Team-BHP - My Tata Ace EV Conversion Project

Hello Fellow BHPians,

Background:

Recently I had seen a lot of videos online where people started converting ICE vehicles to EV. The launch of Nexon EV & MG ZS EV has spiced up the EV market and also sparked an idea in my mind.

Idea:

One of my friend owns a factory in Hyderabad and he owns around 4 Tata Ace vehicles for goods delivery. I approached him with this idea to convert his Ace pickup truck to EV and he was excited as well, as he was fed up with diesel and other maintenance costs. He proposed to start the conversion with 1 vehicle and if it is a success, then we will convert the rest of them.

Problem:

There are a lot of startup's in India like e-Trio and BharatMobi, which by coincidence are all based in Hyderabad and are in to retrofitting ICE to EV vehicles, unfortunately they currently do not offer any readymade kits for Tata Ace vehicle.

One fine day me and my friend started visiting local mechanics and the biggest road block here is, almost all of the mechanics are clueless on how to do it. They have no idea how much capacity motor and battery is required or where to start.

Solution:

I decided to take things in to my own hands and I am planning to tie up with some local experienced mechanics and electricians to get the ICE engine removed and retro fit it with Electric motor. This way I will learn something new and can test the waters myself.

So I have decided to start a thread here to capture my journey of EV conversion and I will be updating this thread regularly on the progress, conversion process, cost, road blocks etc. Hopefully this will help others are who are planning something similar and are looking for guidance and assistance.

I deeply value inputs and suggestions from fellow BHPians on this project.

Steps:

Identify the vehicle
Calculate the motor power requirements
Calculate the battery requirements
Actual Conversion
Price Estimates
Testing
Re-engineering (if required)

Identify the vehicle:

This step is done. Tata Ace Diesel has been selected for this project. A bit of technical specifications of the vehicle below

Engine:

Model :TATA 275 IDI Diesel BS IV
Type :4 stroke, naturally aspirated, indirect injection diesel engine
Max. output :11.3 kW (16 HP) @ 3200 r/min
Max. torque :37.5 Nm @ 2000 r/min
Displacement :702 cm3
Special items :Catalytic converter (only in BS IV)

Dimensions:

Length (mm) :3800
Width (mm) :1500
Height (mm) :1845
Wheelbase (mm) :2100
Front Wheel Gauge (mm) :1300
Rear Wheel Gauge (mm) :1320
Loading Deck Length (mm) :2140
Loading Deck Width (mm) :1430
Height of Side Panels (mm) :300
Min. Turning Circle Diameter (mm) :8600

Weight:

Max. GVWR : 1550 kg
Kerb Weight : 840 kg
Seating capacity : Driver + 1

Source - https://ace.tatamotors.com/tata-truc...fications.aspx

Calculate the motor power requirements:

Weight = 840 kgs
Length = 3800 mm = 3.8m
Width = 1500 mm = 1.5m
Height = 1845 mm
Max Speed = 50
Efficiency = 85%
Wheel Size = 13 inches
Wheel Radius = 6.5 inches = 0.165
Linear Distance Traveled = 2πr = 2 x 3.14 x 0.165 = 1.0362

Speed = 50000/3600 = 13.88 m/sec

RPM = 50000/(1.0362*60)=804.24

Power=[(Mass in kg) x (Velocity in G) x (Velocity in m/s) x (Rr)] + [(Air Density x Cd x Area (Length x Width) x Velocity to power of 3)]

= (840*9.8*13.88*0.01) + (0.6465*0.6*5.7*2674)
= 1,142.6 + 5,912.29
= 7,054 watts

Drag coefficient Cd source - https://en.wikipedia.org/wiki/Drag_coefficient

As per above calculations, we have concluded that we would require approximately 7,054 watts power motor. However, currently in market we can get either 6,000 watts or 8,000 watts kit, so we decided to procure 8,000 watts motor kit.

We contacted a supplier in New Delhi from Karol Bhag area and got a quotation of around 1 lakh for the electric motor, controller, wiring and charger (battery excluded), as it is a big investment, we wanted to be 100% sure before we proceed with the motor purchase

Anyone any thoughts on the above calculations? We will double check the calculations and will take thoughts from other mechanics and electricians as well before we proceed.

Mod Note: Please feel free to move the thread to appropriate thread.

DISCLAIMER : I AM NO EXPERT IN THIS FIELD.

