Minimum Recommended Battery Options for Inverters:
This is a selection guide to help you choose the right battery to power your 240V inverter.
|
12V to 240V Inverter Size |
1000W |
2000W |
3000W |
Good |
|||
| Zeal 200Ah | |||
Better |
Renogy Pro 300Ah |
||
Best
|
|||
|
|
|||
|
Victron 100Ah (High Current) |
*Use the corresponding size battery to calculate how long your appliances can run in the table below.
Calculate how long your 240V appliance will run via inverter:
|
Appliance |
Power Draw (Watts) |
Battery Size Ah |
Run Time Hrs (at full load) |
|
| x | ||||
| x | ||||
| x |
*Assumes appliance is running at full load
*Assumes inverter has 90% efficiency
*Assumes battery voltage is 12.8
Hot Tip: Thinking of running a domestic refrigerator in your caravan?
Although it might sound appealing to pickup a cheap domestic 240V fridge/freezer with a highly efficient energy star rating it is important to understand the whole picture.
To run a 240V fridge your inverter needs to be powered up 24 hours a day. All 240V inverters consume power even when no load is applied. So this is another device depleting your battery storage. Secondly the inverter consumes extra power to convert 12V DC power into 240V power. These losses are considered in the table above. A reputable 12V DC caravan fridge will be more efficient than a domestic 240V fridge. Caravan fridges are designed with greater insulation and can withstand the rigours of mobile applications.
Case Study 1: Domestic vs Dedicated Caravan Fridge
Example: Westinghouse 225L Refrigerator
Domestic fridges will provide a kWh/year in this case it is 282 kWh/year. Therefore 773Wh per day.
So 32Wh is the average power draw at 240V. We then add an average of 15Wh for the inverters constant no load power draw, thus the total average is now 47Wh .
Using the table above this model would run for 39.2 hours from a 200Ah battery.
Comparing with a Dometic RUC 8408 12V 224L Fridge the average power consumption is 3Ah. If you were to run it with the same 200Ah battery as the example above it would run for 53 hours.
This is a huge difference when travelling out on the road and should be considered.
Case Study 2: Powering An Induction Cooktop
To power a Dometic 2 Zone Induction Cooktop off-grid you could use an Enerdrive 2000W Inverter and an Enerdrive 200Ah Lithitum Battery.
This induction cooktop has the following power requirements: Induction zones 1000W (Left), 1300W with Boost Function 1700W (Right)
If you were to run the left zone at 1000W the table above shows a run time of 1.8 hours from Enerdrive 200Ah Battery.
Another way to look at this is 30 minutes of cooking time would use approximately 22% of the Battery.
Pro tip: The Enerdrive 2000W Inverter with RCD & AC Transfer Switch and the Enerdrive 2600W Inverter with RCD & AC Transfer Switch are a recommended option for a caravan and RV inverters due to their inbuilt RCD safety feature.
Cable Sizing For Inverters
High powered 240V appliances when connected via an inverter will lead to higher currents (Amps).
Undersized cabling will result in efficiency losses to heat, damage to cabling and appliances and voltage drop. Here is a general guide for cable sizing to connect a battery and inverter:
|
Inverter Capacity |
1000W |
2000W |
3000W |
|
Recommended Fuse Size |
150A |
250A |
350A |
|
Cable Size 1m |
16mm2 |
50mm2 |
90mm2 |
|
Cable size 2m |
35mm2 |
70mm2 |
120mm2 |
