DESCRIPTION

Curtis Model 803 combines in one instrument a completely 

solid state battery discharge indicator, an LCD hour meter and 

lift lockout, housed in a 52mm case. Void of moving parts, this 

combination instrument is exceptionally reliable even in severe 

operating environments.

APPLICATION

Model 803 is a combination gauge ideally suited for 

electrically powered vehicles.

MODEL 803

FEATURES

‘Fuel’ Gauge Features

• Multicolor 10-bar LED displays state of charge (5 green, 

3 yellow, 2 red LEDs).

• Flashing red LED signals “energy reserve” alarm at 

70% discharged.

• Double flashing red LEDs signal “empty” alarm at 

80% discharged.

• Normally closed relay opens at 80% discharge for lift lockout. 

This unique holding relay will only lock out at the end of a 

lift cycle.

• Recognizes improperly charged battery.

• Keyswitch activated LED display (Fuel gauge electronics are 

energized as long as they remain connected to the battery).

• Wide range adjustable discharge profile.

• Dual reset methods in each gauge: Open Circuit Reset for 

vehicles that exchange batteries and Charge Tracking Reset 

for vehicles whose batteries remain connected to the gauge 

during recharge.

Hour Meter Features

• Monitors use-time throughout the equipment’s lifespan.

• Records and displays up to 99,999.9 hours on its LCD, rolls 

over and continues to count and display.

• Hour meter LCD remains on as long as battery is connected.

• Stores latest total in EEPROM nonvolatile memory, without 

need of power.

• Operates and displays in temperatures from –40 ̊C to +65 ̊C

under harsh conditions of vibration, shock, moisture and dust.

System Voltages

Available in single voltages from 12 VDC to 80 VDC, or in dual 

voltage of 24/36, 36/48, 24/48 or 72/80 VDC. Operating 

range is ± 25% of nominal voltage.

SOLID STATE BATTERY

‘FUEL’ GAUGE & HOUR METER

www.curtisinstruments.com
SPECIFICATIONS

MODEL NUMBER DESCRIPTION

803 RB

Case Style

2448

Voltage

B

Reset Type

/Level

C

Discharge

Profile

J

Output

3zzO

OEM

Code

RB=Round 

(52mm)

w/black bezel

12

1224

2436

2448

3648

7280

B=CTR/OCR (3zzO)

 =HVR/OCR (1zzO/2zzO)

 where

 OCR=2.09vpc

 HVR=2.35vpc

 C T R =2.35 vpc full,

 2.10 vpc empty

C=Adjustable

 1.57vpc to

 1.93vpc at empty

J=N.C. holding relay

 Contact rating=3 Amps

 when continuously closed,

 1 Amp when opening.

K=N.C. relay

Y=N.O. relay

 contact rating=1 Amp

(2zzO and 1zzO 

are earlier versions)

O=Curtis logo

Specifications subject to change without notice ©2013 Curtis Instruments, Inc. 50024 REV F 3/13

MODEL 803

 is a trademark of Curtis Instruments, Inc.

WARRANTY Two year limited warranty from time of delivery.

DIMENSIONS m m

• Hour meter accuracy: +0.1%

• Operating Temperature: 

–40°C to +65°C

• Shock & Vibration:

Meets SAE J 1378

• Humidity: 

95% RH (non-condensing) at +38°C

• LCD Character Height:

5 mm

• Mating Connector:

Molex 8 pin, 39-01-2085

• Discharge Range:

Empty from 1.57 volts/cell to1.93 volts/cell.

• Reset Levels: 

Open circuit reset (OCR)at 2.09 volts/cell.

Charge Tracking Reset (CTR) tracks battery recharge at 2.35 

volts/cell full and 2.10 volts/cell empty.

DISCHARGE

L

M N O P

Q

R

S

T K U

Fuel Gage "LED"

2 Red, 3 Yellow, 5 Green

Bar Height 5mm

Hour Meter "LCD"

Character Height

5mm

0 1/2 1

43.6 Max

51.8 Max

42.5 Max

57.8 Max 8.9 Max

"U" Clamp for 0.8 to 6.4 

Panel Thickness

Black Bezel

Thumbnut 4mm

Washer 4mm

- +

*Keyswitch turns on “fuel gauge” display and enables the 

hour meter. To accumulate time in the hour meter one or 

both of the HRM+ and HRM– inputs must be connected.

Pin No.

1

2*

3

4

5

6

7

8

Relay Option J

HRM (–)

Keyswitch

Relay ARM (+)

Relay N.C. (–)

Common (B–)

HRM (+)

B+ Low

B+ High

CONNECTOR PINOUT

Note: In addition to a “U” clamp and thumbnuts/washers shown in the drawing, 

individually packed units are provided with a mating connector and female pins. 

Bulk packed units are provided with a “U” clamp and hex nuts/washers only.