This has been a trend going on for sometime now and lots of youtube videos which claim successful conversion. In most of these videos , you don't get to see the final product and evaluate its performance after conversion. Even on this forum there was this thread which seems to have ended abruptly.

https://www.team-bhp.com/forum/elect...n-project.html

IMO, For this type of project , you need basically the following.

1. A big enough garage with necessary equipment / tools , possibly a hoist crane and safety equipment.

2. Basic knowledge of electrical motors, control and repair. Not to forget basic ICE repairs.

3. Most important : Time, patience and money.

4. Machine shop nearby with necessary skilled technician to make all those brackets, adapters etc.

The basic problem, if you ask me , would be to match a Trany built for a ICE to a electric motor. The torque speed curves just won't match. The elephant in the room would be, of course, sourcing necessary batteries which are costly.

So here's wishing you all the best.

PS : Did not know that TATA ace produced only 16BHP.

Quote:

Originally Posted by srini1785 (Post 4720207)

I totally agree. Most of the videos only provided basic knowledge of how to convert, the long term reliability is still a big concern. Having said that, we are planning in such a way that if not satisfied with output, we will revert back to the ICE Engine. It would be a costly mistake, but good learning experience.

Due to budget constraints we are not going with lithium batteries, we will be using conventional batteries, though they eat up a lot of space and require more time to charge and maintain, they are costing 10% of lithium batteries.

Unfortunately we do not have a garage at our disposal, we are completely relying on the local mechanic shop for this. We have finalized couple of mechanics who were enthusiastic about the idea. They were really excited about this and one of them even agreed for free services as it would be learning curve for him as well (Maybe he intend to start conversions as well). We are yet to finalize a mechanic. We wanted to be 100% sure on the motor capacity before we proceed.

Quote:

Originally Posted by Shreyans_Jain (Post 4720241)

You've not included the torque multiplication provided by the gearbox and drivetrain in your calculations. Ideally, you need to figure out the torque at wheel at different rpms in each gear, and select your motor accordingly.

These CVs are geared short to maximize the go from these tiny engines. Actual torque on wheel will be much higher than what your math suggests.

Agree, however, we are planning to make it automatic and not manual transmission. Any thoughts on this? Also are the calculation for power tight? Any inputs will be appreciated.

Quote:

Originally Posted by ramnaresh_2000 (Post 4720260)

Agree, however, we are planning to make it automatic and not manual transmission. Any thoughts on this? Also are the calculation for power tight? Any inputs will be appreciated.

All EVs including Teslas are direct drive. They do not have a gearbox, whatever reduction there is is provided by the drivetrain and differential itself. EVs produce max torque straightaway at zero rpm hence don't really need multi speed transmissions, especially for low speed applications. Only Porsche is experimenting with a 2 speed gearbox on the Taycan for better efficiency at high speeds.

You can benchmark with a basic electric rickshaw. If a rickshaw with , let's assume x hp motor weighs 150kg and carries 2pax + driver, we are looking at 3*75 + 150 = 375kg. So if your Ace weighs say 1500kg with load, you'll need a motor with 4x hp to power it, and should expect performance similar to an electric rickshaw.

Alternatively, the engine in the Tata Ace is rated at about 17hp which is approx 12.5kw. So you can consider starting off with a 10kw motor and see where it gets you.

The Mahindra eSupro van has a 25kw motor, for reference.

As this is something for actual real world usage and not an engineering final year project, I'll suggest the best way forward is to consider the eSupro van as it is for your application. A proper and factory made vehicle backed by warranty.

Quote:

Originally Posted by Shreyans_Jain (Post 4720324)

You can benchmark with a basic electric rickshaw. If a rickshaw with , let's assume x hp motor weighs 150kg and carries 2pax + driver, we are looking at 3*75 + 150 = 375kg. So if your Ace weighs say 1500kg with load, you'll need a motor with 4x hp to power it, and should expect performance similar to an electric rickshaw.

Alternatively, the engine in the Tata Ace is rated at about 17hp which is approx 12.5kw. So you can consider starting off with a 10kw motor and see where it gets you.

I agree with this calculation and I actually tried with Mahindra Treo which is 350 kgs and has 5.4 kw motor and can carry 3 extra people along with driver. So 350 (vehicle weight) + 300 (4 persons weight) = 650 kgs with 5400 watts motor which is around 8.30 watts per kg.

