1. UPS Battery Battery Sizing
Paolo Frisoni
Application Engineer, DPG
Liebert Hiross UPS

2. Battery Sizing Type of batteries used in DPG UPS
Batteries for extended runtime
How to assess backup times and size extra batteries
Special requirements (NiCd, 10 Years)
Other requirements

3. Battery Sizing Battery Used for micro UPS / On-Line
For GXT2-3000RT230 a 15 Amp. 72V Battery Charger (same look) is available its PN is: GXT2-1000RBC.072

4. Battery Used for micro UPS - Off Line
Battery Sizing
Battery Used for micro UPS - Off Line

5. Battery Used for small UPS
Battery Sizing
Battery Used for small UPS

6. Battery Sizing Battery Used for Micro & Small UPS
The most part of our products use :
Valve regulated lead-acid battery 5 Years of life
Blocks of 12Volt (6 cell on each) with 7-7.2Ah
The dimension are standard for different supplier but the terminals must be Fast-on 6,3 mm
Hinet and its Batt.Cab. can be supplied without internal batteries. The internal Batt.Charger provide Amp
A complete Kit of Battery cable can be provided for the internal connections (HNBATTCABLE)
The GXT 5&10kVA can be supplied without internal Batteries the PN is GXT5000T-230NB & GXT10000T-230NB with improved Battery Charger (4,5Amp)

7. Battery Sizing Battery Used for 10 Years Applications
For special requirements like 10 Years Battery
for 12V 7Ah Blocks
The NP7-12 (Yuasa) can be replaced with the RE7-12 the increasing cost is 70%
for 12V 38Ah Blocks
The NP38-12 (Yuasa) can be replaced with NPL cost increase 15%
for 12V 65Ah Block
The NP65-12 (Yuasa) can be replaced with NPL cost increase 15%

8. Battery Sizing Ambient Temperature Number of Charge/Discharge Cycles
Key Factors in Battery Life
There are 4 factor that strongly affect the Battery Life
Ambient Temperature
Number of Charge/Discharge Cycles
Deep discharge
Floating Charge Temperature

9. Battery Sizing AMBIENT TEMPERATURE
Effect of the Temperature on Lifetime

10. Battery Sizing Number of Charge/Discharge Cycles
Depend on number of Deep Discharge Cycles (%)
We will reach the DDL only when the Main fail last more than the UPS autonomy

11. Battery Sizing Deep Discharge
The lowest recommended Voltage Under Load were the Battery can works or Cut off Voltage
Below this limit Battery will be damaged
UPS Topology also lead to cycle on to battery operation frequently
OFF-LINE Worse
LINE INTERACTIVE Less Worse
ON-LINE Best Behaviour

12. Battery Sizing Deep Discharge
Some UPS the Cut Off voltage can be adjusted, like Hinet (The default Value is 1.66 V/cell)
Some others UPS this Limit change automatically with the load (all GXT series)

13. Battery Sizing Float Charge Voltage versus Temperature
Float Charge Voltage need to be maintained between 2.275V/cell +/ (at 20°C)
For Hinet is adjustable (factory set to 2.25 V)
For GXT is Fixed to 2.3V
Optimisation will be reached when this value is adjusted with temperature :
at 0°C V/cell = 2,35V
at 40°C V/cell = 2,15V
Hinet --> next step
Improvement

14. Design Criteria Run Time Calculator
This Tool perform the calculation of Run Time of the UPS for a given:
Power of Load (kW)
Battery Capacity (Ah)
It work on Excel
It is based on the Lead Acid Discharge Curves
it optimise the calculation of autonomy time for the battery that is considered working down to Deep Discharge limit for a given current
gives tested results

15. Design Criteria Run Time Calculator
The Standard Capacity nominal value of a battery is for 20 Hours of discharge time to a final voltage of 1.75V per cell
The nominal capacity of a battery is reduced when is discharged at value of current that exceed the 20-Hour discharge rate
That means the real Capacity you can extract from the Battery is: k * C where is a reduction coefficient k < 1
How does the Calculator works:
Input:
Load Power (kW)
Battery Capacity (Ah)
Nominal Battery Voltage
Output :
the Run Time for the assigned Capacity (Ah)

