Formula E

[Andres125sx]

It would have to be compulsory, unless the races are deliberately one lap longer than the battery capacity? Then you can roll the dice on slower lap time or safety car or VSC and ditch the stop...

There´s no race lenght for battery capacity, same battery can last 20 laps or 50, depending on the power used,
how much coasting, etc.

True, but to help with the spectacle of racing, the race length does tend to very closely coincide with the battery being dangerously close to 0% capacity on the final lap...

It´s the other way around, whatever race lenght, drivers will manage battery to use as much power as possible while it still can finish the race, and obviously that implies reaching the checkered flag very close to 0%. If battery is not very close to 0% at the checkerred flag, driver managment was poor as he could have used more power during the race, or do lesss coasting and be faster.

Or race lenght was much shorter than planned due to SCs as we have seen several times

[AJI]

There´s no race lenght for battery capacity, same battery can last 20 laps or 50, depending on the power used,
how much coasting, etc.

True, but to help with the spectacle of racing, the race length does tend to very closely coincide with the battery being dangerously close to 0% capacity on the final lap...

It´s the other way around, whatever race lenght, drivers will manage battery to use as much power as possible while it still can finish the race, and obviously that implies reaching the checkered flag very close to 0%. If battery is not very close to 0% at the checkerred flag, driver managment was poor as he could have used more power during the race, or do lesss coasting and be faster.

Or race lenght was much shorter than planned due to SCs as we have seen several times

Finishing a race with no fuel is the object in every form of motorsport. The downside of a battery powered car is lap times get worse as the energy gets lower.
My suggestion is that with the option of adding a hot swappable auxiliary battery (or not) gives you more options than a fast charge. No one will take a 30 second fast charge (which really translates into more than a minute when you include in and out) for a few extra kWh's, but if you have the option of running a lighter car or maybe a 5 second battery swap then it becomes a little more interesting, no..?

[Big Tea]

True, but to help with the spectacle of racing, the race length does tend to very closely coincide with the battery being dangerously close to 0% capacity on the final lap...

It´s the other way around, whatever race lenght, drivers will manage battery to use as much power as possible while it still can finish the race, and obviously that implies reaching the checkered flag very close to 0%. If battery is not very close to 0% at the checkerred flag, driver managment was poor as he could have used more power during the race, or do lesss coasting and be faster.

Or race lenght was much shorter than planned due to SCs as we have seen several times

Finishing a race with no fuel is the object in every form of motorsport. The downside of a battery powered car is lap times get worse as the energy gets lower.
My suggestion is that with the option of adding a hot swappable auxiliary battery (or not) gives you more options than a fast charge. No one will take a 30 second fast charge (which really translates into more than a minute when you include in and out) for a few extra kWh's, but if you have the option of running a lighter car or maybe a 5 second battery swap then it becomes a little more interesting, no..?

Would a battery with manageable parameters, plus removal and re- installation give much more benefit than 30 second charge in the time required? It would have to be of manageable size and weight, and also be a replaceable unit for the prior section of the race or the car would be under weight, so easy to remove, including connections.

[AJI]

Would a battery with manageable parameters, plus removal and re- installation give much more benefit than 30 second charge in the time required? It would have to be of manageable size and weight, and also be a replaceable unit for the prior section of the race or the car would be under weight, so easy to remove, including connections.

You're taking this piss, right?
How difficult is it and how many human beings are required to change 4 tyres on a current F1 car in under 2 seconds?
A hot swappable auxiliary battery swap isn't exactly building the space shuttle. Perhaps the future of EV recharging should follow the path of least resistance in the short term?
Regarding 'under weight', I thought I was pretty clear that you take the weight reduction (or) extra energy, but perhaps I didn't explain myself well enough.

[jjn9128]

If a 51kWh battery weights 285kg it follows that a 4kWh removable battery would be ~22.5kg. When you start talking about protecting the mechanic(s) plugging it in from electrocution with a 1000V system you can add a few kg to that for isolation and cooling, plug carry handles and connectors. I don't think it's "taking the piss" to question these things. Just because someone doesn't follow your world view.

[Big Tea]

Would a battery with manageable parameters, plus removal and re- installation give much more benefit than 30 second charge in the time required? It would have to be of manageable size and weight, and also be a replaceable unit for the prior section of the race or the car would be under weight, so easy to remove, including connections.

You're taking this piss, right?
How difficult is it and how many human beings are required to change 4 tyres on a current F1 car in under 2 seconds?
A hot swappable auxiliary battery swap isn't exactly building the space shuttle. Perhaps the future of EV recharging should follow the path of least resistance in the short term?
Regarding 'under weight', I thought I was pretty clear that you take the weight reduction (or) extra energy, but perhaps I didn't explain myself well enough.

Not taking the piss at all (which is I suppose unusual for me). You seen sure of it so just asking the question. It is not just the weight of the battery, but the mounting, cooling, protection and coupling to the other battery.

If, as jjn9128 suggests it comes in at around 30kg, space must be found to accommodate it in a position where its weight will be OK and pit crew will have ready access to it in a position they can lift it out and in. Take for instance removing and refitting a truck battery in 30 seconds v plugging in an adaptor which is installed and accounted for in the design of the car, it looks to me a close run thing at best.

