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Lauri
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01.24.2010, 11:31 AM

My point was that for passanger car you'd need to have battery capable of no more than 0.5C because you'd like to drive at least 2 hours - that is 110 mile / 180 km range on average cruising speed.

Most batteries are capable of higher burst currents. And you don't need longer bursts than 10 seconds. 10 seconds will get up over the legal speed limit anyway.

Maybe we'll see cars with some supercaps that are able to give boost to the main battery. They'd only have to help for few seconds.

So for my passanger car I see no reason to have battery thats capable of more than 1C discharge. The same thing applies for charging. You just can't get enough power from the power grid to charge batteries with 1C or even 0.5C currents.

So charging max 0.25C and discharging max 0.5C and very high power density - this would be the ideal batt for passanger car in my oppinion.

BTW - I know about the power sag / voltage drop under load. But when talking about C-values one could assume that the battery does handle it without too much voltage drop ;)
   
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lutach
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01.24.2010, 12:31 PM

Quote:
Originally Posted by Lauri View Post
My point was that for passanger car you'd need to have battery capable of no more than 0.5C because you'd like to drive at least 2 hours - that is 110 mile / 180 km range on average cruising speed.

Most batteries are capable of higher burst currents. And you don't need longer bursts than 10 seconds. 10 seconds will get up over the legal speed limit anyway.

Maybe we'll see cars with some supercaps that are able to give boost to the main battery. They'd only have to help for few seconds.

So for my passanger car I see no reason to have battery thats capable of more than 1C discharge. The same thing applies for charging. You just can't get enough power from the power grid to charge batteries with 1C or even 0.5C currents.

So charging max 0.25C and discharging max 0.5C and very high power density - this would be the ideal batt for passanger car in my oppinion.

BTW - I know about the power sag / voltage drop under load. But when talking about C-values one could assume that the battery does handle it without too much voltage drop ;)
I understand, but most of the EVs need to have the appropriate cell used, not just common laptop cell designed for longer lasting low energy consumption application. You know EVs are not low energy consumption products like a laptop. You can try this in a smaller scale if you want and you will see my point. Before high discharge rate lipos came out, I was messing with high energy lithium cells and guess what, they all failed in a R/C, now think what can happen in a full size car. The cell used in the Tesla in my opinion is not safe. The people I speak to know that a EV to be compatible with the I.C. version, needs a battery capable of more the 0.5C. Why you ask, fast charging. The current grid can support such fast charging if you move away from the 110 or 220 standards. You can have a higher voltage coming from the grid set up to offer the fast charging. A lot of the energy produced by current power plants is wasted anyways. I think of things ahead instead of thinking of common things that we see. Now in order for your 0.5C discharge to work, you will need a much higher voltage then current EVs are using. A few set ups I know of can handle up to 960VDC, but some can go up to 1200VDC. Also, to have a battery only put out 0.5C for a EV, you need to look at the whole vehicle and not just at the battery. How much will the vehicle weigh, how aerodynamic is the vehicle and how much power will the motor need to maintain a certain speed? When you figure all those in, you will then see why you will need a battery capable of more then 0.5C. Even at the weight of 1000lbs., the Tesla pack can't handle the load as it needs water cooling. When a battery can't deliver the current asked, it'll overheat and that causes a very short life cycle. Tesla could've went with SLA batteries at the same weight which would offer better performance, faster charging capabilities and would be much safer.



So do a little test in your R/C with plain energy cells. Example, get a few of the Panasonic cell used in the Tesla and wire them in the voltage you use in your R/C, then do the same with similar sized cell from A123 or K2 (Not the 26650 sized, but the 18650 1100-1200mAh cells) and see which ones will perform better. Also, try charging the Panasonic cell at the same high rate as the A123 or K2 cells. Let us know your results.
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Lauri
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01.24.2010, 07:12 PM

My laptop only lasts about 3h on batteries. I think any electric passanger car should last longer. So considering that passanger car cells could be about the same as laptop cells :)

Ok. I think it is stupid to have 10 000 of some small cells but its up to what is cheaper and more efficient to use at some time. Like said, you have to plan ahaed many years when building a car. It would be smarter to use something like those 20Ah LiFePO4 cells just to have fewer of them.

