7.2v Charger

C

D

E

R1 1 OHM 50W 20-25 AMP FUSE

J1

S1 #16 Ga. Wire LD1 "POWER" LED

20 AMP DPST

. BLACK

ULN2803A U6E 5 10 IN COM 9 GND

TO U6, PIN 20 ZD1

OUT

R2 1 OHM 50W

14 K2 12V 10A RELAY R3

10 V

1 2

1 OHM 50W

R4 680

6 10 TO U6, PIN 18

U8 7805C

IN COM

OUT

1 2

13 K3 12V 10A RELAY

ULN2803A

R5

U6G 1

OUT

3

7 10

+5 V TO U6, PIN 17

IN COM

OUT

+

U6H ULN2803A 8 11 OUT 10 IN COM 9 GND

D2 1N4148

C3 22UF 25V

ADJ

+

D3 1N4148

+1.8 V

+

R7 270 +

1

2

2

3

1 2 CON2

C4 10UF 20V

FAN 1 12VDC FAN

U7E 7407 10

R6 1/2 MIN. DELAY 560 K U5E 40106 11 10

U9 LM 317T VOUT

J4

+5 V

TO U5, PIN 12

VIN

1 OHM 50W

K4 12V 10A RELAY

C1 10UF 20V

+12V OUT

3

CON2

12

ULN2803A

2

IN

GND

3

CON2 J3

U6F D1 1N5401

4

J2 Red

1N5240 ZENER

1 2 CON2

Black

LARGE ALLIGATOR LEADS #12 Ga. WIRE 1

K1 12V 10A RELAY

11

U7F 7407 12

C2 22 UF 16V

TO U1, PIN13

F1

TO U2, PIN 13

RED 1 4

B

Kyoso Female Plugs

A

13

U6D 15 1 +

ULN2803A 4 OUT IN 10 COM

2

R8 120

HEATSINK THESE 2 DEVICES

2 COOLING FAN TO BLOW ACROSS POWER RESISTORS

NOTES; ONE TO 4 CHARGER INDIVIDUAL SELECTABLE CHARGEING TIMER SET AT 16 MINUTES, LED BAR GRAPH READS 2 MINITE INTERVALS.

1

7805

UNIT DRAWS 700 ( ALL DISPLAYS APROX. 20 AMPS FOUR BATTERIES

LM 317T

Ma. IDLE LIT ) WITH ALL CHARGEING. 1

COPYRIGHT 2001, ELECTRONIC ENGINEERING SERVICE Title

1

3

1

FAN TURNS ON ANY CHARGE, AND STAYS ON 1/2 MINUTE AFTER CHARGER HAS TIMED OUT. FRONT PANEL LED SERVES AS A LOW VOLTAGE INDICATOR, DIMS AT 12 VDC SOURCE VOLTAGE, OUT AT 11 VDC.

