Test/Review of Tmashi 5 port 4A

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HKJ
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Test/Review of Tmashi 5 port 4A
Tmashi 5 port 4A

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Official specifications:
  • AC wall charger with 5USB ports Plug US,EU,UK and SAA for choose
  • Supports charging 5 devices simultaneously through just one wall socket.
  • Designed with blue LED indicators.
  • Glossy design prevents scratches
  • Solid and sturdy shell prevents break or cracks
  • High-class click-spring design prevents AC pins from slipping out
  • Built-in IC smart fuse with double protection to check on overheat, overcurrent, overload and short circuit
  • High efficiency and low energy consumption.
  • Compact, lightweight, portable and very easy to operate.
  • Ideal for indoor use only.
  • Input: 100-240V AC, 50/60Hz
  • Output: 5V--4.1A /20.5w (For 1-5*USB)((1-3 port for Apple iPad; 4-5 port for Samsung Galaxy tabs & smartphones; all FIVE are also applicable on iPhone/samsung/htc phones or other USB-charged electronics
  • Plugs: EU,US,UK,SAA for choose
  • Color:White

I do not know where I got it, but it can found at Ebay dealer: tmashi-store

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I got this charger in a plastic bag.

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The power plug is seperate from the charger and it is possible to order it with different plugs, but not with all plugs for travel usage.

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There is a blue led between port 1&2 and 4&5.

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Measurements
  • Power consumption when unloaded: 0.25 Watt
  • Usb output is codes as Apple 2.1A and Samsung tablet
  • All usb outputs are in parallel.


Tmashi%205%20port%204A%20%231%20load%20sweep
Tmashi%205%20port%204A%20%235%20load%20sweep

There is not much different between usb port #1 and #5, except #5 is slightly higher in voltage.

Tmashi%205%20port%204A%20load%20sweep

Running all outputs in parallel up to 5A works fine, but I would have liked a overload protection kicking in (I did a fast test up to 8A without seeing any protection).

Tmashi%205%20port%204A%20load%20sweep

No problem running at 4A for one hour.
The temperature photos below are taken between 30 minutes and 60 minutes into the one hour test.

Temp1791

M1: 51,6°C, M2: 41,0°C, M3: 40,0°C, HS1: 73,6°C
HS1 is probably the transformer and the temperature is acceptable for a transformer.

Temp1792

M1: 45,2°C, HS1: 52,3°C

Temp1793

M1: 44,1°C, M2: 37,7°C, HS1: 64,3°C
HS1 must be the rectifier diode.

Temp1794

M1: 57,1°C, M2: 43,2°C, M3: 40,2°C, HS1: 57,6°C
M1 must be the mains switcher and HS1 must be the rectifier diode.

10ohm

At 0.5A the noise is 38mV rms and 550mVpp. The rms noise is fairly low, but there is some spikes that gives a high peak noise.

2.5ohm

At 2A the noise is 62mV rms and 570mVpp

1.2ohm

At 4A the noise is 69mV rms and 510mVpp


Tear down

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It looks like a lot of parts has been removed from the design. Most of the missing parts are designed to reduce EMC and make it less sensitive for spikes on the main.
The MOV3 part is not legal to mount, it would directly transfer spikes from the mains to the low volt side.
The input side has a fuse, bridge rectifier (4 diodes), capacitor and a switcher IC (Below a heatsink).

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Between the usb connectors is is possible to see the leds.

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The power starts at usb port #5 and usp port #1 has the longest traces on the circuit board, that is the reason for the small performance difference between them.
Note: The port numbers I am using is the ones on the box, not the ones on the circuit board that are reversed.

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There is no issues with the isolation distance, it is fine.


Testing with 2500 volt and 5000 volt between mains and low volt side, did not show any safety problems.



Conclusion

This charger might have been a fairly good charger, before all the parts where removed from the design, without these parts I doubt it will pass the EMC part of the CE test.
The safety looks good, except the missing overload protection, both for each usb port and for the full device.




Notes

Read more about how I test USB power supplies/charger

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

Rolz
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HKJ thanks for the review. Dissapointing that they removed many of the components, otherwise as you say it may have been a good charger.

Lord_Niksidor
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How did the solder/trace on the low voltage side of the transformer get all smashed up?

HKJ
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Lord_Niksidor wrote:
How did the solder/trace on the low voltage side of the transformer get all smashed up?

I am not sure about what you mean?

Some part of the trace is covered with solder mask, other parts are not. The uncovered parts of the trace will get a layer of solder. The solder is used to improve current handling.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

Pulsar13
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73.6°C on the side? A bit high won’t you say? That can hurt you if accidentally touched – e.g unplugging it right after a charge.

Might as well recommend integrating a cup holder – keep your charger cool, keep your coffee hot. Wink

HKJ
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Pulsar13 wrote:
73.6°C on the side? A bit high won't you say?

I bit high, but I doubt it will burn you, due to the fairly slow heat transfer in plastic.

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Lord_Niksidor
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HKJ wrote:

Lord_Niksidor wrote:
How did the solder/trace on the low voltage side of the transformer get all smashed up?

I am not sure about what you mean?

Some part of the trace is covered with solder mask, other parts are not. The uncovered parts of the trace will get a layer of solder. The solder is used to improve current handling.

In the last two pictures, looks like the upper pin has just cracked the solder, but the lower one looks like it ripped the trace right off the board.

Sirius9
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Lord_Niksidor wrote:

In the last two pictures, looks like the upper pin has just cracked the solder, but the lower one looks like it ripped the trace right off the board.

You are right, I am surprised that it worked at all!

 

HKJ
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Lord_Niksidor wrote:
In the last two pictures, looks like the upper pin has just cracked the solder, but the lower one looks like it ripped the trace right off the board.

This is most likely from the teardown. The transformer is very close to the plastic and when pressing on the plastic with a vice I might also have pressed on the transformer.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

Lord_Niksidor
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Ahh true, do you do the insulation testing prior to tear down? I once had this happen on the high voltage side, the sound was amazing, 50Hz, I certainly knew about it when i plugged it in.

HKJ
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Lord_Niksidor wrote:
Ahh true, do you do the insulation testing prior to tear down?

Yes, the plastic is sometimes part of the insulation and the charger would fail with it removed.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

sp5it
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Without EMI filtering it is a garbage. Produces a lot of noise transmitted wideband.
Stay away.
Mike

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