# Could an electric formula car series work?

205 replies to this topic

### #151 bigleagueslider

bigleagueslider
• Member

• 1,117 posts
• Joined: March 11

Posted 10 September 2012 - 03:52

Well, until recently even F1 race could be consisted to consist of several 'sprint races'- and I guess a 'quick change' battery systems could be easily developed instead of refuelling. Say, battery pack with quick release mechanism in car's floor that gets dropped when the car is raised for tyre change and new one is wheeled in and installed immediately...

F1 EV's might work with a series of shorter "heat races". Similar to what speedway bike racing uses.

As for the notion of "amazing" advancements in EV battery technology, these advancements should be weighed against those of recip IC engines. In terms of cost, efficiency, reliability, etc. modern recip IC engines are still keeping ahead of their battery-electric competition.

### #152 MatsNorway

MatsNorway
• Member

• 2,239 posts
• Joined: December 09

Posted 10 September 2012 - 08:55

Battery swaps can be done quickly too.

### #153 Duc-Man

Duc-Man
• Member

• 1,150 posts
• Joined: November 08

Posted 10 September 2012 - 11:24

I appologize for this post. Sorry for getting OT again.

Wait, wasn't it 600Km (380 miles) a day?

Dude, get your story straight.

Dude, I have my story straight. Do I have to explain you 1st grade mathematics and what average means?

Okay here we go with an example:
Little Johnny loves eggs and eats them every day. Monday he eats 3, tuesday he eats 1, wednesday he eats 7, thursday the eggs are empty and he eats none, triday he eats 4 saturday he eats 2 and sunday he eats 2 again. How many eggs does little Johnny eat average a day?

First we add up how many eggs Johnny eats total:

3
+ 1
+ 7
+ 0
+ 4
+ 2
+ 2
____
19

So Johnny eats a total of 19 eggs in a week and we know that a week has 7 days.
Now we divide the number of eggs eaten by little Johnny by the number of days a week has:

19:7=2,714.....

So Johnny eats an average of 2,71something eggs a day.

Do you understand now the concept of math and average or do I have to explain it a third time?

For everybody else who has a proplem with my numbers, just believe me, I know wtf I talk about.

Back on topic: there was a proposal for a battery swap system in Israel. I think that was under development with Renault and meant for the Renault Fluence.
I remember seeing something about it on TV some time ago. It was supposed to be a fully automatic swap station. Does anybody know details about it?

Edited by Duc-Man, 10 September 2012 - 11:25.

### #154 Duc-Man

Duc-Man
• Member

• 1,150 posts
• Joined: November 08

Posted 10 September 2012 - 12:59

No that wasn't it.
I meant battery-swap-stations (analog to gas-stations) where you drive up, the empty battery is taken out of the car and gets replaced by a full one and you drive away.

### #155 Duc-Man

Duc-Man
• Member

• 1,150 posts
• Joined: November 08

Posted 10 September 2012 - 14:20

Thank you, that was what I meant. If that works for a road car it is sure possible to have something similar in racing.
Ofcourse a racing version needs to be faster than 5 minutes.

Edited by Duc-Man, 10 September 2012 - 14:20.

### #156 Kalmake

Kalmake
• Member

• 858 posts
• Joined: November 07

Posted 10 September 2012 - 14:55

Thank you, that was what I meant. If that works for a road car it is sure possible to have something similar in racing.
Ofcourse a racing version needs to be faster than 5 minutes.

Something like this. Formula Lightning series ran for 10 years.

### #157 Wuzak

Wuzak
• Member

• 4,540 posts
• Joined: September 00

Posted 11 September 2012 - 02:55

Does it need to be batteries?

What about flywheel storage systems? Surely they could be charged more quickly and last longer?

### #158 Greg Locock

Greg Locock
• Member

• 4,912 posts
• Joined: March 03

Posted 12 September 2012 - 00:02

Does it need to be batteries?

What about flywheel storage systems? Surely they could be charged more quickly and last longer?

energy/unit mass for flywheels is about the same as a lead acid battery

### #159 Duc-Man

Duc-Man
• Member

• 1,150 posts
• Joined: November 08

Posted 12 September 2012 - 09:25

Does it need to be batteries?

What about flywheel storage systems? Surely they could be charged more quickly and last longer?

