When to add battery pack and when to get a bigger UPS

[Anonymous user]

I am faced with the task of re-doing our server rooms UPS infrastructure. I have a rack with 2 SUA3000RMXL3U units for redundancy. I have about 11 servers in this rack. Each server has one power supply being fed by each UPS to prevent power loss in the event a UPS or circuit goes down. The problem that I have right now is that if one UPS does go down, all power will be transferred to one UPS and will probably overload the one UPS. Some things that I know:

Approximate power draw of the entire rack = 2900W
1 SUA3000RMXL3U supports about 2700W of equipment.

So I'm wondering if I can just add external batteries to these units to add power capacity, or if external batteries are only for extending the run time? Do I need to replace the SUA3000RMXL3U units with beefier UPS's like the Smart UPS 5000 or will adding an external battery to both units do the job and save me a lot of money?

[Anonymous user]

External battery packs only add runtime, not capacity. Do you know how much load the ups is reporting powering half of your load? If it is over 50% then you will need to either move some of the load to another ups or upgrade to a 5000VA ups or
larger.

APC does have a trade-up program you can use to get a discount on your new ups' and will cover the return cost of the old ones.

[Anonymous user]

yes load is over 50%. This is what I thought, but I wanted to get confirmation from someone else out there. Thanks!

[Anonymous user]

According to APC's web site the SUA3000RMXL3U is probably maxed out around 2200 watts.
Steve

[Anonymous user · Accepted solution]

Just to clarify, the original poster was correct that the maximum wattage the SUA3000RMXL3U can support is 2700.

However to avoid overloading the ups and possible other issues, it is recommended that you do not load the ups over 80%, which is about 2160 watts.