I thought this most interesting.

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Grandad
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I thought this most interesting.

Post by Grandad »

All I can say is wow!
Looks very innovative.
I love the idea it can reverse into parking spaces by itself, not to mention the break away system still under development.
Now imagine if they can get that working.

https://www.caravancampingsales.com.au/ ... sc.8126025

T1??? Lithium Ion???
Is this the next step?

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Jim
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T1 Terry
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Re: I thought this most interesting.

Post by T1 Terry »

Hmmm...... a 16kWh battery as a 12v lithium battery would be around the 1230Ah (LiFeP04 nom battery voltage is 13v) 115kg for the battery pack comes in at around 140Wh per kg, quite within the believable range with the Tesla battery packs coming in at around the 207Wh per kg.
The bit I'm most interested in is the VFD (variable frequency drive) and associated electronics that drives the hub motors, how does this link into the drivers control set up. To get 16kW from a 52v hub motor it will require around 300 amps, so we are talking about some serious equipment and cabling.
As far as I know it is still illegal to have a vehicle drive system without full control being integrated into the driver control system, even with the up coming autonomous vehicles. The driver must still be in a position to take over full control of the vehicle. The fact that "full control" is rather grey area when towing a caravan at any time becomes even worse if control is lost and the caravan actually starts to push the tow vehicle over and above the problems already encountered with weight and the tail wagging the dog.
From the article [quote16kW/508Nm hub motor to drive the wheels][/quote] If that is per wheel and they plan to add one to each wheel on a tandem axle van, then that is a total of 64kW drive at the wheels, more than quite a few tow vehicles produce at the moment .... can you imagine the carnage if that ran amuck and started pushing the tow vehicle down the road? No way you could stop it with the brakes, that has already been proven a number of yrs back with the computer controlled throttle cars that went berserk and killed a lot of people before they tracked down the cause.

I've put forward this idea some 20 yrs ago for highway trucks, a simply fuel powered gen set in the prime mover and a drive motor on each wheel that can double as a brake with regenerative braking. The powers that be said no way on a public road because of the possibility of the loss of control of the drive motors. They already use this principle in the big mine trucks, each wheel has its own electric drive and all controlled from the cabin, but I'm yet to see it on a trailer .....

A great idea if they can get it through the ADR's and can get the things legal on the road and it would spell the end for any RV type house battery sales in the future because the battery pack would already be part of the vehicle.

T1 Terry
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pet-els
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Re: I thought this most interesting.

Post by pet-els »

Because they are a motor driven trailer, does this make them a Motor Home ??

PeterH
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Grandad
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Re: I thought this most interesting.

Post by Grandad »

Terry, surely the ability for the driver to take control would be as simple as having the motors connected to the brake lights in the same way we now control electric brakes. Touch the brakes and all hub motors cease driving.
Under normal circumstances I would assume that when braking the hubs would be in regenerative charging mode anyway. Not drive mode.
So this connection with the brake lights would be a failsafe thing. Perhaps a double failsafe might be bluetooth control from the brake peddle in the case of a failure of the copper wire connection?

When I first saw the 16K Kw/hr figure I did a quick little Ohms law calcuation and came up with the same 1230 ah you did but thoughht, no way is that feasible. How about that? It IS feasible. Bloody amazing.

It's that break away thing they're working on that fascinates me. I'm just imagining all the things they have to overcome. For just one consideration, the jockey wheel would need to be steerable. Now that would make for one very interesting jockey wheel.
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Re: I thought this most interesting.

Post by Busman »

I wondered about the 52 volt system, seems an unusual number ?
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T1 Terry
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Re: I thought this most interesting.

Post by T1 Terry »

pet-els wrote: Sat Mar 02, 2019 5:18 pm Because they are a motor driven trailer, does this make them a Motor Home ??

PeterH
It gets even greyer Peter. Some of the bendy buses we see running around the metro areas have the engine and drive in the back of the first part, that makes the second part a trailer and by law it is illegal to carry people on a moving trailer or caravan.
Some I saw in WA had the engine and drive in the rear "trailer" section and it pushed the front half along. In this case the driver must have had control of the drive train and the whole steering thing must have been a crazy mix of hydraulics and computer control so the rear didn't jack knife the front when going around a corner and accelerating at the same time.

The difference with a powered caravan is the hitch point and no hydraulic rams either side to control the angle. If the caravan started to push the tow vehicle via the hitch which is centre and already mounted a long way past the rear axle (more than 60% of the wheelbase or the distance between the front and rear axle) the caravan would become the steering device with absolutely no control or direction. This is the cause of all the caravan roll-overs to date, so adding even more push has only got to make the problem worse.
Of course this would only happen in a failure in the caravans drive control and we all know computers never stuff up :P

T1 Terry
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T1 Terry
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Re: I thought this most interesting.