Porsche uses flywheel technology in their GT3 hybrid. IIRC that flywheel is good for a short boost of <10 seconds.
How big must such a device be to be able to store a decent amout of energy? The one in the 911 is about the size of a big suitcase.

In order to get something useful you have to build a big and also heavy device...you want to stick into a formula race car...?

Something like this.

OMG that's funny. I thought about something a little more...professional.

### #160 gruntguru

gruntguru
• Member

• 5,995 posts
• Joined: January 09

Posted 13 September 2012 - 05:14

What about flywheel storage systems? Surely they could be charged more quickly and last longer?

Any system that recharges by moving energy alone (eg electricity or mechanical work) across the system boundary will suffer to some extent from the following limitation. Say you have an energy storage device with enough capacity to deliver an average 200 kW for one hour. If wish to recharge that device in one minute, the charge rate will need to be 60 x 200 = 12,000 kW (plus perhaps 20% or more for charge/discharge ineffficiencies). To recharge in 6 seconds would require 120,000 kW (160,000 hp) - not easy to do, even mechanically via a shaft (assuming you have a source which is capable of that sort of power output.) You would probably need a "pit flywheel" which has been charging for the last hour while the car was out.

Note. Conventional refuelling involves moving matter (fuel) across the system boundary. This equates to a very high "recharge" rate due to the energy density of hydrocarbon fuels. One litre (quart) per second is equivalent to about 8,000 kW after allowing for IC engine conversion efficiency.

### #161 Wuzak

Wuzak
• Member

• 4,540 posts
• Joined: September 00

Posted 13 September 2012 - 23:46

Any system that recharges by moving energy alone (eg electricity or mechanical work) across the system boundary will suffer to some extent from the following limitation. Say you have an energy storage device with enough capacity to deliver an average 200 kW for one hour. If wish to recharge that device in one minute, the charge rate will need to be 60 x 200 = 12,000 kW (plus perhaps 20% or more for charge/discharge ineffficiencies). To recharge in 6 seconds would require 120,000 kW (160,000 hp) - not easy to do, even mechanically via a shaft (assuming you have a source which is capable of that sort of power output.) You would probably need a "pit flywheel" which has been charging for the last hour while the car was out.

Note. Conventional refuelling involves moving matter (fuel) across the system boundary. This equates to a very high "recharge" rate due to the energy density of hydrocarbon fuels. One litre (quart) per second is equivalent to about 8,000 kW after allowing for IC engine conversion efficiency.

Understood.

In the case of batteries the higher charge rates reduce the life of the batteries. Does partial charging and discharging also reduce the life of batteries?

Also, Greg's point about the enegry density of flywheels is understood. How does it compare to the best batteries today?

### #162 Greg Locock

Greg Locock
• Member

• 4,912 posts
• Joined: March 03

Posted 14 September 2012 - 02:21

"Does partial charging and discharging also reduce the life of batteries?"

It doesn't much affect lead acids or NiMh or LiPo. Famously it hammers NiCd. I can't remember with AgZn, but that is not a practical chemistry. I don't know about other chemistries

http://scholar.sun.a...e/10019.1/17864 for flywheels, seems to suggest 400 Wh/kg based on 30 seconds of reading, roughly the same as a lithium primary cell, or 4 times that of a LiPo rechargeable cell.

### #163 kikiturbo2

kikiturbo2
• Member

• 724 posts
• Joined: December 04

Posted 14 September 2012 - 03:06

Porsche uses flywheel technology in their GT3 hybrid.

witnessing that bloody thing accelerate trough the Nurburgring 24h pitlane and turn on the IC engine only at the end of it, was one of stranger experiences I had.. Marvelous car, should have won on it's maiden outing, had it not been for a IC engine failure..

### #164 MatsNorway

MatsNorway
• Member

• 2,239 posts
• Joined: December 09

Posted 14 September 2012 - 06:24

To recharge in 6 seconds would require 120,000 kW (160,000 hp) conversion efficiency.

Thats one hell of a Gyro if its going into a flywheel type.

### #165 Wuzak

Wuzak
• Member

• 4,540 posts
• Joined: September 00

Posted 14 September 2012 - 07:05

http://scholar.sun.a...e/10019.1/17864 for flywheels, seems to suggest 400 Wh/kg based on 30 seconds of reading, roughly the same as a lithium primary cell, or 4 times that of a LiPo rechargeable cell.

