Not related, but I hate this unit. Can't we just talk about Joules?
Joules are tiny it takes 3.6 million Joules = 1kWh
Watt-hours are tiny, it takes 1 thousand Watt-hours = 1kWh ;)
What does a kilowatt hour look like?
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Re: What does a kilowatt hour look like?
#62Less acronyms please. (COP, PV, and even EV)
COP: Coefficient of Performance. PV: Photovoltaic. EV: Electric Vehicle. TMDA: Too Many Damn Acronyms (It's a joke I heard at a company that had acronyms for everything).
Well, a TLA is a TLA, but an FLA is not an FLA (it is also a TLA)...
Re: What does a kilowatt hour look like?
#63Re: What does a kilowatt hour look like?
#64Not related, but I hate this unit. Can't we just talk about Joules?
It's not pretty,but it's practical. Especially when it comes to electricity - watts and hours are quite easy to work with.
It doesn't make much difference whether you use Watts or Joules, since 1 Watt = 1 Joule per second, so both are just as convenient for electricity: 1 Watt = 1 Volt Amp, so 1 Joule = 1 Volt Amp Second = 1 Volt Coulomb (although amps seems to be more "normal" than coulombs).
It's a bit redundant to multiply power by time, when that's just an energy, but going between Watts and Joules is trivial (by design), so it's not too bad.
However, I can't think of a reason why hours would be easier to work with than seconds (as kiloseconds, if you want the same order of magnitude), especially regarding electricity?
Re: What does a kilowatt hour look like?
#65"deliver 4-5 kWh of low-grade heat (or cold) into your home (depending on COP of a heat pump)"
If you don't use a reverse cycle system you can more like 8 kwh of heat or cold
Re: What does a kilowatt hour look like?
#66Given 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…
Maybe throw the whole mess into an out building with a fire suppression system of some sort? It says more details are to come, my curiosity is peaked.
Re: What does a kilowatt hour look like?
#67What does a Newton-meter of torque feel like? Reopening a plastic soda bottle. From a web interactive I wrote: http://www.clarifyscience.info/part/ZoomB?v=A&p=CK6Ji&m=torq... (2014)
> Newton-meter
I do not know why (and I do not have a strong opinion on this), but somehow this (relatively recent) tradition of naming units after people feels weird to me. I know we are already used to these units, but imagine the unit of mass was called Einstein instead of kilogram.
Re: What does a kilowatt hour look like?
#681 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.
I like the analogy of a bag of peanuts is equivalent to a teaspoon of petrol (properly aspirated) or a stick of dynamite
Re: What does a kilowatt hour look like?
#69Given 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.
Even just drawing in parallel from batteries like this is a fire hazard.
I think you've confused parallel with series; in parallel, the batteries will naturally balance themselves to the same voltage and discharge proportionally to their capacity. It's the series configurations that are riskier and need extra balancing circuitry.
Also, I'm pretty sure the bulk of fires are from the much more fragile pouch "lipo" cells, not hard-cased 18650s like these. You may note the extremely large number of lipo fire videos on YouTube as evidence.
On the other hand, 18650s tend to be quite a lot more robust and difficult to ignite: