# Solar ac for car

1. Mar 13, 2013

### ironman_marvel

Hi,

This is my first post here. I am planning to work on small project for my car, wherein I could power up a small inverter which would in turn start a fan / ac in my car.

I am just confused on how many panels I would need to accomplish this project.

solar panel output 4V -100 ma

inverter specs

power rating 100W

input 12V

I think I would need around 1000 this small panels. can anyone please confirm this?

2. Mar 13, 2013

### Staff: Mentor

Welcome to the PF.

The usual problem with placing a big enough array on top of your car to effectively cool it is that the array will be valuable enough to be stolen. Where are you planning on parking your car?

3. Mar 13, 2013

### ironman_marvel

I am planning for something that can be detached/attached as and when required. Just want an idea for proper number of solar panels. Or any other idea to use solar power to provide power for ac

4. Mar 13, 2013

### Staff: Mentor

But if you detach it when you leave the car alone, it will be very hot when you return...

(Can you tell that I recently went through this math with someone else...?)

Last edited: Mar 14, 2013
5. Mar 14, 2013

### Bobbywhy

ironman marvel, Welcome to Physics Forums!

You may use power to get some idea of the size of the solar panel necessary. Power is measured in watts. Power (in watts) = Current (in amps) X Voltage (in volts).

1. Solar panel power output = 0.1 amps X 4.0 volts = 0.4 watts (in full sun)
2. Inverter capacity (full load) = 100 watts. Assuming you’d want the ability to draw full load (maximum power) with your loads (fans?), and inverters are typically only around 80% efficient, you’d need to apply roughly 130 watts to the input of the inverter to get 100 watts out.
3. How many 0.4 watt solar panels do you need to equal 140 watts? Perhaps 350 panels!

Why are you trying to drive AC loads? There are lots of fans that operate on 12 VDC and every other imaginable electrical appliance used in RVs, trailers, etc. can operate on 12 VDC.

Why bother using an inverter at all? I suggest you consider using 12 VDC appliances and solar panels to recharge the 12 VDC system.

Cheers, Bobbywhy

6. Mar 14, 2013

Hi guys,