So a flywheel could have the same energy density as the best batteries?

And it would, surely, last longer?

### #166 Greg Locock

Greg Locock
• Member

• 4,912 posts
• Joined: March 03

Posted 15 September 2012 - 09:04

So a flywheel could have the same energy density as the best batteries?

And it would, surely, last longer?

Yes, a 20 year no maintenance life is feasible, and useful, in things like solar cell power storage for remote microwave stations.

### #167 Wuzak

Wuzak
• Member

• 4,540 posts
• Joined: September 00

Posted 15 September 2012 - 12:39

Yes, a 20 year no maintenance life is feasible, and useful, in things like solar cell power storage for remote microwave stations.

But not for electric car use?

### #168 Wuzak

Wuzak
• Member

• 4,540 posts
• Joined: September 00

Posted 15 September 2012 - 12:44

Bosch flywheel modules that were developed for KERS, but not taken up by any teams (at least in F1).

Edited by Wuzak, 15 September 2012 - 12:44.

### #169 Greg Locock

Greg Locock
• Member

• 4,912 posts
• Joined: March 03

Posted 15 September 2012 - 22:01

But not for electric car use?

Well it would be a bit heavy. Those were intended to be zero maintenance, basically helicopter in the entire solar cell and flywheel power module, wire it up to the repeater, and never look at the thing again for 20 years. They'd have used steel flywheels. A lighter one would need more maintenance, and would cost more - the 400 Wh/kg ones use a lot of carbon fibre.

### #170 Grumbles

Grumbles
• Member

• 326 posts
• Joined: September 09

Posted 17 September 2012 - 03:25

The solution is obvious, and it's lead-acid batteries. Spinning at 50,000rpm...

### #171 Paolo

Paolo
• Member

• 1,673 posts
• Joined: May 00

Posted 17 September 2012 - 14:58

Went to rental electric Karts last weekend (www.Kart1.it ).

Amazing. Much more powerful than conventional rental karts.

One of the most interesting features is that engine power can be graduated by a track officer via remote.
This means you start with a very low powered kart and once you've shown ability to go under a certain time they increase your power.
Your allowed power settings are also registered on a database for future runs.
This avoids the need for "low power -harmless to all" karts that usually plague rental venues.
Even kids can go on the same karts as adults (of course in separate stints), via adjustable pedals and a very low power setting.

Also, remote allows instant punishment for over-enthusiasts, bouncers, idiots etc: officers can nearly shut their vehicle on track, letting only enough power to slowly return to pits.

I am not allowed full power yet, but had my first increase and the Kart completely changed, going from terminal understeer to slight oversteer. Already better than any rental I tried bar a couple.

From the track owner perspective, this "license" system allows for customer's increased frequency and fidelity.

These electric thingies rock.

Edited by Paolo, 17 September 2012 - 15:00.

### #172 MatsNorway

MatsNorway
• Member

• 2,239 posts
• Joined: December 09

Posted 17 September 2012 - 19:47

I would have been mega pissed if someone gave me less power than my brother or father.

Or reduced it because i was trying to drift the thingy.

But if it goes faster than those what is it? 5hp? 15hp carts im all for it anyway.

### #173 Paolo

Paolo
• Member

• 1,673 posts
• Joined: May 00

Posted 17 September 2012 - 21:26

I would have been mega pissed if someone gave me less power than my brother or father.

Or reduced it because i was trying to drift the thingy.

But if it goes faster than those what is it? 5hp? 15hp carts im all for it anyway.

It's actually quite fair. if you break the set time you get more power.

### #174 Duc-Man

Duc-Man
• Member

• 1,150 posts
• Joined: November 08

Posted 18 September 2012 - 16:34

Can somebody give me any technical specs on these?

### #175 Paolo

Paolo
• Member

• 1,673 posts
• Joined: May 00

Posted 19 September 2012 - 17:08

Just what they have on the site: Kart has a differential (!) and front-rear brakes.

### #176 Rasputin

Rasputin
• Member

• 960 posts
• Joined: February 10

Posted 19 September 2012 - 21:08

The batteries and their charging is still the problem, one liter of gasoline holds about 9.4 kWh, while a typical car battery is 20, the Tesla S 40 kWh, the equivalent of 4.2 liters of gasoline.