3

2 2 A

B

C

7.2 V FIELD CHARGER (4 BATTERIES) Size A Date:

Document Number /7.2V CHARGER Thursday, May 31, 2001 D

Rev A Sheet

1

of E

2

A

B

C

D

E

D5

1.8 M

1 2 3 4 5 6 7 8 9 10

1 2 3 4 5 6 7 8 9 10

VCC

GND

IN COM

7

R13 10K

18

18

+5 V

OUT

14

74164

CLR

R12 10K

CLK

C5 40106 33UF 16V

8

+

+5 V 3

U2

U6A ULN2803A

9

+5 V

1 10

3 4 5 6 10 11 12 13

4

1 2

+5 V

7

3

QA QB QC QD QE QF QG QH

74164

9

CLR

CLK

GND

1 2

VCC 8

14

33UF 16V

A B

C6

IN COM

U1

QA QB QC QD QE QF QG QH

2

1 10

U5B U6A ULN2803A

OUT

U5A 40106

7 +

R11

3 4 5 6 10 11 12 13

14

+5 V

1

4

LED BAR DISPLAY

R10 1.8 M

A B

4

20 19 18 17 16 15 14 13 12 11

D4 LED BAR DISPLAY USE RED BEZEL IN FRONT OF DISPLAYS

20 19 18 17 16 15 14 13 12 11

1.8 V

+5 V

3

+5 V R14 10K TO U6, PIN 5

U7A 7407 2

S2 1

14

U7A

TO U6, PIN 6 S3

START # 2

1

R15

+5 V 7407

7

START # 1

10K

20 19 18 17 16 15 14 13 12 11

2

D6 LED BAR DISPLAY 1 2 3 4 5 6 7 8 9 10

20 19 18 17 16 15 14 13 12 11

R16 1.8 M

C7 33UF 16V

9

7

GND

+5 V

+5 V

TO U6,PIN 8

40106

74164

7

+5 V

R18 10K

U7D 7407

S4 START # 4 8

9

R19 10K 1

EES Title

U7C 7407 6

7.2V FIELD CHARGER (4 BATTERIES ) 5 +5 V

S5 START # 3

TO U6, PIN 7

Size A

R20 10K A

Date: B

2

9

CLR

CLK

VCC 8

U6C ULN2803A

1 2

3 10 16

+5 V

IN COM

74164

OUT

GND

CLR

VCC 8

14 +

CLK

QA QB QC QD QE QF QG QH

40106

1 2

33UF 16V

C8

A B

U5C 6

5

U4

40106 + 14

U3

12

3 4 5 6 10 11 12 13

U5D

1 2 3 4 5 6 7 8 9 10

1.8 M

8

3 4 5 6 10 11 12 13

R17

9

QA QB QC QD QE QF QG QH

D7 LED BAR DISPLAY

A B

2

1

U5F 13

C

Document Number /7.2V CHARGER Thursday, May 31, 2001 D

Rev A Sheet

2

of E

2

7.2 V FIELD CHARGER (4 BATTERIES) Revised: Thursday, May 31, 2001 /7.2V CHARGER Revision: A Bill Of Materials May 31,2001 9:53:53 Page1 Item Quantity Reference Part ______________________________________________ 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

1 2 1 1 4 1 2 4 1 1 4 4 1 1 4 1 1 1 1 4 7

22 23 24 25 26 27 28 29 30 31 32 33 34 35

1 1 1 1 1 4 1 1 1 1 1 1 1 4

RED BEZEL PLASTIC ( FOR LED 4 DISPLAYS ) C4,C1 10UF 20V C2 22 UF 16V C3 22UF 25V C5,C6,C7,C8 33UF 16V D1 1N5401 3A DIODE D2,D3 1N4148 DIODE D4,D5,D6,D7 LED BAR DISPLAY FAN 1 SMALL 12VDC FAN F1 20-25 AMP FUSE J1,J2,J3,J4 KYOSHO CONN. K1,K2,K3,K4 12V 10A RELAY LD1 "POWER" .2" LED RED LARGE ALLIGATOR LEAD R1,R2,R3,R5 1 OHM 50W R4 680 OHM R6 560 K R7 270 OHM R8 120 OHM R10,R11,R16,R17 1.8 M R12,R13,R14,R15,R18,R19, 10K R20 S1 20 AMP DPST S2 S2 S3 S4 MOMENTARY CONTACT SWITCH PANEL MOUNT LED HOLDER FAN FINGER GUARD FRONT PANEL FUSE HOLDER U1,U2,U3,U4 74164 I.C. U5 40106 I.C. U6 ULN2803A I.C. U7 7407 I.C. U8 7805C REG. U9 LM 317T REG. ZD1 1N5240 ZENER 3/8" GROMMET 1/4" GROMMET

This charger was designed by me in 1993 to fill a need that I had. This was I had two R.C. model boats that needed 2 batteries each and I needed to charge them simultaneously, from my car battery. I could not find a commercial unit to do this, so came up with a neat project to fill the bill. Layout was done on a 2 proto-boards, one lays flat, and the other vertical for the bar graph displays. The displays a need red filter in front of them. The unit is novel as it’s display graph shows you the time the battery has been charging in 2 minute intervals up to 16 minutes when finished. The “power” led indicates source voltage as it dims, and goes out at 11 vdc, this is needed because the unit draws 20 amps fully charging 4 batteries as you will need to run your engine or you will walk home!! The d.c. fan needs to be situated as to force air across the power resistors, the fan has a circuit to turn off ½ minute after the unit quits charging. Heat sink the two regulators (U8 & U9) to the metal case also. All of the parts are easy to get, most available at radio shack, allied, or digi-key Good luck and happy charging, Dave M.