Appropriate Charging Voltage for a 3.6V Ni-Cd Battery Pack

Question

What voltage should the 3.6V Ni-Cd battery pack charge?

Freddy · Answer

In such a way that the final voltage does not exceed 1.4V per piece, i.e. max 3 * 1.4 = 4.2V.
You should also ensure that the maximum charging current of 1C is not exceeded.

However, it's best to build a simple charger on the system, e.g. MAX712.

kwazar · Answer

Ni-Cd batteries are not charged with voltage, but with electricity. You need a power source. The voltage that will be set on them is only the result of charging with electricity. Charges a specific current at a specified time.

Anonymous · Answer

Charging from a power source. You stop charging when applicable - dV / dt and / or + dT / dt.

retrofood · Answer

Will it tell a lot to the questioner?

kwazar · Answer

And this will say more? I have written clearly that a power source is needed. If he doesn't know what it is, let him read. I will not explain to anyone that it charges with stabilized voltage, because it is not done that way. You need to put in a little effort to learn something. If he reads a bit and asks specifically, I will present him with a diagram. Added after 4 [minutes]: Freddy, with all due respect, but this is a charger for fast charging of batteries adapted for this. I would not recommend such a charger to a beginner, but rather simple and safe with a C / 10 charging current.

retrofood · Answer

Just. You even pay attention to whom you tell?

kwazar · Answer

Let's start again ...

Ni-Cd batteries are charged with stabilized current. That is, a power supply that gives a constant current regardless of the voltage on the batteries. This is called a current source.
You can make such a source from literally several elements, but you need to know what capacity batteries have. The most commonly recommended standard charging current is around 14-16 hours. is current with the value of C / 10. This means that the battery capacity is divided by 10 and we get the charging current.
E.g. with 600 mAh battery capacity, the charging current is 60 mA.

Qwerti12, if you still don't understand something, ask.

Freddy · Answer

Currently manufactured batteries can easily withstand C / 4 current from this charger. Why am I writing like this because I think it is a freshly bought package. Otherwise, the user would have registered on the forum earlier than 25.07 PS. I was very amused by the report on my post # 2 - the content of the report: Nonsense. The user who did this is not brave enough to admit and justify his decision. Probably the only word he knows. Please prove to me what is bullshit, or point out my blunder, I publicly bark it back.

kwazar · Answer

I hope it's not recycled ... For now, we have to wait for more data from the person concerned.

Jawi_P · Answer

In principle, when charging with c / 10, only time counting remains, because dV may not work.

kwazar · Answer

It certainly won't work. The ?U detection is for fast charging.

_jta_ · Answer

With fast charging, the battery heats up strongly and then its SEM decreases - this is what the minus delta V method detects. At slow no, but charging with current limitation (stabilization is not needed) to 1.4V / cell gives a sensible result.

Anonymous · Answer

30-50% capacity. 350mA is enough for -dV / dT to work properly. For good AA size cells it is just ~ 0.15C where 1C allows the manufacturer ... Strong heating is ~ 35-40 * C at 400-800mA in the last phase -dV ... link and others to read. PS. IMAX B6 for 87PLN covers the topic.

_jta_ · Answer

I took measurements of the NiCd AA battery voltage at changing temperatures - from what I remember, a temperature increase of 1 ° C caused a voltage drop of 0.2mV. You mean a temperature increase of 35 ÷ 40 ° C? I don't think so down 35 ÷ 40 ° C at 25 ° C ambient temperature? The first means a voltage drop of 7 ÷ 8mV, the second by 2 ÷ 3mV.

Maybe the easiest way will be to place a temperature sensor (even a transistor) next to the battery - the base-emitter voltage of the silicon transistor decreases by almost 2mV with a temperature increase of 1 ° C - 10 times more than the battery voltage, so detection of this is much easier, and changing the charge is not causes sensor voltage changes ...

kwazar · Answer

As a side note, I wonder why many people write the interrupt charging method as -?V / ?t
The voltage symbol is "U" and not "V".
If you write -?V, you would like to write -?V / ?s, meaning volts and seconds. But symbols of size are written, not units.
Interesting issue, but on a different topic. I will delete answers here. [Retrofood]

OKAY.

Qwerti12 · Answer

Okay, I will deal with these NiCd links. But if someone could, I would ask for some pattern For Aroma 3-FM-4.5 gel battery (6V 4.5AH)

_jta_ · Answer

Well, you have written on this battery. There are two basic charging systems: up to a certain voltage, and then disconnect the charger (cycle use), or maintain a certain voltage without a time limit (standby use). And both of them you will find schemes on the forum.

Qwerti12 · Answer

OK thank you

Appropriate Charging Voltage for a 3.6V Ni-Cd Battery Pack

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