Questions on Sigma backup NiMH batteries.

Issue

Questions on Sigma backup NiMH batteries.

Product Line

Satchwell Sigma

Environment

X32

X96

NiMH batteries

Cause

Questions on the battery packs supplied with Sigma X96 controllers,

1. What is the shelf life of these batteries? (average)
2. Can the voltage of these batteries be checked without disconnecting them from the controller, via measurement points on the PSU board?
3. What is the recommended preventative maintenance interval to check the batteries, if at all?
 

Resolution

1.       Long-term storage for more than a couple of years can damage the cells. They tend to go short-circuit in long-term storage. This is a trait of all NiMH cells.

2.       The battery pack needs to be disconnected from the controller to measure its voltage, else you will be measuring the voltage from the charge circuit. It is feasible to switch off the controller completely (both the mains switch and the battery switch) and measure the voltage by inserting meter probes into the battery connector, past the wires into the back of the connector. Battery voltage is not necessarily a good indicator of battery health. The only way to test battery health is to measure the run-time while operating on battery power, or otherwise to take out the battery pack and use a commercial battery analyser.

3.       As far as I am aware there is no preventative maintenance interval specified, as battery life is dependent on many things, such as temperature, for instance.