And overheating the cells when using them? Well... it comes down to IR of the cells and the power you take from them. It would be wise to use such cells that don't need cooling. It is a simple high-school fysics equasion to figure it out how much heat is generated by driving a car.

I think that Tesla is overkill considering its acceleration and power needs. Don't know about Tesla but I'd like to have a mode that limits the power to a regular passanger car. No need for better acceleration than 9sec 0-100kmh (0-60mph).

I don't like comparing RC with passanger electric car. Those are very different things. One is high performance 10-minute running and another has totally different need for the batt.

Don't belive there will be high voltage charging stations available in 3-4 years. You could have one at your house but then you usually don't need to charge the car fast...
   
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lutach
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01.24.2010, 07:43 PM

Quote:
Originally Posted by Lauri View Post
My laptop only lasts about 3h on batteries. I think any electric passanger car should last longer. So considering that passanger car cells could be about the same as laptop cells :)

Ok. I think it is stupid to have 10 000 of some small cells but its up to what is cheaper and more efficient to use at some time. Like said, you have to plan ahaed many years when building a car. It would be smarter to use something like those 20Ah LiFePO4 cells just to have fewer of them.

And overheating the cells when using them? Well... it comes down to IR of the cells and the power you take from them. It would be wise to use such cells that don't need cooling. It is a simple high-school fysics equasion to figure it out how much heat is generated by driving a car.

I think that Tesla is overkill considering its acceleration and power needs. Don't know about Tesla but I'd like to have a mode that limits the power to a regular passanger car. No need for better acceleration than 9sec 0-100kmh (0-60mph).

I don't like comparing RC with passanger electric car. Those are very different things. One is high performance 10-minute running and another has totally different need for the batt.

Don't belive there will be high voltage charging stations available in 3-4 years. You could have one at your house but then you usually don't need to charge the car fast...
Check out how much power your laptop consumes and then compare that to how much power Tesla consumes. If Tesla is to be a true sports car, it would need top notch batteries. For $120K, they could've went with a better drive train, battery system and charger.

Now in one of those small cars, then you could use some sort of energy cell, but in a LiFePO4 form. I know places in China that uses a small 10KW drive train along with LiFePO4 ranging from 100Ah-200Ah. They only use 72V or 144V. Using those large format cells only 20 or 40 cells would be needed.

Comparing our R/Cs is the best thing one can use. Wonder how Tesla failed on selecting their components? If your idea of using energy cells compared to power cells is correct, then try it out and let us know. I've done my research since 1998 and I know a laptop energy cell can't come close to performing as well as any power cell.

Currently that are chargers available. Everything is available to make this go forward, but currently the morons doing them are not using them. I don't know if it's the cost or if they don't know where to look. People make things expensive, but if you know where to look, it's very cheap all it takes is some research. I've been speaking with a lot of folks in the EV components market and guess what they say about our R/C components, "We are way ahead of the full size EV and the auto industry in general."
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Lauri
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01.24.2010, 08:07 PM

Tesla has limited maximum speed. What is the time it gets up to that speed? I bet it is under 10 sec. So the maximum power need from the battery is a true burst current of under 10 sec. Then driving at any speed doesn't consume more than 1C - otherwise you'd be able tu run less than a hour.

I get what you are saying but when talking about passanger cars you don't have anything sporty about them. RC cars are sporty in a sense that they use all the power available in under 10 minutes (6+C current). Only thing sporty about passanger car is the not-so-often happening acceleration.

Tesla - a passanger car that has good acceleration compared to other pertrol engine cars. It is not anything special considering what electric car could do.

I'm not trying to argue with you. I'm just pointing out some things.
- passanger electric car can't consume high burst current for more than 10 seconds otherwise it would be going too fast for regular traffic. And even this high burst current isn't anything crazy considering the amount of batteries needed to be able to get decent milage.
- you want decent milage from a passenger electric car. Lets say 200miles/300km. This makes the average current only maximum of 0.3C and any battery can handle this.