Comparing with Tata Ace which is approximately 800 kgs + 2 persons + additional 1000 kgs load which comes to 1950 kgs, so I would need 16.2 kw motor. Finding 10 kw motor is impossible these days, so 16.2 kw motor was out of question. The max I was able to find was 8 kw motor, the supplier said he can provide 10 kw on special order and will import from China and will take around 1-2 months :Frustrati. Again not trying to break any speed records, we will be happy with 50 km/h top speed.

Also done with the torque calculations

Torque Calculation

Efficiency = 85%

E = P Output / P Input

P O/P = E X P Input

Torque X W = 0.85 X 7,054

W = (2pi X RPM) / 60

W = (2 X 3.14 X 804.24) / 60

W = 84.17

Torque = (0.85 x 7054) / 84.17 = 71.23

Battery

Requirement - Distance per charge and at what speed?

Suppose I require 80 kms per charge at maximum speed of 50 kmph

In 1 Hour at 50 kmph power consumption = 7054 watts

7054/50 = 141.08 wh/km

Electric Motor = 60v

Ah used per KM = 141.08/60 = 2.351 ah/km

Ah = 2.351 X 80 X 1.25 (1.25 for 20% Battery left after drive) = 235 ah

Lead Acid = 235 x 1.8 = 423 ah

Lithium Polymer = 235 x 1.05 = 246 ah

Quote:

Originally Posted by AdityaDeane (Post 4720347)

Why don't you contact them at the page below and see, before venturing into the project yourself and getting stuck midway?

But their kits are quite costly. I had asked them about converting my Tata Nano to electric, and they didn't have a kit for it. But they told me that a typical conversion process takes about a minimum of Rs.6.5 Lakhs. So, depends on whether you want to do a DIY and spend a lot of time and money and get it approved at the RTO yourself, or give them your moolah and get it done in about Rs.6.5 Lakhs a piece.

Yes we did contact them, but the response was different to what they gave to you. We were told they have a kit, but they are currently doing it for bulk orders only for large fleet companies like Uber/Ola. Also 6.5 lakhs for retrofitting is plain non-sense, it maybe Nano or Ace, the ROI is non justifiable. We had a fixed budget of 2 lakhs and it would be a nice learning curve.

Also they have been very cheeky on their website if you observe closely. They currently do not have any kits for Ace, they just mentioned about Ace it in "Our Solutions" section and not in "Our Products" section. Also no information available on Ace kit like power etc, however, all details mentioned in "Our Products" about EV 150 and EV 180. This is just marketing strategy to attract customers, once they acquire customers, they will then design from scratch or something like that.

Quote:

Originally Posted by Shreyans_Jain (Post 4720324)

You can benchmark with a basic electric rickshaw. [Snip]
The Mahindra eSupro van has a 25kw motor, for reference. [Snip]
I'll suggest the best way forward is to consider the eSupro van as it is for your application. A proper and factory made vehicle backed by warranty.

A very good suggestion. Both rickshaw and a esupro van would be a good starting point since you don't need to worry about the compatiblity of the controller to the motor. If you go ahead with this suggestion ,i suggest that you get it as a set i.e Battery, Controller and the motor.

Quote:

Originally Posted by AdityaDeane (Post 4720347)

I had asked them about converting my Tata Nano to electric, and they didn't have a kit for it. But they told me that a typical conversion process takes about a minimum of Rs.6.5 Lakhs.

Probably quote includes labor. Its very labor intensive work. The kit alone would be lower i guess. I may be wrong.

Quote:

Originally Posted by honeybee (Post 4720417)

How about regenerative braking?

Not to worry at this stage. Just get the troika running :D.

Quote:

Originally Posted by honeybee (Post 4720417)

How about regenerative braking?

EVs too will have some kind of an ECU, right? Will you be able to get this off the shelf?

And since it's not a project, how will you ensure the resultant vehicle is road legal? I doubt if the RTO would register or endorse such a mod.

Regenerative braking is currently not in scope. In my honest opinion it is a totally hyped concept. EV's like Kona have regenerative braking, but how much energy it is actually sending back to battery is unknown. Some videos says it hardly sends 5% charge back.

EV kit we are procuring has a controller in it. If the initial test vehicle is successful, then we are planning to get ARAI certified kits for remaining vehicles. RTO already approved retrofitted ev vehicles in Hyderabad.

You can check below link for details. Fuel type will be indicated as "Battery" in RC of vehicle

https://www.autocarindia.com/car-new...ana-rto-412304