Working out the number of amps your 1000 watt inverter uses can be a little confusing.
There’s lots of conflicting and complicated information out there.
That’s why I’ve written this article to give you the simplest answer possible.
This should help you to decide whether you can run your appliances with your inverter and battery set up or whether you need to upgrade.
I’ll answer those questions for you here.
How Many Amps Does A 1000 Watt Inverter Use?
At full load, a 12V 1000 watt inverter draws about 100 amps, and 24V 1000 watt inverter at full load is 50 amps.
Calculating the Amps Used By a 1000 Watt Inverter
So now you know that a 1000 watt inverter running at full capacity uses 100 amps, it is important to understand how this is calculated. This will help you to learn what you can run and how many amps you will draw with different devices connected.
The amount of amps drawn is due to the appliance that you connect, not the inverter itself. If there is nothing connected, then you won’t be drawing any amps (or very little, an inverter uses a tiny amount of energy for its own systems)
To find amps you need to divide the watt being drawn by the inverter voltage. Then you need to divide this by the inverter efficiency. Here’s the formula:
Watts ÷ volts ÷ efficiency = amps.
So for a full 1000 watt load it is:
1000w ÷ 12v ÷ 85% = 98 amps
The efficiency number of 85% is important as no inverter is 100% efficient, most are between 85% and 95% so I use the lower number to be safe.
You can use this formula on any load you want to draw. Let’s say you just want to know how many amps your TV will use on your inverter. Let’s say the TV uses 70 watts:
70w ÷ 12v ÷ 85% = 6.8 amps.
It’s that simple!
Now you know the amps you will be drawing you can easily work out how long your batteries will last.
How Long Will Battery Last on a 1000 Watt Inverter?
Now you know how to calculate amps you can quickly work out how long your batteries will be able to run with your chosen inverter.
We’ve just found out that a 1000 watt inverter will draw nearly 100 amps on full load for a 12-volt battery. That means it will use 100 amps of energy every hour or 100 amp-hours (Ah).
Battery capacities are measured in amp-hours (Ah) – for example, you can get 100Ah, 150Ah, 200Ah batteries.
So to work out how long your inverter and appliances will run you just divide the battery Ah by amps drawn.
Battery Ah ÷ Amps Drawn = Run time.
As we found out above, for a 12V battery, 1000 watts is 100 amps.
So the equation is: 100Ah battery ÷ 100 amps drawn = 1 hour.
Drawing 1000 watts from a fully 100Ah charged battery, a 1000 watt inverter would run for 1 hour.
The example of the TV above using 6.8 amps results in 14 hours of run time.
100 ÷ 6.8 = 14.7.
Conclusion on Amps of a 1000 Watt Inverter
That should give you a good understanding of how many amps a 1000 watt inverter draws.
It’s quite simple once you understand how to do the simple maths. You just divide watt drawn by voltage, then divide that by 85%. (The 85% just takes into account the efficiency of an inverter.)
So the max amps used by a 1000 watt inverter is – 1000 ÷ 12v ÷ 85% = 98 amps.
Thanks for reading.
