Understanding amperage for different inverter wattages is crucial for safe and effective use. It determines how many devices you can power and how long your inverter can function. In this article, let’s explore the inverter amp draw calculator for 1000W, 1200W, and 1500W.

**Inverter Amp Draw Calculator**

To calculate the amp draw for inverters at different voltages, you can use this formula

**Maximum Amp Draw (in Amps) **= ( Watts ÷ Inverter’s Efficiency (%)) ÷ Lowest Battery Voltage (in Volts)

Let us see an example of an inverter amp calculator for a 1500-watt inverter

**1500 Watt Inverter Amp Draw Formula**

The maximum current drawn by a 1500-watt inverter is influenced by the following factors:

- Inverter’s Efficiency
- The voltage of the battery at its lowest

**Maximum Amp Draw for 85%, 95% and 100% Inverter Efficiency**

**A. 85% Efficiency**

Let us consider a 12 V battery bank where the lowest battery voltage before cut-off is 10 volts. The maximum current is

= (1500 Watts ÷ Inverter’s Efficiency (%)) ÷ Lowest Battery Voltage (in Volts)

= (1500 watts / 85%) / 10 V **= 176 amps**.

**B. 95% Efficiency**

Let’s consider a scenario for a 24V battery bank where the lowest voltage before cut-off is 20V.

Now, maximum amp draw (in amps)

= (1500 Watts ÷ Inverter’s Efficiency (%)) ÷ Lowest Battery Voltage (in Volts)

= (1500 watts / 95% ) / 20 V **= 78.9 amps**.

**B. 100% Efficiency**

In this case, we will consider a 48 V battery bank, and the lowest battery voltage before cut-off is 40 volts. The maximum current is,

= (1500 watts / 100% ) / 40 **= 37.5 amps**

Therefore the 1500W inverter’s efficiency (at maximum load) is approximately 85%.

Also, to determine its run time, check out How Long Will a 1500 Watt Inverter Run?

The efficiency of the inverter is not always 100% but sometimes 80%, 85%, and 90%, this is because it depends on the inverter type and design, load level, input load level, and manufacturing types. Inverters with a greater DC-to-AC conversion efficiency (90-95%) draw fewer amps, whereas inverters with a **lower efficiency (70-80%) draw more current**.

**Note: **The results may vary due to various factors such as inverter models, efficiency, and power losses.

**Watts to Amps Converter Calculation for 750W, 800W, 1000W, and 1200W Inverters**

Here is the table showing how many amps these inverters draw for 100% and 85 % efficiency. In reality, inverters have some efficiency losses, and the actual amp draw might be slightly higher. The lowest battery voltages taken for 12V, 24V, and 48V battery banks are 10V, 20V, and 40V respectively.

Wattages | Voltage | Amps drawn for 100% Efficiency | Amps drawn for 85% Efficiency |

750 Watts | 12 V 24 V 48 V | 75 37.5 18.7 | 88.2 44.1 22.05 |

800 Watts | 12 V 24 V 48 V | 80 40 20 | 94.1 47.05 23.5 |

1000 Watts | 12 V 24 V 48 V | 100 50 25 | 117.6 58.82 29.4 |

1200 Watts | 12 V 24 V 48 V | 120 60 30 | 141.17 70.8 35.2 |

You can also use this Inverter Battery Calculator app to find out the required amps for different wattages. The app is also useful for battery charging time, current, and voltage calculations.

**Note: **The results may vary since the app shows data for 100% inverter efficiency and does not account for power losses.

**Also See:** How Much Power Does An Inverter Draw With No Load?

So, we can use an inverter amp draw calculator and figure out the average amperage for a particular battery voltage. Additionally, considering factors such as inverter efficiency for various wattages and no-load power consumption, you can confidently power your devices while ensuring the longevity of your inverter. To access more such interesting content, keep exploring our website.