NomaSense O2 P300 and P6000 have incorporated battery pack made with 4 rechargeable Ni-MH AA batteries. When buying a device, a charger and an USB cable are provided.
For recharging the batteries connect the supplied USB cable to the USB connector on the bottom panel of the device. Then you can connect the USB cable to a USB port of a PC / notebook. The batteries will be charged when the PC / notebook is turned on. This connection is also used to link the device with the computer. You can also charge the batteries by connecting the NomaSense O2 to the power supply with the USB-power adapter. Plug the USB cable to the supplied USB-power adapter (5 VDC, min. 1 A) and connect the adapter to the main power grid.
Extra batteries can be purchased in case one wants to have spare batteries. To replace the batteries, simply open the battery compartment on the bottom panel using a screw driver or other tool that fits. Take out the battery pack as far as the connection wires allow, and then remove the battery connector. Now you are able to remove the battery pack and exchange the 4 Ni-MH AA rechargeable batteries. When you are done, put the battery pack back in the battery compartment and connect it to the battery connector again. Push the wires down so they will not be caught in the thread when putting the screw cap back on. Tighten the screw cap and make sure the sealing ring fits properly to avoid moisture entering the battery compartment.