Powering the LI-8250 Multiplexer

Three options are available to power the LI-8250: a bare-leads power cable to connect to a user-supplied DC power source (part number 8150-706), an indoor AC-to-DC power supply for connecting to mains power (part number 8250-772), or an outdoor AC-to-DC power supply for connecting to mains power (part number 8250-770).

Using the bare-leads power cord

The bare-leads power cord (part number 8150-706) is used to connect the LI-8250 Multiplexer to a DC power source (10 to 30 VDC, 80 W) such as a solar power supply with deep-cycle batteries. See Power requirements and consumption to estimate your total system power requirements.

Note: A 24 VDC power supply may provide more dependable performance than a 12 VDC power supply because the voltage delivered is well above the low voltage threshold of the device. Low-voltage power supplies can suffer voltage drops that lead to undesirable power cycling.

To connect the power cable to your system, connect the red wire lead to the positive side of your power source and the black wire lead to the negative side. Then connect the power cord into the PWR IN port of the LI-8250 Multiplexer. Once connected, the LI-8250 will automatically power on.

Using the indoor AC-to-DC power supply

The indoor AC-to-DC power supply (part number 8250-772) provides power to the LI-8250 Multiplexer using mains power (100 to 240 VAC; 50 or 60 Hz). This power supply is also used to power the 8250-01 Extension Manifold when running the purge pump with the Flask Sampling Kit (part number 8250-660). It connects to the ALT PWR IN barrel jack inside the case. Once connected, the LI-8250 Multiplexer will automatically power on.

The indoor power supply can be used to power the multiplexer while you configure the system before field deployment. The lid of the case must be left open to use the indoor power supply.

Alternatively, you can route the power supply connector through the analyzer connection panel for long-term indoor use. To route the power supply connector through the analyzer connection panel, remove the metal seal from the panel (see Figure 2‑4) and connect the power supply into the ALT PWR IN barrel jack (Figure 2‑5). Removing the seal makes the LI-8250 longer weather resistant.

Figure 2‑4. The metal seal can be removed to access the alternate power jack.
Figure 2‑5. Route the indoor AC-to-DC power supply through the analyzer connection panel after removing the metal seal.

Warning: The indoor AC-to-DC power supply is for indoor use only and should not be exposed to the elements. Using the indoor power supply in wet conditions may result in electric shock or damage the equipment.

Using the optional outdoor AC-to-DC power supply

The outdoor AC-to-DC power supply (part number 8250-770) can be used to power the LI-8250 Multiplexer using mains power (100 to 240 VAC; 50 or 60 Hz).

Before plugging the power supply into a power outlet, first connect the cord between the power supply and the LI-8250 Multiplexer. Connect one end to the power supply and the other to the PWR IN port of the multiplexer. Align the key with the slot and then tighten until snug. Press and turn a little more until the connector is fully seated.

Once the power supply is connected to the multiplexer, connect the power supply AC cord into the power supply and then plug it into an outlet. You will hear a click when the cord is connected to the power supply. If you do not hear a click, your connection may not be fully sealed.

The LI-8250 Multiplexer will automatically power on once power is connected.

Warning: To protect against electrical shock, the power supply must be connected to a grounded AC receptacle. We recommend that the mains power to the instrument be supplied by a ground-fault circuit interrupter (GFCI).

Power requirements and consumption

A LI-8250 Multiplexer long-term system deployed in the field can be run on mains power using the outdoor AC-to-DC power supply (part number 8250-770) or on a user-supplied external DC power source, such as solar panels or a fuel cell.

Table 2‑1. Typical long-term system power consumption (Wi-Fi off) based on the number of chambers and additional consumption for the LI-870.
Chambers Extension Manifolds Idle (W) Active (W)
1 0 4.9 20.1
2 0 5.2 20.4
4 0 6.0 21.2
8 0 7.5 22.7
15 1 10.9 36.4
22 2 14.3 39.8
29 3 17.8 43.3
36 4 21.2 46.7
Additional for LI-870 – 5.0 5.0

The LI-8250 Multiplexer has three power supply options discussed in more detail in Powering the LI-8250 Multiplexer. The LI-870 CO2/H2O Analyzer is powered by the multiplexer as are each of the 8250-01 Extension Manifolds and 8200-104/C Long-Term Chambers. The Table 2‑1 shows typical power consumption based on the number of chambers, extension manifolds, and whether an LI-870 is included.

Each LI-78xx Trace Gas Analyzer must be connected to a power source. Either mains power of 100 to 240 VAC, using the universal power supply (part number 9968-232), or a user-supplied external DC power source of 10.5 to 33 VDC, using the auxiliary power supply adapter (part number 9968-242), will work.

Warning: The universal power supply (part number 9968-232) is not weatherized and should not be exposed to the elements. Using the indoor power supply in wet conditions may result in electric shock or damage the equipment.

LI-78xx Trace Gas Analyzers include rechargeable lithium-ion batteries. These batteries should be installed even when connected to an external power source. The Table 2‑2 shows the power consumption for the LI-78xx Trace Gas Analyzers.

Table 2‑2. Power consumption for the LI-78xx Trace Gas Analyzers.
Steady state operation (W) Universal power supply during warmup (W) Auxiliary power supply during warmup (W)
22 Up to 100 with batteries charging Up to 65

Additional information about powering LI-78xx Trace Gas Analyzers is available at licor.com/78xx-support.