Auxiliary Power Supply Mounting Location

[RAL]

@RAL:  If I have an AL600ULX or an AL400ULX with a back-up battery in the same can, do you mean the outputs from the battery connect to the "input"  side of the LPD and the the "out" from the LPD then goes to the "+ BAT -" connection on the circuit board in the AL600ULX (which is described in the installation instructions as "Battery Connection (non power-limited)"?  
 
Or am I missing something?

 
The Inputs to the LPD connect to the power supply board, and the outputs of the LPD connect to the battery.
 
The LPD monitors the voltage coming into the input terminals.  When the voltage drops below 10.5V, the relay drops out and the output is disconnected, and remains disconnected until the voltage on the input rises above 10.5V again.
 
So, at the time the AC power goes out, the relay is closed, and the battery voltage continues to hold the relay closed.  Once the battery drops below 10.5V, the relay opens.  It stays that way until the AC power comes back on and re-energizes the relay, and begins to charge the battery.
 
If you connect the LPD backwards, with the battery connected to the input side, it will work - just once. Initially, the fully charged battery will activate the relay and allow the power supply to keep it charged.  When power goes out, the relay will still be closed, and the battery will power things until the voltage drops below 10.5V and the relay opens.  Once that happens, when the AC power comes back on, the relay won't close, and the battery won't charge because the LPD is looking input side voltage, where the battery is still below 10.5V.
 
Here's a picture of the correct way to wire it.
 

 

[TurboSam]

RAL, thank you--for both the explanation and the diagram.
 
I kept thinking that if the input terminals on the LPD were connected to the power supply board and the LPD output terminals were connected to the battery, the LPD would cut off the battery (and thus power from the battery) when the AC went out--just when battery power was needed the most.  
 
I think I got to that point because the Altronix intallation instructions for the LPD say to "connect devices to be powered to terminals marked {- OUT +]," and I was not distinguishing between what happens on loss of AC power and what happens when there is less than 10.5V from the battery.  
 
I didn't realize (and please correct me if I'm wrong) that, on an AC power failure, the battery (with at least 10.5V of power in it) would continue to supply power "through" the LPD to the power supply board so it could know to switch over and use that battery power until the actual low power disconnect happens when the battery goes below 10.5V.
 
Again, thanks.
 

 

[JohnDennis]

I watched a youtube video "bounder27" I think describing how to install a smaller Altronics  power supply for a Vista Alarm board.  He suggest that it is necessary  for all the 12v power supplies to share a low voltage common for proper voltage.

 

[TurboSam]

You'll find multiple post here also that highlight the need for a common negative between the Altronix and the alarm panel.

 

[giansiro]

Altronix AL100UL Single Output Linear Power Supply/Charger - 12VDC @ 750mA
Input:

• 16.5VAC, 20VA from UL Listed, Class 2 transformer (sold separately).

Output:

• 12VDC output.
• 750mA supply current.
• Class 2 Rated power limited output.
• Filtered and electronically regulated output.
• Short circuit and thermal overload protection.

Battery Backup:

• Built-in charger for sealed lead acid or gel type batteries. (batteries sold separately)
• Automatic switch over to stand-by battery when AC fails.
• Maximum charge current 0.5 amp.
• Low battery disconnect prevents batteries from deep discharge.

Supervision:

• AC fail supervision (form "C" contacts).
• Low battery supervision (form "C" contacts).

Visual Indicators:

• AC input and DC output LED indicators.

Electrical:

• Operating temperature: 0° C to 49° C ambient.
• 4.6 BTU/Hr.
• System AC input VA requirement: 26.45VA.

 
 
 
http://www.lowvoltagesupply.com/product-p/al100ul.htm