Tomo Power bank M2

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Official specifications:
I got it from Banggood

How does it look

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The power bank is delivered in a cardboard box with a window and some specifications on the back.

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It contains the power bank, a usb cable and a "instruction sheet".

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All connectors is placed at one end

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On the other end of the box is a display.

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There is no doubt when the power bank is turned on.

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This is the power status display,

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When charging a mains cord is shown to the left and the bars in the batteries are animated.

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When current is drawn the display will show voltage and current for each slot. The display will not indicate charging.

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The box do not include any batteries, it is up to the user to supply one or two batteries.
The length of the batteries can be from about 58mm to 69mm.



Measurements



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The specification sheet says the box can deliver 1.5A on the 1A output, this is a bit optimistic, overload trips at 1.4A

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The 2A output is rated for 2.2A, but again the overload protection kick in a bit early at 2A and also a bit early for a 2.1A coding.

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The output looks the same with connected charge power.

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Running both outputs in parallel gives slightly more current, but the current limit also works here.

Current

The current display is not a precision meter, but it will easily show if the connected device is charging and give a very good idea on how fast charging is.

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Nice stable output voltage until the battery is about empty.

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AT higher current the output voltage is a bit lower, but again very stable until the battery is empty.

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Two batteries gives about double time.
Note: I am only measuring current and voltage on one battery.

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At 2A the output voltage is fairly low, but stays stable until the batteries are empty.

10ohm

Noise is 8mV rms and 76mVpp

5ohm

Noise is 11mV rms and 85mVpp

2.5ohm

Noise is 16mV rms and 129mVpp, all noise values are very low.

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It uses a nice CC/CV charge algorithm, but do not really stop charging, instead it will pulse the current when the voltage drops slightly.

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The box will draw nearly 1A from usb when charging two batteries, this means about 0.4A for each battery.

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A 0.5ohm resistor in series with the usb supply to simulate a weak power supply or long cable do not prevent the box from charging at about the same speed.




Conclusion

This power bank has many good details:
But the standby current is a bit on the high side, i.e. the batteries has to be charged every few months even when not using it. I would also have like a bit more current on the 2A port and auto coding.

I will rate it as fairly good.



Notes

The power bank was supplied by Banggood for a review.

Read more about how I test USB power supplies and chargers