£55
pledged of £6,000pledged of £6,000 goal
9
backers
Funding Unsuccessful
The project's funding goal was not reached on Mon, March 11 2019 2:23 PM UTC +00:00

DIY solar-powered electric car with the range of a Tesla!

Can you build a Reva G-wiz to have the range of a Tesla at a fraction of the cost? This is the question I aim to solve with your help

DIY solar-powered electric car with the range of a Tesla!

Can you build a Reva G-wiz to have the range of a Tesla at a fraction of the cost? This is the question I aim to solve with your help

£55
pledged of £6,000pledged of £6,000 goal
9
backers
Funding Unsuccessful
The project's funding goal was not reached on Mon, March 11 2019 2:23 PM UTC +00:00

About

Join me on an adventure and be the first to witness this novel concept become a reality. With your support and your pledges we can make this happen. 

Last year I built a solar-powered tricycle and sleeping pod trailer as an experiment to see if I could travel without the need for a car or fuel. This project was a huge success and I rode 500 miles to the south coast on sun and pedal power towing my home with me!

Below is a picture of this DIY contraption using re-purposed junk from around the house (apart from the technical things like solar and motor etc).  

 I have always been a bit of a DIY inventor and have other ideas that could help change the world for the better and give us the inspiration and easy access to little hacks that will ease our dependence upon the current polluting options without compromising on practicality.  I am also a forager of wild food and I have reduced my footprint considerably over past few years. This next project should eradicate my dependence on polluting transport and inspire others to do the same with video logs and updates on my progress. If it works I can possibly offer to assist/give advice to others who want to take the leap without buying a Tesla!

Although I teach foraging for a semi-living and I am self-employed, I do not quite earn enough outside of basic expenses to purchase what I would require to enable a full scale testing and exploration of the possibilities that I wish to achieve. This is where any help from you would be greatly appreciated and would open up the doorway into an area that other folk, even you could potentially benefit from without the risk of losing any large expense if the project fails to meet the intended requirements or expectations.  

The REVA G-wiz was a quirky car first produced in 2001. Not quite a car, this heavy quadricycle paved the way for practical local city vehicles that enabled city living to be that little bit cleaner.  The G-wiz originally had 200 ah of lead-acid batteries weighing in at 265 kg giving a tiny 35-40 mile range before requiring an 8 hour re-charge.   

 TURNING A G-WIZ INTO A TESLA

A JOURNEY INTO BUILDING A DIY LONG RANGE ELECTRIC CAR

I have been researching for quite some time the potential re-fit of lithium batteries into a G-wiz because the fundamentals of this car are simple. It has four wheels, it has a motor, a motor controller, weather proof and has all the lights and other things required to be road legal without starting from scratch. With basic wiring it is easy to navigate around this car and at a low cost of £675 without batteries but with a full MOT and a custom towbar you cannot go far wrong as a base to start from. The towbar increases its practical capacity by enabling a small trailer to be connected.

Before I committed to the purchase of a G-wiz, I did some digging and found some snippets of hope that what I would like to achieve has already been done in some form or another. In India 150ah of lithium polymer batteries were fitted and gave the car a range of 62 miles, but this was also towing a trailer that increased the maximum capacity to 8 passengers!

Below is the only video I found on this particular project.

Pedalease in the UK who specialize in e-bikes also built one with 10 x 20ah LiFePo4 batteries which had a range of upto 60 miles but these batteries are big, bulky and quite expensive. There is not a lot of information about any of these projects. I had to find the easter eggs and read deeper/contact people to understand what has already been done on this front. Pedalease confirmed that their G-wiz is running fine and has covered 300 miles since they fitted their 200ah of LiFePo4. There are a couple of technical issues such as the light for lead acid battery fluid and the repair sign stay lit on the dashboard, but nothing major that prevents the car from functioning. 

Below is a video showing a very brief demonstration of Pedalease's success. 

With the good news that you can retro-fit lithium batteries into a G-wiz, I decided to push on with this project and this is where I am today...
 

Above picture: Battery tray space where I plan to install the lithium batteries.
 

BATTERIES BATTERIES BATTERIES!

