iSee mini USB 5V 2.5A (Haier)

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Official specifications: I got it from ebay dealer plugplayers

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This charger arrived in neutral box inside a envelope.

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Measurements

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The charger can deliver the rated 2.5A before output voltage drops.

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At 120VAC it can deliver a bit more.

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Running the charger with 2.5A total output current for 1 hour not work. After 10 minutes the output voltage dropped and after 56 minutes the charger died.
The temperature photos below are taken between 30 minutes and 60 minutes into the one hour test.

Temp6683

M1: 102.6C, HS1: 103.0C
HS1 is the switcher IC and M1 is the rectifier diode.

Temp6684

HS1: 67.4C

Temp6685

HS1: 108.7C
HS1 is the rectifier diode.

Temp6686

HS1: 78.7C
HS1 is the transformer where the black blob on it touches the enclosure.

Temp6687

M1: 58.8C, HS1: 99.1C



Tear down

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I had expected to break the charger apart, but it did not work, I had to cut.

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The design is fairly standard with a fuse (F) at the mains input, four diodes (D1..D4) as bridge rectifier, the switcher (U1: LA-520). A real safety capacitor (Blue capacitor) and opto (U2) feedback. On the low volt side is a large rectifier diode (D7), a inductor (L1) between the two output capacitors and a reference (U3: TL431) for the feedback.

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It uses some very small leaded resistors on the low volt side. The reference (U3) is in a 3 pin leader transistor package.

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The circuit board is single sided. The crack in the circuit board is due to my try with a vice on opening the box.

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The distance between mains a low volt side is about 6mm below the opto coupler.

Testing with 2830 volt and 4242 volt between mains and low volt side, did not show any safety problems.



Conclusion

This charger with a 2.5A rating it is not very good, it gets way to hot (Above 100C), the output voltage is not stable and it dies.




Notes

The charger was supplied by a reader for review.

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