Can I Put a Solar Panel on my Car Roof?

Can I Fix A Solar Panel To My Car Roof - charging an EV

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Solar panels are predicted to be the future of cars in many diverse ways. The advantage of solar powered cars is obvious – they use renewable source of energy and therefore we get to conserve our environment and also save money for gas.

You can put a solar panel on the roof of your car but there are 3 things to consider before attempting it:

  • What is the purpose of the solar panel to run an electric vehicle or to power accessories?
  • How big is your car roof? Solar panel power output is directly proportional to the area of the panel
  • Would it be roof-rack mounted or fitted directly to the roof of the car?

What to Consider Before Purchasing a Solar Panel For Your Car Roof

car roof rack for fitting solar panels

1. Roof rack – Does your car already have a rack or do you need to install one first? This is because solar panels sit better on a rack as you can simply bolt your solar panels directly to it – this is the easiest and secure way.

2. Type of Roof material – different roof materials need different methods of installation. If your roof is made of flat metal you can use the VHB mounting tape methods which is very efficient and strong. If your roof is made of rubber, use screw-in z brackets and lap sealant

3. Roof strength – have you considered if your car roof is safe for a solar panel installation? If your car is an old car, is it strong enough to install a solar panel?

4. Roof shape – is your roof curved, or is it flat? There rigid flat ones might be suitable for flat roofs and flexible solar panels more suitable for a curved roof.

Types of Solar Panels for Car Roofs

1. Flexible Solar Panels for Car Roofs

flexible solar panels for car roofsThey are constructed from normal solar cells with a protective plastic film glued over top. Flexible solar panels are light in weight and due to their bendability, they are less likely to crack if treated roughly.

Flexible solar panels don’t have frames and this makes it possible for them to be able to curve to a car’s roof contours.

100 watt solar panels are suitable for mounting on top of vehicles, , given their dimensions. because they are very strong and durable, but there is an issue with fixing them in place.

Many RV owners have mistakenly glues flexible panels directly onto the roofs of their vehicles leaving no air-gap between the panels and the roof.

Solar panel output reduces rapidly as the temperature rises, degrading the material and reducing its working life.

100 Watt 12 Volt Flexible Monocrystalline Solar Panel For Car Roof Fixing

  • It is thin and can bend up to 248 degrees

  • It is not weighty compared to other solar panels (5 lbs instead of 25 to 50lbs)

  • It is very suitable for installation on curved surfaces

  • It’s only a 1/10 inch thick so you don’t have to be worried about how your car will look like with a solar panel showing on top of your roof. 

  • You wouldn’t have to remove it because this type of panel can endure seasons of extremes in temperatures and weather conditions

  • It already has holes drilled for mounting, complete will reinforced eyelets for fixing to roof racks or directly onto the car roof material. (Depends how fussy you are about the car’s appearance.)

  • When mounting it on your car’s roof, it is advisable to use silicone structural adhesive at the back of the panel but remember that an air gap between the solar panel and the roof is advisable, particularly in hot climates.

 

2. DIY Solar Panel For Car Roof Use

The advantages of DIY is that it’s cost effective. It’s actually very easy to mount a solar panel yourself. It saves you the money that you would have used for the installation.

It also gives you a sense of satisfaction and makes you feel like you have achieved something for yourself instead of waiting for someone to do it for you.

You don’t have to drill a single hole on your roof if you don’t want to – good news for owners of newer cars! You can simply use adhesive to mount the solar panel.

3. Glue Solar Panel To Car Roof

Worried about drilling holes to your car roof? Worry no more. VHB tapes are suitable for gluing your solar panel to your car roof.

It’s a safe way to glue your solar panel, it is water proof and can handle high temperatures. Also if you want to remove it, that’s not a problem. There is a solvent that is used to remove the tape.

This tape lasts for years, but it depends on the strength of your roof and the amount of tape you use. Use plenty of tape and check it regularly.

VHB tapes work well with clean dry roofs made of aluminum or fiber glass. They are suitable for flat roofs with no signs of rust or flaking paint.

Monocrystalline Or Polycrystalline panel For Your Car Roof?

Monocrystalline solar cells are formed form one continuously grown tubular ingot of silicon. The structure is more uniform than polycrystalline and so they are more efficient at 20% to 22% instead of 13% to 15% for polycrystalline.

As car roof space is very limited, it’s an obvious choice to choose monocrystalline flexible solar panel, either fitted to a roof rack or glued in place.

The  best brands for solar include LG, Panasonic and Sunpower – their products have a 25 year warranty. The products are more expensive than cheaper panels from China with no brand names but the long-term benefits far outweigh the short term savings from buying cheap panels.

I’ve bought such panels in the past and found that the panel output in watts is often 20% to 30% less than specified and that the construction is not the best quality. When such panels are flexed, for example, the film often comes unstuck around the fixing holes and moisture can creep in.

A word of caution – if you you bend a flexible panel in coldish weather, you might hear a small cracking sound. This sound indicates that one or more of the metal bus-bars connecting the solar cells has broken, reducing the output of the panel.

Electric car charging roof solar panels mounting

How Much Power From A Solar Panel Mounted on A Car Roof?

The are of the average car roof is between 30 to 40 square feet. Even if completely covered in solar panels they would generate only about 0.56 KW of power. This is nowhere near enough to power an electric vehicle.

However, it could significantly extend the range of an EV, but feeding into the battery while the car is running. This idea is worth exploring but care should be taken with solar panel sizing and the effect of the car’s warranty conditions.

 


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