Sentinel: Using an External Battery (Opt 631)

How long does the internal battery power the instrument?

The duration quoted in the Sentinel User Guide is for OTA measurements only.

(90 minutes measurement, or 60 minutes transport mode and 60 minutes measurement.)

We do not spec for other types of measurements, but we expect it to be in the range of 60-90 minutes if there is no OTA fitted, if an OTA card is fitted then it may be less than 60mins.

What sort of external battery can be used?

A battery pack with a USB-C PD profile of 20V 5A may be connected, this can be used to extend the duration of both transport mode and measurements carried out without mains power connected. This will also charge the internal battery while the Sentinel is switched off and disconnected from mains power.

If mains power is connected it will be used in preference to the USB-C input.

How long will the instrument operate with an external battery?

This depends on the capacity of the external battery. For comparison, the internal battery has a nominal voltage of 22V and nominal capacity of 4.4Ah. The nominal energy of the internal battery is approximately 97 Wh. Note that operation from an external battery will not be as efficient dues to losses in the charging circuit.

Do I need to activate the use of an external battery?

No, Sentinel will automatically detect the presence of an external battery and use it to charge the internal battery

Can Sentinel charge an External Battery?

No, Sentinel will not charge an external battery

Can I start Sentinel with a completely discharged internal battery by using an external battery?

Sentinel operates from the internal battery. The external battery charges the internal battery. If the internal battery is completely discharged, it should be charged for at least 15 minutes before attempting to start the instrument.

Can I use an external battery to extend transport mode?

Yes, an external battery will continue to charge the internal battery during transport and will extend the transport time