Ok... you could have 1:1 electric dragster or a racing-car but Tesla isn't non of them. Tesla is a sporty looking passanger car that has good acceleration compared to regular internal combustion engine cars.

My point being is that Tesla consumes ABOUT THE SAME AVERAGE POWER AS A LAPTOP! Average laptop runs 2-3hours on a battery. Tesla runs even longer I think (driving optimal speed). And YES you can compare those two this ways. This all comes down to average consumption aka C-value of the batt which is about the same.

I just checked out the carts from Tesla. Running optimal long distance comes to about 10 hours driving (their calculated charts). So when you'd want to do distance records with Tesla you'd be running a lot lower power than any laptop! Regular driving would be about the same.

Think it this way - which ever battery you put on the car you can limit the power consumption of the car so that the battery would handle it. You MUST do it because of the crazy torque available but not needed. You can limit the power abilities of the car by telling it how long distance you have to go. The car must monitor the state and temp of the batteries. If they are getting too hot the car can just limit the power that is drawn from them etc.

To come back to the original question. You want to have a battery that can accelerate you to top speed every 2-3 minutes? You are not accelerating from 0 to top speed, then braking to 0 speed and then accelerating again like you are doind with a RC car. Usually you accelerate from 0 to cruising speed and then drive to next red light or a hundred miles. And you'd like to get good milage from the battery and you don't want to pay too much for them. There are many things more important than the pure power characteristics of a passanger car battery.

Last edited by Lauri; 01.24.2010 at 08:16 PM.
   
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lutach
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01.26.2010, 09:00 PM

Here's what bugs me the most Lauri. In order for electric vehicles to be as competitive as a I.C. vehicle it needs to have good range and fast charging capabilities. The chargers are available, so are the batteries, plus other technologies for longer electric only range and a grid can be implemented. Now, if the Government are so concerning, why don't they start putting some chargers at gas stations? They are more interested in spending money with the companies making the vehicles and not looking into setting up a nice infrastructure to support them first. Tesla got a nice $520+ million loan from the Government which means we the people paying taxes in the US loaned that money. With that amount of money, Tesla can easily start using better cells, because there current one is not capable of fast charging at all.
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redshift
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01.26.2010, 11:00 PM

That 520 mil might as well have been a handshake and a wink to "keep things as they are". It pisses me off to no end, how many jobs would that money have created?
How many thousand better uses can I think of?

As long as gov't continues to speak out of both sides of it's mouth, nothing improves.

They could have subsidized independent researchers (such as yourself), or even made a contest of sorts. Imagine the response to something like that!

As long as they funnel $ into a single company, there is no real incentive for them to innovate. What the hell, the money is in their hands. They don't have to do jack.

These things always look so good on the surface. But they will likely end up doing more harm than if they'd not given anyone any money. Hard not to be a cynic when you have some inkling how these things operate. UUUUGH.
   
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zeropointbug
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01.27.2010, 12:34 AM

Hey, I'm back again, and again I have nothing to add really, Luc said much of what can be stated.

It is a sad state of affairs the technologies of the world are in right now, with so much of it on what is called a "gag order", in other words, it "Threatens National Security"... give me a fucking break (pardon the language), but what a crock of shit (again...). I'm not sure how many here know this, but there is currently over 5000 of these 'gag orders' for various technological patents in the US, yes, that's just the US. I mean, just look at the impressive tech the millitary has which IS NOT on gag order, so, it occurs to me that if these impressive techs are non-disclosed, then what the F#$K do they have behind those doors.

