- 1 Why I wanted to install a solar panel
- 2 Decide the specification of solar system
- 3 Purchased equipment and parts
- 4 Wiring diagram
- 5 How each equipment is installed
- 6 Comparison between 12V system and 24V system
- 7 The price of purchased equipment and parts
- 8 Useful Sites
- 9 Note
Why I wanted to install a solar panel
When I travel by a car, sometimes I stay in one place for several days, and in such case, solar system is very convenient.
Additionally, in Japan, major earthquakes are expected,and if you use a car as a shelter, solar system is indispensable.
So I decided to install a solar photovoltaic system to my HIACE VAN.
In this article, I’m going to explain how to select each equipment, and how to install the system.
Decide the specification of solar system
What appliances do you want to use in the car?
I want to use the followings.
Electric water boiler 440W
Electric blanket 60W
Portable refrigerator 30W
USB charger 30W
=>Total capacity should be not less than 600W
Larger is better, but number of solar panel should be 1 to minimize wiring and panel fixing work. So I selected the panel with maximum available output 210W.
I chose 24V system because wires can be thinner and more inexpensive than 12V system. ( In the end, I thought 12V system may be better.)
Number of Batteries
Because the system is 24V, connect 2 of 12V batteries in series.
Type of battery
Lithium ion battery is still very expensive, so I used deep cycle batteries.
Inverter capacity and type
Capacity: as mentioned above, not less than 600W
Type: for electric blanket, sine wave is required. (Modified sine wave is NOT applicable.)
It is said that MTTP type is 30% more efficient than PWM type, so I chose MTTP type.
Purchased equipment and parts
The thickest wire required in this system is 8 SQ. ( 8 SQ is size of cables which has 8 mm2 nominal area of conductor.)
To connect terminals to such thick cables is difficult for an amateur like me, so I bought ready to use thick cables from Chikuden system.com.
This device transforms 24V DC into 12V DC. I thought I can distribute 12V DC current from charge controller, but it can only pass the system voltage via it’s load contact.
So I was obliged to buy the converter.
It offset the cost advantage of thinner cables for 24V system.
The instruction manual of charge controller I bought says circuit breaker must be installed
- Between battery and charge controller
- Between charge controller and equipment connected to load connection
- Between the solar panel and the charge controller
So I purchased 3 circuit breakers additionally.
The size of solar panel is 808mm × 1,580mm, so I purchased below below carrier. It is 1,490mm wide and 2,870mm long.
Sorry, it is informal and Japanese.
How each equipment is installed
I found many examples of running wire from solar panel into car cabin, but still couldn’t find how I should run the wire without making any hole on the body of the car.
I tried several route, and finally found the route that can avoid any harm by rear hatch.
Through the route, the cable barely escape any harm by rear hatch.
If the cable run through the weather strip which runs vertically, water will come inside of the car.
So pull the cable to the point where weather strip runs horizontally.
Pull the cable up to the underside of the door, and raise it up in the cabin.
The charge controller, inverter, and DCDC converter are attached to a wire net (https://matome.naver.jp/odai/2141999753102395601) witch I bought at 100 yen shop.
Look down the HIACE VAN with solar panel
The height of my HIACE VAN is 1,980mm. The top of the roof carrier is higher than the face of solar panel attached to the roof carrier, and the height of HIACE VAN with roof carrier is 2,200mm.
The maximum height allowed to enter Times parking. ( Times is largest toll parking lot operator in Japan.)
The solar panel weighs 15kg, and roof carrier weighs 25kg, so it weighs 40g together.
The section size of the beam of the carrier is 20mm×30mm, so I purchased this bracket to attach the panel.
To ease the fixing and wiring work, I bought a ladder.
The batteries are placed on the floor of the luggage room, under the bed floor.
I was worried if I could lift this heavy battery and move it, but it was not so difficult.
I was considering to put the batteries in a dish to avoid to be overturned, but the height of bed floor is almost same as the batteries, and it’s no problem as it is.
I don’t have enough time to prepare cables completely, so some were just wound around the terminal post directly.
Comparison between 12V system and 24V system
Generally speaking, charge controllers and solar panels are compatible with both 12V and 24V system. But inverter is NOT compatible, and 12V model cannot be used in 24V system, and visa versa. So the voltage of solar system should be carefully determined.
Advantages of 12v system
Converter from DC 24V to DC 12V is not required.
Isolator can be installed to charge the batteries while driving.
In case of 24V system, alternator generates 12V DC current, and an isolator cannot transform it into 24V. So it is not easy to install an isolator.
Advantages of 24v System
The wiring between inverter and batteries, or between batteries are thinner and inexpensive compared with 12V system.
If you use 100W bulb,
In case of 12V system, current between the inverter and the batteries is 100/12= about 8 A.
In case of 24V system, current between the inverter and the batteries is 100/24= about 4 A.
8 A current require thicker cable then 4A current, and thicker cables are expensive.
You can use same charge controller with larger capacity solar panel.
Power controller is specified by max current such as 20A.
In case of 12V system, maximum power to be processed is 20A × 12V = 240W
In case of 24V system, maximum power to be processed is 20A × 24V = 480W
Therefore, you can use larger capacity panel with 24V system.
The price of purchased equipment and parts
As shown in the following table.
High quality and inexpensive solar equipment are available. But not sure oversea delivery is possible.
Thank you for reading my article.
The original article was written and published on Oct./10/2017.