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My Generator Solar Calculator Advice

Choosing solar panels and camping batteries made easy by My Generator

“WHAT SIZE SOLAR PANEL & BATTERY DO I NEED?”…this is the most commonly asked caravan / camping solar panel and battery question and can sometimes seem like quite a technical, challenging task. But for most applications, it’s actually pretty simple and straightforward – here we try and make it easy for you.

First follow these four simple steps;

Step 1 & 2: Total Power Consumption of Your Favourite Caravan, Camping & Off Grid appliances.

Step 3: Solar Panel selection and calculation

Step 4: Battery bank sizing & calculation

Read on for more detail how to go about completing each of the steps. Then we have also included a “Power Draws of Common Caravan, Camping & Off Grid Appliances” table to assist you in your calculations.

Note: solar power calculator assumes 12V solar panels are connected in parallel.

 Step 1: Find Out The Power Draw Of The Appliances You Want To Run.

It is best to get the amp hour (Ah) figure from the manufacturer’s specifications. We have included a table below / at the bottom of the page of some common examples of caravan/camping appliances power draw.

E.g. A Dometic Waeco CFX-95 portable fridge freezer when set to one side as a fridge (+5°C) and one side as a freezer (-15°C), the average amp hour draw is 3.6Ah.

If you do not know the amps per hour (Ah) then you can use this simple calculation by taking the average wattage of the appliance and dividing it by the voltage which will give you the amps per hour.

Average Watts Per Hour System Voltage Average Amp Draw Per Hour (Ah)


For example:

iPad/tablet charger draws about 45 watts per hour therefore, 45 / 12 = approximately 4Ah


 Step 2: Calculate How Many Hours Per Day Will Each Appliance Run

Decide on how many hours per day each appliance will run. Enter this information into the solar calculator below accordingly.


 Step 3: Solar Panel Selection and Calculation

The total hours of sun varies based on your location. You can choose from a list of Australian capital cities. In our solar panel calculator we have listed the average sun hours for each location throughout the year. Please note, that there are more sunlight hours available in summer and less sunlight hours in winter.

Use the calculator to trial the best solar panel size and configuration to best suit your needs. Ideally, you will want more amps going in than coming out – look for the green tick! 


 Step 4: Battery Bank Sizing & Calculation

Enter in your battery bank size (amp hours). Then choose the type of battery you have or are looking to purchase. The calculator will tell you how many days you can camp with all your appliances powered up.

For your convenience we have added in a section for autonomy. Autonomy refers to the amount of days that you will power your system in the event of little to no solar power (bad weather).


Caravan & Camping Solar Panel & Battery Calculator

Step 1 Step 2
Appliances Average Amp Draw Per Hour (Ah) Hours Run Per Day Daily Consumption
Total Daily Consumption
Step 3
Location (Sun Hours) Solar Panel Output (Amps)* Number of Solar Panels Total Amp Yields Per Day
Daily Power Draw On Battery Bank
Step 4
Battery Bank Size (Amp hours) Battery Type Usable Battery Bank Hours* Days With Power**


The calculator below will tell you how long you can travel off-grid if solar is not available

Autonomy (it's raining/no sun):

*Based on industry standard

**You will be able to camp off-grid indefinitely provided there is sufficient sunshine


  • Solar power calculator assumes 12V solar panels are connected in parallel.
  • Please note, amp hours in this calculator have been rounded to the nearest whole number.
  • Need help choosing an inverter? Check out our blog.


Power Draws of Common Caravan, Camping & Off Grid Appliances

Appliance:Average Power Draw:Please Note:
28 Litre Fridge 1.0 Ah  
35 Litre Fridge 1.0 Ah  
40 Litre Fridge 1.0 Ah  
50 Litre Fridge 1.0 Ah  
65 Litre Fridge 1.5 Ah  
75 Litre Fridge 2.0 Ah * Both compartments set as a fridge
95 Litre Fridge 3.0 Ah * Both compartments set as a fridge
45 Litre Upright Compressor Fridge 1.5 Ah  
55 Litre Upright Compressor Fridge 1.5 Ah  
80 Litre Upright Compressor Fridge 1.5 Ah  
110 Litre Upright Compressor Fridge 1.5 Ah  
140  Litre Upright Compressor Fridge 2.0 Ah  
180 Litre Upright Compressor Fridge 3.0 Ah  
225 Litre Upright Compressor Fridge 3.0 Ah  
Laptop Charger 4.0 Ah  
Phone Charger 0.5 Ah  
Tablet Charger 1.0 Ah  
Caravan Air Conditioner 100 Ah  
12V Caravan Water Pump 3.5 Ah  
12V Fan 3.5 Ah  
12V Television (Small) 6.0 Ah  
12V Television (Large) 10 Ah