Yelantra_logo
 
 
Experiment
Battery Sizing

Introduction: To derive maximum performance benefit from a UPS battery it is important to pay attention to the sizing details and selection of battery type. Equally important are the installation practices employed. An attempt is made here to provide some insight into these aspects.

Battery Selection: There are two steps to calculate the battery Ah capacities for UPS application or single load duty requirements.

  • Load current (Idc)
  • Ah capacity calculation.

Load Current:

  • IDC = KVA rating x Load Power factor x 1000
  • End cell Voltage/Avg. Discharge Voltage x Number of cells x Inverter efficiency
  • Note: Load current can also be calculated if the rating is given in watts as below: IDC = Watts/system DC voltage

Ah Capacity Calculation:Ah = IDC x K-factor x Design margin x T- factor x Aging factor

  • K-factor: Depending upon the End Cell Voltage & Back-up duration, the k-factor shall be selected to arrive at the required capacity at standard rate of Discharge and these factors are manufacturer dependent.
  • T-factor: Necessary Temperature correction factor needs to be considered for temperatures below 27°C to support the duty cycle requirements even at low temperature operation. You may also refer the manufacturer published data for this purpose.
  • Aging factor: In line with IEEE recommended practice of sizing Lead storage batteries, it is recommended that a battery be replaced when its actual capacity drops to 80% of its rated capacity. Therefore the battery’s rated capacity should be at least 1.25 times the load expected at the end of its service life. This factor of 1.25 is known as aging factor or life factor (L).
  • Design Margin: It is prudent to provide a capacity margin to allow for unforeseen additions to the DC system and less than optimum operating conditions of the battery due to improper maintenance, recent discharge, temperature variations or combination these factors. A method of providing this design margin is to add 10% to the cell size determined by calculations.Choose the nearest highest capacity available from the range based on the calculated Ah capacity in the above steps.
top

Quanta Constant Power Discharge Ratings in Watts per Battery.

1.8 ECV Duration
 MODEL 5 min 10 min 15 min 20 min 30 min 60 min 2 hrs 3 hrs 5 hrs 8 hrs 10 hrs 20 hrs
 12AL026 910 638 498 408 302 193 116 79 53 34 29 13
 12AL042 1395 1010 800 672 505 305 180 130 89 58 50 23
12AL065 2270 1595 1250 1025 775 475 295 210 142 93 80 36
 12AL078 2582 1888 1521 1246 934 534 335 253 170 111 96 47
 12AL084 2747 2008 1618 1326 994 568 357 270 181 119 102 50
 12AL100 3310 2420 1950 1598 1198 685 430 325 218 143 123 60

1.7 ECV Duration
 MODEL 5 min 10 min 15 min 20 min 30 min 60 min 2 hrs 3 hrs 5 hrs 8 hrs 10 hrs 20 hrs
 12AL026 1010 707 538 440 320 202 118 80 54 35 30 14
 12AL042 1555 1092 842 693 520 320 185 132 90 59 50 24
 12AL065 2520 1763 1351 1095 825 504 302 213 145 94 81 37
 12AL078 2863 2067 1680 1295 967 569 348 257 175 115 104 47
 12AL084 3046 2199 1789 1378 1029 606 370 274 187 122 104 51
 12AL100 3670 2650 2155 1660 1240 730 446 330 225 147 125 61

1.6 ECV Duration
 MODEL 5 min 10 min 15 min 20 min 30 min 60 min 2 hrs 3 hrs 5 hrs 8 hrs 10 hrs 20 hrs
 12AL026 1067 716 557 456 340 211 120 82 56 36 30 15
 12AL042 1639 1136 882 715 565 330 192 134 91 60 51 25
 12AL065 2645 1710 1400 1122 852 515 310 215 147 96 82 38
 12AL078 3042 2143 1761 1322 1032 589 358 262 181 118 99 48
 12AL084 3237 2281 1874 1407 1098 627 381 279 192 125 105 51
 12AL100 3900 2748 2258 1695 1323 755 459 336 232 151 126 62
top
Powered by iVision