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Excellent progress and good write ups. I really enjoyed a good read this morning along with the difficulties you had in the project. I'm curious on the project cost you had to endure? Maybe do a recap of all of the components in one place when it is all said and done so some may be able to use your information.
 

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Discussion Starter #22
Can you tell us the motor specs?
The motor is a 4kw BLDC motor, with a peak draw of 12kw. Max rpm of 2000, peak torque of 75nm. A fairly generic motor from aliexpress. With hind sight I probably would not chose this motor if I were to do this again (I have another quad already lined up, so it's likely). I would probably go up a bit in power.
When I bought this motor I was not that far into the project and very new to the whole thing.

Csecrist12 said:
I'm curious on the project cost you had to endure?
Currently the project cost is just over £3,400. Original budget was an optimistic £2,000.
The Costs are split into 5 categories. Just over £1,000 on the bike and restoration of it to a good condition.
Just under £2,000 for the motor, batteries and related wiring etc.
£170 on the drive train modifictations
£32 on 12v wiring since that was redone completely.
Just under £300 on mistakes, buying components that didn't fit quite right etc.

I expect there to be a few more costs to finish off the 12v wiring, make the chain guard, finally buy a right hand foot peg and register it for agricultural use.
I'll do another list once it is complete.

I have a short video of movement!
https://youtu.be/i9OxpLYsoVA

Once the fields dry out I'll be able to do some range testing.
 

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Hi Lrben
That is decent output then.

Will you do another build thread for the new quad? I'm very impressed by QS Motor mid drive motors. The 3000W does up to 20kw without problems and they are releasing an 8000w motor also which would be perfect for a 4wd quad.

Thanks for sharing.

Cheers
Tyler
 

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Discussion Starter #24
Will you do another build thread for the new quad? I'm very impressed by QS Motor mid drive motors. The 3000W does up to 20kw without problems and they are releasing an 8000w motor also which would be perfect for a 4wd quad.
My next project is still up the in air. But what ever it is I will make a thread for it. The Quad is an easy one to do, but I am also replacing the head gasket on my MG F at the moment, if the head on that turns out to be warped then that will jump to the top of the queue for electrification.
I have also been looking into converting one of the tractors on the farm, a UTV would also be an useful conversion. I also would quite like a commutable vehicle as well if the MG doesn't happen, so perhaps a motorbike.
So one of those... I'll keep that QS motor in mind though if I do the quad.

There is still a bit to do on this project though, the cell voltage drop came back when I did a long range run last weekend. I noticed that the cell is also higher than the other cells when charging, by the same amount it drops by. So that might throw a big spanner in the works as I haven't been able to find any more of those E48 pouch cells.

Everything is on hold now though as I don't live close enough to the quad bike to get there with the current movement restrictions.
 

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Discussion Starter #25
Obviously very limited progress recently. I can no longer make special trips to work on this, but am managing to put in an hour or two here and there when I am near the unit for work purposes.

I have decided to redo the braking system. My intention was to use the rear brake light switch to activate the motor regen. However this is just an on/off switch and the max motor regen is very strong. So I am going to remove the front brake lines and hook up a 5v pressure sensor to the brake master cylinder, this will then give me some finer control over the motor regen.
I was never very happy with how I redid the front brake system and it wasn't really fit for purpose. Given the low speed and non-road going nature I don't think they will be missed.
I will still have the rear brake for a mechanical back up and for the hand brake.
 

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I have decided to redo the braking system. My intention was to use the rear brake light switch to activate the motor regen. However this is just an on/off switch and the max motor regen is very strong. So I am going to remove the front brake lines and hook up a 5v pressure sensor to the brake master cylinder, this will then give me some finer control over the motor regen.
I was never very happy with how I redid the front brake system and it wasn't really fit for purpose. Given the low speed and non-road going nature I don't think they will be missed.
I will still have the rear brake for a mechanical back up and for the hand brake.
You could trigger regen from the rear brake, presumably using a spring and a position sensor on the mechanical linkage, and keep the more effective hydraulic front brake. I understand that this would require reworking the front brake system, but it would make much more sense to me: rear wheels electrically driven and braked (handling low-speed braking), front hydraulic friction brakes (handling the highest braking effort, particularly from higher speed).
 

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Discussion Starter #27
You could trigger regen from the rear brake, presumably using a spring and a position sensor on the mechanical linkage, and keep the more effective hydraulic front brake. I understand that this would require reworking the front brake system, but it would make much more sense to me: rear wheels electrically driven and braked (handling low-speed braking), front hydraulic friction brakes (handling the highest braking effort, particularly from higher speed).
If this was a road going or higher speed bike, that would be a good suggestion as it isn't ideal to lose the good brakes. But in this build I am less concerned about the controller over heating and shutting down as it will never be going at a speed where it would really matter.
 

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Discussion Starter #28
It's done! Well it's been done for a month or so now.

As a farm run around I would say it is perfectly capable. It has good power for the muddy bits and a great battery life. It can tow but the motor doesn't have any fins or other form of cooling so it doesn't like going above 4kw for very long, the phase wires are also pretty thin.
I have towed this trailer attached with 100kg of weight in it, with one completely flat trailer tire up a reasonably steep hill. It didn't complain but the motor was very hot. I am considering adding a water jacket to the motor and changing the phase wires for something thicker in order to cope with some higher power outputs for longer.

I actually still need to do the chain guard, which I think I will combine with fairing sides that completely enclose the engine bay. I also ordered the 4kw QS mid mount motor today. So that might end up in this bike with a bigger reduction for more torque and a useful top speed.
 

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