Need more battery capacity to run your inverter?
Well, the obvious way to achieve this is to simply connect more batteries to your power inverter.
But you’ve got to be a little careful!
Because there is a limit to how many batteries you can hook up.
And it depends on how you connect them all together.
So let’s go through the amount of batteries you can wire to an inverter, plus the best way to achieve your objective.
How Many Batteries Can Be Connected to an Inverter?
There is no set limit to how many batteries you can connect to your inverter.
But you must understand how you connect your batteries together affects what you can and can’t do!
For example, connecting your batteries in series will be different to connecting in parallel.
If you decide to wire your inverter batteries in series it will increase the voltage and limit how many you can hook up to your inverter.
Many people prefer to connect batteries and inverters in parallel. This is because there is less limitation on how many batteries you can connect to your inverter at once.
The other thing to consider is your battery charger. The bigger your battery capacity and overall amperage, the more powerful your battery charger needs to be. This can add limitations if you use an inverter charger rather than a separate charging unit.
But let’s look at each part of this in greater detail so you can work out what’s best for you.
How Many Batteries Can I Connect to Inverter in Parallel?
In theory, there is no maximum limit on the amount of batteries you can connect to your inverter in parallel. In reality, you don’t want to go wild as you will run into problems like the amount of charging energy you need.
The big benefit of connecting in parallel is that the voltage to your inverter remains the same while the overall energy capacity. So if you use 2, 5, or 10, 12V batteries the voltage would remain at 12V. This is important as your inverter will be designed for a specific input voltage – usually 12V or 24V.
For example, if you connect together two 12V 100Ah batteries the voltage remains at 12V but you now have 200Ah of battery capacity.
And that’s good, because if you want to use multiple batteries it’s probably because you want more battery capacity.
To sum up: Parallel keeps voltage the same but increases battery Ah capacity.
Charging Current
The only thing you need to check is the charging current. It is best practice not to exceed a battery capacity of more than 12 times the charging current. If you connect too many batteries you may struggle to fully charge them all!
For example, if you have a 25A charger you would simply calculate 25A x 12 = 300Ah battery capacity.
This might be restricted if you have an inverter with a built-in charger (inverter charger). I prefer to use a dedicated battery charger with plenty of amperage/current.
How to Connect Batteries to Inverter in Parallel
When you connect batteries in series to an inverter it essentially means that each battery is connected to the next via both positive and negative terminals. Here’s a diagram of what it should look like:
How Many Batteries Can I Connect to Inverter in Series
When you connect batteries in series the overall voltage of your system increases, it actually doubles! Adding to this, your battery energy capacity does ot increase as the electricity is flowing at a higher force.
If you connect together two 12V 100Ah batteries you end up with a 24V 100Ah capacity battery bank.
You must be very careful doing this as an inverter will have a specific input voltage such as 12V or 24V.
Let’s say you have a 12V inverter and try to connect two 12V batteries in series.
You should only connect in series if you need to increase the voltage rather than the battery capacity.
To sum up: Series increases the voltage but Ah capacity remains the same.
How to Connect Batteries to Inverter in Series
When you connect in series you connect one battery to another connecting the positive to negative terminals between batteries. A bit like people holding hands! Here’s a diagram of what it should look like:
How to Add More Batteries to an Inverter
To add more batteries to an inverter you need to check how your equipment is connected. You should assess whether the batteries are wired in series or parallel.
If they are wired in series, you won’t be able to add more batteries as the voltage will increase rather than the battery capacity. Your inverter is built for a specific input voltage and it won’t be able to cope with this wiring setup as we discussed above.
If wired in parallel then you can go ahead and hook up another battery in the same way – connecting the positive to positive and negative to negative terminals of the batteries. This will increase your battery Ah capacity while keeping the voltage the same. Just be sure you use the same voltage battery as the ones already connected.
Here’s a handy video to walk you through the process:
How to Calculate Battery Size for Any Inverter
You need to know desired runtime, wattage, and inverter voltage.
Runtime: This is how long you want your inverter and appliances to run.
Wattage: How many watts will your inverter draw? An inverter doesn’t always draw maximum wattage. The appliances determine how much power you use. For example, you might only draw 300W from a 1000W inverter.
Inverter voltage: This is the input DC voltage from the battery. Usually, this is either 12V or 24V.
With this information, we can do some easy maths. Let’s say we are using a 300W, 12V inverter and want to run for 5 hours.
- Multiply runtime x watts = total watts. – 5 hours x 300W = 1500W
- Divide total watts ÷ inverter voltage = total amps. – 1500W ÷ 12V = 125A.
So your total energy usage will be 125A to run for 5 hours. This means you need a battery with at least 125Ah capacity.
Protip: Never completely deplete a deep cycle battery so always use a bigger battery capacity than you need.
Can You Run an Inverter Without Batteries?
No, you can’t run a normal off-grid power inverter without batteries. You might be thinking of connecting directly to a solar panel, but this will deliver very poor performance. Your power output will be limited to what the solar panel can produce which will vary all the time.
The only exception to this is if you are using a grid-tie inverter which is designed for large home and commercial solar panel systems. These systems tie in with the mains grid electricity supply which helps to maintain a constant electricity flow from both solar and mains so no battery is needed.
Final Words on How Many Batteries Can Connect to an Inverter
I hope you now have a better understanding of how many batteries you can connect to your inverter.
It all comes down to the basics of how you wire up your batteries. If you connect in parallel you can have a battery capacity upto 12 times your charging current. So you can always use a bigger charger if you need. This is the best way to increase your energy capacity.
If you connect in series, you will be restricted to the voltage of your inverter. So once you wire up your batteries you can add any more. Plus you can only ever alter the voltage and not add any more battery capacity.
Thanks for reading.
