Battery tester for 1.5v Li-ion

Hey All,

This is my first experience with 1.5v rechargeable Li-ion cells
and the brand I’m using (pownergy) isn’t performing as I’d
hoped. The cells came packaged with a USB cable for charging.
According to what I’ve read these are 3.7v cells stepped
down with a circuit board that prevents my current charger
from reading any measurements.

I would appreciate any advice on a tester/ analyzer
that would display the status such as capacity (mAh), IR, voltage
etc.

Thank you for any consideration

You can’t measure these batteries because everything is hidden behind the circuit.

As SammysHP states, won’t work, can’t do it.
You might want to read this review for a similar cell to be more familiar with what you have gotten into.
https://lygte-info.dk/review/batteries2012/TenaVolts%20AA%202775mW%20(Black-blue)%20UK.html

While I am able to use in-line USB devices to capture a reading of their capacity after a recharge, it doesn’t appear possible to get an indication of remaining capacity/condition.

Also FWIW not all brands can even deliver said capacity as required. I’ve tried several of these and while great for low-to-moderate drain device that would benefit from a steady 1.5V source (e.g., meters, direct drive 3V LEDs….) my personal experience has been that most do not perform well with higher drain devices (e.g., x7135 or FET bases Lights, …)

Those that could not perform were not dead, they simply tripped their protection circuits. Fortunately resetting was a simple matter of a few seconds of recharge to restore working order.

Battery - Was able to deliver high draw
Tenavolt Black & Blue) - Yes
Amptorrent (Black) - Yes
Epoch (Black) - no
EBL (Black) - no

1.5a > 2.0a seems to be a functional maximum for this kind of cell. The conversion circuitry gets hot and trips protection.
For……very….low drain they don’t seem a good fit either. Good LSD NiMh, or alkaleak of your persuasion.
Medium draw with a requirement for 1.5v seems to be their niche.

Thanks for the replies.

There are three instances where I wanted to use a 1.5v rechargeable
where a 1.2v doesn’t work.

1. Analog wall clock
2. Rayovac DIY3AAA-BXTB flashlight
3. Landline telephone (3 cell) caller ID

On the flashlight, I tested the cells by powering
it for four minutes intervals. On for four minutes
then off for four minutes nine times for a total of
36 minutes before the light began to strobe. After
a fresh charge I left it on for 12 minutes and the
temperature of the housing rose to 116F degrees
(uncomfortable to hold). BUT the light is much
brighter than the 1.2v cells.

On the telephone, I gave up and replaced the
batteries with a wall wart.

The clock will continue using regular lithium’s.

Those cells maintain a constant voltage no matter what the cell’s voltage, so it’ll go go go go go and then suddenly drop dead.

You can take a fixed load (ie, resistor) and measure the voltage across it from fully charged to dead. If 500mA and it goes for 5hrs, then it’s a 2500mAH (at 1.5V) cell. That does NOT translate to a 2500mAH Li cell (which is “3.7V”).

Likely can’t measure “internal resistance” as it’s an active circuit.

And again, it’ll keep a solid 1.5V from freshly charged to dead.

I have some small motion activated lights I use them in. As Lighthbringer says, they go, until they don’t. As you saw, in flashlights they maintain brightness for the duration. Maybe not as good if sudden darkness would be an issue.
They also work well in small underpowered motors. I have a small scrub brush and a portable toothbrush they work well in.
I read they work well for some keyless locks.


I have one from Keeppower. I use it in mouse, as it's 10 g lighter, then eneloop pro
I only tested how much it takes while USB charging, and it takes 4.23Wh (tested on FNB48)
And it claimed capacity is 2260mAh 3390mWh
It lasts 2 weeks in the mouse, the eneloop pro last much longer (don't remember how much longer, will test that too)

I will try to test it on discharge in a bit. I bought this not long ago. https://pl.aliexpress.com/item/1005003580707807.html