Accumulator/battery and weight (charged vs depleted)

[evava]

I wonder if here on the forum is some physicist, who can calculate weight of the battery/accumulator which is depleted vs fully charged.
Is it significant amount of weight, or not any at all?

Energy delivered to the battery/accumulator should appear somewhere?

E=mc²

[amyk]

Not significant but the energy does contribute a really really tiny amount of mass.

[evava]

How much tiny?
Tesla car battery 80kWh, how much it weights fully charged vs depleted?

[Gyro]

Far too small to measure. 

[Kleinstein]

The formula is already give: a rough calculation in the head give something around 1 ng for the large battery.

[IanB]

How much tiny?
Tesla car battery 80kWh, how much it weights fully charged vs depleted?

Yes, it's an interesting question. But you already posted the answer: E = mc²

E = 80 kWh = 3e+8 J
c = 3e+8 m/s
m = E / c² = 3e+8 / (3e+8)² = 3e-9 kg = 3 µg

That's more than I might have thought, actually.

[bdunham7]

That'a not how it works.

Actually that is exactly how it works.  Although the binding energies and enthalpy change in chemical reactions or ion intercalation are much less than in a typical nuclear fission or fusion, the idea is the same--energy is released or absorbed depending on the relative energies of the before and after states and the mass of the system changes in proportion to that energy change.

[tooki]

I wonder if here on the forum is some physicist, who can calculate weight of the battery/accumulator which is depleted vs fully charged.
Is it significant amount of weight, or not any at all?

Energy delivered to the battery/accumulator should appear somewhere?

E=mc²

Just a little FYI, since you made a point of adding the term “accumulator”: in English, that word does not mean “rechargeable battery”. (It does, in quite archaic usage, refer to lead acid rechargeable batteries, but only lead acid, and again, it’s obsolete English.) I know that many European languages use “accumulator” to mean any rechargeable battery, but English does not.

[mzzj]

How much tiny?
Tesla car battery 80kWh, how much it weights fully charged vs depleted?

Yes, it's an interesting question. But you already posted the answer: E = mc²

E = 80 kWh = 3e+8 J
c = 3e+8 m/s
m = E / c² = 3e+8 / (3e+8)² = 3e-9 kg = 3 µg

That's more than I might have thought, actually.

540kg battery and 3ug. That is almost measurable, ie Mettler HK1000MC mass comparator has 1kg capacity and 0.1ug resolution.
Scaled to tesla battery size that would be 54ug resolution

[shakalnokturn]

Looking at energy densities taking only that delta into account shows how much room is left for improvement in battery solutions 

[thm_w]

https://physics.stackexchange.com/questions/34421/does-the-mass-of-a-battery-change-when-charged-discharged
https://www.physicsforums.com/threads/weight-difference-between-a-charge-and-discharged-battery.703057/page-2
https://www.reddit.com/r/askscience/comments/1hj8k7/do_discharged_batteries_weigh_less_than_fully/

The answers here are assuming a perfectly sealed ideal battery but that is usually not the case. From the third link it looks like you have to go deeper, and consider the chemical effects as well, some will lose some will gain.

[evava]

Thank you all for answers!
Interesting subject.