4QD Ltd

14/10/2026

Here's a video we put together to look at the maths behind making a Greenpower car perform well.

A look at the maths behind making a Greenpower car perform well. We...

07/10/2026

Hey, are there any Greenpower teams out there who are using a Pro-100 or 160 and have some data log files from actual races that they'd be willing to share with us? [confidentially of course!] We're working on a slide set to show how all the variables interact. Please send the files to [email protected] Thanks very much!

30/09/2026

Here's something new for us. John needed a new controller for a Mini-EL. A Pro-160-HC is sufficient to match the specs of the motor. The big puzzle was finding a throttle pedal to fit the space, but a Land Rover unit eventually did the job.

28/09/2026

Mike sent us this picture of Coleg Gwents Greenpower car. What stands out is that they managed to get a lap record in only their 2nd year of competition. They are using a Pro-160-S which is probably a bit of overkill, but after a long discussion today they will be using the data logging and coulomb counting features to completely re-work their race strategy. I suspect a podium finish is not far off.....

24/09/2026

Our next video looks at whether it's best to connect motors in series or parallel.

A quick look into the trade-offs between connecting electric motors...

17/09/2026

Here's the next in our series of videos on the Pro-100 / 160 / 360 features. This one is all about how the current limiting works.

16/09/2026

When we designed the Pro-160 hardware we included a CAN port but up till now we've not had the time to write the software for it. But Erica has been burning the midnight oil recently and has now got it working. It means that all operational data can be streamed out, and operational commands for duty cycle, current limit, and regen current limit can be sent in. It will apply to the Pro-100, 160, and 360 models. It will be included in the soon-to-be released 2.5.7 software. It will also need a small CAN expansion board.

09/07/2026

Go Cambridge!
https://www.youtube.com/live/VxsVPBy9P9E?si=XvrIzfq7Go6IEBYe

10/06/2026

Sometimes you’ve just gotta do the maths!
A customer of ours is on a mission to get his Sinclair C5 to do 40mph [we won’t ask why!]
The original motor was 250W and would push the C5 to about 15mph, so fitting a 750W motor should be a big improvement, right?
Well it turned out not quite so easy. The new motor briefly pushed the C5 up to 27mph but then expired in a cloud of smoke. Running the numbers on the gearing showed that the motor was only reaching 2600 rpm and not its 3300 peak efficiency speed. This meant it was not spinning fast enough to generate sufficient back emf and that the controller was forcing nearly 1kW into it with predictable results.
So how much power would be needed to reach the magic 40?
The power required is dominated by the aerodynamic drag which scales approximately with the cube of the speed.
We used the formula
P2 = P1(V2/V1)3
Substituting the values
P1 = 250W
V1 = 15mph
V2 = 40mph
It kicked out the answer of 4.7kW which means that he’ll need to either find a much more powerful motor, or do some serious work on improving the aero, and reducing the rolling resistance.

22/04/2026

We're sponsoring a Cambridge University team to compete in the Monaco Energy Boat Challenge. This involves a series of speed, endurance, and slalom races. They're using a Lynch motor and one of our Pro-360-HCs. The data logging feature is proving its worth. Here's a clip of them in early testing....