F1 Energy store density for 2026 and hot swap batteries

[Zynerji]

For this type of TJI turbo engine layout, would it be worth to just increase the stroke by 5mm? Would that significantly change the output hysteresis? I mean. Same flow limits, but more time acting on the pistons?

... Not reducing bore. Just increasing stroke. Make them 2.0l or whatever.
I'm just thinking more action time on piston extracts more energy. With flow limits in place already, they would not really gain from the displacement increase in the traditional sense...

there isn't 'more action time on the piston'
with the same rpm the 'action time' is the same fraction of the time of the whole cycle (regardless of stroke)
unless they change the relationship of upward stroke time to downward stroke time - as the true Atkinson engine did
also ....
if the rpm is lower (seeking more 'action time') .... either .....
the charge per cycle is bigger for the same massflow so the mep is excessive ie unsurviveable ...or ....
the charge per cycle is not bigger so the mep isn't excessive - but the massflow is less and so the power is less

As always, your well thought out answers are very welcome. Thank you!

[mzso]

Why not (wireless) quickcharge at 1000Kw ?

You would go back to "heavy fuel rigs" again except this time you have to wire the entire pitlane and isntall massive transformers i suppose.

You mean the whole track. 30s seconds in the pit lane is not much even at 1000kW.

What I'm bringing up is hot-swap-able energy stores.

I guess it's theoretically possible. However a battery pack that's both placed safely and is replaceable quickly is not an easy problem.

[diffuser]

Why not (wireless) quickcharge at 1000Kw ?

You would go back to "heavy fuel rigs" again except this time you have to wire the entire pitlane and isntall massive transformers i suppose.

You mean the whole track. 30s seconds in the pit lane is not much even at 1000kW.

What I'm bringing up is hot-swap-able energy stores.

I guess it's theoretically possible. However a battery pack that's both placed safely and is replaceable quickly is not an easy problem.

You'd think that if battery replacement was on someone's radar, you'd hear about it. I know that they've said the battery is gonna be larger but I'm not under the impression that it will hold more than a 1 lap charge. If that is the case, replacing it is futile.

[PlatinumZealot]

Wheels are large and fastened safely by one fancy lug nut. F1 surely can figure out fastening for a 25kg battery pack.

It may be a small robo-jack with torque sensing wrenches that the car drives on, and it pilots itself towards the battery to unbolt it and then bolt in the new one.

Keep in mind I'm assuming that the batteries are so depleted over the race (net discharge higher than net recharge) if the driver so wishes to access that extra pace...

Risks come with the time for the robo-jack to swap the battery... But a nice fresh battery to unlock maybe 8 tenths a lap solidly in the final stint could be worth the stop!

[PlatinumZealot]

Why not (wireless) quickcharge at 1000Kw ?

Oh forgot to add.. That lithium batteries do catch fire at times... 1 megwatt of charging can cost life is something goes wrong.

Active cooling will aboslutely be a must... And that's dead weight to the cars already heavy battery cooling auxilliaries.

[wuzak]

You'd think that if battery replacement was on someone's radar, you'd hear about it. I know that they've said the battery is gonna be larger but I'm not under the impression that it will hold more than a 1 lap charge. If that is the case, replacing it is futile.

The battery capacity is 4MJ.

The allowed recovery per laps is 9MJ.

The battery won't last a full lap. It will be constant charging and discharging.

[mzso]

Wheels are large and fastened safely by one fancy lug nut. F1 surely can figure out fastening for a 25kg battery pack.

It may be a small robo-jack with torque sensing wrenches that the car drives on, and it pilots itself towards the battery to unbolt it and then bolt in the new one.

Keep in mind I'm assuming that the batteries are so depleted over the race (net discharge higher than net recharge) if the driver so wishes to access that extra pace...

Risks come with the time for the robo-jack to swap the battery... But a nice fresh battery to unlock maybe 8 tenths a lap solidly in the final stint could be worth the stop!

Tires are exposed and designed to bear mechanical loads, batteries lie deep within and are fragile and normally reside deep within the car, with good reason.

Battery swapping would only make sense if it was a major energy store. Especially if it was the only energy storage.
The current pitiful amount of storage it's not worth the bother. F1 might even go full electric with some bleeding edge battery tech (that in particular lacks a flammable electrolyte) and 3-4 swaps per race, if they figure out how to do it relatively safely.

Oh forgot to add.. That lithium batteries do catch fire at times... 1 megwatt of charging can cost life is something goes wrong.

Active cooling will aboslutely be a must... And that's dead weight to the cars already heavy battery cooling auxilliaries.

