_DIY_Book Archieven - Rebbl
- By ivovandenbrink
When you have plans to convert your car or boat to electric, one of the first questions that will pop your mind is: What budget will I need? Well, anything between €5.000 and €100.000 is realistic. That’s not much of an answer. Here are the 10 major factors that determine your EV Conversion budget.
1. DIY vs professional workshop
Think twice about letting someone else do the conversion job for you. There is a lot of knowledge out there readily available to make it possible to convert your car or boat yourself. It will be your hobby for the coming months and you will save €5.000 to €10.000 in workshop hours, or even more. So if you are kind of smart, have the time and want to save some money: go for DIY. If you have the budget and want your project to be ready ASAP: go for the professional workshop.
2. The type of vehicle
You can imagine there is a big difference between converting a heavy modern car like a 2014 Mercedes 500S and a 1982 Fiat Panda. The Mercedes has a lot of complex computerized systems, so you will need a solution to work with the computers and secondary functions like airconditioning, power steering, etc. The Merc is also very heavy; over 2000kg. The Panda is just plain simple and lightweight: under a 1000kg. It needs half the batteries.
3. Sporty vs economy
Is it allright that your car does 0-100km in over 10 seconds or do you want the Tesla way and count to three? Does top speed matter to you? Max 100km/hr is totally different from a maximum speed of 200km/hr. You will need a different motor/controller setup, maybe even two electric motors.
4. Regenerative breaking
Do you need regen? Overall you can win 10% of battery capacity with regenerative breaking. But that’s only when you drive in a surrounding where you have to break every once and a while: a city environment. So if you do more stretches outside the city, you might not benefit from it at all. If you want regen you go for an AC (or brushless DC) drivetrain. In general AC is about 30% more expensive than brushed DC.
It’s easy to think of an electric car going more than 200km on just one charge. But do you really need it? Because this has a serious impact on your budget. In a small oldtimer like a Beetle, a 70km range will cost you €2.000 in lead-acid batteries. 120km range will cost you € 6500 in lithium and >200km will cost about €12.000. With the amount of batteries rising, the cost for casing, cables and your BMS will also rise.
6. Is it done before?
Sometimes standard parts like a motor mount and batterycasing are already available for specific models, so you can just order them from the shelf. If you are the first to convert a specific type of car, you might need to hire an engineer for these parts. Furthermore, the company needs to mill just 1 piece, so the cost cost will be significantly higher. Last but not least: getting a unique car approved by your local Road Institute could be a lot more expensive than a car that has been approved before.
Now and then cheap lithium batteries, as a result of bankruptcy’s or damaged cars, are dumped on the market. These can be a nice push to launch your project. Disadvantage is that there is no warranty on these batteries. Back-up and information should not be a problem when you visit internet fora and blogs about these type of batteries. A good example is the dumping of batteries out of the Better Place bankruptcy early 2014. Also, every now and then some Ampera or Leaf batteries are for sale, out of a damaged car.
8. Upgrade early electric cars
From 1990 to 2005 automotive brands like Fiat, Peugeot, Citroen and Renault launched low budget electric alternatives for models like the Panda, Kangoo, Berlingo, 106. These cars are now available on popular websites like E-bay, Autoscout etc. You can easily upgrade these cars by replacing the Lead acid or Nickel Cadmium batteries by adding Lithium batteries for example. You will have to replace the charger as well, but after that you have more 2000 duty cycles to go, less weight and more power.
9. Basic vs complex battery management
If you keep your BMS simple, like a basic battery balancer with a basic State of Charge meter, you can save money. You will have to keep an eye on your batteries every now and then and be more conservative with charging and de-charging. But if you like better protection and a lot less looking around, and a fancy State of Charge meter on your dashboard, you will end up spending €2-3.000 more on your conversion.
Last but certainly not least: when you use one 2500W charger on a small battery pack like 17kWh, it will be full in 6-7 hours. If you would like to charge with 22kWh, a 22kW AC charger will do the job in less then an hour. It will cost you €4500 more though.
The budget you need for your electric car conversion depends on your wishes. If you want a rock bottom conversion, your best option is to buy some second hand kit and lead acid batteries and put it in a small city car. You will have a nice drive around the village. Ranges over 200km will certainly do 25k€ in components. If you want a Tesla killer reserve a 100 grand and call us for help 🙂
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