NexSens CB-150 Data Buoy

User Guide



The NexSens CB-150 Data Buoy is designed for deployment in lakes, rivers, coastal waters, harbors, estuaries and other freshwater or marine environments where environmental data collection is planned. The floating platform accommodates both topside and subsurface environmental monitoring sensors including weather stations, wave sensors, thermistor strings, multi-parameter sondes, Doppler current profilers and other monitoring instruments.


First-Time Setup
What’s Included1.1
Common Accessories
X2-CB User Guide1.3
Instrument Cage Attachment2.1
Ballast Weight & Stability3.2
Mooring Options4.1
Additional Resources 
How To5.2
Battery Check5.5
Battery Replacement5.6
Solar Tower Testing6.1

First Time Setup

1.1 What’s Included

The CB-150 includes the following accessories and spare parts for deployment.

  • (3) 2″ diameter sensor holes with female NPT threads for sensor deployment
  • Integrated 8-watt solar panels for 24 total watts of solar charging
  • 10” ID x 13.5” deep data well for  batteries, data loggers, and sensors
  • (3) Top-facing stainless steel eye nuts for handling
  • (2) Bottom-facing stainless steel eye nuts for mooring
  • Instrument Cage


Rendering of CB-150 data buoy, showing the data well and 2″ pass-through ports


1.2 Common Accessories

The following are common accessories to the CB-150 Data Buoy for power, mooring and ballast, and sensor mounts. Additionally, this list includes a recommended beacon and the optimal data logger for the CB-150, the X2-CB Buoy Mounted Data Logger.


PowerMooring & BallastData LoggersSensors & Mounts
NexSens CB-A01 Data Buoy Battery Harness

NexSens Buoy Cage Anti-Rotation Collar

X2-CB Buoy-Mounted Data Logger


NexSens Buoy Deployment Pipe Assemblies

NexSens CB-A05 Data Buoy Battery Harnesses

NexSens CB-Series Data Buoy Ballast Weight



NexSens M550 1-3NM Solar Marine Light

NexSens CB-Series Battery Float Charger Kits

NexSens CB-Series Buoy Zinc Anode


1.3 X2-CB User Guide

The X2-CB is an all-in-one environmental data logger specifically designed for use with a NexSens CB-Series data buoy. It automatically recognizes sensors and sends data to the web via cellular, radio, or satellite telemetry. If an X2-CB was purchased with a CB-150, follow the link below to learn more about the X2-CB data logger.

X2-CB User Guide



2.1 Instrument Cage Attachment

  • The instrument cage should always be attached to the buoy to improve stability and provide a portion of necessary ballast weight.


Instrument Cage for CB-150


  1. Attach the cage to the buoy frame using the ¾” bolt, lock washer and castle nut.
    1. Reference the CB-150 diagram below

Cage attachment to buoy frame


CB-150 Diagram


  1. Tighten firmly with 1-1/8” wrenches or large crescent wrenches. Be sure to flatten the lock washer and lineup the hole in the bolt with the notches in the castle nut.

Cage to frame connection


  1. Place the cotter pin through the hole in the bolt, and bend the long leg of the pin to prevent the nut from coming loose.




3.1 Deployment

Safety First

Always follow safe marine and boating practices.


  • Heavy gear and boat clutter during deployment is unsafe. Care must be taken during deployment to maintain a clean and safe environment.
  • Use proper protective equipment (work boat, lifting rig, gloves, safety footwear, etc.) when deploying any buoy system.
  • Buoy systems are heavy, and personnel can quickly become entangled within mooring lines. Flotation gear should be worn at all times when working on or near the water.
  • Never deploy buoys in unsafe weather conditions.


3.2 Ballast Weight and Stability

To prevent overturning and ensure stability, additional ballast weight may be needed.


  • As configured at the factory, the buoy’s center of gravity is near the water surface. Any weight added above the water surface must be appropriately counterbalanced by additional ballast weight below the surface.
  • Be sure to keep topside devices lightweight and positioned as low as possible on the tower. Mount the ballast weight as low as possible on the underside of the buoy. It is preferred that the ballast weight be connected to the eye of the instrument cage.
  • It is recommended to use galvanized chain for ballast, however, the exact weight is dependent upon the conditions at the deployment location.
  • Before final deployment, some experimentation with ballast weight may be required to properly balance the buoy.



