I just received the YZXstudio 7th Gen 4-cell powerbank. The construction of this thing is top notch, and the available settings is astonishing! The most remarkable configurations are:
Set output voltage for both 5V and QC 9V (+0.5V)
-Set discharge cutoff voltage, charge termination voltage and current.
-Set battery charge current up to 4.5A (1A+ each)
I’m still trying to figure out some of the calibration features (the UI is in Chinese only), but so far I have correctly calibrated battery capacity and battery full voltage.
4x Sanyo GA as battery source
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1x 5V & 1x 9V USB out, microUSB and 4mm input (shares the same plug as the sony PSP).
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Empty
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Loaded
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Close-up of the board, some of the components are never seen in any powerbank before.
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I calibrated the internal voltmeter to match my most accurate DMM and the skyRC MC3000. It tops the battery at 4.207V
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I haven’t done all of the output testings but I did a quick discharge test at 1.5A and got 94.2% efficiency. This is the highest effieicncy I’ve seen not only in a powerbank, but in ANY DC-DC boost converter.
Battery capacity as measured by MC3000 at 0.5A discharge rate, with D-reduce of 250mA down to 2.5V: 3380mAh, 4 of them makes 50.02Wh. Note that the sanyo GA does not reach the spec’d 3,500mAh in real discharge tests.
Output at 5.15V 1.5A by using the YZX dummy load: 47.12Wh
So far I’m amazed by the performance of this powerbank… to be honest this is one of the finest electronic device I have ever used. Will soon upload more discharge tests.