how charge directly a BL-5C using ACP-12X?

[kyosho]

there are selling in the market, the desk charger, which enabled us to charge our phone and additional battery. because from the place i am from, i cannot get to buy this kind of item, so i am planning to get one of this done by myself, i just want to know how's the connection. i know i can charge my handphone battery using the charger, but when i want to charge additional battery i need to swap the existing battery with the additional battery and then plug in the charger again... i was wondering is there any circuitry or connection that i can use to straight away charging my battery without using my handphone as the medium... based on the knowledge i know, the nokia BL-5C has built-in protection circuit.... is it possible? please help.... thx in advance...

**broken link removed** is the product that i was talking about...

 

[Edmond]

The BL-5C is a NOKIA Li-ion battery without overcharging protecting electronics inside (Unom=3,6V, Umin=3V, Umax=4,2V, C=900mAh). The ACP-12 is a current generator 480mA max. 6V. You can connect it directly to the battery and the charging procedure will start. The charging current will be ~480mA. BUT DO NOT DO THIS. If the battery voltage reach to the 4,2V the charge current MUST CUT OFF. If you overcharge the Li-ion battery then it will explode. Very dangerous game.

 

[kyosho]

thx Edmond, and can i know one more thing, is it possible to create a cutoff circuit that enable the charging automatically cutoff once the battery is fully charged?

 

[Edmond]

Yes of course. The sent circuit is a simple, but complete Li-Ion charger. The first step is to connect the power supply of 9-12V to the input. Adjust the output voltage to 4,2V (using the R4) without the battery. Connect the battery and that’s all. The circuits will cutoff the current when the voltage reaches the 4,2V. You can leave the battery connected to the charger. The charging current depends on the R1 resistor (Ich=UBE/R1 approaching =0,7/R1)

:!: Sorry, there was a print mistake on the previews schematics. I corrected them, so the recent one is good. (The mistakes was the next: the output voltage must be adjusted to 4,2V for one cell (one of BL-5C) and not 8,4V. The 8,4V is when you use two batteries in series. The output current is not 850mA, it refers to the capacity (850mAh). The output current is approaching 700mA using R1=1OHM)

 

[kyosho]

thx again Edmond, can i use ACP-12X and add an additional circuit to cut off the charging process when the battery is fully charged?