DIY MG ZS EV Mod Provides Superb Regen Braking & More

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Yesterday, I was invited back to the cluttered but always exciting electronics and engineering workshop of Francisco Shi. He unveiled his breakthrough saying: “If Elon Musk tried this modified MG ZS EV, he would tell his minions to go and modify the Tesla. An all-wheel-drive Tesla and a track with this technology would be amazing!”

Hey Elon Musk
Modded MG ZS EV with engineer Francisco. Photo by David Waterworth.

Francisco has retrofitted his wife’s MG ZS EV for “one-pedal driving.” Before the retrofit, the MG had some regen braking but would not come to a complete stop. It slowed to about 8 km/h and then would continue to creep forward — similar to his BYD Atto 3, but a little better.

After the modifications, the MG will come to a complete stop without using the brakes. He has reset the level 1 braking to act like the old level 3 braking. Not only that, but the car battery receives the same amount of regen no matter what speed you are doing. Previously, the slower the car was moving, the less regen it received.

Perhaps he might make this available to others, as a paid service?

Francisco explains further: “How much braking you get is limited by the maximum torque of the engine and how much power the battery can take in. With the MG, the maximum input is 50 kW. On the lower settings, the maximum braking force at 60 km/h will bring you to a complete stop. I have designed the technology so that the full regen force is available all the way to a stop and can be as finely controlled as if you were using the mechanical brakes. The new level 2 is twice the new level 1, level 3 brings to bear the full torque of the motor.”

Francisco has previously experimented on an i-MiEV, and is perfecting his modifications with the MG. After a short test drive around the industrial estate which is his base, I can attest that it takes some practice to get used to it. I have previously driven an unmodified MG ZS EV. This one is much peppier, and does indeed come to a complete stop. He can even allow the car to roll backwards.

Francisco’s modification has also fixed an issue with the MG ZS EV cruise control. Previously, the cruise control would allow the car to accelerate down a hill until the speed was significantly higher than the legal limit (say, from 100 km/h to 105 km/h) and then apply the mechanical brakes. With the modifications, regen slows the car and keeps it at a constant speed down hills. This is a more energy efficient form of braking and saves on wear and tear. Why didn’t the MG engineers think of this one?

Unlike the Tesla, you do not take your foot completely off the pedal as you use the motor to brake. With this method, you can brake later, adjusting your foot to manage your braking. Francisco tells me that for him, it feels like a nicer drive. My inexperience made the drive a little “lumpier.” The car actually belongs to Krystal, Francisco’s wife. She would prefer not to drive it now, as she also has a BYD. She thinks that the modified MG would spoil her for driving the unmodified BYD.

Francisco tells me that his modification not only enables one-pedal driving, but also provides “obscene accelerator response — far more immediate than any other EV. Put your foot down, take it off immediately, and you can spin the front wheels. It’s like an underpowered GT.” On our test drive, he had an opportunity to demonstrate this. Spin the wheels, he did.

Hey, Elon Musk, take a look at this modded MG ZS EV.

For those without the patience to watch a 20-minute video, the key points are: The unmodified MG takes longer to brake and eventually the mechanical brakes have to be engaged. This is then compared with a Kona which has more aggressive regen and brakes to a stop 50 metres earlier. Now, the modified MG takes the same test and brakes to a full stop using regen and without using the brakes. It is worth noting that the brakes are still there if the driver needs to use them. Comments under the video hail Francisco as a genius.

On a side note, the skid marks on the road in the video show that locals use the area to practice their ICE vehicle braking also — burning up some rubber!

Why not modify the BYD Atto 3, I asked. Apparently, it would be too difficult, as all the controls are internal. It would be hard to put the modifications into one “box” as he has done with the MG. The “box” is simple and can be unplugged easily to return the car to its unmodified state. Francisco feels that the prototype pictured is a bit messy. The final version will be in a box and blend in with the rest of the “under the bonnet” landscape.

Hey Elon Musk
Francisco magic box plugged into the MG ZS EV. Photo by David Waterworth.

To modify a Tesla, Francisco says he would have to hack the communications — a tough job and he’s not sure he could do it without some cooperation from Tesla engineers. A basic Tesla has two and half times the power that the MG has. Imagine what it could do with Francisco’s tech? He says that the he has to be careful with the modified MG in sport mode — he is worried he could make his passengers throw up.

He would like to patent his concept and technology but fears there is little interest. He has had some knockbacks with his ideas to revolutionize manufacturing. “It was hard to get the right person to listen. I ended up talking to middle management and they soon realised that my ideas would mean that their jobs were no longer necessary. Naturally, the ideas were never passed upward.”

He is hoping to sell the device in kit form for the MG, and is also working on kits for other cars. There is a LEAF in the workshop that he is currently playing with. He has to work through the issues around warranty and insurance. Mind you, he points out that the after-market ICE industry does modifications, with the advice to the customer that they are bearing the risk regarding warranty and insurance. He might just do the same. Modifications on an EV are safer than those on ICE vehicles because the components in an EV protect each other, and are programmed to shut down if necessary.

Not satisfied with racing the Cybertruck to market wit his converted Pajero, Francisco is now improving other EVs on the market.

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David Waterworth

David Waterworth is a retired teacher who divides his time between looking after his grandchildren and trying to make sure they have a planet to live on. He is long on Tesla [NASDAQ:TSLA].

David Waterworth has 738 posts and counting. See all posts by David Waterworth