Smart-UPS 1400 RM XL external battery amp hours?

[BillP]

I have a Smart-UPS 1400 RM XL, I have removed the internal batteries and am running a pair of 77AH AGM batteries externally (in series for 24v.)

On the network card, there is a field for 'Number of External Batteries'

What is the AH rating of the APC external battery pack? ie: How many 'battery packs' should I tell the UPS that it has attached?

Also, when the UPS is showing the available (calculated) runtime (based on number of battery packs installed)...

is this calculated runtime used to shut down the UPS after a certain number minutes OR does the UPS run until a certain battery voltage is reached?

thanks

bill

[BillP]

Hmm, I was thinking that UPS would use a 48V battery system...

I also found this which I was poking around in that also said 48V.. http://www.apcmedia.com/salestools/ASTE-6Z8L99/ASTE-6Z8L99_R0_EN.pdf

Can you confirm the exact SKU from the rear of the UPS? Once I confirm the correct battery pack, I can look further into the AH capacity of it.

As for what the user sees, the UPS will shutdown when it reaches a "low battery" which is a value in minutes. I think probably internally it also factors in that it shouldn't discharge the battery below a particular battery voltage though.

[BillP]

SU1400RMXLB3U

I measured the voltage at the battery connector before connecting the batteries up, 27.6 volts.

thanks

bill

[BillP · Accepted solution]

Thanks! I was able to look up the UPS user's guide and found it supports SU24RMXLBP2U.

Now, if we look at that (http://www.apc.com/resource/include/techspec_index.cfm?base_sku=SU24RMXLBP2U), it says:

Battery Volt-Amp-Hour Capacity - 864 - someone helped me to determine that 864VAH/24V = 36AH.

When I dug into the build instructions for the external battery pack SKU, just to double check, I see that the SKU actually has two battery strings in it and each string has qty (4) of BATTERY 12V 9AH. This is wired in parallel to give you a 12V 36AH battery string. So, seems as though 36AH per pack is accurate as there are two 12V strings wired in series to give you a 24V, 36AH battery pack.