karana wrote: ↑19 Dec 2025, 00:21
diffuser wrote: ↑18 Dec 2025, 23:54
vorticism wrote: ↑18 Dec 2025, 20:08
Regarding battery tech posted here and elsewhere: The pack weight and capacities are regulated so the ES performance differentiation should presumably arrive via durability & cost (budget cap) unless the minimum pack weight and maximum charge/discharge rates are hard to achieve.
Minimum ES weight
2025: 20kg
2026: 35kg
ES usable capacity/lap
2025: 1.1kWh
2026: 1.1kWh
ES total recharge/lap via MGUK
2025: 0.6kWh + unregulated MGUH recharge
2026: 2.5kWh
ES total discharge/lap
2025: 1.1kWh
2026: unregulated
ES mass increase: 75%
ES max recharge/lap increase: 125%
ES max deployment increase: infinite (1.1kWh to the now unlimited amount)
It’s a larger pack put through greater charge-discharge cycles per lap, although the increases are not numerically identical. Solving for the lattermost figures above may be where any development race occurs. Max total discharge/lap is not regulated but the total recharge/lap is, so that is the primary confine. It will allow a difference between max recharge and what the driver chooses to deploy, as some here have alluded to. As it relates to this post, that extra discharge relative to the peak recharge rate may be another development differentiator.
Kind of sad ....
Energy density Wh/kg.
Given Energy capacity: 4 MJ
Battery mass: 35 kg
Convert MJ → Wh
4MJ = 4,000,000J
1Wh = 3,600J
4,000,000÷3,600=1,111Wh
Energy density
1,111Wh ÷ 35kg = 31.7Wh/kg
If we look at the batteries for the Audi e-tron S6, the energy density of those batteries are 130 or 135Wh/kg. FIA aren't asking for cutting edge of battery technology.
If my calculations are right, they could have made the min battery weight easily 10KG.
hmmm but the F1 Batteries can be discharged over two times per lap (9MJ charge limit per lap) so maybe that's playing into it. Don't think you could do that with the AUDI e-tron batteries.
One thing to keep in mind is that the battery capacity is likely higher than 4MJ, only the difference in SOC must be at most 4MJ. I think I remember there being discussions about this somewhere on this forum.
Also, the 35kg applies to the entire ES main enclosure, not just the ES itself. The ES main enclosure in the old regulations had a minimum weight of 31kg.
Thanks for this correction. That alters the mass increase % comparison in my post. I notice that the cell mass share of the 35kg enclosure weight seems to not be listed. In 2025 it was 20kg of the 31kg enclosure. Unless it's listed elsewhere this might be another area of differentiation i.e. what percentage of the enclosure mass is cell mass.
Revised key figures:
ES enclosure mass increase: 12%
ES cell mass increase: unknown
ES max recharge/lap increase: 125%
ES max deployment increase: infinite (1.1kWh to the now unlimited amount)
ES max charge & discharge rate increase: 290% (120 to 350kW)
The point remains: note the pack weight increase vs the total deployment and energy flow rates. This could be an area of differentiation if it's a challenge to reach these figures. I added the charge-discharge rate increase, it further illustrates how much more intensely these not-much-larger packs will be used.
