Need 9V battery charger

I need a battery charger circuit (Preferably IC) for 9V/900mah Li-Ion battery. Standard available chargers are not suitable for this high power 900mah battery & takes very long charge time. **broken link removed**
if anyone have circuits, please share with me.

Thanks & Regards
Udhay

Hi,

9V is not typical for LiIon.

For ICs look at chip manufacturers.
Usually they have interactive selection guides.

Klaus

You can use LM317 lineer regulator with a pass transistor(for high current).

You can find the circuit samples in its datasheets.

udhay_cit said:

I need a battery charger circuit (Preferably IC) for 9V/900mah Li-Ion battery. Standard available chargers are not suitable for this high power 900mah battery & takes very long charge time. **broken link removed**
if anyone have circuits, please share with me.

Thanks & Regards
Udhay

Click to expand...

I didn't think 9.0V Lithium batteries were rechargeable. I have a non-rechargeable one, which is amazing 9.0V and lasts a long time.
Any high currents can be dangerous. ( Any temperature rise degrades battery chemistry quicker and requires fuse protection.)

A 20hr charge is safe even if it can handle a fast charge... it will last longer. Depleting to only 50% SOC, will also extend Ah * cycles = lifetime Ah capacity.


Normally Stage 1 CC, 2 CV, 3 OFF

Lean & Mean charger

900mAh /20h= 45mA and run off a small 12V <<5W brick supply in series with an array of WHITE LEDs in parallel with a 10 ohm/1W series resistor to monitor current (voltage drop. )With 2.8V cutoff on the LEDs and 3~3.5V nom , the charger will drop out at a reasonable level.... Test to verify.....

If your supply is poorly regulated and goes to 15V with no load, extra power diodes in series are needed.
Charger efficiency of battery is < 60% so put 1.5Ah in to get ~900mAh out. ie. 50mA x1day or so

Keep records of charge and discharge time and label each battery with a SN to gain experience.

The problem with these batteries are they are stacked cells without a charge & balance circuit.

You cannot just charge these without a balance circuit ( a system where each cell is matched before full charging)
It is dangerous, batteries may explode , especially as the stack gets older and cell storage parameters drift further apart.

go look at some of the RC charge circuits used for model cars etc.