Now the electric drive-train is some 2.5-3 times more efficient that a gasoline one, but the battery will still not equal more than 10 - 13 liters of gasoline, enough for a few laps perhaps?

The KERS-thing is another myth, if you bring a 700 kg car from 300 km/h to standstill and recover all of that energy, no brakes, it's still no more than 0.675 kWh, or 0.07 liter of gas.

Edited by Rasputin, 19 September 2012 - 21:12.

### #177 gruntguru

gruntguru
• Member

• 5,995 posts
• Joined: January 09

Posted 19 September 2012 - 22:51

The KERS-thing is another myth, if you bring a 700 kg car from 300 km/h to standstill and recover all of that energy, no brakes, it's still no more than 0.675 kWh, or 0.07 liter of gas.

Erm . . . let's be consistent here. "the electric drive-train is some 2.5-3 times more efficient than a gasoline one" So your braking example is equivalent to 0.175 - 0.21 litre of gas not 0.07 litre.

### #178 desmo

desmo
• Tech Forum Host

• 14,276 posts
• Joined: January 00

Posted 20 September 2012 - 02:56

I think an electric series could be far more interesting and technically relevant than your typical boring spec support class. It doesn't need to be the best, just better than the worst.

### #179 gruntguru

gruntguru
• Member

• 5,995 posts
• Joined: January 09

Posted 20 September 2012 - 03:22

Agreed. FSAE is one example where the electric category is growing rapidly at the expense of IC. Performance in the electric category is on par and beginning to overtake IC eg the record in the acceleration test is now held by an electric car.

Innovation abounds. One team saved weight by adding AWD . Yep, adding drive to the front wheels massively increases the regen available (front axle typically does 70% of the braking) allowing a significant reduction in battery size.

### #180 Rasputin

Rasputin
• Member

• 960 posts
• Joined: February 10

Posted 20 September 2012 - 05:29

Erm . . . let's be consistent here. "the electric drive-train is some 2.5-3 times more efficient than a gasoline one" So your braking example is equivalent to 0.175 - 0.21 litre of gas not 0.07 litre.

True, but an F1 car don't do that, neither is all energy accumulated, the 400 kJ, or 0.11 kWh, stored over one in the old KERS-systems equals 0.012 liter of gasoline, 3 times that is still nothing.

The 800 kJ per lap from 2014 and on, still represents no more 0.06 liter of gasoline per lap, even with the factor 2.5 for the higher efficiency. 60 laps is 3.6 liters.

Edited by Rasputin, 20 September 2012 - 05:48.

### #181 Wuzak

Wuzak
• Member

• 4,540 posts
• Joined: September 00

Posted 20 September 2012 - 06:19

The 800 kJ per lap from 2014 and on, still represents no more 0.06 liter of gasoline per lap, even with the factor 2.5 for the higher efficiency. 60 laps is 3.6 liters.

It is 2MJ per lap recovered, and up to 4MJ used per lap, with a maximum storage of 4MJ.

So, using your maths it works out at 9l over 60 laps.

### #182 Rasputin

Rasputin
• Member

• 960 posts
• Joined: February 10

Posted 20 September 2012 - 07:35

It is 2MJ per lap recovered, and up to 4MJ used per lap, with a maximum storage of 4MJ.

So, using your maths it works out at 9l over 60 laps.

Right, but I guess that's the maximum allowed, I stand corrected, but I wonder what an MGU and battery for ten times the storage from 2009 would be like, when said 2009 system was 20+ kg?

### #183 MatsNorway

MatsNorway
• Member

• 2,239 posts
• Joined: December 09

Posted 20 September 2012 - 10:15

http://www.formula1....sport/8763.html

Currently 35kg according to the article. I believe they are lower on weight now. i believe Mclaren has sub 30kg. 25kg pops up.

http://www.gizmag.co...one-kers/11324/

30kg in 2009 according to that article

Edited by MatsNorway, 20 September 2012 - 10:28.

### #184 Rasputin

Rasputin
• Member

• 960 posts
• Joined: February 10

Posted 20 September 2012 - 13:31

http://www.gizmag.co...one-kers/11324/

30kg in 2009 according to that article

30 kg with a 60 kW MGU and 400 kWs (kJ) batter, imagine a 160 kW MGU with a 4 MWs battery in 2014, get outa here.

