External backup batterries.

[ohtapa]

Hi all,

Does anyone can help to calculate the maximum current of external batteries to maintain system up to 8 hour ? . Incase we need to install ipLDK600 as the following order ( 5 KSU, 5 RGU, 1 PRIB,35 SLIB2E, 1 AAIBE,1 VOIBE ).
I'll very appreciate if anyone kindly show me the step to calculate above requirement.
Anyway! sorry for my English.

Many thanks,
Ohtapa

 

[Chamvari]

This might be difficult since pbx usage determines the duration of the standby battery the more incoming calls the quicker the batteries goes flat.

My assumption is 40 amp hr per cabinet. i dont have a formula sorry

 

[ohtapa]

Hi Petros,

Many thanks for your suggestion.

 

[doktor]

If you can list up all boards in the 5 KSU's I can give you an approx. amp value.
The VMIB, VOIB and WTIB boards are using quite a lot power on 5 Volts, and the Local and CO board use less, so I need the full list to be more accurate.

///doktor

 

[ohtapa]

Hi Doktor,

Thanks for your help. The full list are following order,

- 5 KSUs with 5 PSU(350W)and 5 RGUs,
- 1 PRIB
- 35 SLIB2Es
- 1 AAIBE with VCEUE
- 1 VOIBE
- 12 DTRU4s,
- 1 DTIB12

As above are the total we need to install.

Many thanks,
Prasan

 

[doktor]

I will give you an answer after this weekend, as I am not in the office this week.
///doktor
p.s.
Most power consuming units are:
- AAIBE/VCEUE
- VOIBE
- DTIB12 w/up to 12 keysets.
(How many keysets are installed?)

 

[ohtapa]

In this case we need to install 12 DKTUs.

///Ohtapa

 

[doktor]

Hi again

According to our experience and nomal way to calculate this a battery delivering 40 Ampere hours pr. KSU is needed for 8 hours of use of your PBX without public power is connected. This was also petros' suggestion.
So you need a battery capable of delivering 200 AH for your PBX.

///doktor

 

[doktor]

Here I found some additional information;

The external batteries must provide 24 Volts DC. This is generally accomplished by connecting two 12
volt batteries in a series arrangement. Operation on batteries is controlled by the PSU. This LDK-300
PSU will provide charging current to the batteries during normal AC power operation at a maximum of
about 500 mA. During battery operation, the battery operation of PSU will be stop if the AC power reapplied
or the battery voltage is too low to maintain proper system operation.
If a low-battery cut-off occurs and a new battery is installed, it is necessary to reset the Battery Back-Up
circuit in PSU manually by momentarily pressing the switch marked as BATT. RESTART located on the
upper side of PSU (in only PSU3). LDK-300 PSU will be restarted by the battery switch on.
The length of time that the system will operate on the batteries is dependent on several elements
including, battery charging state, condition of the batteries, capacity of the batteries, and the size of the
system (number of station ports). The chart below gives the approximate back-up time for several
system sizes and different battery capacities in ampere-hours.
Battery Capacity/DKTU 24 Ports/DKTU 72 ports/DKTU 120 ports
20AH / 6 hours / 3 hours / 1.5 Hours
40AH / 12 hours / 6 hours / 3 hours
* Note
Turn on the battery switch on the side of the KSU only after the installation of the IP LDK-300/300E
system is finished and AC power is turned on.
Make sure that the type and capacity of the 2 backup batteries are identical.


///doktor