Post by T1 Terry »

Grandad wrote: Sun Mar 03, 2019 9:05 am Terry, surely the ability for the driver to take control would be as simple as having the motors connected to the brake lights in the same way we now control electric brakes. Touch the brakes and all hub motors cease driving.
Under normal circumstances I would assume that when braking the hubs would be in regenerative charging mode anyway. Not drive mode.
So this connection with the brake lights would be a failsafe thing. Perhaps a double failsafe might be bluetooth control from the brake peddle in the case of a failure of the copper wire connection?

When I first saw the 16K Kw/hr figure I did a quick little Ohms law calcuation and came up with the same 1230 ah you did but thoughht, no way is that feasible. How about that? It IS feasible. Bloody amazing.

It's that break away thing they're working on that fascinates me. I'm just imagining all the things they have to overcome. For just one consideration, the jockey wheel would need to be steerable. Now that would make for one very interesting jockey wheel.
Jim
I'm guessing the steering would be via skid steer, slow one side tandem drive and speed up the other. I'm guessing a jockey wheel up front on a hydraulic ram that could be self lowered and the jockey wheel itself on a swivel roller mount so it could swing in any direction the van's drive wanted it to go. It would make caravan parking very easy, just unhook and drive the van back in via a remote.
Another possible would be a much better front dolly arrangement on the caravan that is in permanent contact with the road so the tow vehicle no longer carried any of the weight on the hitch, it just guided the direction the dolly steered.

The driver taking control is the whole issue here, it has already been shown that the computer can stuff up and take control all by itself, a lot of people were killed by these run away cars. we all know just how often the control of the electric brakes on the van can be lost and the frequency of a Bluetooth signal drop out is very high. Remember the red faced incident for Mercedes Benz when the cars that were supposed to have computer control that would stop them from running into vehicle in front, instead ploughed into each other when the front vehicle stopped suddenly, in front of all the press cameras :lol: Turned out the satellite signal was lost because they were under ground. These advanced controls stuff up, that is why a driver must still be ready to take control, but there would be no driver in the caravan ....

T1 Terry
A person may fail many times, they only become a failure when they blame someone else John Burrows
If we have data, let’s look at data. If all we have are opinions, let’s go with mine. – Jim Barksdale, former Netscape CEO
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T1 Terry
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Re: I thought this most interesting.

Post by T1 Terry »

Busman wrote: Sun Mar 03, 2019 9:46 am I wondered about the 52 volt system, seems an unusual number ?
14 x 3.6v nom. cells in series =52vdc. To convert that to AC for the 3 phase hub motors is the bit that I can't get my head around the maths at the moment. They are either 48v 3 phase motors or 36v 3 phase motors. The fact all the electric car makers are going up in voltage not down says there are a lot more looses at the lower voltage end than the high voltage end. 720vac 3 phase and higher are becoming more the norm than the exception. There are already inverters to produce 240vac from these battery packs so nothing new to develop there.
A centre mounted Chev Bolt drive would make a lot more sense. Put the VFD and control in the tow vehicle so any loss of signal from the VFD or control would turn it back into a caravan and probably apply regenerative braking. The problem now is integrating the Chev Bolt stuff into the tow vehicle stuff, can be done but it is no longer a simple hitch up at the caravan yard and drive off. Each time the tow vehicle was changed the whole drive gear and interface for the caravan would need to be swapped over as well.

I see a move to electric and hybrid drive motorhomes being the more likely move in the near future making them a cheaper per km unit than dragging a caravan around. This might just be an attempt to put forward the idea of a self drive caravan even if it isn't practical, much like the idea of "Clean Coal" :roll: Sounds great and they are always just on the edge of making it a reality ...... for the last 20yrs :twisted:

T1 Terry
A person may fail many times, they only become a failure when they blame someone else John Burrows
If we have data, let’s look at data. If all we have are opinions, let’s go with mine. – Jim Barksdale, former Netscape CEO
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Re: I thought this most interesting.

Post by Greynomad »

pet-els wrote: Sat Mar 02, 2019 5:18 pm Because they are a motor driven trailer, does this make them a Motor Home ??

PeterH
Also my immediate response, Peter.
Remove the drawbar, and you have a motorhome. ;)
Then they could join That Organisation as full-voting members! :lol: :lol: :lol:

Of course, balancing on a single axle would be fun.
Even on a dual axle, if two people went to one end of the van, it would drop to the ground.
T1's front dolly idea would probably solve that for the forward end, but what if the bed is at the rear, as is common?
It would also make load distribution fore-&-aft critical.
Maybe they need to consider trailing wheels as used on dragstrip funny-cars & motorcycles to prevent them flipping over backwards under acceleration...
Or maybe adapting the balancing software from the Segway??
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Ray
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Re: I thought this most interesting.

Post by BruceS »

You always have to do things the hard way Ray.
A quick call to Collyn would sort it out & he could write another book about it!
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