If you plan to connect a 1,500 watt inverter to a battery bank to power your home appliances while out camping in your RV, van, or van then you need to select the right gauge of wire and corresponding fuse rating for your installation to perform optimally and safely.
In this post, you’ll find helpful wire size and fuse information for your 1,500 watt inverter.
The Battery to Inverter Wire Gauge (AWG) for a 1,500 watt Inverter
For a 1,500 watt, 12V inverter (up to 6 ft of cable)
As a guide, use a minimum of 2 AWG wire to connect the 1,500 watt, 12V inverter to the battery bank up provided the cable lengths are up to 6 ft.
For a 1,500 watt, 24V inverter ((up to 6 ft of cable)
If the inverter is a 1,500 watt, 24V, use 4 AWG up to 6 ft of cable. Note: In general, these are minimal cable sizes and you can use thicker gauges however, they are thicker, more difficult to bend or connect, and are more expensive.
How to Choose a Wire Gauge for your Inverter
The actual gauge of wire you use depends on the battery bank voltage, cable length, and the acceptable voltage drop.
Therefore using a higher voltage allows you to use thinner (higher AWG), less expensive than a lower voltage. Longer cable lengths also require the more expensive and more difficult to use with a lower gauge to minimize the voltage drop.
Keep the inverter to battery cable lengths as short as possible to minimize voltage drops.
What Gauge of Wire to Use for various Battery Cable Lengths?
Depending on the location of the battery and inverter, you may need to extend the inverter to battery cable length.
Note, that you’ll need to change the wire gauge accordingly to minimize the voltage drop and ensure that your inverter continues working reliably and safely.
#1. First, work out the DC current draw of the inverter. Use the formula, current draw (amps) = (power rating of the inverter/ battery bank voltage) x inverter efficiency.
For a 1,500-watt,12V inverter with an estimated efficiency of 80%, using the formula, the current draw is about 157 amps at maximum power.
#2. Use a chart to select a suitable wire gauge depending on the inverter current and length of battery cables you plan to use. One such chart you can consider is Windynation’s load amperage chart.
As an example, using the chart for a 1,500 watt, 12V inverter, for 10ft of cable you need 1/0 AWG compared to 2 AWG for 2 ft of cable.
Always keep the battery cable lengths as short as possible to minimize voltage drop and avoid using the more expensive thicker cables at are also difficult to work with (bend).
What Gauge of Wire to Use on the AC Side?
You can use 14 AWG or larger for the inverter to appliance cable for the estimated current draw of 13 amps from the inverter at maximum power. 14 AWG has a current carrying capacity of about 15 amps.
You can work out the current draw of the AC side using the formula: inverter power(watts) / inverter AC voltage AC, i.e. 1,500 watts/ 115V, or 13amps.
In addition to selecting the suitable wire gauge, you’ll need to select a fuse size on the DC side. The rating of the fuse selected should be sized to protect the wire from excessive current draws.
The Dangers of undersizing your cable lengths
if you use thinner or higher AWG battery cables than recommended the cables will overheat and burn causing a fire risk that can damage other equipment.
Additionally, undersizing the battery cables causes voltage drops that reduce how much DC voltage is available at the inverter which can cause the inverter to shut down.
Fuse rating (amps) for a 1,500 watt, 12V Inverter
You can use a 250 amp DC fuse to protect the 2 AWG battery wire. The fuse should be connected to the positive battery cable as close as possible to the battery.
Use 2 AWG wire for the battery cables for your 1,500 watt, 12V inverter. If it is a 1,500 watt, 24V inverter, you can use the thinner and less expensive 4 AWG.
This assumes that the cable lengths are up to 6 feet long. For longer cable lengths, you’ll need to use thicker (lower AWG) cables to minimize voltage drop.