Moreover, for a 160 kW MGU to store 2 MWs over one lap, it must be active for 2000/160 = 12.5 sec, I'm not sure if a GP track has that much useful braking time?

### #185 MatsNorway

MatsNorway
• Member

• 2,239 posts
• Joined: December 09

Posted 20 September 2012 - 14:34

Your going off topic but in practical terms F1 teams got few limits from 2014 on their KERS system.

1Kw is not uncommon on RC car motors

they weight in at 170grams typically.

Similar figures leaves you with the motor alone at around 28kg.

Efficiency will likely go up with the size of the motor but since cooling becomes harder due to packaging im guessing the weight is not far of.

Since they will struggle with harvesting due to traction, batteries will be smaller but support higher burst.

Does anyone have a idea of the current motor weight?

So we can estimate more precise

Edited by MatsNorway, 20 September 2012 - 15:11.

### #186 MatsNorway

MatsNorway
• Member

• 2,239 posts
• Joined: December 09

Posted 20 September 2012 - 15:04

http://www.greencarc...0-rpm-7-kg.html

Peak efficiency 99%... (holy shit.. impressive)

7.8kW pr kg.

Motor weight: 6.9kg

6.9 x 7.8 = 53.8kW

Did i miss something?

for comparison a RC car motor at the above mentioned outout usually has around 88-90%

Say the weight is not improved..

160kW / 7.8kW pr kg = 20.5kg

Actually.. if the efficiency is that high would it not be better to sacrifice some of it for more weight reduction?

http://www.magnetima...xcellences/kers
Did they in a wierd way say that the motor is around 5kg here?

Edited by MatsNorway, 20 September 2012 - 15:20.

### #187 Duc-Man

Duc-Man
• Member

• 1,150 posts
• Joined: November 08

Posted 20 September 2012 - 16:15

Just what they have on the site: Kart has a differential (!) and front-rear brakes.

Sorry but I don't understand any italian and I didn't find anywhere a button to change the language.

...no more 0.06 liter of gasoline per lap, even with the factor 2.5 for the higher efficiency. 60 laps is 3.6 liters.

...your maths it works out at 9l over 60 laps.

Guys! It doesn't matter if we talk about 3.6 or 9 or maybe 15 litres over 60 laps. KERS in F1 is just an eyewash to make the people (that just fell out of a cows a...) believe they're now ecologically thinking.
And even so: it is still a drop on a hot stone.

### #188 Rasputin

Rasputin
• Member

• 960 posts
• Joined: February 10

Posted 20 September 2012 - 16:41

Your going off topic but in practical terms F1 teams got few limits from 2014 on their KERS system.

1Kw is not uncommon on RC car motors

they weight in at 170grams typically.

Similar figures leaves you with the motor alone at around 28kg.

Efficiency will likely go up with the size of the motor but since cooling becomes harder due to packaging im guessing the weight is not far of.

Since they will struggle with harvesting due to traction, batteries will be smaller but support higher burst.

Does anyone have a idea of the current motor weight?

So we can estimate more precise

Hold on now, 1 kW from an RC-motor is probably at around 60 - 80 kRpm, which is just not suitable for an F1 MGU
and the 99% efficiency is also fantasy if you include all electrical transmission and battery power in and out.

But anyway, the paramount problem is still the batteries, how much do the state-of-the art 40 kWh Tesla S battery weigh?

200 kg for 40 kWh perhaps, which including 3 times higher efficiency equals 12.7 liters of gas, a few laps around a GP track?

Edited by Rasputin, 20 September 2012 - 18:05.

### #189 Paolo

Paolo
• Member

• 1,673 posts
• Joined: May 00

Posted 20 September 2012 - 16:41

Sorry but I don't understand any italian and I didn't find anywhere a button to change the language.

Of course, that's why I translated the only relevant info. The rest is just boasting: "top technology, high resistance" etc. No info on batteries and such.

### #190 Rasputin

Rasputin
• Member

• 960 posts
• Joined: February 10

Posted 20 September 2012 - 19:42

450 kg for 56 kWh, the latter translated to 5.9 liters of gas, or 14.8 liters with an "efficiency factor" of 2.5.

