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Discussion Starter #1
Hello,

This is my first post. My name is Brett and I am from South Africa.

My wife runs a photobooth business with various options available. One of them being a photobooth in a VW kombi. We currently have one 1972 kombi with photobooth inside.

We have just bought a 1957 split window Kombi which we will be doing the same thing after its restored.

Since the Kombi is taken to events which can be more then 300km away we pull the kombi around with an A-Frame. These old engine are not very reliable and very slow :). Arriving at the event late also not an option. So, the engine in the Kombi only used to move the Kombi around into position at the event and park it back into its garage when arriving home.

I currently have access to a 48v 10KW BLDC Golden motor with controller for a very good price. Would this suffice for what I need it for? I dont want want speed, just enough torque to maneuver the kombi around. The original 1100 motor in the 1957 Kombi only produced 22kw and 63 NM at its peak RPM range at full throttle. Surely with 10KW electric motor producing 30NM would be equivalent (or better) to half throttle of the original engine?

Your input here would be greatly appreciated.
 

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10kw is probably close to enough to drive the Kombi at highway speeds.

It's certainly enough power to shuttle it around a parking lot.

I'd say you're good to go.
 

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Discussion Starter #4
The Golden motor will be difficult to use due to the high rpm it has to spin to have any power. So you'll need an extra reduction in between the motor and the existing gearbox to not burn out the 'golden' motor.
What makes the Golden motor different from other electric motors? Is it because it’s brushless?

I was thinking of adding a reduction just to be on the safe side. I have purchased the 10kw Golden motor system. Got a really good deal.

Thanks for the input guys.
 

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What makes the Golden motor different from other electric motors? Is it because it’s brushless?
Nothing, it's just a small motor, more sized for go-carts, motorcycles, etc.

also nothing wrong with it, just don't overload them as they don't have the best reputation for ruggedness.

Small motor usually means 'high rpm'

I couldn't find a torque / rpm or power / rpm curve for this motor, does anyone have one?
 

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so where can I see how much torque or power it produces at 50RPM? or 1500 rpm?
You can't. Results like these are from a crude test which consists of spinning up the motor with nothing but a brake attached, then applying the brake while measuing the brake reaction torque, until the motor stalls. The data from free-spinning to peak torque (at 3443 rpm in this case) is published, telling us nothing about the rest of the operating speed range... and so nothing about the important part of the operating range.

All of NetGain's data (except for data for the HyPer 9, which presumably comes from the actual motor manufacturer) is similarly bad. In another discussion the Kelly hub motor web page was linked, and it also has this sort of junk data.

You could generously assume that torque and current are constant at the max value from the max torque speed down to zero, and calculate the power (linearly rising from zero to the test peak at the peak torque&power point)... but that would be optimistic and efficiency would still be a mystery.
 

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Okay so i tried to plot the 48V golden motor data to get the current vs torque and speed curves, shown here.

The slope of the blue line gives the motor torque constant, Kt=0.1076 in m-N/Amp (SI units). This is also the motor speed or back-emf constant, Kb, in SI units of Volts per radian/sec. Taking the inverse of Kb and converting speed to RPM, gives 88.7 RPM/Volt.

So this means that to turn the motor unloaded at 50 RPM only requires about 1 Volt or less at the motor. But as the load increases, then the controller will need to raise the voltage such that the current required to meet the torque load is provided.

Too bad they didn't load the motor down to stall speed and get that current and torque reading, it would be more useful than that crap they provided...
 

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Discussion Starter #11
The test data they they provide is really useless.

I am going to go for a 3:1 reduction using 30mm wide HTD belts and pulleys. This should do the trick right? I should have about 90NM peak torque. Way more than this Kombi ever had :p

I am really battling to find a drawing for the gearbox mounting flange. I thought this would be readily available. I could measure it up but I know many people have made adapter plates for these gearboxes onto various motors so there must be something out there unless they all keeping it a secret. Anyone have a source for these?
 

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I am going to go for a 3:1 reduction using 30mm wide HTD belts and pulleys. This should do the trick right? I should have about 90NM peak torque
I would check the reference documents from the belt manufacturer.

I am really battling to find a drawing for the gearbox mounting flange. I thought this would be readily available. I could measure it up but I know many people have made adapter plates for these gearboxes onto various motors so there must be something out there unless they all keeping it a secret. Anyone have a source for these?
VW Beetle adapter plate

If you stay with Volkswagen's design it isn't simply a flat plate, because the engine (or adapter) is located on the transmission by the circular ridge.
 

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Discussion Starter #13 (Edited)
I would check the reference documents from the belt manufacturer.
The belt will handle the torque. I was wondering what your/everyone's thoughts were on a 3:1 reduction. Or do you think 2:1 will suffice?

VW Beetle adapter plate

If you stay with Volkswagen's design it isn't simply a flat plate, because the engine (or adapter) is located on the transmission by the circular ridge.
This is exactly what I am looking for. Thank you so much. Will get the drawings done ASAP and revert back.
 

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Discussion Starter #14
Managed to find a VW bus trans-axle CAD drawing. Its not the same as on my bus but the bell housing mount pattern is the same. See attached images. Just need to source appropriate bearing blocks for the output shaft.

I am also looking for suggestions for the shaft coupling. I see some use the existing flywheel and clutch assembly. I'm not planning on using a clutch. I don't actually have one. Getting a coupling made with the spline of the trans-axle input shaft is going to a bit a challenge...
 

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I have purchased the 10kw Golden motor system. Got a really good deal.

Hi Brett
All the best for your eVolksieBus project !

Where did you source the motor and i assume controller ?
What are you going to do about batteries ? BMS ?

Where are you based ?
 

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Discussion Starter #16
Hi Brett
All the best for your eVolksieBus project !

Where did you source the motor and i assume controller ?
What are you going to do about batteries ? BMS ?

Where are you based ?
Thanks. There was a guy nearby that imported the motor and controller from Golden motor. He was going to use it on his yacht. He got everything installed and working well and then realized his yacht does not have the space required to mount the solar panels with the power requirement.

I plan to use 4 x 105AH lead crystal batteries. I really don't need much battery capacity. As for BMS, as far as I understand its not to critical to have a high end BMS system as required by lithium batteries? I think just a low and high voltage cutout will do the trick. Still need to find a decent charger though. Any suggestions?

I am from Durban, South Africa.
 

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No I meant Lead crystal. They are like Lead acid but with much better properties. They can be charged twice as fast and recover fully from 100% depletion. They are commonly used in golf carts and solar systems.
I hadn't heard of that term. Lead Crystal is a brand name for AGM batteries from Betta, not a generic type. The name comes from the use of a SiO2 based electrolyte which apparently crystalizes, and lead calcium selenium alloy plates are used. This sounds like a gel battery to me, and as the patent application describes, the electrolyte is still acid so it is still a lead-acid battery.
 

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Discussion Starter #20
I hadn't heard of that term. Lead Crystal is a brand name for AGM batteries from Betta, not a generic type. The name comes from the use of a SiO2 based electrolyte which apparently crystalizes, and lead calcium selenium alloy plates are used. This sounds like a gel battery to me, and as the patent application describes, the electrolyte is still acid so it is still a lead-acid battery.
Yeah its basically is a gel battery. Betta Registered the term "Lead Crystal". A few other brands are also using the term "Lead crystal" now. 100% agree they are all ultimately Lead acid chemistry.

A friend of mine has been using Lead Crystal batteries on his yacht for 6 years now and he hasn't noticed drop in performance or capacity. I'm sure there must be, just not noticeable. If used properly they can be good for 15 years.
 
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