Test/review of Blackube AA 2550mWh USB (Gray)

HKJ · 2019-09-08T17:17:26.000Z

Blackube AA 2550mWh USB (Gray)

Official specifications:

Voltage: 1.5V
Energy: 2550mWh
Output current: 4000mA
Charging current: 5V/350mA
Charging time: about 2h
Cell type: Li-polymer
Life time: 1000-3000 cycles
Weight: 19g

This is a USB charged 1.5V battery, there is a LiIon cell, a buck converter and a charge circuit inside.

Behind the hole is a red led, it shows red while charging and turn off when finished.

Included with the batteries is a 4 way USB charging cable, i.e. any 2A USB charger can charge four batteries simultaneous.

The capacity depends a bit on the load current, but output voltage is stable.

At low current the capacity is also lower, because the internal regulation also needs some current. This cannot really be seen from my curves here, i.e. the internal current consumption is very low and the battery will last for many months before it has discharged itself.

The battery can deliver up to about 4A before the overload protection kicks in.

The electronic circuit makes the internal impedance look strange.

Output voltage do not change much when load is turned on or off.

It looks like the buck regulator runs at about 1.2MHz. The noise is less than 30mVpp, but I cannot measure lower with the current setup.

Conclusion

These batteries has less capacity than normal NiMH, but run at a higher voltage, making the energy about the same. This makes them ideal for most equipment that has trouble with NiMH batteries. They also weight considerable less than NiMH, this can be significant in some circumstances. There is one disadvantage: Battery meters do not work with them.
The USB charging makes it very easy to find a charger for them.

Notes and links

The batteries was supplied by Blackupe/roca-sup.com for review.

How is the test done and how to read the charts
Compare to other AA/AAA batteries: Alkaline/NiMH/Lithium

toobadorz · 2019-09-10T13:33:30.000Z

This cell looks good, at least its current limit is much higher than the other 1.5V li-ion + buck solutions. Can it handle, say, 2.5A~3A continuous discharge?

Superstocker · 2019-09-10T14:02:31.000Z

Thanks HKJ! Another interesting cell that it is nice to to be aware of.

HKJ · 2019-09-13T11:50:23.000Z

toobadorz:

This cell looks good, at least its current limit is much higher than the other 1.5V li-ion + buck solutions. Can it handle, say, 2.5A~3A continuous discharge?

I have added a 3A discharge curve.

toobadorz · 2019-09-13T16:10:04.000Z

HKJ:

I have added a 3A discharge curve.

Thanks HKJ, really appreciate that :+1:

amishbill · 2019-09-13T16:21:08.000Z

Those look interesting. I like where the USB port is.

To be honest, I’d be tempted to try them just for the 4 port charge cable.

I’m guessing that putting them in a standard charger is completely verboten?

HKJ · 2019-09-13T16:26:59.000Z

amishbill:

I’m guessing that putting them in a standard charger is completely verboten?

Of course it is, but I doubt anything will happen if you do.
The internal switcher converts 3-4V down to 1.5V, feeding 2V into the 1.5V output will most likely be harmless. If the open circuit voltage of the NiMH charger is 4V or more, it may damage the battery.

amishbill · 2019-09-13T17:06:15.000Z

HKJ:

amishbill:

I’m guessing that putting them in a standard charger is completely verboten?

Of course it is….

It never pays to underestimate your average idiot, and their ability to make life…. interesting. :person_facepalming:

flydiver · 2019-09-13T17:49:04.000Z

amishbill:

HKJ:

amishbill:

I’m guessing that putting them in a standard charger is completely verboten?

Of course it is….

It never pays to underestimate your average idiot, and their ability to make life…. interesting. :person_facepalming:

For extended reading on this see the comments in [Slickdeals] or Amazon.

prepro · 2019-09-24T08:19:00.000Z

Anyone know where to get these?
(Amazon does not seem to ship them to Australia)