Test/review of Blackube AA 2250mWh USB (Black)

can we do teardown on this battery ?

I may do that later together with a few other of same type.

He’s done a very similar cell before: Disassembly of USB charged batteries

Is this LED only used during charging?

Can it be used to indicate remaining capacity at all?

Given the flat voltage curve, I’m guessing it’s not easy to tell how much juice is left in it.

The led is only for charging, there is no way to see how much energy is left in the cell.

The one thing about these Tenavolts cells is that they don’t have a usb port, so you’d better not lose the supplied charger, but if you have 12 of them, then I guess you already have 3 of their chargers as well. :slight_smile:

Easy to get another ‘charger’. Do you lose your chargers? :wink:
An advantage, If you want to call it that, is it only takes one USB connection to charge 1 > 4 cells. Personally I think I prefer that over the USB direct connection.
The charger is a box barely larger than a storage pack for AA. If you buy it with the charger, that’s what it gets shipped in. I guess you could store them in it. Don’t know if there is a low grade drain, but I think not.

A single usb cable that comes with the Blackube cells can charge 4 cells as well.

A splitter cable, good idea.
Seems then that it comes down to preference, IF you care to bother with these. The USB port adds one more bit of electronics to the cell, which is a pretty cramped space.
By my measurements using a ZB206B+ (an FET discharger, not resistance) I get about 140mAh more than HJK for the Blacktubes. 0.5A and 100mAh for 1.5A. I think the difference may be that port. I didn’t push beyond that since it’s evident the buck converter seems to overheat and fail. I had hoped to use them for underwater strobes and it became evident it was not a serviceable idea.

If they are a tech that works for you, either would seem to suit. Not sure how they’ll show themselves for the long haul. Thus, the purchase and experiment. I’ve got a bunch of Eneloops going on 12+ years old that need replacing so thought I’d try these out for ….some……uses.

Yup, I ordered some Tenavolts just for S&Gs since they were on sale. Still don’t know what I’m going to use them in.

They’ll work in almost any application under 1.5A. I find the best uses is a travel Sonicare that takes AA. It was lame on NiMh, almost as good as the lithium power ones on Tenavolt. Similarly a nose trimmer and a beard trimmer both work with more punch. Also a bunch of LED night lights I have around the house. They don’t dim, and the battery is a tad smaller diameter so pops in and out of the slot much better.

Haven’t bothered to try them in very low drain applications. Don’t see that as their best use.

Curious what their self discharge is like compared to LSD NiMH cells.

FYI, I did a quick write-up on these, in case anyone is interested:

Trying to get them here in the UK is a pain.

Anyone got any links to them?

Blackube battery is available on Amazon.UK

Hi, do you know how these battery would react over time if charged very often ?

Here is my use case :
A device is adapted to fit in a charging station with magnetic connectors using this battery.
During the day, the device would be regularly used during 15 minutes and returns to a charging station between each use (could be 5min to 2h).
During the night, the device would stay in the charging station.

I can eventually program the plug of the charging station so that it is not always on.

I wonder if the battery would support such a use-case, what do you think ?

Thanks for your help,
SB

I do not know how these batteries works, but generally for LiIon:

1) Frequent charge do not degrade the cells.
2) Time at 4 to 4.2 volt will degrade the cells, faster at higher voltage.

The second point is the issue, keeping it in the charger most of the time, means it will be at 4.2V most of the time (Most chargers will charge it to 4.2V when it is connected). This means the fastest wear rate (Depending on temperature). I do not know anything about how fast this wear rate is.
Most single chip chargers will charge a LiIon battery to 4.2V and then go into standby, each time the battery is connected.

Thanks for your answer HKJ,

So point 1 is not a problem.

Regarding point 2, if I understand correctly what you said, staying in charge a long time could be a problem unless the chip goes in standby, correct ?

Sil

Correct. It can be checked with a voltmeter in parallel with the battery. The voltage will drop slightly (Some tents of mV) when the charger stops charging.

If you are in doubt about how to connect a meter while charging, see here (Charge voltage):
https://lygte-info.dk/info/Measurement%20UK.html

I also had in mind to check the voltage to confirm.
I’ll do it as you suggested.

Thanks a lot for these informations !
SB