Wiring Second Power Supply to Alarm System

[Pierre_P]

Many instances you are required to add a secondary power supply to your alarm system.
We recommend lately with all the load shedding to power only bus modules like expanders and keypads to be powered from the control panel only.
Even powering the keypads and expanders with its own power supply can be done thus extending alarm system backup time fullest.

This saves and extends the amount of time your alarm system will be operational during a long load shedding.

17 or 18Ah batteries with a 6.4Amp power supply is more the norm.
We are finding that battery damages resulting from load shedding as it cuts the batteries life cycle.
Batteries in this instances will not last even a year.
The goal is to have a long as possible backup as can be.
For adding bigger batteries like 28Ah - this will not work due to charger limitations, battery will need more time to recharge before the next load shedding schedule.

For complete wireless systems this is not required, adding just a 18Ahr battery to the main panel should do it.

Also consider low battery cut out switches inline with panel and battery.
The battery disconnects at a certain voltage and thus saving the battery cycle time.

Using the Sherlo Lithium charger and lithium battery would result in same method.

See this image below for wiring a control panel with the secondary power supply.
Note, the + (positive) from panel and power supply is not connected with each other.
Only the - (negative) is share between power supplies