General question on Power Modules versus Battery Modules

[Anonymous user]

We have Symmetra rack mount solution in place in a small server room. Currently, it is fully loaded with 4 power modules and 3 battery modules and the intelligence module. We also have a slave unit attached with an additional 4 battery modules. I'm curious what the number of power modules determines as I'm considering changing the number of one versus the other in order to improve battery run-time in case of an outage. If its what I suspect is the case, and that the number of power modules determines just how much you can have drawing power through the UPS at one time, how best could I safely determine what our current needs in that server room are?

Charlie Arias

[BillP]

Hi Charlie,

So from your description, you have a Symmetra RM 6kVA and a 4-battery Extended Run cabinet. The main Symmetra chassis is fully populated with 4 SYPM2KU power modules in bays L1-L4, and you also have all three battery bays full of SYBT2, R2-R4.

You are correct that the number of battery modules determines the amount of on-battery runtime for a given load on the UPS.

The number of power modules establishes the amount of load the UPS can support while on-line or on-battery.

By default, the PowerViewRM display on your Symmetra will display data depicting the battery charge level, UPS load utilization level, Voltage In and Out, and Estimated Runtime.

Since you have 4 power modules, you can run the UPS at 100% load indefinitely while still having redundancy, since only 3 power modules are required to support a 100% 6kVA load. We would recommend you always maintain at least N+1 redundancy, so that UPS can remain online in the event a power module fails. Without redundancy, the UPS would have to go to bypass where you would have no battery back-up, or the UPS would have to shut down your load if a failure occurred while on-battery.

If your load is currently less than 67%, you could "trade" a power module for a battery module and still maintain redundancy. Battery modules can be installed in the L2, L3, and L4 bays in place of power modules. At any time, you can find your redundancy level by going into the Status menu on the PowerViewRM display. Scroll down to the page that shows UPS capacity and the # of power modules. This page will show your redundancy level.

You are welcome to simply purchase another Extended Run cabinet to increase your runtime if you would like to maintain your current level of redundancy.

[Anonymous user · Accepted solution]

Thanks for the explanation!

Charlie