16. Design Criteria
Run Time Calculator

17. Design Criteria Run Time Calculator
It performs the calculation of the Battery Current:
Then the Ratio of the Battery Current and the Battery Capacity
This value is Located On the Deep Discharge Characteristic this is a non linear passage , the K coefficient is so detected

18. Design Criteria Run Time Calculator
Finally the Run time is calculated Like :
Output

19. Design Criteria Run Time Calculator Accuracy
GXT Internal Deep. Disch. Char.

20. Battery Sizing
Some Autonomy Data

21. Battery Sizing
Some Autonomy Data

22. Battery Sizing
Some Autonomy Data

23. Battery Sizing
Some Autonomy Data for GXT x 240VBATT Batt.Cab.

24. Battery Sizing
Some Autonomy Data for GXT + 240VLRT Batt.Cab.

25. Battery Sizing
GXT6000 (1x1 & 3x1) can be extended with the limitation of two Cabinet 240VBATT max for Thermal reason
GXT8000 3X1 & GXT10000 (1x1 & 3x1) can be extended either with Cabinet 240VBATT and Cabinet 240VLRT
The max numbers of Cabinets depend by the allowed recharging time ( the Batt. Charger rating is 1.5Amp)
If more than two Cabinets 240VLRT are necessary then is recommended to use the GXT5000T-230NB & GXT10000T-230NB with improved Battery Charger (4,5Amp) But they are not CE certified

26. Battery Sizing
Some Autonomy Data for Hinet with Batt.Cab.

27. Battery Sizing Ni-Cd Battery
Some application require high life despite of the price (Very High Price !!)
The Voltage/Cell for Ni-Cd Batt. change like this:
1,4 V/el in Floating
1,07 V/el in end of Discharge
If you have an UPS design with Lead Acid Battery to switch with Ni-Cd is necessary to increase the Number of Cells in the same ratio as the V/el
For instance Hinet requires 192 Cells in Pb and for Ni-Cd 192* (2,25/1,4) = 308 Ni-Cd Cells

28. Battery Sizing Ni-Cd Battery
The Low Battery Limit must be adjusted in the same way
308* 1,07 = 329 Volt
Hinet allow to easily adjust these limits so it’s open to be supplied with Ni-Cd Batteries.
The recharge current for Ni-Cd Battery must be well regulated
The Hinet Battery charger feed a constant current that can be Amp up to Floating Point were the Float voltage will be held Fixed.

29. Nfinity Extended Batt. Cabinet
This Cabinet Allow to use the same Intelligent Battery Module of Nfinity frame
P/N is N900Exx00000
It is a Matching Cabinet
Need two Intellislot Battery Card (IBC),
1on Nfinity, 1 on the Cabinet + serial cable for communication
2 shipped with each Extended Battery Cabinet
The DC Power connection cable
P/Ns: NPNPEXTBC3, NPNPEXTBC15
These include specially designed connectors
In the UPS configuration Menu select :
Change Settings (press <Return>)
Intellislot Battery Cabinet (press <Return>)
enter the quantity of extended Battery Cabinet installed
press Return and ESC

30. Nfinity External Batt. Cabinet
Can 10 years batteries be used?
Not inside the main UPS Frame
Only 5 years Battery Modules are designed for Nfinity UPS
By using the External Battery Cabinet:
New version has same front bezels as Nfinity
Cabinet type: CZ1 Size 90Ah/120V with Battery Charger
Batteries Used are Power Batteries SLF12105
Note the difference between: External Battery Cabinet and Extended Battery Cabinet
External BC is not an “Intelligent” backed up Battery
does not use Nfinity Battery Modules
the Battery Module will not disconnect from the others when a failure is detected

31. Battery Sizing
EXTERNAL BATTERY CABINET CZ1 the Old and New one

32. Battery Sizing Where is the Battery charger ?
located in the Power Module
the charger has a temperature compensation with a current limited to 3,2A
Others functions of the Power Module are:
Power Factor Correction Circuit working with PWM at 20kHz.
Input Power Factor close to 0,99 (see following slide)
Output Inverter
Starting from version G3 (mid-2002) :
Able to accept three phase and single phase input line
Older G2 modules cannot be fitted in new 3x1 frames

33. Thank you for your attention
For more questions contact:
Product Support Desk on