[bill shoe]

Formula E tries to promote electric cars in a financially realistic and reusable way. For example, the Michelin tires do not get changed during a race because Formula E and Michelin don't want to promote the idea of throw-away tires. In a similar manner, it's much better for the promotion of real-world electric cars if they can be seen recharging during a race rather than switching out battery packs. I also suspect the technical challenge of switching battery packs from deep within the safety of the carbon chassis is a bigger deal than people imagine, but that's secondary to Formula E's wanting to promote electric cars in a certain way.

[Andres125sx]

I´d love swapping batteries so they can use more reasonable batteries in size and weight, making cars lighter and faster, but if that would be an option, they´d be doing it since season 1

The limiting factor I think is power delivery. Battery limit in power delivery is directly proportional to capacity, that´s the reason they´re labeled with a C rating (1C, 2C, 5C...) depending if they´re low discharges cells for applications like mobile phones (1C or less) or high discharge for cars, tools, etc.

New FE batteries will be 50kWh, 1000v, wich means they´re 50Ah. To provide 350kW of power for qualy mode they must be 7C discharge (350kW / 1000v = 350Amps... /50Ah = 7C). That also means a swappable 5Ah/5kWh wich is a tenth in capacity will need a 10 times higher discharge rate to provide same 350kW, wich means a 70C discharging rate

Same for charging/regen, except charging rates are always a fraction of discharging rates. With Lipos (wich I know much better) a 20C discharge battery usually can be charged at 1C max, 40-50C batteries at 2-3C and 80-100C batteries (wich I´m not sure if they exist in LiIon cells) can be charged at 5C max.

So if they want to regen same 350kW they need same 70C charging rate, and that´s simply out of reach for any current technology, and by a huge margin. Actually a charging rate of 7C wich is the plan for new 2022 batteries is quite impressive, so they simply can´t go with a smaller battery, they´re on the limit

[AJI]

Slightly OT, but I think it's relevant to the discussion, what do we suppose the C rate of the F1 ES is?
I know we don't have any data for the battery capacity or chemistry or packaging etc... but we do know the max/min weight and we know they are only allowed 2 per season (I think?) and we know that they absolutely get punished almost every single lap

[ajprice]

There's a 'Gen 2 EVO' coming with the tops of the front wheels open https://www.facebook.com/fiaformulae/ph ... 777468683/

04.02.20 is probably 4th February, but it might be 2nd April.

[Scorpaguy]

Naked tyre tops mean very little...unless you are just trying to ape the F1 look. To me opening up such is a step back. IMHO FE needs to stop pursuing such optics as they are patently cosmetic...FE's speeds and tyres do not require the aero which has molded the F1 shape. 4WD/4WS, torque vectoring, shorter & quicker cars (not faster), more robust configurations, and the sort could be just what FE needs on their short/tight courses.

Do not get me wrong, I enjoy the series...just do not think chasing the "F1 paradigm" is the most prudent strategy for this series.

[El Scorchio]

If it makes the cars look less like stupid plastic little toy car batmobile crossovers then I'm all for it.

I say actually make it look more like F1. Then you might be more likely to bring over some of the audience.
And while they are at it, put races on some decent tracks with a bit of width that don't look like a race through a car park and lead to just a procession of cars because it's far too tight to really overtake.

Maybe drop the horrible ugly on screen graphics and the rubbishy gimmicks like fan boost and that stupid mario kart type thing where you go offline to get a boost.

[jjn9128]

Naked tyre tops mean very little...unless you are just trying to ape the F1 look. To me opening up such is a step back. IMHO FE needs to stop pursuing such optics as they are patently cosmetic...FE's speeds and tyres do not require the aero which has molded the F1 shape. 4WD/4WS, torque vectoring, shorter & quicker cars (not faster), more robust configurations, and the sort could be just what FE needs on their short/tight courses.

Do not get me wrong, I enjoy the series...just do not think chasing the "F1 paradigm" is the most prudent strategy for this series.

Aerodynamically it's quite a drastic difference. I think the change is more structural - they want the front end less robust so the drivers can't do the battering ram overtakes.

[izzy]

If it makes the cars look less like stupid plastic little toy car batmobile crossovers then I'm all for it.

I say actually make it look more like F1. Then you might be more likely to bring over some of the audience.
And while they are at it, put races on some decent tracks with a bit of width that don't look like a race through a car park and lead to just a procession of cars because it's far too tight to really overtake.

Maybe drop the horrible ugly on screen graphics and the rubbishy gimmicks like fan boost and that stupid mario kart type thing where you go offline to get a boost.

yes the tracks are basically too narrow to race on aren't they. Fundamental problem! So they beefed up the cars and threw away racing rules instead, and now it's bumper cars and more ridiculous than ever

[El Scorchio]

100%!
I think the ridiculous tight layout of a lot of the circuits is the biggest handicap. Even the straights are really narrow with barriers immediately on either side and the drivers don't have a lot of options other than just divebombing someone at the end of a long one.

Yes the racing is close, but it's just a high speed traffic jam. Must be like racing through a neverending tunnel.