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ZAP Signs Deal with PML FlightLink for New Electric Wheel Motor

ZAP signed an exclusive agreement this week for an advanced wheel motor technology from PML FlightLink Limited of Hampshire, United Kingdom. ZAP secured the PML wheel motor technology to play a key role in the development of next generation electric vehicles being developed with Lotus Engineering. (Earlier post.)

PML is a co-developer of the in-wheel, plug-in series hybrid conversion of a MINI—the MINI QED—shown last year at the British Motor Show. (Earlier post.)

ZAP has undertaken a feasibility study with Lotus Engineering to explore the development of next generation electric vehicles that incorporate the latest advances in technology. The two companies met last week at ZAP’s headquarters in Santa Rosa for discussions with potential suppliers and distributors. In exchange for exclusive rights, ZAP has agreed to an initial order of approximately $10 million in PML wheel motors, subject to terms and conditions agreed on by both parties.

PML’s Hi-Pa Drive—the wheel motor used in the MINI QED—packages an integrated motor and drive electronics in one unit. Three power levels are available, ranging from 40 kW to 120 kW, with torque from 350 Nm to 750 Nm.

Hi-Pa In-Wheel Motors
Torque 350 Nm 500 Nm 750 Nm
Speed 2,000 rpm 2,000 rpm 2,000 rpm
Power 40 kW 80 kW 120 kW
Weight 18 kg 21 kg 25 kg



This is a real step towards the future, I just wish ZAP would build an F150 series hybrid with a smallish battery pack and diesel genset, that would move the market.


2 - 40kW motors would be enough for a compact vehicle (107hp with torque that would put a diesel to shame) to have quite good performance.

4 - 40kW Motors would make for a fairly high performance AWD sedan/wagon.

2 - 120kW motors for a full size truck? Probably overkill.


2,000 rpm is good for 135 mph with direct gearing on average size tyres (185/60R14). 20 kg is a bit heavy for a non-damped item though.

Kirk Ellis

Remember that with a wheel motor you don't get any multiplication of torque because there is no transmission or differential.

So these torque numbers are not all that great.

The 40KW motors -- used on all four wheels -- would give a combined 1400NM torque to the road, which is less than many small four cylinder engines would provide in 1st gear. A typical 1st gear torque multiplication with trans and differential is 15 to 1, so a 90NM torque four cylinder would provide as much low-end torque as using an AWD system with these 40KW motors.

The benefit would be not needing to shift and constant torque through the full speed range. Hill climbing would still not be good, though, and neither would 0-60 times.

It seems like overkill, but I think the only way to get high-performance on even a modest sized vehicle would be to use the 120KW motors in AWD, just as they did in the Mini QED.


Yes, good point. Then again, you also have most of the torque available from 0 rpm and save the 3-4% in losses through internal friction of the transmission and differential (not that those losses make much of a difference).


Your average 4-cylinder car is only in 1st gear up to about 30 mph or so (for a spirited start). If you compare the PML Mini to a Viper, which can get up to 60 mph in first, things get a little more interesting. The Viper has a 1st gear ratio of about 8:1, and engine-out torque over the curve is around 500 N-m. This gives it 4000 N-m at the wheels in 1st, compared to the PML Mini's 3000 N-m. So the Viper is faster than the Mini up to 60 mph.

When the Viper shifts to 2nd (5.5 gear ratio), torque at the wheels drops to about 2750. The PML Mini generates 600 N-m per wheel at top speed, so it will be at least 2400 N-m over the speed range at which the Viper is in 2nd. Once the Viper hits third, the Mini will be out-accelerating it.

As for the 4x40 kW configuration, it would have similar acceleration to a 2nd gen Miata in first gear. Once the Miata shifted to second, the 4x40 would pull away rather briskly.

Dallas Kachan

Inside Greentech interviewed the head of PML FlightLink in a story today today. Read what PML's Martin Broughtwood had to say about ZAP, other automotive deals, volume production and more here.


Well the difference is in time they can make 1000 nm motors for e drives that are just as efficent as the weaker motors... and likely nearly as small too.


It seems to me that wheel motors can provide very good traction and stability control. The control loop does not have to contend with the play in the drive line, it has direct control. If they can make them cheap, powerful and rugged enough, they just might win the design race.

Paul Berg, Sweden, Västerås

Its time for Zap to show the world the eestore system! Because the world need a system like that if it is as good as they say !


how about getting back to 36HP,max and cruising speed 68 MPH.Alas the old Beetle.

Going down a flooded street with a 250v in wheel electric Motor,good Luck.


Paul: I'd like to hear the final verdict on eestor too; but it won't be from ZAP. You must have been thinking of Feel Good Cars (Zenn).

Great: I think you'll find that the wheel motors are very well sealed against dust and water. I haven't had any trouble with mine.

Kirk Ellis

So this article says ZAP has an exclusive deal and the Inside Greentech article says non-exclusive.

I hope it is non-exclusive since I have my doubts about ZAP's ability to follow through.

I'd also like to see somebody take advantage of marketing retrofit kits using wheel-motors. Slap a pair of the 120KW motors onto the rear of a fwd sedan, plus a smaller motor to disconnect the accessories from the engine and drive them electrically as well.

You might be able to convert a lot of vehicles to hybrids for <$10K which would appeal to a lot of people and fleets as long as the equivalent new vehicles are still $30K+.


I look at the conversions as a non-starter. When you look at the conversion costs, the life of the car, the payback period and the various makes and models, I do not think so. PHEVs is one thing. Prius is one model and you are adding batteries. Hybrid conversions sounds nice but I do not think that it is realistic. That is just me and it does not mean that I am right. I wish kits for many cars were available now, but I just do not see it happening at all.

Kirk Ellis

I don't know how large a market there would be for conversions, but there are people out there spending a few grand just to squeeze an extra 50hp out of their gas or diesel vehicle.

$10K to add awd, an extra 300hp, and fuel savings ? On paper it looks plausible. Hard to predict the techno-hot-rodder market, though.

Chris Brown

Does ZAP have the capital for this deal and all thier others? I like ZAP, but it seems they have a ton of these deals going and a new one every few weeks.


People might want conversions, but will anyone supply them? If you look at all the DOT regulations for safety that you would have to pass for a retrofit, I do not know.

It is one thing to sell a hot rod manifold in the after market and another to sell a complete drive line retrofit.

I can remember comments about PM motors and a drive circuit failure that could energize all coils and cause skidding. I thought that was odd, because a fuel pump could fail at 70 mpg and produce similar results.

John Schreiber

I feel that there is a market for conversions, but here in the US fuel would need to cost $6.00 or more, and the conversion would need to be $6000.00. Personally If I could get a hydraulic system with accumulators today at $3000 I would order it today. With so many front drive cars on the road, there should be a relatively simple way to set this up as a kit for the rear wheels. For spark ignition engines though, idling and light load is just so inefficient. However shutting the engine off would be a problem as brake and steering assist would also be inoperative.


In theory with independent wheel hub drive you could do a 360 while sitting in place (by running the right wheels forwards and the left wheel backwards), that would look cool, chew up the tires though, but get some treads on and the conversion to electric tank will be complete.


Does anyone know anything about the prices of the 3 motor types.


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