31–40 of 147 posts
Earlier quoted context omitted.
As a reference point, a Tesla 85D uses 290 watt-hours to go one EPA rated mile. So 1 kWh takes you 3.448 miles.
> one EPA rated mile Are EPA miles not the same as normal miles?
There is a series of standardized driving profiles that is averaged to get a comparable, somewhat realistic value.
Given how popular (and damn near impossible to discern) unsafe and unprotected lithium-ion batteries are, the idea of making a homegrown power wall terrifies me in ways I can't even begin to contemplate. An 18650 battery, if combusted, can produce hydrofluoric acid with just water vapor in the air (or the water in your lungs) if they use lithium hexafluorophosphate as the electrolyte. Hydrofluoric acid can and will c…
Just use sealed AGM batteries, don't burn your house down or deal with spilling chemicals everywhere.
Even just drawing in parallel from batteries like this is a fire hazard. Charging is an out of your mind goal.
1 Wh is about 0.9 kilocalories. So 1kWh is about 100g of butter. The energy expenditure of a human in one day is about 2kWh. 1kWh is about the energy needed to heat 10L of water from 0 deg celsius to 100 deg celsius.
It's interesting to realize thought that we programmers are code producing machines that run on roughly 2kWh per day. If we produce 100 lines of code in a day, that's 20Wh per LOC. Not bad, actually.
Reopening a plastic soda bottle.
From a web interactive I wrote: http://www.clarifyscience.info/part/ZoomB?v=A&p=CK6Ji&m=torq... (2014)
1kWh as gasoline is about 1/10 liter. Though one will not get anywhere near that much high-quality electric energy with consumer/small-scale methods.
1kWh as aluminium is about 66g (assuming 15kWh per kilo manufacturing input) or about 4 drink cans.
Given how popular (and damn near impossible to discern) unsafe and unprotected lithium-ion batteries are, the idea of making a homegrown power wall terrifies me in ways I can't even begin to contemplate. An 18650 battery, if combusted, can produce hydrofluoric acid with just water vapor in the air (or the water in your lungs) if they use lithium hexafluorophosphate as the electrolyte. Hydrofluoric acid can and will c…
I came here to say just that. This is a horrible idea and definitely not something you should do. Just use sealed AGM batteries, don't burn your house down or deal with spilling chemicals everywhere. Even just drawing in parallel from batteries like this is a fire hazard. Charging is an out of your mind goal.
Earlier quoted context omitted.
Joules are tiny it takes 3.6 million Joules = 1kWh
SI prefixes FTW. 1kWh = 3.6 MJ
Might as well just say 1 billion joules per second aka 1 GW then tack on or remove an hour if needed.
Given how popular (and damn near impossible to discern) unsafe and unprotected lithium-ion batteries are, the idea of making a homegrown power wall terrifies me in ways I can't even begin to contemplate. An 18650 battery, if combusted, can produce hydrofluoric acid with just water vapor in the air (or the water in your lungs) if they use lithium hexafluorophosphate as the electrolyte. Hydrofluoric acid can and will c…
Recycled 18650 cells that have worked fine in laptops for years are very unlikely to suddenly explode on you for no reason. I'd be more worried about the mystery Chinese ones you can get new on the web!
Here's some Materials Science students at Oxford who built packs using recycled laptop cells. They used controller software that monitors the health of each individual cell:
https://m.youtube.com/watch?v=RW1Xugey8j0
(It's towards the end of the vid)