The Remora3 has in-built battery monitoring capabilities. It is critical to any application that:

1. The batteries last long enough so that frequent changes are not necessary
2. Low battery alerts are sent in a timely manner - so that battery changes can be made before batteries run flat. 

The Remora3 should only be used with the below battery type

• Lithium Thionyl Chloride (LTC)

See Battery Recommendations [Remora3] for detail on selecting the right batteries.

The Battery Meter - Coulomb Counter

The Remora3 is fitted with a battery meter (coulomb counter) that tracks energy (mAh) used by the battery.

A coulomb counter is a device which measures the total amount of charge flowing out of the battery*. This can be used to estimate the battery percentage, and remaining battery life.

This is can provide more information than voltage alone. Considering the discharge profile graph below, for the first 600mAh per cell of capacity used, the voltage changes minimally. So we can't make accurate capacity estimates when we only have voltage to go off. However the battery meter would be able to detect this and therefore tell what percentage has been utilized - i.e. 600mAh/1200mAh = 50%.

Despite the excellent battery capacity estimates the battery meter provides, these estimates still rely on an assumption of the total capacity of the batteries. This can vary per battery type, and even on a single type quite significantly due to temperature variations. So the estimates aren't infallible. 14Ah capacity of the 2 x D Cell LTC batteries is assumed.

*The percentage resets on whenever the batteries are replaced or on a power reset (same batteries taken out and placed back in) as it assumes a battery change has occurred

Example: Below is the discharge profile of Energizer Ultimate Lithium L92 (AA) batteries.

[Source: Energizer]

Other battery types, and adjusting the capacity assumptions

The assumptions for battery mAh and capacity can be changed under this parameter tab in System Parameters if required.

In general, these should remain unchanged (do not touch these parameters unless you know what you are doing). However if you are finding you are regularly getting greater/less capacity from your batteries, or you are using a different type of batteries with a different total capacity - they can be adjusted. 

Setting up Low Battery Alerts

Information about editing parameters is available → OEM Server - Getting Started

The below are already configured by default - so we don't need to go make any changes, or configure anything unless we have special requirements.

Battery Good + Battery Critical Flags

The device keeps two battery 'flags':

Battery Good Digital Input 

• Mapped to Digital Input 1 by default.
• Also appears as Bit 1 in the Device Status Flags 
• Active '1' when the percentage is above the Battery Low Percentage - and inactive '0' when below this threshold (default is 15%). 
• If a brownout occurs this is set to '0' - whatever the percentage.

Battery Critical Digital Input

• Mapped to Digital Input 2 by default
• Also appears as Bit 5 in the Device Status Flags
• Active '1' if a brownout occurs. 
  • On the Remora3 - this is if the voltage ever dips below 3.3V/cell LTC - which is too low to properly power the device. If this occurs - it is because the batteries are on their last legs, and need to be replaced immediately! The device needs at least 3.3V to operate.

The above flags mean we have 3 distinct states