Whenever you plan to buy an inverter battery, there is a desire to know some important information in your mind. Like how much will be the backup of the inverter battery, how many hours of backup will be available for how many ah batteries, etc. In this informative information, here you will know the backup time calculation formula.
Backup Time Calculation Formula:
Backup Time = Battery Capacity (in Ah) * Battery Voltage (in V) * Battery Efficiency (in %) / Connected Load (in W/h)
For example:
Case 1: Lead Acid Battery
If you have any capacity of lead acid battery (80Ah to 200Ah), then you can calculate battery backup time as per below example. I have taken here the most popular inverter battery 150Ah battery. When we calculate battery backup time of any type of battery, we ideally use 400-watt home load, so the connected load is 400 watts per hour. Let’s calculate backup time now:
Backup Time = 150Ah * 12V * 0.75 / 400 W
= 1350 W / 400 W
= 3.3 hrs.
Note: An efficiency of lead acid battery is approx. 70% to 75%
That means, if we run 400-watt home loads on 150Ah inverter battery, then it gives approx. 3 hr. 30 minutes backup time. Depending upon backup time, you can choose battery capacity.
Case 2: Lithium Battery
If you choose a lithium battery for home inverter such as 100Ah, 12.8V, then you can calculate backup time as per above formula. All parameters will be same, let’s know backup time of lithium battery:
Backup Time = 100Ah * 12.8V * 0.98 / 400 W
= 1254 W / 400 W
= 3.13 hrs.
Note: An efficiency of lithium battery is approx. 95% to 98%.
That means, if we run 400-watt home loads on 100Ah lithium inverter battery, then it gives approx. 3 hr. 15 minutes backup time. Like this example, you can calculate backup time of CAML 100, 5kWh lithium inverter battery.
Source: Himanshu Chaprana, Student of B. Tech (Electrical & Electronics Engineering) - Manav Rachna International University, Faridabad, Haryana
हिंदी में पढ़ें: जानिए अपने Inverter Battery Backup Time को कैलकुलेट करने का तरीका!
15 comments
Syed
Goal: zero grid power. Our monthly consumption is 250KWH/month (Summer) 300Kwh/month winter. Karachi gets has low cloud cover, low rainfall. Utility Sanctioned load for the house is 6 KW, With no AC max monthly demand is 2.5KW. Also have 3KVA genset and 1.5KW UPS will remain as back up of solar. How many bifacial PV – 585W plates would we need for 6KW capacity, and how much battery cap. I am estimating 260×2 lead acid batteries. Our current monthly bill 25K. Simple pay back of 31 months. Do these figures make sense or is there anything significantly wrong. Your guidance is appreciated.
Arun Abraham
You can calculate backup time using the tool. https://backupcalculate.com
Ntege Willy
FM Radio Broadcasting Equipment, 8KW and 4KW Transmitter systems for two sites and at each location there is 12000btu Air Conditioner (3516w power capacity), I do need a Quotation for Grid Solar Inverter Battery Bank System for FM Radio Broadcasting.
Ntege Willy
FM Radio Broadcasting Equipment, 8KW and 4KW Transmitter systems for two sites and at each location there is 12000btu Air Conditioner (3516w power capacity)
Abdul aziz from pakistan
V good sir
Babul nath
My 1 one 5 ⭐inverter AC 8 fan 12 watt 20 nos. Who mach Requirement Microtek inviter
200Ah ×36 V ups 3750va
Babul nath
My 1 one 5 ⭐inverter AC 8 fan 12 watt 20 nos. Who mach Requirement Microtek inviter
Adeyinka Adetola
How to calculate backup time of lithium battery. And how to determine capacity of inverter to charge lithium battery?
JOEY AJAINO
but this is how I calculate mine, in lead Acid/tubular battery,
battery (ah) x battery (v) / load… =backup time in hrs
For lithium battery 15kwh/2000w(load) =7.5hrs backup time…
Ch.poojitha
Battery backup calculation
joy halder
how do i calculate battery backup time for two batteries each 100Ah 12.8v lithium connected in series with a load of 5000kwh
Ssali
Hello Eng. How can I calculate the backup time for 2 batteries connected in series, 200ah/12v lead acid, supplying a load of 450w. Thx
Ssali
Hello sir , how do I calculate battery backup time for two batteries each 200ah, 12v lead acid connected in series with a load of 450w?
Padmaraja Jinnappa Dulappanavara
Looking for laptop UPS backup
Syed afaq
Hi sir . Plz tell me about battery .
My load DC 5 amp. And run it about 7hors .
Battery capacity??