The inverter and determine the required capacity
- Calculate the battery power to the inverter (i.e. the battery voltage) * AH.
- Time = (converter efficiency * battery voltage * AH) / load in watts)
How to calculate the size of the battery
- Load = 1000W (it can be calculated here using our previous guide, or it can be the maximum capacity of the inverter)
- ASI input = 24V.
- Travel time required = 1.5 hours.
- UPS efficiency / power factor = 70% or 0.7 (use this if you don’t want to estimate it)
- Battery type = lead acid (therefore an autonomy factor of 1.
Here’s how to size an inverter
- List all the devices you want the UPS to protect.
- Enter the amps and volts for each unit.
- Multiply VA by the number of devices to get VA subtotals.
- Add the VA subtotals.
- Multiply the sum by 1.2 to get the sum.
- Use the grand total to select an inverter.
The key is to use the watts you know to calculate the amps at the battery voltage. For example, suppose you want to power a 250 watt 110 VAC light bulb through an inverter for 5 hours. Amp hours (at 12 volts) = watts / 12 volts = 1470/12 = 122.5 amps.
Usually the manufacturer specifies the maximum emission. This is to ensure that the battery is not charged. What you need to understand is the Ah device. If a battery is 150 Ah it means it can deliver 150 amps for 1 hour, 300 amps for 30 minutes, and so on.
Remember, you will need a battery that will provide 3 hours of backup. So a battery with a capacity of 130 Ah is right for you. So if you want to run 3 fans, 3 fluorescent lamps, 1 energy saving lamp and 1 TV for 3 hours in the event of a power failure, you need an 800VA inverter and a 130 Ah battery.
A UPS battery is the most vulnerable part of the system. UPS applications use many different types of batteries, but lead acid (LA) batteries are the most widely used technology today. In special cases with special requirements, nickel-cadmium or lithium-ion batteries are sometimes used.
UPS. (Uninterruptible Power Supply) A device that provides battery backup in the event of a power failure or drop to an unacceptable voltage level. Small UPS systems provide enough power for a few minutes to shut down the computer properly, while larger systems have enough battery for several hours.
Once the load and driving time have been determined, the size of the battery bank can be calculated. The first calculation is to divide the load (in watts) by 10 for a 12 volt system or by 20 for a 24 volt system, which provides the required battery bank amplifiers.
at 1800 watts
The 200AH battery can be charged at 200A for 1 hour, 100A for 2 hours or 10A for 20 hours.
Converting Amp hours to Watts
Reference Design Calculator
You can take your car’s battery CCA rating number and multiply it by 0.7 - if you have a CCA of 600, you get about 420 in AH. You can reuse the car battery’s AH rating number and multiply it by 7.25 - if you have 100 in AH, you get about 725 in CCA.