You definitely wouldn't charge 25kg worth of Li-ion at 1000kW. That's more like 4-500kg-s worth of batteries

[PlatinumZealot]

Read NFLers quote. I was addressing that.

This thread is about hot swap batteries.

I guess your view is against them for mechanical reasons? And for that it's not worth it unless it is major energy store? But check the premise of the thread in my first post.

We can actaually calculate the required size in Kwhrs of the energy store required based on the premise I set.

[mzso]

Read NFLers quote. I was addressing that.

This thread is about hot swap batteries.

I guess your view is against them for mechanical reasons? And for that it's not worth it unless it is major energy store? But check the premise of the thread in my first post.

We can actaually calculate the required size in Kwhrs of the energy store required based on the premise I set.

What I said still counts as hot swapping.
Anyway, your premise is a tad weird. They will drain and recharge the battery multiple times per lap, no amount of skimping on generation would compensate for time lost changing such small capacity batteries.

Mechanical/practical and safety reasons. A small battery like this is deep inside a car. Hard to get to. A big one would necessary be maybe all around, it would need its own strong protective casing. But could be more accessible.

[DenBommer]

Wheels are large and fastened safely by one fancy lug nut. F1 surely can figure out fastening for a 25kg battery pack.

It may be a small robo-jack with torque sensing wrenches that the car drives on, and it pilots itself towards the battery to unbolt it and then bolt in the new one.

Keep in mind I'm assuming that the batteries are so depleted over the race (net discharge higher than net recharge) if the driver so wishes to access that extra pace...

Risks come with the time for the robo-jack to swap the battery... But a nice fresh battery to unlock maybe 8 tenths a lap solidly in the final stint could be worth the stop!

Tires are exposed and designed to bear mechanical loads, batteries lie deep within and are fragile and normally reside deep within the car, with good reason.

Battery swapping would only make sense if it was a major energy store. Especially if it was the only energy storage.
The current pitiful amount of storage it's not worth the bother. F1 might even go full electric with some bleeding edge battery tech (that in particular lacks a flammable electrolyte) and 3-4 swaps per race, if they figure out how to do it relatively safely.

Oh forgot to add.. That lithium batteries do catch fire at times... 1 megwatt of charging can cost life is something goes wrong.

Active cooling will aboslutely be a must... And that's dead weight to the cars already heavy battery cooling auxilliaries.

You definitely wouldn't charge 25kg worth of Li-ion at 1000kW. That's more like 4-500kg-s worth of batteries

What do you mean with bleeding edge battery tech and flammable electrolyte?

Can i find some more info about this?

[PlatinumZealot]

@Mzso

Let's create a scenario for hot swapping..

Current rules.. Max 4MJ per lap deployment....
New rules max 8MJ per lap deployment.
Current typical average battery capacity among teams ~ 10MJ (this is not limited by the rules so there is a weight to capacity trade-off).
New rules typical average battery capacity 16MJ.

Note that actual charging energy from the car would be the same assuming same brake by wire rules.

Lets say the maximum a car can charge on a lap with full harvest settings is 6 Megajoules at a loss of 2 seconds a racing lap.

To fully charge your new 16MJ battery you run three laps with charging. So a net defecit of 6 seconds race time.

When this deployed the car can go 1 second a lap faster for two laps. This is on top of the normal 4MJ max deploy we have now. So in this case you go slower by focusing on charhing your battery during the race. (we sawthis is Spa when Lewis went into charging mode to get fastest lap).

Lets say a fresh battery at the pitstop adds 2 seconds to the pitstop. But now you have the full charge of battery. This fresh battery allows full deployment for a few laps so means you just gained a net 4 to 6 seconds of race time.

Something like this. Note the numbers are very conservative but you can always play with it.

You could argue what about road relevance?
Well i think it is road relevant.

[wuzak]

@Mzso

Let's create a scenario for hot swapping..

Based on 2026 rules?

Current rules.. Max 4MJ per lap deployment....
New rules max 8MJ per lap deployment.

2026 rules specify 9MJ recovery, unlimited deployment, per lap.

So, in effect, 9MJ deployment per lap.

Current typical average battery capacity among teams ~ 10MJ (this is not limited by the rules so there is a weight to capacity trade-off).
New rules typical average battery capacity 16MJ.

Where are you getting those numbers?

Lets say the maximum a car can charge on a lap with full harvest settings is 6 Megajoules at a loss of 2 seconds a racing lap.

To fully charge your new 16MJ battery you run three laps with charging. So a net defecit of 6 seconds race time.

The maximum harvest is 9MJ per lap.

