if you have a 100Ah battery and are curious about what size inverter will be suitable for your 100Ah battery so you came to the right
in this article, I’m gonna share a few points to keep in before sizing the inverter for your battery
in short, You can use a 300-1000W inverter with a 100Ah battery but the size of the inverter will depend on the total output AC load
Now let’s discuss some factors which can play an important role before sizing inverter size for your battery
How to determine inverter size according to battery size
First of all, calculate the total AC load which you would like to run on the inverter
if you’re looking to run some basic appliances like TV (50W), LED bulb (20W), charging phone (5W), laptop (100W), & ceiling fan (150W). The total load of these appliances will be 325 watts
so minimum you’ll need a 350w inverter to run your appliances along with a 100Ah battery
A rule of thumb is to add 25% to the total AC load when sizing inverter. the extra 25% is added because of safety factors because solar inverters are not 100% efficient the common efficiency rate in inverters is 85% which means a 100W inverter will consume 115W DC power from the batteries in order to run 100W AC appliancs
so if you’re using a 100W invretr to run your 100W AC appliances but the inverter will be producing 85W AC power or in somecase it’ll be working beyond its full capacity which can damage the inverter or even your appliances
Most of the gurus suggest doubling the watt size of inverter then your total load is, but what i have experience and which is most sweet spot is adding 25%
The size of the inverter is usually calculated according to the total AC output load. You can use any size inverter with your battery in relation to output AC load.
For example: if want to run a 1000W AC load with your 100Ah battery so you’ll need a 1200W inverter which will fully drain the battery in an hour
Solar panel size & inverter size (What’s the relation)
So if you’re charging your battery while connected to an inverter then the size of solar panels will play a role in sizing the inverter
Yes, you can connect a large size inverter with your batteries but it’ll only draw high watts if the battery is fully charged
But what if you have a lead-acid 100Ah battery and has DOD at 50% which means only 50% charge is remaining and you can’t draw your battery below then 50%
so in this case the size of solar panels and how much power they are producing will determine how much you safely draw from your battery.
Let’s say you have two 200W solar panels connecting in series and the total output DC power you’ll get from your solar panels per hour will be 320W. So the maximum number of AC load you can connect with your battery should be 272 AC watts (320 – 15% inverter efficiency)
in this case, you’ll need a 350W inverter to run your 270W AC appliances with your 100Ah battery
why is this relevant? If you don’t like to charge your batteries and wanna use the power right away then calculate the size of an inverter according to the size of your solar panels by doing this if accidentally add some extra appliances with the inverter it will simply turn off without drawing the battery below it’s DOD limit
you may not need this information but wanted to add someone of you may need it.
Video – Pure sine wave Vs Modified sine wave inverter
Tips on using inverter
- Use a pure sine wave inverter which provides the most smooth output power which will reduce the chage of getting your appliances damaged
- Choose a right size cable, thicker the cable is better it is because you’ll face current if you’re using a low quality of thinner cables
The size of the inverter for 100Ah will depend on the total output AC load and then add 25% to the output AC load.
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