different temp different RH

[Bartolomeo]

Salt test them....

[Fugu]

1 hour ago, Jbhunter223 said:

The temp. Is 2 degrees higher on the right. But this makes sense different temp different RH

Doesn't make sense, but either way: The temperature info displayed is not related to the rH-measurement (this is compensated independently).

Results are proving that you indeed need to perform your own calibration, given you are not satisfied with the results (as stated, instruments could still be within their specified range of measurement uncertainty) and that "never-needs-calibration" is nothing less than frivolous advertising gimmick.

[mwaller]

There likely is no way to calibrate them.  The equipment to measure relative humidity is considerably more inaccurate than other low-cost sensing technologies for variables like temperature and pressure.  It's not hard to find a thermometer that is accurate to 0.1%.  On the other hand, a hygrometer with 10-times that tolerance (+-1%) is incredibly uncommon.

+-2% is about the best accuracy you will find among consumer-grade hygrometers.    

[PigFish]

27 minutes ago, Fugu said:

Doesn't make sense, but either way: The temperature info displayed is not related to the rH-measurement (this is compensated independently).

Results are proving that you indeed need to perform your own calibration, given you are not satisfied with the results (as stated, instruments could still be within their specified range of measurement uncertainty) and that "never-needs-calibration" is nothing less than frivolous advertising gimmick.

This does depend on the architecture of the instrument. If you look at two of my data loggers, you will typically find that two can closely agree with each other. If you see an rH and temperature difference, then calculate the aH based on both numbers, I typically find them almost identical. A lower temp will reflect a higher rH given the same aH if the instruments agree! I do see this. Well homogenize water vapor with a temperature differential that ultimately gets reflected in rH. rH, being dependent on temperature.

I am always thinking outside of the box here and that is what caused me to talk about temperature. In the background it appears to me that there are TE cooler fan(s). Is this correct? If so, then the two instruments might correlate quiet well, and your circulation could be an issue with both cold, wet, warm, dry airstreams. The fact is, if you want to correlate the two instruments put them in a stable and homogeneous environment, not a home wine cooler humidor.

Unless you really understand where you are at related to cooling cycles and airstreams in your humidor, and how the cool, wet or dry air runs off the coils, the dynamics of your humidor, you could very well be blaming the wrong source, a common occurrence on cigar boards.

Food for thought! -Piggy

[Fugu]

1 hour ago, mwaller said:

There likely is no way to calibrate them.  The equipment to measure relative humidity is considerably more inaccurate than other low-cost sensing technologies for variables like temperature and pressure.  It's not hard to find a thermometer that is accurate to 0.1%.  On the other hand, a hygrometer with 10-times that tolerance (+-1%) is incredibly uncommon.

+-2% is about the best accuracy you will find among consumer-grade hygrometers.    

Of course can you calibrate them. You must distinguish between measurement uncertainty and precision, i.e. repeatability. While the uncertainty (absolute error in laymen's terms) can be poor, the latter usually is fairly good even in a cheapo, for a confined range of temperatures. (see - these devices are mostly not being "calibrated" ex works, sensor chips are simply selected to comply with a certain spec.). Therefore, even in the cheapest capacitive (or resistive)-sensor-based device it is always worth doing your own calib, provided you know what you are doing.

1 hour ago, PigFish said:

A lower temp will reflect a higher rH given the same aH if the instruments agree!

...why I was saying differences don't make sense (in a logical, physical way that is)

The temperature reading will be wrong as well here, both devices rather be subjected to +/- identical temperature and humidity conditions.

But be it as be, I'd keep it with Bart here - salt-test them!

[Jbhunter223]

Thank you for all the replies, I always learn a lot from these types of threads.  Will be salt testing, I understand these are accurate to +/- X degrees and X% so we'll see how close they get. 

[El Presidente]

I have had $10 hygrometers and $500 commercial ones. Even the commercial ones would be out 1-2%.  That is not a problem but my experience is that their performance (all) deteriorates over time. 

......just like the rest of us 

[Jbhunter223]

25 minutes ago, El Presidente said:

I have had $10 hygrometers and $500 commercial ones. Even the commercial ones would be out 1-2%.  That is not a problem but my experience is that their performance (all) deteriorates over time. 

......just like the rest of us 

Can't argue with that!

[El Presidente]

2 minutes ago, Jbhunter223 said:

Can't argue with that!

With a permanent marker, I just write on the Hygrometers how far they were out (+2, -3, -1). Normally we run a commercial grade Hygrometer and three cheapies. 

[Jbhunter223]

38 minutes ago, El Presidente said:

With a permanent marker, I just write on the Hygrometers how far they were out (+2, -3, -1). Normally we run a commercial grade Hygrometer and three cheapies. 

I never thought of doing this, good idea. Thanks!

[Fugu]

9 hours ago, Jbhunter223 said:

I never thought of doing this, good idea. Thanks!

Use removable labels (I use Post-It bits, just the sticky part), as you might need to adjust numbers from time to time, in particular in new devices....

[PigFish]

From another thread. This is a calibrated temp/rH transmitter.

If you have a label maker, they are great for this! -Piggy