CB-150 Ballast Weight diagram


4.1 Mooring Options


Single-Point mooring diagram


Single-Point Mooring

When to Use

  1. In calm waters
  2. When monitoring sensors are attached to the instrument cage or housed in 912-M deployment pipes located within the three buoy pass-through ports.
    1. Secure sensor mounting prevents damage from debris and limits the entanglement from mooring lines.


  1. Attach a stainless steel mooring line to the bottom eye of the instrument cage.
    1. Ensure that the mooring line has adequate length to remain taut in the water column.
  2. Shackle a heavy chain to the bottom of the mooring line.
    1. Confirm that the chain is long enough so that the anchor cannot be lifted during high water conditions.
    2. Size the chain and mooring line such that a small portion of chain is suspended in the water column during low water conditions.
  3. Connect an anchor to the bottom of the chain.


Two-Point mooring diagram


Two-Point Mooring

When to Use

  1. When monitoring sensors or sensor strings are deployed in the water column directly below the buoy.
    1. This setup allows the mooring lines to be pulled taut away from the buoy, freeing the water column for a suspended sensor line.


  1. Attach short mooring lines to opposite eye nuts located on the bottom of the buoy frame.
  2. Secure each surface line and a water column line to a marker buoy.
    1. Ensure that the water column line has adequate length to remain taut in the water column.
  3. Shackle heavy chains to the bottom of each water column line.
    1. Confirm that the chain is long enough so that the anchor cannot be lifted during high water conditions.
    2. Size the chain and mooring line such that a small portion of chain is suspended in the water column during low water conditions.
  4. Connect an anchor to the bottom of each chain.


Important: This section contains only general information on the available mooring options for CB-150 data buoys. To develop an effective mooring strategy, a variety of application-specific criteria (water level fluctuations, currents and wave action, debris loads, etc.) must be thoroughly reviewed prior to deployment. NexSens does not endorse any particular mooring strategy for any specific application.



Additional Resources

5.1 Troubleshooting

Visit the CB-150 Troubleshooting Section of the NexSens Knowledge Base to learn effective troubleshooting strategies for the CB-150.



5.2 How To

Visit the CB-150 How To Section of the NexSens Knowledge Base to learn advanced and user-friendly ways to utilize the capabilities of the CB-150.

How To


5.3 FAQ

Visit the CB-150 FAQ Section of the NexSens Knowledge Base to find answers to common questions asked about the CB-150 from NexSens customers.




5.4 Storage

Proper storage of a buoy system is essential to maintain the integrity of its electrical and physical components. Follow the link below to learn the appropriate storage guidelines for the CB-150 Data Buoy, along with common errors to avoid.

X2-CB Storage Requirements


5.5 Battery Check

Use a DC multimeter and measure the voltage between pins 3 (V+) and 4 (GND) on the SOLAR port.

Healthy SLA battery voltage is 12.0-14.9V.

CB-Series Buoy SOLAR port pin-out.


5.6 Battery Replacement

The 12V sealed lead acid batteries installed in the data well of CB-Series buoys may require replacement if their charge falls below ~10V or every 3-5 years as their integrity declines with age. This article highlights the basic steps required to test, and if necessary, replace the A05 12V 28 A-Hr battery commonly equipped in quantities of 1 to 3 on the NexSens CB-450, CB-650, CB-950, and CB-1250 data buoys

Follow the link below for a step by step process on replacing a CB-Series battery.

Replace a Battery in a CB-Series Data Buoy


6.1 Solar Tower Testing

Three 8W diode-protected panels allow for solar charging when the buoy is facing any direction. As a precaution, these panels are diode protected in the instance that they are not receiving direct sunlight. When configured with factory installed batteries, a solar regulator is included in the data well. Otherwise, a solar regulator is required from an outside source.

Solar panel voltage output between pin 1 and pin 3 of the UW-6 SOLAR plug will vary between 8-20V depending on the available sunlight.

Connect the leads of a DC voltmeter to pin 1 and pin 3 to confirm the panels are producing the expected voltage.



UW-6 Plug pin connections


For step by step instructions, follow the link below.

Test a CB-Series Buoy Solar Tower



6.2 Links

In the event that NexSens systems need returned for maintenance or repair, please click the link below and fill out our service request form.

NexSens Return Materials Authorization