This is the most important aspect of the build. Some chemistries result in a reduced total capacity that can fit under the seats, whilst others cost far too much to even consider purchasing.  Sourcing the right kind of batteries and the right capacity is crucial for my project to be viable. Through many hours of messaging people, learning new information, getting quotes and even considering building the batteries from the ground up by myself, I have finally gathered all the information I need to proceed. 

When I started my research I had no idea how a lithium battery pack was built or how to measure the space available for the ideal capacity. Now I feel like I can build one with my eyes closed!

Here is a technical rundown of what I understand so far:

  • G-Wiz Peak / Continuous current (amps): 270  / 100 
  • Number of cells in parallel: 234
  • Current divided for singular values per parallel cell group (amps): 1.15  / 0.43 
  • Based on these values almost any 18650 cell can be used but the higher the max continuous rating of any cell used would result in a better performance and a longer lasting battery. 

WIRING IN PARALLEL

  • 13s26p (13 cells in series and 26 cells in parallel).
  • Dimensions = 27 x 52 x 7 cm
  • 9 packs split between trays.
  • Each pack (ah) = 75.4 / 89.7
  • Total capacity (ah) = 678.6 / 807.3 
  • Total range (miles) = 271.5 / 322.9

ADVANTAGES: 

  • Max capacity achieved utilising the available space. 
  • Easy to wire up and connect straight to the motor controller.
  • Bigger modules means cheaper cost per module.

DISADVANTAGES: 

  • Hard to build stable modules of that size without using cell holders. This would increase the dimensions of the pack and it will no longer fit into the space available. 
  • Hard to switch out faulty packs.
  • Less potential to use one big BMS or expensive to buy 1s cell equalisers for 9 packs of 13 cell blocks (it might require 117 1s active equalisers @ £20 each). 
  • Halving the size of the packs (which is an option) means that 18 in parallel might be too many and cause balancing issues during charge/discharge cycles. Far too many individual packs to consider wiring up 1s equalisers.

PLEASE NOTE: With good cells it should be many cycles before they fall out of balance but it will eventually happen and the 1s cell equalisers I found are efficient in ensuring a balanced voltage across cell blocks rather than the tiny discharge using resistors in a BMS. 

Below is the 1s balancer in action:

WIRING IN SERIES 

  • 13 x 8 = 104 cells wired in one huge parallel block.
  • Dimensions = 27 x 16 x 7 cm
  • 26 packs split between trays.
  • 13 cells in series  = 48 v (3.7 v per cell)
  • Two complete packs of 48 v modules.
  • Each pack (ah) =  301.6 / 358.8  
  • Total capacity (ah) = 603.2 / 717.6  
  • Total range (miles) = 241.3 / 287.0

ADVANTAGES: 

  • 3.7 v cell blocks are easy to wire up a BMS and other monitoring systems. 
  • Easy to balance the cells using only 26 x 1s active equalisers to achieve a longer cell life and available capacity.

DISADVANTAGES: 

  • Lose 89 ah of capacity reducing total max range by up to 35 miles. 
  • Requires bigger wires between packs. In series you will have to accommodate a draw of 100 / 270 amps. Split over two 48 v modules is not as worrying. Estimated 50 / 135 (peak) draw per module. 
  • It will cost more to have packs built in this way opposed to the simple 9 large 48 v parallel modules.

ALTERNATIVE SERIES CONFIGURATION

  • 13 x 2 = 26 cells wired in parallel per block.
  • Dimensions = 27 x 4 x 7 cm
  • 117 packs split between trays. 
  • 9 x 48v complete modules.
  • Each pack (ah) = 75.4 / 89.7
  • Total capacity (ah) = 678.6 / 807.3
  • Total range (miles) = 271.5 / 322.9

ADVANTAGES: 

  • Using max available space and would match the range of 9 modules in parallel. 
  • Individual small cell groups makes it easy to replace if any have a fault.
  • Amperage split between 9  might make it easier to wire together (rather than big wires for 2 packs).
  • The ability to buy one 13 s cell group at a time and build the pack up over time.
  • Would work for people who do not want to go as high as 358 ah capacity.

