Advice on extending run time

[EdInAus_apc]

This was originally posted on APC forums on 1/3/2016

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Afternoon All

I am in regional QLD and we have a small data centre which is a demountable building (that part is important bear with me), we have three racks and 3 Smart UPS 3000's as our UPS's devices. these only have s short run time but it is usually enough to get the generators up and running before they fail.

I have been asked to look at taking our UPS run time to 12 hours, This is not in my usual domain of support but i am grabbing the ball and running with it.

Now i know we can get larger batter packs and even though we have the room for them (I could fill almost a whole rack with batteries) we are concerned about the extra weight as the building is a generic demountable. 

I don't have the budget (or available down time) to move/upgrade buildings so i am wondering if there are large external (preferably suitable for outdoors use) battery packs that I could have mounted outside the DC then run IP66 rated cables to the UPS's  or even replaces the rack UPS's with two outdoor units supplying two separate circuits connected to the rack power rails.

I am open to better suggestions.

Thanks

[MarkC_apc]

This was originally posted on APC forums on 1/4/2016

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My experience with APC (Schneider) UPSs is in the area of re-purposing used SMART UPSs for "renewable" energy systems, i.e. solar systems combined with large battery banks for "off-grid" emergency backup.  Some observations;

APC units are robust with high quality components - specifically designed (by their microprocessor programming) for relatively short backup power supply to allow an orderly shut down and/or turn on a generator for long term power supply.

They handle large auxiliary battery backup systems (that are properly designed), however, their microprocessor systems are not equipped to provide the correct battery condition information (remaining run time, % battery remaining, etc).  This makes them unacceptable for most "critical" system backup services using non-APC battery designs.  Schneider may comment on this limitation???

The available NMC's are powerful and can be used to provide data that is useful to monitor the battery energy usage.  However, this requires a development and testing protocol to ensure your UPS/battery system will back up your "critical" users and also properly monitor a large battery bank.

A casual observation is that you need a high reliability generator system to provide the specified 12 hours backup - if you have any significant loads.  

I'd be interesting in any "expert" comments on this concept as it is foundational to a significant recycle/reuse of literally thousands of UPSs in a less critical service - rather than being sent to the recycle pile. 

[voidstar_apc]

This was originally posted on APC forums on 1/4/2016

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Other factors to consider:

- Be sure to ask sales support how long it will take to charge your desired number of batteries. There is no limit to the number of external battery packs you can use according to the manual, however runtime estimation only recognizes up to ten, but more importantly, the battery charger in the SMX3000 (I can't find the specs for this on APC's website) may not be able to provide a suitably fast charge for so many batteries. Therefore you might need to rig up an external battery charger. Or you could use a higher power UPS model such as a Symmetra with a larger battery charger.

- Batteries are a consumable lasting 3-5 years under good conditions, less if you regularly discharge them or expose them to high temperatures. I mention it because people who want 12 hours of runtime might be experiencing regular outages which will be murder on the batteries, and also you may want to price out the cost of replacing so many batteries.

- Generators are the usual solution for longer runtimes.

- Schneider offers some solutions based around shipping containers that can be placed outdoors. You might ask them if they have any for your needs.

[BillP · Accepted solution]

This reply was originally posted by Mike on APC forums on 1/4/2016

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I thought that the Smart-UPS of that size typically had a recommended maximum battery string of around 10 external packs ?

I would have imagined you'd be looking at Symmetra-PX and upwards to get the combination of run/charge-time and external battery location.

The run-time charts on their website should give you a guide as to how far you can expect to go with each model.

However, as mentioned above, for outages of that length a battery solution is perhaps not the best option.

I'd be looking more to generators for that, and ensuring there is enough battery run-time to cover short outages where its still economical/practical to use them.