Formula E

[Andres125sx]

Would Lipo's be safe for racing tho? They tend to burn fast and hot when compromised and not much puts them out.
I know the stuff that we use for RC is quite dangerous if mis-handled or damaged while in use. (or sometimes charging!)

I´m using lipos for more than a decade now, never got a fire

Lately I´m flying a drone wich drains the battery in 7 minutes, wich equals around 10C continuous discharge, and that´s without any cooling at all (helicopter type). They are quite hot at the end, but for car use they usually are not pushed that hard. I´m using 20C batteries (today I´ll test some new 25C, actually the same andy linked) because don´t need higher discharge rate tough, but there are batteries prepared for 3x faster discharges, so the power density is far from a problem

While charging the only problem is if you try to charge a lipo with a Niquel program

Anycase I´d try to put them a bit far from myself on a car, or with some fire-resistant material in between, safety first

At Pike Peak a year back, one of the electric cars hit the wall, there wasn't much left after the fire. Dunno what kind of batteries he had on-board but the marshal I was talking with said it was a pita because there were 7 different types of battery technologies being used and everyone had a different fire extinguishing requirements/materials. On top of that no one was allowed to touch a failed vehicle but the team that owned it, in order to make sure the marshals were safe because each car had to be disarmed differently.

7 different types of batteries? I´m missing some... Lipo, LiIon, LiFe, LiMnxxx, NiMh, NiCd... Maybe some new LiS prototype? And I can´t think they´re still using NiMh and NiCd, there must be more types I don´t know

Anycase, a CO2 fire extinghiser will solve any type of fire, don´t aim the driver tough but if he has jumped out the car, that would be best option I think

[machin]

Ah, pretty sure that the current F1 turbo mills demonstrate a characteristic ICE climbing torque/rpm = hp curve..

nope, 'fraid not, see curve below:

.

The parabolic power curve of the current V6's, as shown above, is very reminiscent of a typical electric motor's power curve (which you'll find on an earlier page of this thread), and very different to the old V8's (also shown above).

[mycadcae]

The new circuit formula E from Malaysia---race in NOV 2014 ---Vanue PUTRAJAYA , MALAYSIA. .



picture FIA Formula E Malaysia.

[theblackangus]

Anycase, a CO2 fire extinghiser will solve any type of fire, don´t aim the driver tough but if he has jumped out the car, that would be best option I think

I'm not sure this is quite correct, I have read that particular batteries are dangerous as they supply oxygen from the chemicals in the battery therefor something special is needed to extinguish them.

I asked the marshal - you don't just use a standard type 3 or 4 extinguisher ,and he said no.

And while Lipos are fairly same when you handle them properly, its when they become damaged that they are dangerous (I fly helis, planes, and a quad/hex) I have seen RC cars at the hobby shop that have burned, and even seen a heli go up in flame in the air!
However you are of course correct, the heli is much more likely to have a problem because of the draw needed vs a plane (not acro) or drone.

[mzso]

Those batteries are dangerous that have flammable electrolytes. Others don't even catch fire.
eg:

[Pierce89]

If you have never operated a vehicle with an exciting, rewarding powerband.. ..too bad..

Maybe like a (2 stroke) KTM 125sx?

That bike is the reason for my nickname, it was the funniest bike I´ve ever owned and the one I learnt more with

https://imagizer.imageshack.us/v2/735x4 ... mhjeNT.jpg
I still laugh when I see this picture, it was one of the first times I did this jump, and it´s easy to see in my bodylanguage
https://imagizer.imageshack.us/v2/640x4 ... trail3.jpg

Now there´re no 125´s, they all were substituded by 4 stroke 250´s. They have a much much flatter powerband, what means they provide better accelerations, they provide more traction and they are easier to ride. They also are much more boring, but much faster, inarguable.