DISADVANTAGES:

  • 9 total modules is a lot of cells to wire up to 1s equalisers and would be very costly.
  • Would be hard to wire up a single BMS. I would need one on every complete 13s module.
  • 117 individual packs might cost more per cell due to more packaging and other components like G10 fire resistant protection. 
  • It will cost more to have packs built in this way opposed to the simple 9 large 48 v parallel modules.

PLEASE NOTE: That the projected range is estimated by 40 miles per 100 ah usable capacity lead acid, the 60 mile range on a g-wiz converted to LiFePo4 and the 150 ah 62 mile range of the g-wiz in India. I have also found a third individual who runs a 100 ah LiFePo4 battery and has achieved a 40 mile range (mimicking the lead acid).

TOTAL WEIGHT OF THE BATTERIES:

  • 1. Lead acid 200 ah = 265 kg  
  • 2. Lithium-ion 717 ah = 135 kg (approx.)
  • Weight saving of a whopping: 130 kg
  • Whilst also increasing the capacity and range up to 8 times!

 THINGS TO CONSIDER

  • Estimations are estimations. Without real world testing I will not know what the total capacity of the packs can achieve. 
  • It is unlikely I will ever discharge the batteries 100% to preserve battery life so 90% at most is likely to be the total range within safe parameters. 
  • Without the curtis programming tool it may be limited to a 45 v cut off which is around 30% remaining charge. 
  •  The 130 kg of weight saved by using lithium could increase the range. 

RANGES OF EXISTING ELECTRIC VEHICLES:
                          High end > Low end

  • 1. Tesla model S = 218 - 315 miles  
  •  Reva G-wiz at max capacity 717.6 ah = 287 miles *
  • 2. Tesla model X = 237 - 295 miles  
  • 3. Chevrolet Bolt = 238 miles
  • 4. VW e-Golf = 125 miles
  • 5. Hyundai Ioniq = 124 miles 
  • 6. Ford Focus E = 115 miles
  • 7. BMW i3 = 114 miles
  • 8. Nissan Leaf = 107 miles
  • 9. Kia Soul EV = 93 miles
  • 10. Mercedes B = 87 miles

Ranges are based on pre-2019 figures.

* Estimated range of the G-wiz based on the standard series configuration. If I chose to go with the max capacity of 9 x 13s26p parallel modules or the 117 series packs then the total range could reach 322.9 miles! The estimated mileage at full capacity is phenomenal and it would cost 1/6th of price of buying a used Tesla. The lower estimated range assuming a 70% discharge would place the G-wiz 4th at 226 miles which is at the bottom end of a Tesla's range - still impressive!

I would love to be able to test and play around with these configurations to see exactly what can be achieved with a G-wiz but I only have the funds to personally support 300 ah of the capacity giving me a modest estimated local range of around 120 miles. 

WHAT YOUR CONTRIBUTIONS WILL GO TOWARDS: (up to £12000 is guaranteed - anything beyond are estimations that can vary based on cost/sourcing of materials and progress of what I require to move forward).

  • £ 6000     = Partially self-funded full capacity 2900 mah cells 271 miles max range*
  • £12000     = 100% kickstarter-funded full capacity 3450 mah cells 322 miles max range*
  • £15000     = A better charging system, 1s equalisers, Curtis programming tool.
  • £20000     = Solar panels and tech to charge the batteries from the sun.
  • £25000 +  = Better materials for trailer building, more solar and long-range testing.       
  • Depending on the total raised, and if there is any spare budget, I might employ someone to film and edit a professional video of the project.

* Max range based on the 9 large modules of 13s26p.

PLEASE NOTE: that real world figures to replicate this project to mirror any capacity of mileage that the individual will need for every day commuting would be much less than these projected costs. Anything over £12000 are extras that will make the car fully self-sufficient and off grid and the core of the project lies in the concept of replicating a Tesla's range on a lower end vehicle. If this project is proven to work, the real world prices to convert a G-wiz to lithium would vary depending on what mileage each individual needs to cover. You can also factor in fast charging and daily travel would be increased significantly per ah of battery capacity. For example: If you require a vehicle that can do 80 miles on a commute to work, then for this capacity the price would drop to the region of £4400 (a max estimated range of 120 miles) and with the option to fast charge you could increase this range to 160 miles or more per day discharging only 80% of the capacity at most. The cost for this would still be considerably less than purchasing one of the lower end similar ranged vehicles. The budget simply enables me to push these ideas and concepts to the limits of what can be achieved and see what is possible. 

