3
implication, when a shunt is rated at "100 amps-100 mV." is that it may safely carry
up to
100 amps maximum--however
unfortunately in many cases so-called "100 amp" shunts will not carry this much without overheating--especially some of the
"mini" shunts of this type. For more information, request : "Information on Shunts" from Bogart Engineering, or get it from the
internet address shown on page 1
.
If it is desired to measure
only
total solar input current, or only total load current (and amp-hours):
you must wire
the shunt such that only the solar current, or load current will pass through the shunt. The "Battery % Full" display will be
meaningless in this case. In this case it would be advisable to use Operating Level L3 which will enable you to turn off
the “automatic reset” of amp hours.
Maximum cable length for “G1” wire from meter to shunt for the following wire sizes are:
#26 gauge: 45 feet. #24
gauge: 70 feet. #22 gauge: 100 feet. #20 gauge: 180 feet. #18 gauge: 300 feet. #16 gauge: 400 feet.
If the distance between battery and meter is more than 100 ft (30 meters) you may need to increase the size of the
“G1” wire or possibly “+” wire:
Use wire with resistance less than 2 ohms total for the G1 wire. The G2 and SIG wires
can each be over ten times higher than this with no problem. If the single wire connecting from the meter + and M+
terminals to the battery is over 2 ohms, the "volts" will read slightly less than true. (If the wire is less than 2 ohm, the
meter "volts" error will be less then 0.06 volts--almost negligible). However, wires of
ten times
this resistance may be
used with no "volts" error if a separate (additional) wire is run for the M+ terminal: Disconnect the short wire between the
+ and M+ terminals at the meter terminal block, and connect two
separate
(long) wires to the fuse at the b
terminal--and run one of these to the + terminal of the meter, and the other to M+ terminal.
Meter to shunt cable requirements:
The meter may be located up to hundreds of feet away from the shunt if desired, in an
indoor location, with four or five power and control wires connecting between the shunt and the meter. (These 5 wires
are labeled on the connector on the circuit board inside the TriMetric: “G1”, “G2”, “SIG” and “+B1” and “+B2”.) The
meter can
be connected to the shunt with 5 wires, or a cable with 5 conductors. If only one battery system is being
measured only 4 wires are required.. It would be advisable to use twisted pair wires in the cable if any other power wires
are being run near and parallel with these, however it should not be necessary otherwise. If twisted pair wire is used, it
should be connected as shown in the drawing. The simplest way to connect the meter is to use wire size large enough, as
shown by the following:
TriMetric maximum current capability:
The TriMetric will measure current properly up to 999 amps with the 500 A-50
mv shunt. With the 100 A-100 mv shunt the meter measurements will be OK up to 300 amps. However,
at these
currents the shunt is going to get too hot
: the 100 A shunt as described will be producing the heat of a 90 watt light
bulb, and the 500 A shunt will produce heat equivalent to a 100 watt light bulb. (The heat produced by the shunt will be
proportional to the
square
of the current passing through it, so each time the current is doubled the heat increases by a
factor of 4.)
Serial data output is available that outputs all real time data.
Another data access method for techies.
Mounting the meter
:
TM-2025 RV model comes in a white, surface mount box
(3 x 4-1/4 x 1-1/4 inch deep). It can be
mounted to a wall with screws at the top and bottom flanges.
B. METER and SHUNT INSTALLATION
Even momentarily
connecting “+” wire from battery to meter incorrectly or backwards will destroy
it. Carefully following these steps will minimize that possibility.
•IMPORTANT: A qualified person familiar with safe electrical practices and the local electrical
code should install this meter--particularly when installing the shunt.
Accidentally shorting
the battery with a tool or other metal such as a finger ring can result in severe burns
from an arc (think “arc welder”). Obviously, mistakes in wiring could seriously
damage your electrical system.
•Refer to wiring drawing on last page--please read all notes.
•To prevent damage to meter, do not install into a battery system that has a voltage that will rise
above 65 volts. It is designed for a maximum “nominal” 48 volt battery system.
•A (2Amp, fast-blow) fuse shown
located
near the battery
in the wiring diagram is for safety. If not
provided with your meter, such "in line" fuses are available at Radio Shack.
