ITTSB.EU Blog Forum
ITTSB Blog Specific => ITTSB General Discussion => Topic started by: Kiriakos GR on September 12, 2017, 12:25:58 PM
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UNI-T, instead this investing to compete at market of high performance multimeter which their product are known as very poor performers, this instead made the choice to get in to low-end mobile phones gadgets by an offering of product UT658.
USB tester UT658 this is nothing new, this is a copy of no-name capacity tester this available since 2011 at eBay.
Visual change this is limited to digital display type in use ( liquid crystal ).
Three of March 2017 UNI-T did this product release.
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I thought to bid in one auction for UNI-T UT658 and I did Win 8)
Therefore in about a month time I will be able to touch it and test it.
At my first (Charger's) Tester KCX-017, display screen was crashed due an accident and for some time I am looking for a replacement.
USB Tester KCX-017 (http://www.ittsb.eu/forum/index.php?topic=929.0)
While UNI-T UT658 this is no special regarding functions, it three times larger in dimensions screen this is appealing.
Especially for older people that their eyes do not favor tiny screens any more.
For new eBay users I will pass some advice's.
At eBay actual street price of goods this is never visible to buyers, one educated buyer should be aware of street pricing prior searching eBay.
Most to all eBay sellers from Asia they now set a price according to their expectations.
In most cases this starts from double than real street price and some thief's they could ask up to 10 times of street price.
Shipping cost from China for a long 25~35 Days delivery, this is less than 15 cents.
According my previews experiences, street price of UNI-T UT658 this could be 1.30$ with VAT in China.
This is retail price and seller this is a First-hand = he got it directly from the factory (UNI-T).
One wise overseas buyer him should never accepts paying more than double of street price, because by doing so he does encourages greedy people to ask for more in this pricing stock market.
I did participate in a bidding by having my upper limit based on this concept.
People in China they are not idiots, buyers upper limit in auctions this slowly becomes a pricing that all sellers will follow, because this is what the market is willing to pay for a specific product.
Products of China these are now millions, overpriced goods price this takes long time to become reasonable.
Therefore it is an obligation of every wise buyer him to demonstrate patience, and to wait for a opportunity to engage in a auction.
Nowadays eBay BUY NOW button this by 85% it is a trap when you buy a single item.
Best buying practice this is buying quantity of 10 Pieces, but no one needs so many UT658 testers. ;D
Either way just be careful out there .... educated consumer this is knowledge that comes slowly due upcoming experiences, but by be always alerted, this is a good first step. ;)
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Looks like that my package this is lost, and luckily for me this eBay seller are of the ones that he care for his reputation and I got fully refunded.
Because entire Asian eBay this now using new worthless shipping plan 35-45 days, I thought to have a look at Banggood.
I can hardly believe that these thieves they have currently discount 48% 22-30 October 2017 (one week).
Trained shopper eyes would note that 814 people have this thing in wishlist and never buying it ...... and now Banggood did their move. :)
I did placed my order mostly because they will going to use nothing less than second priority shipping ( 16 - 25 Days for Greece.
Listed Price 3.73 Euro, true price after PayPal 3.80 Euro.
Prior discount USD price 6.99 and now 4.33, even now does not look cheap because Chinese warehouse selling them for 2 USD in China mainland.
This is my first buying experience from Banggood and good opportunity so to benchmark their performance.
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Finally I got one ... :)
Banggood shipping plan was real and this arrived after 23 days.
Production date this is 28 September 2017.
Next step this is product testing:
1) With my Galaxy S5 (G900H) this using 5.3V system for fast charge activation.
2) Non-smart devices consumption tests.
3) Accuracy test at different loads
My first visual impression after plugging it for a first time, this is positive.
White back light this is soft and digits looking very sharp (good contrast).
Single digit dimension this is 6mm tall and 3mm wide, this is much smaller than primary digits in to a multimeter screen.
Such digits dimensions are mostly used for secondary parameter review in to a multimeter, for example if you do own U1272A , temperature indication at top right corner this using close to identical in dimensions digits, even so UT658 digits they are a bit more thinner and you need to step up closer to this gadget so to read it LCD display.
Tiny carton box does not come with English instructions, specific production this is for mainland China distribution.
From the other hand about using it this is much easier than KCX-017 https://cdn.solarbotics.com/products/datasheets/kcx-017%20power%20bank%20testing.pdf (https://cdn.solarbotics.com/products/datasheets/kcx-017%20power%20bank%20testing.pdf)
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Most of times you do read product electrical specifications on paper, and still you are unable to fully understand how this translates in to real world behavior.