THIS IS WHERE THE REAL FUN BEGINS (if more than £15,000 is raised)

  • After installing the batteries and getting the car running, I will plan to build a fully off grid home on wheels like I did with the solar-tricycle. To make this viable weight is a huge issue and so having the funds to build something with light materials would be a valuable asset when it comes to the impact on the range of the vehicle under tow. 
  • This trailer will feature enough foldable solar panels that can be opened out when stationary to enable a modest charge and provide the option and ability to use the sun alone to power the car where ever I might be. 
  • If this gives me a good range per day of charge I will consider doing an 'around-the-world / or Europe' challenge to see just how far it will take me (if the funds are raised to support me on this journey).
  • The solar power will provide a reasonable charge that would save costs in the long run from not having to use the grid for power. This would not be possible with an electric vehicle that had a much higher voltage battery pack without an expensive solar array and equipment.
     

Portable solar power is an easy concept with the new flexible lightweight panels that weigh around 1.5 kg as opposed to the heavy rigid design we often associate with. Here is a picture of the solar that was installed on my tricycle. There was 400 watts of flexi-panels (200 watts on the trailer and 200 watts on the roof) that weighed less than 8 kg vs. 32 kg of the same capacity in rigid panels! The good news is that it works and that it can be up-scaled without worrying about the weight.

Being able to charge lithium batteries directly with solar power without any intermediate processes has been made possible by voltage boost controllers with variable current and voltage settings. 

The green unit in the picture below is the MPT - 7210A controller that is a great unit for the price which solved all my charging needs when I was travelling. It has a rated max input/charge capacity of 10 amps so it would be a little small for this project. There are some amazing boost controllers on the market that would have a max input/charge current of 80 amps but they are over the £500 mark. 

THE BOTTOM LINE

If you have read all of this and feel like you are willing to support a crazy inventor and his interesting ideas I thank you from the bottom of my heart for donating towards the progress of this project. 

This is not just about me, but about what we can achieve by re-purposing, upcycling and using what is within our means to have a better lifestyle that does not support pollution and move one step closer towards saving our planet before it is too late. 

There are thousands of G-wiz still out there today and how amazing would it be to see these little cars achieve the projected range without the need for heavy investments. 

Not everyone will need a Tesla's range and so smaller battery packs would equal a minimal cost to achieve the range they need for daily use. Accompanied with a fast charger, you could save many £'s that you would otherwise spend on tax and fuel. 

The funds raised here will enable me to do the hard work and testing to give people more confidence in taking the plunge and doing it themselves too!

There is very little information out there on the simple task of converting a G-wiz so I will endeavour to record and update on my progress the best I can so that this project can be replicated in the future. 

Help me to change the world, and to create a greener future! 

Thank you... 

I will leave you with a video of my solar-powered tricycle from last summer. Click through to watch the v-logs of the journey down to the south coast. 

Risks and challenges

Risks of completing the project are low: mainly because there is proof that it has been done already in one form or another. The only thing I can think of that could be an issue is the motor controller parameters not working smoothly with the batteries, but this should be easily solvable if I purchased a Curtis programming tool.

The G-wiz runs and was MOT'd at GoinGreen so the risk of the car itself being a failure is extremely low.

The estimated mileage is just that, only guesses based on previous information. But the information I gathered suggests that the validity of this should be close but I cannot promise or claim that the projected mileage will be reached.

The risk of the solar power not working is low as I have already done this on a smaller scale with the solar-tricycle. I simply require the budget to afford the components to upscale it to the G-wiz.

Unknown factors: I have looked at the project from many angles so all bases should be covered.

The only real challenge is raising the funds for me to do this properly. If I do not raise the funds I will not be able to build it to full capacity and thus it will have less range and have less solar which will mean there will still be dependence on the grid.

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