But 450 kg, good Lord, imagine that?

### #191 Duc-Man

Duc-Man
• Member

• 1,150 posts
• Joined: November 08

Posted 21 September 2012 - 13:47

Guys, once in a while I drive a forklift at work. The batteries of those things weight 1700kg and sorry I can't look up any data because I'm off for the next two weeks.

### #192 Rasputin

Rasputin
• Member

• 960 posts
• Joined: February 10

Posted 28 September 2012 - 05:50

That would most probably be a lead-acid battery Duc-Man, lithium-ion like in the Tesla is far more weight-efficient,
but 450 kg for the equivalent of some 15 liter of gas still makes it unsuitable for any serious racing activities.

Perhaps if they can improve the efficiency of induction transfer of electricity?

Edited by Rasputin, 28 September 2012 - 05:50.

### #193 BRG

BRG
• Member

• 13,258 posts
• Joined: September 99

Posted 28 September 2012 - 20:52

Things are moving faster and faster...

### #194 Duc-Man

Duc-Man
• Member

• 1,150 posts
• Joined: November 08

Posted 29 September 2012 - 12:30

...induction transfer of electricity?

Doesn't induction transfer have serious losses?

### #195 Rasputin

Rasputin
• Member

• 960 posts
• Joined: February 10

Posted 29 September 2012 - 15:00

Works on my toothbrush if it's very close, but that's about it so far I'm afraid.

### #196 gruntguru

gruntguru
• Member

• 5,995 posts
• Joined: January 09

Posted 01 October 2012 - 00:36

450 kg for 56 kWh, the latter translated to 5.9 liters of gas, or 14.8 liters with an "efficiency factor" of 2.5.

The "2.5" factor will no doubt rise as regen braking improves. Limitations lie as much in the regulations as the technology. Maximum "harvesting" requires AWD and high-power electrical componentry.

What percentage of F1 engine "work" ends up in braking energy?

### #197 Kelpiecross

Kelpiecross
• Member

• 1,043 posts
• Joined: October 10

Posted 01 October 2012 - 04:26

Say there were no rules just safety requirements, must be open wheel, must be electric (battery not hydrogen), everything else free (?). Could such a class work, would the cars be fast?

To return to the original question - yes, I think such a class would work and the cars would be fast and interesting. In the world of model aircraft and model cars electric motor/lipo batteried models are either equal to, or outperform IC versions of the same model. Electric types are also (obviously) much easier to start (dangerously easy in fact) and much more controllable in power output.
I think Mats is the expert in this area - maybe be should comment. I personally can't see why the models could not be scaled up to full size and be just as effective.

However, I can't see in the forseeable future electric cars being successful on the road - basically because of the seemingly-impossible-to-solve length of time needed to "refuel"/recharge compared to IC cars.

To continue on this same theme - there are model electric motors of 3 horsepower that can be held in the palm of one hand. Back in my days in industry, a 3HP motor was 415 volts AC and was not able to be lifted by one person. Being pretty ignorant of "electrickery" - how can the model motors be so powerful for their size?

Edited by Kelpiecross, 01 October 2012 - 04:39.

### #198 Rasputin

Rasputin
• Member

• 960 posts
• Joined: February 10

Posted 01 October 2012 - 05:18

...
To continue on this same theme - there are model electric motors of 3 horsepower that can be held in the palm of one hand. Back in my days in industry, a 3HP motor was 415 volts AC and was not able to be lifted by one person. Being pretty ignorant of "electrickery" - how can the model motors be so powerful for their size?

I suspect that the paramount reason is the brushless motors with 100 000 Rpm?

### #199 Kelpiecross

Kelpiecross
• Member

• 1,043 posts
• Joined: October 10

Posted 01 October 2012 - 06:33

I suspect that the paramount reason is the brushless motors with 100 000 Rpm?

I was under the impression that this particular motor drove a 30 inch (or so) propeller directly (not geared) - certainly not at 100,000RPM - but I could be wrong.

### #200 Wuzak

Wuzak
• Member

• 4,540 posts
• Joined: September 00

Posted 01 October 2012 - 06:42

Possibly the duty cycle.

Industrial motors have to run reliably for far longer and/or have frequent start stops.