The following automatic battery-charger design is created with a circuit that could qualify as the simplest window comparator ever built around a single transistor (see the figure). It starts charging when the battery voltage drops beyond a preset value, and it stops when an upper preset voltage is attained.
With the help of a precise variable voltage supply, the upper and lower voltage levels were set. The normally connected (NC) lead of the relay isn't joined to the 15-V dc supply, which blocks this voltage from passing to the battery leads. This will accurately set the upper and lower levels. But the charging supply of 15 V dc was connected to the circuit.
First, the variable supply is fixed at 13.3 V dc—the voltage of a fully charged battery—and linked to the battery point of the circuit. The slider of VR1 is turned to the extreme end on the side that's attached to the positive terminal of the battery. VR2's slider should be turned toward the end that's connected to VR1. The transistor turns on, shunting VR1. Then the slider of VR1 is turned toward the other extreme, which is the end connected to VR2.
The test supply voltage is now set to 11.8 V dc, which is the voltage of a drained battery. VR2 is then adjusted so that it just turns off the transistor again. The test voltage is raised to 13.3 V dc again, and VR1 is adjusted so that the transistor turns on. With the upper and lower levels set, the NC point is connected to the circuit (15-V dc charging voltage). Now the battery charger is set and ready to go.
The resistor values are correct. I just tested circuit and every thing works well. Of course the V refers to ohms, you just can't type Ohms symbol. Use a relay with a 12v coil and one that has a NC(no contact connection)which is a 5 pin device i used a car relay.
For Vr1 & Vr2 use variable resistors
Anonymous -July 03, 2009
I also would like to see some answers to these legitimate questions contained within these posts
Anonymous -June 24, 2009
hello
cdmawin -June 05, 2009
I WANT 1 NOS. BATTRY CHARGER
SHAHID ALAM -June 04, 2009
hgfhfhfhgfh
vijay -May 19, 2009
The circuit it is shown that VR1 is 500V is it ohm?also R2 is 290V and R3 is 15V ,should we read this V as Ohm? Please reply me. Thank and regards , Tariq
Tariq -May 18, 2009
hi
I ask for RL1 Whai is ?
Auose -May 12, 2009
diagram of battary charging circuit.
Engineer -May 09, 2009
circuit digram of single transistor battary charging circuit.
amal -May 09, 2009
could u plese talk in tecnical languge.
KK -May 03, 2009
Where is Mr. Elaz Ur-Rehman ? He develioped this design, and I want to ask hem about the component values.
Tom Berge -April 16, 2009
Please, anybody can help me out. I need circuit diagram 1000 watt inverter for inverter using SG3524 IC with pmw
farooq ahmed -April 16, 2009
Where will you print these answers ? I don't know if this is getting through to ANYBODY ? ANYBODY? Please answer me at tberge@gra.midco.net Thanks somebody
Tom B -April 14, 2009
PLEASE tell me what the proper values are for this schematic. VR1, VR2, R1,R2, R3, and whats the dweal on the relar RL1. Thank you
Tom Berge -April 14, 2009
kindly respond to readers query and lets know through this site the correct values VR1, R2 and R3.Thanks
Anonymous -April 08, 2009
good
Anonymous -April 07, 2009
in the circuit it is shown that VR1 is 500V is it ohm?also R2 is 290V and R3 is 15V ,should we read this V as Ohm? Please reply me. Thank and regards , Ashok
Ashok D. Chachad -March 25, 2009
Your ideya is good but where is the circuit?
Ashok D. Chachad -March 25, 2009
Your Comments:
Enter the text from the image below
Please refresh the page if you have trouble reading this text.
Search Electronic Design
Email Newsletter
Sponsored By:
The Find Power Products monthly newsletter brings you the most important new developments within the world of power design. The newsletter includes exerpts from industry leader Sam Davis's exclusive blog, as well as overviews of the latest new products.
Enter Email to Subscribe
Web Seminar
Sponsored By:
Title: Exploring How Good GUIs Drive Adoption in the Digital Power Management Space
Reprints