Can you imagine how it translates specification of DCA 0.0A ~ 3.0A which this is engraved at the back of UNI-T UT658 ?
I will tell you and free of charge .... UNI-T UT658 this is unable to measure below 100mA and therefore LCD screen this reads zero by ignoring that there is DCA current in use ( this be lesser than 100 mA).
At my testing I was able to see measurement down to 160mA this eventual become lower to 120mA and few minutes later LCD display become 0.00.
In the positive side of things, even if DCA meter this reads 0.00A the measurement at capacity meter this still records incoming mAh, and now I am about to leave my phone over night at the charger so to find out real capacity that my battery this it can absorb.
Up to now I have data and pictures of a regular complete charge, I have the awareness that my battery this is almost 2 years + 10 Months old.
Therefore I do consider the measurement of 2.086 mAh as close to my expectations.
By taking 15 minutes to write this reply, measurement changed to 2.100 mAh :)
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Today I can confirm my suspicion (conspiracy theory) :P , that UNI-T UT658 it can steal 100mAh from capacity total value, if you do disrupt charging when Ampere value this seems to be 0.00A .
In my case I did benchmark 2800mAh battery, if I was not a good observer and by me insisting to leave overnight the phone connected to the charger, I would have 100mAh less.
Older generation of mobile phones these using 650 ~ 800 mAh Lithium cells, at such lower capacity 100 mAh lesser this is an significant number.
Final thoughts ...
According to UNI-T specifications, voltage measurement this can introduce 1% Error, additionally and current measurement this can introduce another 1% of Error.
Therefore in capacity measurement combined error this can be as 2%.
Sum of capacity measured after full charge and overnight (balancing period ) this is 2179 mAh, by now calculating Plus/Minus 2% Error real capacity could be :
Lower end= 2.136 mAh
Higher end= 2.222 mAh
And here we have again roughly 95 mAh difference at again roughly 2200 mAh total.
And now I can safely assume that introduced error to 1000mAh cell this would be 50 mAh, and also error at 650 mAh capacity this could be 30 mAh.
Now, in case that under benchmark there is a power bank of 4.400 mAh or 5000 mAh, then you may expect an estimate of 200 mAh (Plus/Minus) as theoretical measuring error.
Product behavior & volts accuracy tests made by ITTSB Blog.
Believing it or not .. UNI-T UT658 this is not an Plug&Play meter.
When I did connect UT658 directly to laboratory power supply and compared input voltage with a 50.000 counts multimeter, UNI-T UT658 this was measuring half volt less when this tested at 3~9V DC.
UNI-T UT658 started measuring correctly DC Volts after this be powered for 10~15 minutes (warm-up period).
I did record input voltage - measured voltage & Milli-ampere which UT658 this required from DC power supply.
Input DCV ....... measured DCV ......... mA
9,005 ....... 9,02 ...... 6.5 mA = DCV - Accuracy Error approximately +0,3%
8,002 ....... 8,02 ...... 6.4 mA
7,003 ....... 7,01 ...... 6.2 mA
6,008 ....... 6,02 ...... 6.0 mA
5,009 ....... 5,01 ...... 5.7 mA = DCV - Accuracy Error approximately +0,3%
4,008 ....... 4.00 ...... 5.5 mA
3,004 ....... 3,00 ...... 4.0 mA = DCV - Accuracy Error approximately -0,3%
Input DCA ....... measured DCA
1,009 A ....... 1.00 A = DCA - Accuracy Error cannot be calculated due limited LCD display resolution
2,006 A ....... 2.03 A = DCA - Accuracy Error approximately +1,5%
According my measurements I can now estimate total of +1.8% Error in the measurement of mAh (capacity measured) by my very own UNI-T UT658.
Voltage measurements was taken by BRYMEN BM869 and Current measurements was taken by U1272A HH multimeter.
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Relative ITTSB Forum Links
Ordered unbranded EP-PG920I Qi charging pad & spotted unexpected QC issues (http://www.ittsb.eu/forum/index.php?topic=1155.0)
How to: Identification of fake smartphone charger without disassembly (http://www.ittsb.eu/forum/index.php?topic=1154.0)
Just the truth. Cell phones fast charging cables 2.4A & micro or B, USB plugs (http://www.ittsb.eu/forum/index.php?topic=1153.0)
DIY test bed: Micro USB electrical measurements’ and cables evaluation (http://www.ittsb.eu/forum/index.php?topic=1172.0)
Galaxy S5 & Bluetooth 4.0 megabytes per second benchmarks with Windows XP Pro (http://www.ittsb.eu/forum/index.php?topic=1328.0)