Blue Sea Systems DC Ammeter - 50-0-50A with Shunt User Manual

Marine Electrical Prod

ucts

Analog DC Ammeter

50-0-50 Amperes PN 8252 2-5/8” Face
100-0-100 Amperes PN 8253 2-5/8” Face
50-0-50 Amperes PN 8254 2” Face

Meter Specifi cations

Input Voltage: 48 Volts DC maximum
Amperage Draw: 1 Milliamp at full scale
Display: Analog scale
Accuracy: 3% of scale range
Face Width: 2-5/8” 66.7mm PN 8252
2-5/8” 66.7mm PN 8253
2” 50.8mm PN 8254
Mounting Hole: 1-7/8” 47.6mm PN 8252
1-7/8” 47.6mm PN 8253
1-1/2” 38.1mm PN 8254

Guarantee

Any Blue Sea Systems product with which a customer is not satisfi ed
may be returned for a refund or replacement at any time.

Installation

Warning

It is not possible within the scope of these instructions to fully acquaint
the installer with all the knowledge of electrical systems that may
be necessary to correctly install this product. If the installer is not
knowledgeable in electrical systems we recommend that an electrical
professional be retained to make the installation.

1. Disconnect all AC and DC power

Before starting, disconnect the main positive cable from all batteries to
eliminate the possibility of a short circuit while installing the meter. Also
disconnect the AC shore power cord from the boat to eliminate the
possibility of electrocution from AC wiring near the DC ammeter.

2. Select mounting location

Select a mounting location which is protected from water on the meter
front and back and is not in an area where fl ammable vapors from
propane, gasoline or lead acid batteries accumulate. The meter is not
ignition protected and may ignite such vapors. There are two mounting
methods for the ammeters, surface mount or panel mount.

Blue Sea Systems Inc. Phone [phone]
425 Sequoia Drive Fax [phone]
Bellingham, WA 98226 USA E-mail [e-mail]
www.bluesea.com

Document 9878 Rev.B

Installation (continued)

Surface Mount Panel Mount

Surface Mount: Drill fi ve clearance holes as shown below. The

part number of the meter will determine the size and location of the
clearance holes. Use the nuts and washers supplied in the accessory
package to secure the four mounting studs to the mounting surface.
This method will work on mounting surfaces up to 5/8” thick.

PN 8254

Micro Meter

Panel Mount: For thicker mounting surfaces, the meter can be
mounted into a 0.125” thick panel. Blue Sea Systems offers meter
mounting panels for our standard size meters only. Use PN 8013 to
mount a single meter or PN 8014 to mount two meters.

PN 8254 / PN 8253

Standard Meters

PN 8254 PN 8252 / PN 9253

3. Shunt Location

Blue Sea Systems’ Ammeters from 50 Amperes to 300 Amperes utilize
an external shunt as their current sensing device. The nature of current
measurement is that the full current to be measured must fl ow through
the shunt. Choose the site in the circuit to be measured where the
shunt is to be installed. It may be either in the positive or negative side
of the circuit. The shunt may be mounted at any point in the circuit,
but mounting it close to the meter will keep the sense wires short,
minimizing voltage loss and interference, creating the most accurate
meter reading.

4. Connections

Blue Sea Systems offers zero center ammeters for the purpose of
measuring fl ow in those circuits in which current at different times fl ows
in different directions. Examples of bidirectional current circuits are:

4.1. Negative wire connecting the ship’s batteries to the negative
distribution bus. During discharge current fl ows toward the
battery and during charging current fl ows away from the battery.
Measuring current fl ow in this wire will tell at any moment whether
the battery is in a net charge or discharge situation.

4.2. Circuits which have auxiliary charging devices mixed with load
devices. Frequently charging devices such as wind generators
and solar panels are connected to circuits that also power load
devices. This mixture of load and charge devices can create
net current values that are sometimes positive and sometimes
negative depending on whether the charge device is producing
more current than the load devices are consuming.

4.3. Inverter/Charger - DC cables connecting the inverter to the
battery. The positive wire of this circuit has current fl owing away
from the batteries during inverter use and toward the batteries
when the inverter is receiving AC input and is acting as a battery
charger. A zero center meter in this circuit will indicate whether the
inverter is acting as a battery charger or is pulling current from the
batteries.

Installation (continued)

4. Connections (continued)

In many situations it will require a thoughtful analysis by the boater to
determine exactly where to place the ammeter sensing shunt in a cir­cuit to obtain the current fl ow information that is sought. As illustrated in
the initial example, it may sometimes be necessary to place the shunt
in the negative wire of the circuit to be able to isolate the exact current
value that is desired. The shunt can be placed in either the positive or
negative line. Assuming one positive wire from voltage source to load
and one negative wire returning to the voltage source, the amperage is
always exactly the same in both the positive and the negative wire.

Marine Electrical Prod

Wiring Diagram

Zero Center Ammeter

ucts