So, you're planning to travel off-grid. You want to pack your home comforts, like a laptop, coffee machine and other AC and 240V appliances. Now you need to work out the most convenient way to run them.
Use a DC to AC inverter from your battery system.
But you can't just buy any inverter. You need to choose the right size for your camping or caravan set-up.
Here's how to do it:
Step 1: Match The Inverter To The Load
Add up the total wattage's of each of your appliances that you want to run at the same time.
Think about your average day - which appliances will you run simultaneously?
More important than their total watts is their initial start-up needs, AKA their peak watts. For example, anything with a pump, compressor or motor will typically have a higher peak power draw than listed in the product specifications.
Sure, it's only for a short time, but your inverter still needs to handle that peak demand. If it can't, the protection system will shut down the inverter, or in the case of a cheap inverter it could cause damage.
Another easy way to mitigate this is to stagger when you turn on appliances. In other words, don't switch them all on at the same time!
To give you an example, lets say you want to make a cup of coffee. When you first turn your coffee machine on it draws around 1300-1800 Watts (depending on your machine). It then drops down to almost nothing between cups.
Then when you go to make another round the power draw spikes back up to around 1300-1800 Watts. Now this is adequate enough if you are only going to run your coffee machine and nothing else.
But if you also want to make breakfast and run other appliances at the same time then you will need a larger inverter.
Step 2: Ensure Your Battery Bank Can Power The Inverter
So, you've sized up your load requirements. Now you need to make sure your battery bank is large enough to power the inverter.
Our rule of thumb for lithium deep cycle batteries?
For every 100Ah of deep cycle battery, you can power a 1000W DC to AC Inverter. But there are a few exceptions..
Take a look at these examples:
2x 200Ah Renogy Lithium Batteries connected in parallel are perfect for larger caravans
Pro Tip: Be wary of cheap lithium batteries advertised online - they are unable to meet the standards set by leading quality brands of batteries with trusted specifications.
AGM batteries do not have as high of a discharge current as lithium batteries. Therefore, you need a lot larger AGM battery bank to power the same size inverters.
This general rule of thumb can be applied:
- A 1000W inverter should be coupled with 2 x 120A batteries.
- A 2000W inverter will need 3 x 120Ah batteries.
Be sure to check the manufacturers specifications for running an inverter from an AGM battery.
Step 3: Consider How Long You Plan To Run These Appliances
A reputable battery manufacturer will display how long their battery can produce its maximum Amp output. It's one thing to say you have a 100Ah Lithium Battery, but it is another to advertise that you can pump out 100A consistently for 1 hour. It's worth checking the specifications on some of the cheaper lithium batteries.
Now let's look at a quick example of calculating how long a battery will run, while powering a laptop from a battery system through an inverter.
If your laptop charger draws 50W continuously while plugged into the inverter, this equates to approximately 4 Amps at 12 Volts. So theoretically, you could run the laptop for around 24 hours continuously on a Renogy 12V 100Ah Lithium Battery.
Keep in mind, you need to consider power draw of the inverter itself. A 1000W inverter will roughly draw around 1 Amp per hour even without any load applied. So, it's best to factor this in to your calculations.
Got a Larger Caravan or RV?
Look to an inverter charger.
The pioneer of inverter chargers is Victron with their PowerAssist feature. This allows you to use some power from AC input (mains power or generator) and some power from your battery system via the DC to AC inverter.
This is particularly handy when running an air conditioner. You can use a small inverter generator coupled with your inverter charger to run your caravan rooftop AC. Great for those hot summer nights!
We recommend the Victron Ultimate Caravan Off-Grid Bundle. This is a 200Ah lithium system with a inverter charger capable of producing a continuous output of 2400W and a peak power of 6000W.
You can easily add an extra 200Ah battery to double the power storage of your caravan's off-grid setup.
There you have it!
Follow the steps above and you'll buy the right DC to AC inverter for your caravan or camping off-grid adventure.
Still have questions about inverters? Talk to our expert team.
DISCLAIMER* Please note, this advice is general in nature and we strongly recommend consulting the product manual and where relevant, a professional installer.