Originally Posted by getyourbone
And your point is? I never said wrong. I said inferior.
Using amp hours is about like saying my boat is 37.
Most would probably assume feet as that is most likely the case but it could be inches, meters, stone...etc...
kWh gives a universal measurement and the individual reading can convert as they see fit
Just sayin’....Not judgin’ just sayin’
Of course you were judging, you used the word "inferior" which involves a judgement about what is superior and what is inferior.
Also using amp-hours is not like saying your boat is 37. 37 is a number, amp-hours are units which are qualitatively different than numbers.
Rather than saying that amp-hours are an inferior unit choice which implies that those they chose that unit for expression have inferior reasoning, you should stop and wonder why it is the pervasive unit choice. . . . .
Because of wiring
is sized based on amps. Within limits it doesn't matter what voltage it carries or if it is AC or DC. Go down to your neighborhood HomeDepot, B&Q or Rona and check the stickers on all the power tools, amps is listed not watts, though watts may be on the packaging somewhere. Then stroll over to the extension cord aisle and you will find cords listed by the amps they will carry.
Most endeavors that use electricity tend to use either 1 or 2 voltages. Houses use mostly 120 or 240ac plus a couple of minor low voltage things like thermostat and doorbell.
Boats use 12v dc for most things, with some having a 120v or 240v ac system for using regular shore-side appliances
Small aircraft use 24v dc.
Autos use 12v.
Airliners and ships tend to have more voltages but that's a different world that a forum full of amateurs like CF would not be addressing.
Given that you have to deal with amps no matter what, and the voltage is implicit using amp-hours for battery capacity is easier, it involves fewer mathematical steps and is therefore less prone to conversion mistakes
Inverters are a specific instance where watts is preferred over amps. Inverters have different input and output voltages and amperages, so using watts prevents mistakes
Also 2.5 kw-hr is bogus too, you should have written 7.5MJ if your really wanted to be universal. Finally it's kilowatt-hours not kilowatts
hours, only the hours is plural and there should be a hyphen between the words.