Can I Convert My Car to Hybrid – DIY Plug-in Car


The latest hybrid electric vehicle models are more attractive, environment-friendly and fuel-efficient as compared to conventional cars. Hopefully, the prices of new hybrid cars will fall in the next few years and more people will be able to enjoy cheaper fuel economy with better car performance. But what are we going to do with the conventional cars that are already in use? Are we going to just abandon them and buy new hybrid vehicles?

Or is there a way to convert conventional cars to hybrid electric vehicles? Being a car enthusiast, hybrid vehicles fascinate me. I already have an old car that I wanted to convert and so, I have been digging about how can I convert my car to a hybrid electric vehicle and almost everything that I needed to know before getting started. Before I started working on retrofitting, I used to think it is possible to convert any conventional car to hybrid and it is as tough as changing a car’s engine. Fortunately, I found very helpful details on this idea that helped me in making better decisions and at the same time to save on costs.

Want to know if it is possible to convert your car to a hybrid electric vehicle? Yes, It is possible to convert almost any car to a hybrid. There are very few cars that cannot be converted without major modifications. You can keep an old gasoline engine and add the electric source for powering your car.

In the past 2 decades, a number of experiments have been conducted on retrofitting cars to hybrid systems and thousands of cars have been converted to hybrid. In the year 2008, a group of students from MTSU (Middle Tennessee State University) successfully retrofitted an old 1994 model Honda Station with a lab-developed retrofitting kit. The overall expenses were only $3000 and the mileage improved to more than 50%.

Later on, a number of startup companies have entered in retrofitting business and started selling DIY retrofitting kits. Until the year 2016, almost 3000 cars have been retrofitted. Following the same year, a single retrofitting company in Utah claimed to have sold over 2000 DIY retrofitting kits. Today, a commercial retrofitting kit costs around $5000-10000 which is still more economical than buying a new hybrid vehicle. However, if you wisely choose all parts according to your car, the cost can be much less.

Multiple retrofitting companies are providing services and necessary equipment. Many auto workshops around the globe have developed a business of retrofitting old cars and selling them for $3500-$8000. There are several online support groups at social media where car enthusiasts share ideas and help the community. If you want to convert your car all by yourself, you must have extensive technical skills and you’ll need technical support for choosing suitable batteries, charger, DC controller, motors, wiring, and other equipment. But before you get started, you need to be sure if your car is suitable for retrofitting.

Can All Cars be Converted to Hybrid?

Most of the cars can be easily converted to hybrid but some cars cannot be converted. While for some cars it is possible but still the conversion is uneconomical and buying a hybrid electric vehicle might be a better option. The conversion process costs around $5000-10000 and spending thousands of dollars on a car that is worth a few hundred might not be suitable if you ever resale it. Buying an economical latter model could be a better choice.

Furthermore, the weight of the battery pack is not suitable for some cars. Hybrid vehicles usually carry lead-acid, nickel-metal hydride (NiMH) or lithium-ion (Li-ion) batteries. These batteries weight a lot and require proper space. Small cars are built for limited weight capacity, they cannot carry heavy batteries. While some cars lack space for the battery pack. Considering the load capacity of the car, even if only a few batteries are installed, the efficiency may not be good enough.

Apart from the technical issues, there are legal issues too. It is illegal to convert a car to a hybrid in some countries while it is legal and appreciated in some countries but there are certain policies that must be complied with. There are certain policies regarding hybrid cars in various countries. Make sure your car complies with the government criteria for retrofitting and it also complies with the policies that will be applicable after it is retrofitted. If you are located in the US, you need certification from EPA or California Air Resources Boarder (CARB). The policies vary from state to state based on the strictness of emissions.

How Can I Convert My Car to Hybrid?

Retrofitting services are available in almost all developed countries, you can avail of their services. Especially if you are located in India, Canada, US or UK, you can easily find retrofitting companies and auto workshops that offer retrofitting services.

Just in case if there are no retrofitting services in your country, you can still covert your car to a hybrid. But as mentioned before, you must have extensive technical skills. You can easily find all the parts and helpful books online.

Follow these steps for retrofitting your car to hybrid electric vehicle

  1. The very first step is to decide the operating voltages of the system. Typically, the voltage range is somewhat between 96 – 192 volts. But some companies have designed hybrid kits for 48 volts. The number of batteries depends upon your operating voltages. The charging system, DC controller and the motors also depend upon the operating voltages.
  2. Once you have acquired all necessary equipment, install electric motors at the rear wheels without disturbing the gasoline-centric mechanical system. Couple the motors with the transmission. You can use a custom plate for reinforcing the coupling. Make sure, the motor and transmission are properly aligned. Improper alignment can lead to low efficiency and permanent damage.
  3. The battery packs, charging system, and the DC controller must be housed properly. You can build a custom platform for mounting the DC controller and secure housing for the batteries. After housing the batteries and DC controller, carefully wire the batteries and the electric system with the DC controller. I recommend the Prius Cell Modules made by Panasonic, click for pricing on Amazon.
  4. It is essential to install a cooling system with the batteries as they heat up during charging/discharging. You can use a blower or a micro air conditioner for regulating battery temperature. It is recommended to use a low-power micro air conditioner.
  5. Computer-based driving systems are easier to hack as they already operate through electrical signals. All you need to do is to find the signal wire, connect your car’s computer with your DC controller. If your car’s computer communicates through CAN bus, you’ll need an external embedded system (CAN bus supported) for communication between the DC controller and the car’s computer otherwise you might have to replace the throttle cable with a potentiometer. In some cases, an electric paddle is also used.
  6. The electrical connection between the batteries and the DC controller is switched using an electric relay. Choose a robust relay that can withstand hundreds of amperes at 96-300 voltages without glitches or prolonged discharges.
  7. In order to power the DC accessories that operate below the operating voltages of the system, a DC-DC converter can be used. To check out the DC to DC converter by Vitron that is available on Amazon, click here.
  8. As your car will operate at both gasoline and electricity, you need to monitor battery charging as well as the gasoline-fuel level. Install a battery level monitoring system beside your fuel gauge.
  9. If you want to power your A/C through the batteries too, you can power it from the batteries using a power converter.
  10. The last thing that you need is a switch for controlling the power source for your battery. Install a switch for turning your car’s electrical system ON/OFF.

How Long Does it Take to Convert a Car to Hybrid?

If you own a manual transmission car, good news, the conversion is comparatively easier for manual transmission cars as compared to automatic transmission cars. The time required for retrofitting varies from car to car and the hybrid system being installed.

On average, retrofitting companies take 6-16 weeks. Although the retrofitting process usually takes 6-8 weeks, the companies run multiple tests to ensure the system is operating properly and is safe to use. However, the case is different when it comes to DIY hobbyists, some people claim to have retrofitted their cars in less than a week and even in 24 hours too.

Are There Any Risks Associated With Retrofitting My Car to Hybrid?

Hybrid electric vehicles operate at high current, enough to cause serious hazards. If you are planning to retrofit your car all by yourself, you must be very careful with the wiring. I wouldn’t recommend doing it by yourself if you are not handy with electrical systems.

Before you install any custom-designed mechanical parts, make sure they are designed according to the requirements. Any flaws can cause serious hazards and permanent damage to the system.

As the process involves the installation of new mechanical parts and modification of the old design, it is not covered under warranty by most of the companies. So if your car is still under warranty, you might lose the company warranty after retrofitting.

Recent Posts