[arklan]

Hi all
While firkling around on the net I came across the Hyundai/Enova units. On a whim I bought one with the idea of converting my old (91) toyota townace.
I am very new to this game so I hope you are all feeling benevolent when it comes to answering stupid questions if I can't find what I want from what is already on the site.
My aim is for electric drive with onboard charging from a tesla turbine driving a bank of alternators. This may well prove to be a ridiculous idea so could change dramatically on the fly, but you have to start with a plan of sorts, don't you.

yes its a rediculous idea
but dont take that as a critisism, rather as something to save u from wasting a lot of time

 

[generalfactotum]

I've no idea how this got here, it was supposed to be in Chit Chat!
Thanks for the response. Which bit is the ridiculous idea?
Contemplating EV-ing a townie or carrying an independent charging system for places with no access to external charging?

 

[arklan]

carrying the charger, youll find that u just wont ever need it
and the extra weight will limit your range by a really small amount.
you could convert the car first and then afterwards if u need a portable charger you can add it

 

[onegreenev]

Just build the car with a large enough battery pack to take care of the range you need. Simple. Keep it that way.

You can test your tesla turbine and calculate how much power it will take to make it work vs what you get out of it for charging your pack. Make a small version. What will you use to power the tesla turbine?

 

[generalfactotum]

It's certainly a good idea to do the conversion first, I shall do that. The problem I have is that one place I go fairly often is 100 miles and there is no access to a charge there so I thought that the turbine which pre-dates the EV idea would be useful.
I already have 16 laser cut 220mm dia discs and spacers so the turbine size is defined.It was decided because the total size will be the maximum that my lathe can take. Next is to ream the centres and freeze the 1" shaft to get a tight fit.
At the moment I am printing parts for a test rig to determine how much energy I can get from blowing various fuels+ air through a 400,000 volt triple arc compared to the input energy.The noise from the arc is awesome!
If that is successful I will power the turbine with a combustion chamber as in a jet engine.

 

[onegreenev]

Just buy an extra pact to cover the extra distance you need. It will be much easier and cheaper. So in other words you want to build a custom turbine powered by jet fuel just to charge your pack so you can get home. Seems rather complicated. A simple battery pack and charge before you leave ensuring you get home. Simple. It's the KISS principle. Follow it and you will save some big bucks.


It's like wanting to use hydrogen to run through a fuel cell to create on demand electricity to power your electric car. Just because you can does not mean it's a good idea more does it mean you should. It's been proven cheaper and simpler to just use a plain old battery.

 

[generalfactotum]

This project being brand new I haven't done any calculations but for a townie loaded with tools and gear at around 55mph I guess will require at least 144volts, and for a guaranteed 100 miles probably needs 2 battery banks.
Wouldn't the added weight of an extra 24 heavy duty batteries be self defeating as far as range is concerned?

 

[onegreenev]

If you plan on using lead acid batteries, yes. Why are you even considering them? Used OEM packs are far more useful and cheaper and lighter in weight.

 

[brian_]

My aim is for electric drive with onboard charging from a tesla turbine driving a bank of alternators.

That sounds like a series hybrid, which by definition is an engine driving a generator, which provides power for an electric motor which drives the vehicle. That can work:

• some production hybrid cars work in series mode some of the time (Chev Volt),
• some production hybrid cars work in series mode most of the time (Honda Accord), and
• some production hybrid cars only work in series mode (BMW i3 with Range Extender); and
• some urban buses are purely series mode hybrids.

Unfortunately, the number of energy conversion steps means that efficiency of every component is critical for the overall result to be useful; the BMW i3 is less efficient than any random cheap compact gasoline-engined car when running as a hybrid. It's also a heavy, complex, and expensive way to build a vehicle, especially if any of the components are not highly efficient or optimally packaged. If you rarely need the engine and generator, you're carrying a lot of hardware all the time for little benefit. Of course, this is why it is attractive to think of some sort of novel turbine engine, which promises to be light and compact (but won't deliver on that promise).

I had forgotten about the Tesla turbine. So has the rest of the world, because it is not a useful engine design... that's why you can't buy one.

Why a "bank" of alternators? All electric machines (motors, generators) are more efficient in larger sizes. It never makes sense to use more than one of them connected together when you can use just one.

This may well prove to be a ridiculous idea so could change dramatically on the fly, but you have to start with a plan of sorts, don't you.

I disagree. I think you should start with an understanding of your requirements, then explore available solutions to meet those requirements. If you start with a design, you can build something, but it's not reasonable to expect that you'll readily reach a desired result.

If you were going on a trip, would you choose a direction and speed and get moving for a while before thinking about where you wanted to get to?

 

[generalfactotum]

I have always made things with what I have available or can easily obtain.
Lead acid batteries are easy, but we don't appear to be swamped with offers of cheap used OEM units here in the UK. If I do find one it would be ideal.

Alternators are also easy to get, although I have just finished making an experimental Haibach effect 3 phase generator which looks promising.

I have been making the tesla turbine because it looked interesting (and I had just bought a sheet of 1/8" stainless for £5 and wanted to try out my new CAD programme).
It is less than a week since I found and bought the motor/controller so research is exactly what I am beginning to do. This dialogue is part of it. I thank you for your contributions as other peoples experience is one of the best means of learning.

 

[arklan]

do the car first, even with the lead acid batteries since they r cheap
afterwards you can upgrade to lithium if thats what u want to do.

carrying around a generator to charge when u get somewhere is going to be really impractical, but making a tesla turbine sounds like a pretty fun project all the same i just wouldnt be carrying it around everywhere.

would be interested to see how the tesla turbine goes when its done

 

[generalfactotum]

Thanks, that's what I'll do. I'm just arranging to get all the parts available to go with the motor kit before I actually do anything physical.

As far as the turbine is concerned I'll keep it as the interesting project it started as. I'm printing a test rig to prove the best disc spacing right now before I assemble the rotor, theory is OK but you can't beat the suck it and see method.

 

[brian_]

I have been making the tesla turbine because it looked interesting (and I had just bought a sheet of 1/8" stainless for £5 and wanted to try out my new CAD programme).

carrying around a generator to charge when u get somewhere is going to be really impractical, but making a tesla turbine sounds like a pretty fun project all the same i just wouldnt be carrying it around everywhere.

Exactly what I was thinking - experimentation is a great way to learn, but an engine which is unlikely to work at any given moment doesn't seem like a good way to handle getting stranded by a lack of charging stations. Why not leave the Tesla turbine at home, and run it to recharge the car when you feel like trying it out?

Since the turbine isn't going to be a high-output device, the set of alternators can just be one alternator.

 

[generalfactotum]

Thanks for the help. Once the system is sorted it shouldn't be too much of a problem, but during testing I thought it would be prudent to have some independent charging capability as I will still need the vehicle for daily use.
I suppose during that phase (which could be a while yet!) I could always bung my 3.5KW honda generator in the back so I could provide 240 volts to the charger for emergencies.