What size solar blanket do you need?

The REDARC Solar range allows you to get away from traditional camp sites and mains power sources. However, a little homework is required to know exactly how much power you use so you can choose the right battery bank size and combine this with efficient battery use and smart charging to achieve the best results.

Amorphous versus SunPower

REDARC has a range of difference sized solar blankets. All solar blankets conveniently fold away for easy storage and are considered lighter than traditional folding solar panels.

So which one do you choose? Below is an example calculation based on running a fridge and one LED light.

Use the following as a guide in your calculations

Step 1

List and record all of your loads and how many amps they use (most items have the amps listed on the label).

In this case;

A fridge will draw 2 amps (average)
A LED light will draw 3 amps

Step 2

Next, multiply current draw (A) of each item by the hours it is used over 24hrs (h) and add together the results. This will give you the total amp hours (Ah) required per day. 

For example;

A fridge will draw 2 amps x 24h = 48Ah
A LED light over 5hrs will draw 3 amps x 5h = 15Ah

Step 3

Tally up all of your items and you will have the total amp hours likely to be consumed in any given day.

Based on the above example it equates to;

48 + 15 = 63Ah used over 24hrs

Now the question remains, what size solar blanket do I need?

Before we answer that we need to know the size of the battery. If you're using a 120Ah deep cycle battery, it should only be discharged 50% to ensure the best battery life. So, for this battery, we will assume 60Ah is usable.

With a 115W SunPower Solar Blanket, which can supply a maximum power current of 5.8A with approximately 6hrs of sunlight a day, your blanket can supply 34.8Ah per day (5.8A x 6h = 34.8Ah).

Therefore, each day, the battery is being discharged by 63Ah consumption, less 34.8Ah charge going into the battery = 28.2Ah

With 60Ah usable and 28.2Ah being used each day you have just over 2 days free camping (60Ah / 28.2Ah = 2.12).

Which means, based on the above information, you would be able to stay off-grid for just over 2 days.

Standard battery charge using portable solar  

The table below outlines how long your battery can last without any other form of charge, using our complete range of portable solar blankets, with the same loads in our example.

Factors such as sunlight hours, weather conditions and a number of other variables can affect actual solar panel output. REDARC has taken the hassle out of manual calculation with its solar calculator on the REDARC website. The solar panel calculator provides an indicative measure on how much power will be needed per day depending on the size of the auxiliary battery bank and appliances used whilst touring.