primitive early design for battery charging - Electronic Circuits Projects Diagrams Free

faomari · 2nd May 2006, 09:58 AM

Hi, im desiging a PWM(boost converter) battery charger for lithuim ion battery cell. Im assuming that the battery will never get to a complete discharge level. so the battery voltage will never have that suddent drop in voltage across its terminals. I want to use the "constant current constant voltage" method. But since the battery will never be discharged fully, i dont have to worry about the constant current part. Now what is it exactly am i sensing to see when the battery is fully charged to eventually stop the charging, the battery voltage terminals wil be constant, so what is it thats gona tell me that the battery is fully charged. keeping in mind that i dont want to get into tempreture sensing.

G8RPI · 2nd May 2006, 03:17 PM

Hi,
First of all,
CHARGING LITHIUM BATTERIES IS DANGEROUS!

You need to follow the makers recomendations exactly. A simple constant current or delta V charger designed for Nicads will not work. Incorrectly charged cells can explode showing everthing with buring lithium.
If you insit doing your own, Maxim ( http://para.maxim-ic.com/cache/en/results/5085.html ) and Linear Thechnology ( http://www.linear.com/pc/downloadDocument.do? )navId=H0,C1,C1154,C1004,C1012,P1220,D4312 do suitable IC's.
Check the specs for the cell you intend to use.

Robert G8RPI.

G8RPI · 2nd May 2006, 03:18 PM

Hi,
First of all,
CHARGING LITHIUM BATTERIES IS DANGEROUS!

You need to follow the makers recomendations exactly. A simple constant current or delta V charger designed for Nicads will not work. Incorrectly charged cells can explode showing everthing with burning lithium.
If you insit doing your own, Maxim ( http://para.maxim-ic.com/cache/en/results/5085.html ) and Linear Thechnology ( http://www.linear.com/pc/downloadDocument.do? )navId=H0,C1,C1154,C1004,C1012,P1220,D4312 do suitable IC's.
Check the specs for the cell you intend to use.

Robert G8RPI.

eng1 · 2nd May 2006, 03:22 PM

The charger charges the Li-ion battery with constant current until the voltage reaches the final value. During this process the voltage is not constant. Then it switches to constant voltage charging.
The voltage of the battery must be sensed with great precision to avoid overcharching.

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2nd May 2006, 09:58 AM	(permalink)
faomari	primitive early design for battery charging Hi, im desiging a PWM(boost converter) battery charger for lithuim ion battery cell. Im assuming that the battery will never get to a complete discharge level. so the battery voltage will never have that suddent drop in voltage across its terminals. I want to use the "constant current constant voltage" method. But since the battery will never be discharged fully, i dont have to worry about the constant current part. Now what is it exactly am i sensing to see when the battery is fully charged to eventually stop the charging, the battery voltage terminals wil be constant, so what is it thats gona tell me that the battery is fully charged. keeping in mind that i dont want to get into tempreture sensing.

2nd May 2006, 03:17 PM	(permalink)
G8RPI	Hi, First of all, CHARGING LITHIUM BATTERIES IS DANGEROUS! You need to follow the makers recomendations exactly. A simple constant current or delta V charger designed for Nicads will not work. Incorrectly charged cells can explode showing everthing with buring lithium. If you insit doing your own, Maxim ( http://para.maxim-ic.com/cache/en/results/5085.html ) and Linear Thechnology ( http://www.linear.com/pc/downloadDocument.do? )navId=H0,C1,C1154,C1004,C1012,P1220,D4312 do suitable IC's. Check the specs for the cell you intend to use. Robert G8RPI.

2nd May 2006, 03:18 PM	(permalink)
G8RPI	Hi, First of all, CHARGING LITHIUM BATTERIES IS DANGEROUS! You need to follow the makers recomendations exactly. A simple constant current or delta V charger designed for Nicads will not work. Incorrectly charged cells can explode showing everthing with burning lithium. If you insit doing your own, Maxim ( http://para.maxim-ic.com/cache/en/results/5085.html ) and Linear Thechnology ( http://www.linear.com/pc/downloadDocument.do? )navId=H0,C1,C1154,C1004,C1012,P1220,D4312 do suitable IC's. Check the specs for the cell you intend to use. Robert G8RPI.

2nd May 2006, 03:22 PM	(permalink)
eng1	The charger charges the Li-ion battery with constant current until the voltage reaches the final value. During this process the voltage is not constant. Then it switches to constant voltage charging. The voltage of the battery must be sensed with great precision to avoid overcharching.