I agree a peaky powerband is a lot funnier, and drivers learn a lot more with one of those. But this is racing, and top level racing, its goal has never been being fun or a good driver school, its only goal is being fast, fastest possible, and for than goal an exciting, rewarding powerband as you say is a really poor choice

So actuallly it´s just the opposite you´re stating, a flat powerband is the perfect one for racing, at least for profesional racing. Peaky powerbands are perferct for having some fun, but this is racing, not a driver entertainment


Moreover, for the audience point of view a flat powerband is more fun, with peaky curves sliding is really difficult, what means cars go on rails, while with a flatter curve it´s easier to slide, and the audience always enjoy watching some sliding.

I promise you my Honda CRF450r does not have a flat powerband. Nor does a KTM 250sxf. They both greatly increase power as the revs rise. In fact, a ktm 250 4t revs ~2000rpm higher than the 125 2t with the power rising virtually to red line.

[Andres125sx]

Anycase, a CO2 fire extinghiser will solve any type of fire, don´t aim the driver tough but if he has jumped out the car, that would be best option I think

I'm not sure this is quite correct, I have read that particular batteries are dangerous as they supply oxygen from the chemicals in the battery therefor something special is needed to extinguish them.

What batteries?

I wonder how to extinguish those...

And while Lipos are fairly same when you handle them properly, its when they become damaged that they are dangerous (I fly helis, planes, and a quad/hex) I have seen RC cars at the hobby shop that have burned, and even seen a heli go up in flame in the air!

I stopped using others peoples problems as a reference a long time ago. I´ve seen people flying with lipos wich were a ballon saying it still works nice. Also with crashed lipos completely twisted arguing the same, they still work...

So when I see/hear/read about some fire, it does not surprise me, but don´t think the problem was the battery either, it´s just that some people ask for problems

I personally discard any battery wich is not perfect. Last month I got rid of a lipo I crashed because it was slightly twisted at a corner. I´m sure it was perfect and could have worked for a long time yet, but using a damaged battery is asking for problems. I will never risk any of my aircrafts using a battery that could be damaged, I think it´s pretty stupid doing so for a battery that cost just a few bucks. Replace it and be safe

This is not exclusive for Lipos, NiCd/NiMh batteries can explode too, just they´re more difficult to damage since they have a hard casing. Actually there are lipos with hard casing to avoid any problem when they´re crashed.

However you are of course correct, the heli is much more likely to have a problem because of the draw needed vs a plane (not acro) or drone.

I said drone because it´s the word everybody hear at tv, but it actually is an octocopter for aerial filming. A big one tough, almost 6kg TOW. But yes, a big heli is one of the most demanding aircrafts for a battery, like my octo, because they draw a lot of current (all the lift comes from the motors) and don´t get any airflow as they fly stationary mainly

[Andres125sx]

I promise you my Honda CRF450r does not have a flat powerband. Nor does a KTM 250sxf. They both greatly increase power as the revs rise. In fact, a ktm 250 4t revs ~2000rpm higher than the 125 2t with the power rising virtually to red line.

An electric motor also increase the power as the revs rise, when we talk about flat it actually is the torque curve wich is flat, power always increase with revs (at the useful range of the powerband)

Difference is electric motors/4 stroke MX bikes/turbo engines have a much flatter torque curve than 2 strokes/aspirathed engines, what makes them much more powerful at low revs. But they obviously also increase the power when the revs rise

[J.A.W.]

In fact - all ICE are "aspirated" meaning they are fuel/air pumping mills..
.. whether running at standard atmospheric pressure or forced induction via supercharging..

2Ts have twice the power-strokes of 4Ts & thus -inherently produce more power (torque/time) for a given tune..
A 4T 125 MX bike would simply be unable to match a 125 2T in a race, if of equal tune.
Indeed, the showroom standard KTM 250 2T MX bike is more powerful than their factory GP Moto 3 4T road-racer..

Electric motors are anodyne, or - boringly predicable & lack interesting characteristics for the race enthusiast..
Possibly the racing per se will be fun, but I doubt it, I guess we shall have to see for ourselves..