In my opinion, I know, beyond the shadow of a doubt, that the US, and other advanced countries (maybe many?) have technology that would set the people of the world free forever, and would advance our society to no end, indeed space exploration. We would have no need for batteries, or any energy storage, as we would have infinite abundance at our disposal. Some of you may think, how can that be, that would violate the laws of physics... well science tells us that there is an underlying infinite energy to the universe, the vacuum, the quantum vacuum, or the 'zeropoint energy'... we know it's there, the general scientific community doesn't know if you can tap it, but perhaps the shadow ops of the government does. Look at the amount of UFO sightings these days, it fits in well with rumor about the military gaining technological advances... I think many of the UFO's are military origin, and perhaps some extraterrestrial. Anyways, I'm blabbering, I'll stop there...

Japan officially has the 'water car' in production, which runs 100% on water, regular water, bottled, tap, or even tea they say. So all we need is a larger water-power gen. set, with a cap bank, and we are set for an SOB of an electric car. You could run an engine on the hydrogen, but i would rather have a electric propulsion system.

Cheers


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lutach
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01.27.2010, 10:55 AM

Quote:
Originally Posted by zeropointbug View Post
Hey, I'm back again, and again I have nothing to add really, Luc said much of what can be stated.

It is a sad state of affairs the technologies of the world are in right now, with so much of it on what is called a "gag order", in other words, it "Threatens National Security"... give me a fucking break (pardon the language), but what a crock of shit (again...). I'm not sure how many here know this, but there is currently over 5000 of these 'gag orders' for various technological patents in the US, yes, that's just the US. I mean, just look at the impressive tech the millitary has which IS NOT on gag order, so, it occurs to me that if these impressive techs are non-disclosed, then what the F#$K do they have behind those doors.

In my opinion, I know, beyond the shadow of a doubt, that the US, and other advanced countries (maybe many?) have technology that would set the people of the world free forever, and would advance our society to no end, indeed space exploration. We would have no need for batteries, or any energy storage, as we would have infinite abundance at our disposal. Some of you may think, how can that be, that would violate the laws of physics... well science tells us that there is an underlying infinite energy to the universe, the vacuum, the quantum vacuum, or the 'zeropoint energy'... we know it's there, the general scientific community doesn't know if you can tap it, but perhaps the shadow ops of the government does. Look at the amount of UFO sightings these days, it fits in well with rumor about the military gaining technological advances... I think many of the UFO's are military origin, and perhaps some extraterrestrial. Anyways, I'm blabbering, I'll stop there...

Japan officially has the 'water car' in production, which runs 100% on water, regular water, bottled, tap, or even tea they say. So all we need is a larger water-power gen. set, with a cap bank, and we are set for an SOB of an electric car. You could run an engine on the hydrogen, but i would rather have a electric propulsion system.

Cheers
You've seen the items I showed you. Think what could be done we more and more companies uses them and push the technology forward. Picture that same 5Ah+ cell I showed you in a 20Ah format. The military tested a 41Ah cell under normal to heavy load and got 120 miles out of it. No regen was used as they have other means to get electricity made to charge and run the electric propulsion. I know many companies that makes the set up you mentioned there zeropoint and it's really amazing. The problem is this, do you think the electric producing giants will let it become popular? It's one of the items I was planning on using to extend the range and plug into the house so it can power that or send electricity back to the grid. The other idea I have can basically give unlimited range. To many it seems unreal, but they don't do the research to find such technology.
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snellemin
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01.27.2010, 01:08 PM

Nice arguments and loved to read both point of views.

I'll put my take on the laptop batteries, as I used them in my rc's. The 18650 cells that I use put out a burst of 45A and go flat in 2-3 seconds. I can only get up to 5A continuous out of them in 1p configs. Tesla is just gay for using them in a car.


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JThiessen
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01.27.2010, 02:25 PM

Another roadblock for EV's is the transportation industry, and the AG industry.

Those vehicles (buses/trucks/tractors) must be able to run for 18+hrs a day, and do it under much more demand than these passenger cars.
I for one was really disappointed that GM never really followed through with the hybrid diesel systems. I really believe that a Diesel fired generator would be ideal for my truck, and many of the farm/transportation trucks.

ps. Lutach - your argument is sound. But until you actually build it, test it, prove it, all it is is an ideal. Get us these "magic" cells, and we'll help you prove it!!!!


