[SOLVED] Charging protected Li-ion battery with a 4.3-7V charger

Hello everyone :smile:

I have Sanyo 103450AR 3.7V 1880mAh lithium ion batteries. They have control circuits. (protected)

I want to use Powerplus adapter (mobile phone charger) (4.3-7V 500mA, 100-240V) to charge them. (I added a picture of it)

I also added the voltage values when battery is not charging and when it's charging. When the battery voltage is 4.20, the adapter automatically stops charging. When the current is about be cut off (while charging), the voltage value i measure is 4.26-4.30V. I unplug the adapter, measure the battery voltage and it's 4.20.

When the adapter is in idle, the voltage is 6.13V.

The battery is full after 4,5 hours of charging. After the battery is charged, i look at the voltage and it's 4.20V and it doesn't drop quickly. Also the battery is always cool.

So, the question is, can we say charging these batteries with this adapter (not an expensive charger) is OK and the charging could efficient enough? Actually i am happy with the run time but one person said the charge is not going long enough. But he could be wrong.

Your helps are much appreciated :smile:

Thank you


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You cant charge li-ion batteries directly with an adapter,
you need special charge management,
shortly; first you need constant current mode and then constant voltage mode
(CC CV)
I had explained some requirements and published at the link (Turkish)
https://320volt.com/li-ion-li-poly-bataryalarin-hizli-sarj-edilmesi/

Is it possible that this charger has "constant current mode" and then "constant voltage mode" ability?

I bought an expensive charger specially designed for li-ion batteries. The man who sold this to me was a electronic engineer and he said a protected battery and this adapter is enough.

But i can't always buy this adapter because it's expensive.

While charging with the PowerPlus, the battery never gets hot and the charging is shut down when the battery voltage is 4.20. What is the worst scenario?

Thank you..

Inefficient charging? %?

Any technical explanation from anyone would be appreciated..

Thank you..

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Pictures.......

The charger is rated at 500 million Amps (500MA, I doubt it). Instead it is probably 500mA.
The charger has a variable voltage range similar to a lithium battery so maybe the charger and protection circuit work together to make a proper charger.
Most phone "chargers" are simply a 5V power supply that feeds the charger circuit inside the phone.

A proper Lithium charging circuit limits the voltage to 4.20V then continues charging for maybe one hour until the charging current becomes very low. Then it disconnects.
If it stops charging when the voltage of the cell reaches 4.20V then the cell is only about 70% fully charged.

After the battery is charged, i look at the voltage and it's 4.20V and it doesn't drop quickly. Also the battery is always cool.

Click to expand...

If it were me, I would call it okay. 1.4V per cell, and cool.

However I only know about nicad and nimh. The AA size get warm at 100mA. Voltage rises to 1.5 or 1.6 V. My meter shows they settle to 1.38 V, several hours after I take them off the charger.

Taking my observations as a reference, your setup appears to work all right. One can't give guarantees about anyone else, however. Saying you'll probably be okay is almost giving a guarantee.

Battery charging has gotten so it needs a smart charger these days. Since you are mixing brands, take nothing for granted (at least for a while).

Monitor the charge current. Get familiar with battery behavior through a few charge/discharge cycles. Make sure your lithium batteries are the type that won't start a fire if charged with too much current.

Consider making a simple temperature alarm. Tape the sensor directly to the battery pack.

Go to www.batteryuniversity.com or www.energizer.com where they tell you how to charge and discharge different kinds of batteries.
A Lithium cell is completely different to Ni-Cad or Ni-MH cells.
I was going to copy it and post a graph here but you can go there to see it yourself.

Audioguru, BradtheRad thank you very much:smile:


Audioguru, i really liked your first message. It's very helpful. After that i looked at the internet and found this:

"TP4056 5V 1A Lithium Battery Charging Board Charger Module" (I'm adding a picture of it)

The given specs are these:

1. onboard chip TP4056
2. MINI USB onboard header, you can directly connect to the computer USB port charging
3. the charge sheet can also be (IN + and IN-) pin power supply
4. set aside TEMP pin interface can be used as battery temperature detection
5. the input voltage: 4V-8V, output maximum charging current: 1000mA
6. the charging indicator light D1, D2 light charging is completed
7. PCB board size: 37.3 (mm) x15 (mm)

I learned that TP4056 is a constant current / constant voltage linear charger. So this charger module is fine for efficient charging right?


But i have one question that if we use a 1000 mA, 5V charger instead of 500mA charger, would it be still allright? I can easily find a quality USB 1000mA charger, but finding a quality 500mA charger is not very easy in my country.

There is one data about TP4056:
"programmable charge current, up to 1000mA"

But i don't know if the "TP4056 5V 1A Lithium Battery Charging Board Charger Module" is programmed to charge the battery at 1000 mA.

In the specs it says "output maximum charging current: 1000mA". This value is if we want to use the battery+module to charge sth else right? I mean not to charge my battery but charge other stuff?

Last thing:smile:, i will use the charging circuit plus the battery has a protection circuit. Could it be a possible "confliction" between the protection circuit and the charging circuit?

Thank you very much Audioguru and others!

I think the TP4056 charger module will be fine to charge your Li-ion battery cell at 1000mA. If you have a new computer then it can supply 1A to a USB jack but an older computer limits the current to 500mA or less.
Did you see the datasheet where it has a "Greed" "LED? Which color is greed?

A charging current of 1000mA is fine for your battery cell.

Hello Audioguru Thank you


"TP4056 5V 1A Lithium Battery Charging Board Charger Module" Does this 1A mean it can charge the battery at 1A?

I think the "greed" is a writing mistake. They want to say "green". There are 2 leds. Charging>Red Charged>Green.


Audioguru, could it be a possible "confliction" between the battery protection circuit and the charging circuit?

Thank you

The module is probably set for an output that is 1A. If its input is 1A or more then its charging current is 1A. A resistor on the circuit board sets the maximum amount of output current.

There will not be a conflict. The charging will be from which one provides the lowest voltage or the lowest current.

Thank you very much! I believe this thread will be beneficial for others too:smile: