Battery bank for UPS

Zombian,

Before you can get a descent answer to the question you need to provide some information.

1) What is the UPS Rating? (kVA)

2) What is the Load? (kVA)

3) What is your required Autonomy Time? (How long do you want to run on Batteries Only??)

4) Is it a 3phase UPS or Single Phase UPS?

5) What Voltage (DC) does the UPS support? (12,24,48...110,120,...500??)

These factors will all need to be provided to give you a reasonable answer?

Regards,
Sapper.

I think you better go through IEEE/ANSI publications on UPS sizing.

Regards.

1. Single units contain its own batteries [Bank] & is accrding to manufaccturers' / Users' accepted requirements. [Normally back-up for 20 minutes]

2. UPS Sytems with more than 2 Inverter modules [1 redundent], Sytem-Module & other Modules eg PFCorrection etc etc have 2 banks are expandable.

3. Bty banks capacity is calculated approx @ 75% of total KAH for back-up time.

Note: Such systems normally have Bty voltge = 500V for 220v 3Φ

Of any help?

We specify UPS systems as a part of our overall design of security systems. Since most of our projects are bid, we submit the requirements and allow subs to propose equipment that meet those requirements.

There are dozens of manufacturers who will supply ANYTHING you need. Just contact them and give them your load, voltage, uptime requirements, etc. They will provide correctly-sized equipment, and you don't have to run any calculations yourself.

Sometimes it's better to take the easy way out.

You have received great comments from experienced people from all over the world.

Here are some items you also need to determine.

1. How critical is your load?

2. Is your utility reliable and do you need a generator to back-up your UPS?

3. Is operating GREEN important in your area? If so, consider a flywheel UPS instead of a static UPS. Going Hybrid is great for the environment, reduced maintenance and battery replacement cost.

I hope this contributes to what you're looking for.

The battery bank configuration is dependant on the DC bus inside the ups. The batteries should all be the same and must be arranged in strings equal to the DC BUS voltage. If you have a 480v dc bus and are using 12v batteries you will need 40 batteries in series for 1 string of batteries. You can also parrallel multiple strings to increase run time. All strings should be breakered. The Amp-Hour(AH) rating of the batteries will determine how long the ups will be able to maintain the load, the higher the AH rating the longer the runtime on battery (assuming the loads power draw is held constant). The ups charge / discharge characteristics curves varies between different battery types and ratings. The ups should be programmed with these curves for best performance. The best solution is to go back to the ups manufacture and get their recommend batteries for replacement.

this is the accurate comment you can count on. DC bus voltage decides No. of batteries and total volt to match DC Bus. Back up time decides AH. Battery manufacturers as well as UPS manufacturers publish tables to choose from to meet the back up time required.