The maximum storage is 4MJ (difference between maximum and minimum state of charger).

To get to a maximum state of charge of 16MJ the battery can have no less than 12MJ as its minimum state of charge.

If all energy recovered came during the braking phase then there would be, theoretically, no loss of time. There would also be no loss of time if the charging can be done with braking and part-throttle charging (burning fuel to charge the battery).

There will be some loss of time if charging has to happen on the straights (lift and coast, full throttle burning fuel to recharge).

When this deployed the car can go 1 second a lap faster for two laps. This is on top of the normal 4MJ max deploy we have now. So in this case you go slower by focusing on charhing your battery during the race. (we sawthis is Spa when Lewis went into charging mode to get fastest lap).

It must also be noted that under the current rules the amount that can be deployed from the battery to the MGUK is twice that going in the other direction. So there is benefit in doing a charge lap, sacrificing a lap to make sure the next lap is started with the maximum possible charge.

For 2026 rules, the energy that can be recovered per lap is more than twice the energy that can be stored.

Lets say a fresh battery at the pitstop adds 2 seconds to the pitstop. But now you have the full charge of battery. This fresh battery allows full deployment for a few laps so means you just gained a net 4 to 6 seconds of race time.

The 2026 rules specifically forbid adding energy to the battery in a pit stop (as do the current rules). Or at least limit it to a very small amount.

Even so, a fresh battery would allow 11s of full deployment before recharging is necessary. That is, 4MJ storage/350kW.

[PlatinumZealot]

@Mzso

Let's create a scenario for hot swapping..

Based on 2026 rules?

Current rules.. Max 4MJ per lap deployment....
New rules max 8MJ per lap deployment.

2026 rules specify 9MJ recovery, unlimited deployment, per lap.

So, in effect, 9MJ deployment per lap.

Current typical average battery capacity among teams ~ 10MJ (this is not limited by the rules so there is a weight to capacity trade-off).
New rules typical average battery capacity 16MJ.

Where are you getting those numbers?

Lets say the maximum a car can charge on a lap with full harvest settings is 6 Megajoules at a loss of 2 seconds a racing lap.

To fully charge your new 16MJ battery you run three laps with charging. So a net defecit of 6 seconds race time.

The maximum harvest is 9MJ per lap.

The maximum storage is 4MJ (difference between maximum and minimum state of charger).

To get to a maximum state of charge of 16MJ the battery can have no less than 12MJ as its minimum state of charge.

If all energy recovered came during the braking phase then there would be, theoretically, no loss of time. There would also be no loss of time if the charging can be done with braking and part-throttle charging (burning fuel to charge the battery).

There will be some loss of time if charging has to happen on the straights (lift and coast, full throttle burning fuel to recharge).

When this deployed the car can go 1 second a lap faster for two laps. This is on top of the normal 4MJ max deploy we have now. So in this case you go slower by focusing on charhing your battery during the race. (we sawthis is Spa when Lewis went into charging mode to get fastest lap).

It must also be noted that under the current rules the amount that can be deployed from the battery to the MGUK is twice that going in the other direction. So there is benefit in doing a charge lap, sacrificing a lap to make sure the next lap is started with the maximum possible charge.

For 2026 rules, the energy that can be recovered per lap is more than twice the energy that can be stored.

Lets say a fresh battery at the pitstop adds 2 seconds to the pitstop. But now you have the full charge of battery. This fresh battery allows full deployment for a few laps so means you just gained a net 4 to 6 seconds of race time.

The 2026 rules specifically forbid adding energy to the battery in a pit stop (as do the current rules). Or at least limit it to a very small amount.

Even so, a fresh battery would allow 11s of full deployment before recharging is necessary. That is, 4MJ storage/350kW.

Sigh. You missed the big picture and focused on whether the ink is spotty and wether a few words are miss- spelled.

The numbers are obviously hypothetical... Switch them with their proper counterpartz if you wish. I'm painting a scenario that shouldn't be affected by that.

The idea is that once there is a large enoughbbattery capacity and a net charging deficit over the race, there is a cross-over point where swapping the battery during a pitstop can give a shorter race time.

[wuzak]

The idea is that once there is a large enough battery capacity and a net charging deficit over the race, there is a cross-over point where swapping the battery during a pit stop can give a shorter race time.

That day is a very long way away.

[PlatinumZealot]

Hmm not really. As i said, depends on the pace each MJ can unleash over a lap, above the normal electrical deployment, current battery capcity and how quickly you can swap a battery in a pitstop.

It may not need to have much more battery density than what we have now... The ever immiment solid state battery tech might coincide with 2026.