[theblackangus]

So when I see/hear/read about some fire, it does not surprise me, but don´t think the problem was the battery either, it´s just that some people ask for problems

I personally discard any battery wich is not perfect. Last month I got rid of a lipo I crashed because it was slightly twisted at a corner. I´m sure it was perfect and could have worked for a long time yet, but using a damaged battery is asking for problems. I will never risk any of my aircrafts using a battery that could be damaged, I think it´s pretty stupid doing so for a battery that cost just a few bucks. Replace it and be safe

This is not exclusive for Lipos, NiCd/NiMh batteries can explode too, just they´re more difficult to damage since they have a hard casing. Actually there are lipos with hard casing to avoid any problem when they´re crashed.

However you are of course correct, the heli is much more likely to have a problem because of the draw needed vs a plane (not acro) or drone.

I said drone because it´s the word everybody hear at tv, but it actually is an octocopter for aerial filming. A big one tough, almost 6kg TOW. But yes, a big heli is one of the most demanding aircrafts for a battery, like my octo, because they draw a lot of current (all the lift comes from the motors) and don´t get any airflow as they fly stationary mainly

Ahh sadly I cannot remember which type(s) have the self oxygenating properties. (I don't think it was Lipo's tho)

And Im with ya on the discarding anything that ins't perfect battery wise! =) Got a few in the garage I still need to dispose of =(. The lipos for the helis can cost 120-200$, even on Ali as they are high C rates.

The point i was making was simply batteries can be (depending on type) very dangerous in a crash type scenario, and even with Lipos that we use I'm not sure I would want to be in a racing machine that was powered by those, w/o alot of fire shielding between me and them!

Yeah drone = multi-rotor!

Actually a few guys I know are thinking about doing a local FPV quad racing league on a buddies farm through the forest. Formula D anyone? =)

[Andres125sx]

And Im with ya on the discarding anything that ins't perfect battery wise! =) Got a few in the garage I still need to dispose of =(. The lipos for the helis can cost 120-200$, even on Ali as they are high C rates.

Big helis need big lipos, but they still are less than 10% of the heli cost

Do you know Turnigy NanoTech 45-90C?

The point i was making was simply batteries can be (depending on type) very dangerous in a crash type scenario, and even with Lipos that we use I'm not sure I would want to be in a racing machine that was powered by those, w/o alot of fire shielding between me and them!

Doing some sort of shielding for the batteries, as they do with EV, should be fine. I wouldn´t put some lipos at my back on a kart fastened with an elastic band for example , but with a box to protect them, allowing some ariflow for cooling designed to be safe in case of a fire, I would be plenty confident.

I don´t think lipos are more dangerous than an extremely flamable liquid, known as petrol

Actually a few guys I know are thinking about doing a local FPV quad racing league on a buddies farm through the forest. Formula D anyone? =)

I´d love it

If you want some ideas, watch this guy videos, he´s the most talented I´ve ever seen!

[Tim.Wright]

The fact that electric motor torque actually starts falling from low rpm - is what makes me doubt their racing pedigree..

Except that it doesn't start falling from low RPM.

Electric motors in use today have a rated current which corresponds to the thermal limits of the windings. This current is able to be delivered from zero until usually about 90% of the maximum motor speed. Only after this point does the torque, being proportional to the current, also start to drop.

At the end of the day, its the power/energy output which is determining the overall performance - not the torque. The discussion on torque is a lot of handwaving and ultimately irrelevant.

[Andres125sx]

Maybe he´s being confused with diesel engines

Petrol (not a weak one exactly)


diesel


Electric


Max torque delivered from still to 9000rpm... and there are electric motors that spin much faster than this one. Actually electric motors can be winded to reach the rpm you want. I know electric motors that spin up to 40.000rpm, they´re small tough

[Andres125sx]

At the end of the day, its the power/energy output which is determining the overall performance - not the torque. The discussion on torque is a lot of handwaving and ultimately irrelevant.

Of course, but since power is proportional to torque, torque curve will tell you a lot about the motor/engine behaviour, if its flat you know it will be powerful at the entire rpm range.

I can´t count the times I´ve read an ICE analysis where the writer praised the engine saying its powercurve looked like one of an electric motor, but for some people this is not good for racing

[Richard]

Repeated posts that electric racing is rubbish and associated bickering have been deleted.

Let's focus on discussion of the technical attributes of the series and cars.