Review of Acu-Rite Hygrometer from Walmart

I just bought a hygrometer from Walmart to make sure my guns and ammo are being stored in a proper environment with low humidity. For those who don't know, a hygrometer tells you the relative humidy (RH) which is a number between 0 and 100%. Well I bought this from Walmart:

http://i51.tinypic.com/2a4zi8j.jpg

And as you can see its already back in the package, ready to be returned to the store. I did a salt test right after I purchased it, which is a way to tell how accurate the unit is. Its really simple. When salt and water are combined in a sealed container, the resulting RH is 75%. That number slightly fluctuates depending on the temperature, but by such a tiny amount that we can completely disregard it. So all you have to do is put some salt and water in a soda cap, and put it in a sealed container along with the hygrometer, and wait about 8 hours. If your hygro reads 75% RH, then you are good to go.

Well I tried this using a ziplock bag, and after 8 hours my hygro read 68%. So I waited another 8 hours. Still 68%. Then I thought I would try the experiment again, but this time using a mason jar and using new salt and water. After 8 hours it was at 69%, and at 16 hours it was going back and forth between 69% and 70%. Obviously something was wrong.

So I opened up the unit and noticed that there was a solder pad that was ripped off the PC board, and the main element of the unit was instead soldered to one side of a resistor that was in series with it. The result is that the electrical path was the same, but the inductance of the circuit was changed. Someone on the assembly line screwed up and did a hack job to "fix" their mistake. I called the manufacturer about it and they denied that it was assembled wrong, and told me I could fix it by taking the battery out and putting it back in. Needless to say I'm not even trying that, and this unit is going back to Walmart. I'm very disappointed, but I guess thats what I get for shopping at Chinamart. I will be looking for a unit made by a different company that is capable of proper calibration.

I was thinking about getting one of these for my cabinet/safe. Glad you stopped me from getting that particular model, although I don't buy anything at Wal-Mart unless it is necessary.

GB

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Originally Posted by GreenBlood10

I was thinking about getting one of these for my cabinet/safe. Glad you stopped me from getting that particular model, although I don't buy anything at Wal-Mart unless it is necessary.

GB

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Good luck finding something electronic that ISN'T made in China. Many of the companies that are selling these things are getting their products from the same factories. You may find one of a different brand, but it's made in the same factory that the others are made in, just put in a different case with a different label.

The quality of all electronics coming out of china sucks. Cold and broken solder joints is common, and in some cases, you can fix the stuff yourself just by going over the board and touching up the bad joints.

Quote:

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Originally Posted by GreenBlood10

I was thinking about getting one of these for my cabinet/safe. Glad you stopped me from getting that particular model, although I don't buy anything at Wal-Mart unless it is necessary.

GB

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Yea like I said, just try to find one that is adjustable so you can calibrate it yourself. I screwed up by doing all my research after I bought it. The thing is, even if the unit is spot on at 75%, it can drift out of calibration over time. Some people suggest that you re-calibrate every six months. With this particular model (and many others available at Walmart) you do not have the ability to make adjustments.

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Originally Posted by streaker69

Good luck finding something electronic that ISN'T made in China.

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I didn't mean I wouldn't buy products from China, even though I buy USAm ade products whenever possible. I would much rather give the money to another company other than Wal-Mart.

GB

Even if you don't find one that is adjustable;

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If yours is not adjustable (like mine), simply make a note of how "off" your hygrometer reads. If it reads below 75 percent, you will need to add the difference to your actual readings. If your hygrometer read above 75 percent on the calibration, you will need to subtract the difference from your actual reading. Here are some examples to help:
Case 1: after sitting in the bag for calibration, my hygrometer read 72 percent. It should have read 75 percent, so the difference is 3 percent. I will now add 3 percent to the readings I take on the hygrometer (e.g. in a tank) to get the actual relative humidity.
Case 2: after calibrating in the bag, a hygrometer read 80 percent. It should have read 75 percent, a difference of 5 percent. I would have to subtract 5 percent from readings when using the hygrometer to get an accurate relative humidity.

Remember: always give a hygrometer about 2 hours to stabilize before taking a reading, as changes in the relative humidity may take a while to register accurately on a hygrometer.

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I bought a couple of these at the Walmart in Willow Grove a while back for $2 a piece. They read about 5% high. Good enough for my purposes.

http://www.walmart.com/ip/Sunbeam-SH...meter/15135864


Jan

the cigar smokers seem to like these:

http://cgi.ebay.com/Little-Havana-Hy...item3364197d0c

This one is higher rated on Amazon, and still cheap.

I just found this:

http://www.amazon.com/HygroSet-Round.../dp/B002QXP0CW

Not only can it be calibrated, but it comes with a calibration kit.