USB battery box 4x18650 Aili

DSC_2128

I found this box on ebay, specifications is something like:


How does it look

DSC_2127

The box arrived in a envelope without any accessories.

DSC_3033 DSC_3035

The box exist in different color combinations, I got the pink version.

DSC_2129

All connections are placed in the same end, micro usb for charging input and normal usb for output. These is also a led for flashlight usage.

DSC_2130

On one side is a current limit switch, it can select between 0.5A, 1A and 2A, but it does not change the coding of the usb connectors and the overcurrent protection is not very good.
The black dot is a switch for the flashlight led.

DSC_2133

On the other side, in a hole, is the switch to reconnect the batteries.

DSC_2132

On the top of the box is the output switch with a red led in it and four green leds for power level indicators.
The red led behind the switch is on when output is on, the power level scale is on when the button is pressed.
When charging a red led, behind the power level scale will light up.

DSC_3132

A closer look at the leds behind the power level indicators, as can be seen there are six leds.

DSC_2134 DSC_2135

To replace the batteries, slide the bottom off the box. The batteries can be up to about 67 mm, but shorter is better, this means that only unprotected cells will fit.

DSC_3129

With a bit of violence it is possible to remove the top from the box.

DSC_3131

DSC_3130



Measurements

USB%20Box%207%204x18650%20Aili%200.5A%20load%20sweep
USB%20Box%207%204x18650%20Aili%202A%20load%20sweep

I did two load sweep, one with the switch at 0.5A and one with the switch at 2A, as can be seen the current limit is changed, but the box does not turns off when overloaded, only reduces voltage.

USB%20Battery%20box%20%237%20out%203%20ohm%20(4xPA18650-31)

With a 1.67A load the box can keep the voltage up for nearly 4 hours. At this load it stops discharging the batteries at about 3.1 volt.

USB%20Battery%20box%20%237%20out%2010%20ohm%20(4xPA18650-31)

Reducing the load to 0.5A, extends the runtime to more than 14 hours and the batteries are run down to just below 3 volt.

USB%20Battery%20box%20%237%20out%2010%20ohm%20(PA18650-34)

With 0.5A load and a single battery the runtime is about 3 hours and 45 minutes with a 3400mAh battery.

USB%20Battery%20box%20%237%20out%2010%20ohm%20(PA18650-31)
USB%20Battery%20box%20%237%20out%2010%20ohm%20(BE18650-26)

load3ohm

With 1.67A load the noise is about 129 mV

load10ohm

Reducing the load to 0.5A will reduce the noise to 35mV


USB%20Battery%20box%20%237%20charge%20(PA18650-34)

The charge profile is a steady declining current, this makes the charging slow, but is acceptable.
The "termination" is at 450mA, this is way too high for a single battery, as can be seen the voltage drops about 0.08 volt when the charge terminates. The charge does not terminate fully, but will continue to charge with a small current until the battery voltage is close to 4.2 volt.

USB%20Battery%20box%20%237%20charge%20(PA18650-31)

USB%20Battery%20box%20%237%20charge%20(BE18650-26)

USB%20Battery%20box%20%237%20charge%20(4xPA18650-31)

With four batteries it works better, here the voltage drop is less and the remaining charge current is much less due to higher voltage.
The charge time is slightly above 10 hours.



Conclusion

The box is acceptable, but there are a couple of details that could be better:
Due to the high standby draw, it is best to remove the batteries, when storing the box for more than a month.
The charging is acceptable when the box has four batteries in it, but has to high termination current for one or two batteries, i.e. they are not fully charged.
I do not really see the point in the current switch.




Notes

Read more about how I test USB power supplies and chargers