Losi 8T 1.0, Savage Flux - XL style, LST XXL, Muggy, 3.3 E-Revo Conversion and sitting outside 425hp, 831 Tq Dodge Ram Turbo Diesel. It SMOKES

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lutach
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01.27.2010, 02:43 PM

Quote:
Originally Posted by JThiessen View Post
Another roadblock for EV's is the transportation industry, and the AG industry.

Those vehicles (buses/trucks/tractors) must be able to run for 18+hrs a day, and do it under much more demand than these passenger cars.
I for one was really disappointed that GM never really followed through with the hybrid diesel systems. I really believe that a Diesel fired generator would be ideal for my truck, and many of the farm/transportation trucks.

ps. Lutach - your argument is sound. But until you actually build it, test it, prove it, all it is is an ideal. Get us these "magic" cells, and we'll help you prove it!!!!
It can be done JThissen. Like you said, a hybrid diesel and a few hub motors or axle motors would be ideal.

All the things I've said and posted have been tested by not only our US Military, but a few race cars that got scrapped pretty quick. If the Military is using it in various vehicles then you know it must be good. The way this economy is going I need to make sure my little one will not fall short of the magic $$$$. If I had $100K to spare right now, I would get a nice pack made with the actual not magical cells and I can send you datasheets and military test results if you would like to see it. I've contacted a few folks in the race car community, but they don't seem to understand this technology yet. The problem that is keeping anyone from making an awesome EV are the big corp. companies. I can think of many advantages for going electric in general and still make the oil giants happy. It seems that nobody has come up with that pitch yet though lol.
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lutach
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01.27.2010, 02:53 PM

Forgot to mention this again, but here goes. Tesla did not get started with their own ideas. They got the TZero from AC Propulsion as a loaner to get potential investors and they nailed one called Elon Musk, but now Mr. Musk took over and the founders (Not sure if only one is not with the company) are not there anymore. Now Tesla claims to have their own technology, but it's still the same old AC Propulsion technology, but they claim to have a version of the drive train that puts out more power.

I should loan a Prius load it with about 500lbs. of extra battery and show it to potential investors to see what would happen . Tell them I have 500lbs. less then the Tesla and get an actual 200mpg to see if they fall for it.
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JThiessen
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01.27.2010, 04:23 PM

Data sheets are fine for theory - I'm more interested in the dynamics of real world system tests. Stick these cells in a system, beat the living snot out of it - hopefully until they fail, and see where the down side is with them, then improve them, or build in the fail safes needed. Then compare it to what others have done (like Tesla).
There may be an upside to the lower C systems. I would liken it to the difference between Diesel and Gas powered vehicles. You can have a 400hp/600ft-lb gasoline motor, and a 300hp,600ft-lb diesel. The spec sheet on that car would be fantastic compared to the diesel - but I wouldn't pick the gas motor for towing.

Take your data to a respected automotive engineering college. I suspect you will have open ears (and minds) there. The downside would be give open liscense to a technology, for them to develop further. The upside is that it is good for all of us down the line.


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zeropointbug
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01.27.2010, 05:42 PM

Quote:
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Forgot to mention this again, but here goes. Tesla did not get started with their own ideas. They got the TZero from AC Propulsion as a loaner to get potential investors and they nailed one called Elon Musk, but now Mr. Musk took over and the founders (Not sure if only one is not with the company) are not there anymore. Now Tesla claims to have their own technology, but it's still the same old AC Propulsion technology, but they claim to have a version of the drive train that puts out more power.

I should loan a Prius load it with about 500lbs. of extra battery and show it to potential investors to see what would happen . Tell them I have 500lbs. less then the Tesla and get an actual 200mpg to see if they fall for it.
Yeah! And get this, they fired some 100 employees by some email... an email!!! What the F#$K !? How would you feel if you got fired in such a manner? No one really knew that they were fired even a month after the emails were sent out, and IIRC, the guy who sent the emails was fired after as well! What a horrible company, that is another reason why I am boycotting them.

Not to mention they are a disgrace to the name Tesla. They should be destroyed.


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