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Comment by ttul | Hacker News Reader

Assuming a human can carry 20kg with relative ease (say, in a backpack or strapped to a bike), this new battery allows one to carry around 24kWh - enough to run a North American house for several hours. Or to drive an e-bike for 1,000 miles… Really stretches the imagination.

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Or they could carry about 2 liters of kerosene.

Plus a machinery to convert it to electricity :)

Perhaps convert an old lawnmower and power drill to power one’s desktop PC? Simple and perfectly safe/convenient with additional respirator and ear defenders.

Cue this old Nissan Leaf ad: gas powered everything

https://www.youtube.com/watch?v=Nn__9hLJKAk

Wow 11 years ago. i switched to an electric car recently and still frequently smell exhaust fumes from cars that are running rich or burning motor oil. I might be alive to see the end of internal combustion engines in cities which seems inevitable now.

Living in a urban area I can see the end of the ICE in the next 10-15 years. The game changer in my opinion is the ebike, if we can get just a slight shift in thinking, eg taking the ebike to the gym or store instead of driving an ICE car doesn't stand a chance in the city.

Kerosene contains 10 kWh of potential energy per liter (about 800g). So yes you’d need 3kg of kerosene to provide 24kWh of energy. But that is heat energy.

An efficient gasoline generator produces 1.7kWh per liter. So for 24kWh, you’d need to consume 14L of gasoline and also carry around the generator. I would personally prefer the battery option.

> An efficient gasoline generator

And how much does it weigh?

The smallest one I can easily find is 10kg.

My 1.6 KW generator is around 40 lbs. without fuel. and about the size of a carryon. Not at all practical compared to a battery.

It's odd to think about the danger of such concentrated energy sources. Right now I'd treat a couple gallons of kerosene with way more respect than a battery. But if this battery tech was deployed, it could be more dangerous than liquid fuels in certain ways.

It largely depends on how easy it is to get the energy out all at once.

A stick of butter represents about 1kWh of chemical energy, and a 2000kg vehicle at 225 km/hr represents about 1kWh of kinetic energy. The latter is intuitively more dangerous because the energy could easily be transferred (to e.g. a person standing in its path) in an instant.

Heck the specific energy of any given piece of matter is c squared, but we don't (as of yet) know how to get it out except under a few very special circumstances :)

No need to give such examples out of left field. Just compare the danger of a gallon of gasoline vs a gallon of diesel. Or a stick of TNT vs a an eye dropper of plutonium.

> Right now I'd treat a couple gallons of kerosene with way more respect than a battery.

Lithium-ion batteries are far worse than kerosene as a hazard. New York City has a big and growing problem with people charging scooter-sized electric vehicles in apartments.[1]

[1] https://www.nytimes.com/2023/02/21/nyregion/lithium-ion-batt...

> Assuming a human can carry 20kg

20 pounds maybe... but 20kg (44lb) would be a serious effort for most people.

My kid weights 14kg and my 60 kg wife can still pick him up and walk with him. 20 kg with a good backpack is achievable to pretty much everyone.

Yes it's possible, but it's not something the average person can do for very long.

I can squat 1.5X my own weight, but I still get pretty tired carrying a mere 12kg backpack through a long airport walk. Sure you can build up to carrying 20kg all the time, but it's not normal for most people in the world. And it would not be accepted as reasonable by the people in the world who could afford it.

The key is a good pack like that used for hiking with a proper frame and a large padded belt, not a normal school type backpack that you carry just on your shoulders (often just slung over one shoulder). The proper pack setup loads your muscles more like squatting. The difference is pretty striking. I think 20kg is appropriate in that instance.

(Normal guideline is hike pack should not be more than a third your body weight to avoid injury, which for the average American male would be 60 pounds and the average American female would be 50 pounds… there’s enough margin so that even if you’re talking just those in a healthy BMI of like 23, there’s enough for a 44 pound pack for the average height American male and female.)

You need a good framed backpack. Not all backpacks are the same.

Soldiers are routinely expected to carry far more than this. They may be carrying it in a more effective pack and/or distributed over more of their body.

Quick google search indicates plenty of US Troops were hauling 90+ pounds of gear around in Iraq and Afghanistan due to need to carry a pack + body armor + weapons.

I'm no soldier but I have certainly hiked with a 50lb load in a good internal frame pack.

And in any case the eBike example was listed. 50lb is not a very heavy load on a bicycle at all. But a battery like this would be better used to make an eBike much lighter. Today they are comically heavy in ways that creates all kinds of extra problems.

If you make the battery 1/4 of the weight of a current eBike with a 100 mile range all of a sudden you don't have to supersize everything on the bike and make it heavy, hard to handle, and un-aerodynamic. It would make the whole bike's performance improve even more.

Are you a parent?

20 kg is heavy, but I've gone hiking for days with a 16 kg backpack and I'm not very big. Stronger people than me carry more, and those with better skills for ultralight packing carry less.

I think that you are right, it is serious effort, but you can carry 20 kg for a full day if you need to.

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