Amps or Amphours - Please try to get it right.

That means I got my Solar Calculator wording correct ... Hey !!

Rgds

Steve - Still learning about DC power .. 24 Days to go !!

Hi Lex
I guess you mean.. It's average current 'draw' is 4 Amps ???
Am i being pedantic ??

Actually it is its not it's as it's is it is not belonging to it ... Now that is pedantic !
LOL

Mandrake

Hey Lex

I being pedantic , but you might want to check your figures.

Just another few bobs worth. I found these words that can also make it easier for some to understand. Firstly as with a lot of things these days spelling seems to be left out some times. For amphours "read amp" hours. Its two words. And I do not want to wake up that spell checker thread again. If you don't believe me try putting "amphours" in Google and search for it. Okay enough of that. As a tech I fully undrstand it but as a scribe I leave a lot to be desired. So I quote the following that I came across recently when looking at fridges.

This is quoted from the following address: http://www.fridge-and-solar.net/amps.htm

"
Amps, Amp-hours, Watts !! what's that all about?


Ok, let's start with Amp-hours verses Amps....

I think it's easer to understand if I give you some examples to work through.

For the sake of this explanation lets say you have a 12 volt compressor motor fridge, and this fridge draws 5 amps while it's compressor motor is running, now if the compressor motor ran for a whole hour the fridge would have drawn 5 amps in total for that hour, or 5 amp hours (5Ah), and if it like this for 24 hours it would have drawn and consumed 120 Amp-hours in total, 5Ah x 24h = 120Ah.

But the fact is the compressor motor should not be running continuously for the whole 24 hours, they should cycle on and off as required to keep the temperature constant in the fridge, so if it was running at say a 50% duty cycle, i.e. running on and off for only half of the hour in total, it would still be drawing 5A when it's running, but for only half the time, so that would now be 2.5Ah it draws from the battery each hour, and 60Ah over a 24 hour period.

So along these lines lets look at say an electric 12 volt water pump, it may draw 10A while it's running, but if it only runs for a total of 15 minutes each day, it's total draw for the whole day would be only 2.5Ah, not much at all.

Ok some electrical appliances are rated in Watts rather than Amps, but that's ok, it's easy to convert these Watts to Amps.

You simply take the stated Watts, and divide that by the Voltage and this gives you the Amps that the item will draw

So lets say for example you have a 120 Watt light globe (like the type you find in some car spot lights) and divide this 120W by the 12V that is used to power it and you end up with 10A at 12V.

This also works the other way around, if you have the amps and the voltage of an item and you want to know the Watts, simply multiply the amps by the voltage and you have the Watts.

So for example remember that water pump that was drawing 10A at 12V, well 10A x 12V = 120 Watts


Now this works for any Voltage, Watts and Amps combination.

Like a 100W household light globe at 240V = 0.41A.
"

This says it better than I can.

Phil

Oops left out a bit.

"Amphour" I believe is less likely to be misinterpreted.


(Typing is my fourth language)

Now for the new challange, is a day 24hrs or 12 hrs or is it gunna be 4amps/hr or 2amps/hr.

Just haveing a bit of a laugh

'OK maybe I'm being pedantic'

Maybe you are right.

But then, I'm one who doesn't get too hung up on such things. As long as I understand what a poster means. I don't get in a tiz about spelling either. But that's just me.

Lex M

I have to agree with you 100%.

Amps is an instantaneous current measurement

Amp-hour is the consumption of current over a given time. (one hour)

NB. This passed the spell checker. (apart from Lex and Redeye)

Redeye

I'll kick in on two angles

electrically and grammatically


Ampere is an instantaneous value

and Ampere is spelt with a capital because it is a Pro-noun!!!!LOL


Cheers
Garth

Lex,
you posted:
"The correct terminology for this fridge could be:

It uses 48 Amphours a day.
It average current is 4 Amps"



So is this a normal 'day' = 24 hours ?

if so, then the fridge draws 48 / 24 = 2 (not 4)

The fridge must only run for 12 hours, (not at night) ?
48 / 12 = 4 Amps

Do the numbers tell the truth or lie ?

Maîneÿ . . .

This thread started off ok but now seems to have degenerated into a heap of tech stuff that probably makes sense to Auto sparky's or the like, but to us fence sitters = crap. LOl . Anyway I know it is my choice , I don't have to read it if I don't want to but most ordinary people on this site just want a fairly straightr forward answer to a straight forward question? Is that reasonable?
If we want to go to Uni in order to understand the technical lingo relating to a simple question, perhaps we should ask it on another forum.? Just my opinion!! Cheers

I'm sure it was Mainey that went bananas on this topic on the overlander site, am probably historically mistaken if so apologies mainey.

But I find it an excellent topic and am keen for the correct correct consenus of the electrically educated.

Though I think it is agreed that there is no such thing, other than band names, as "amps" so therefore amp hours, or amperes depending upon level of education with such marvels, is the correct measure and leads to a reduction of obfuscation.

As soon as someone started quoting SI Units I knew this was going to get deep.

Without detail focused people the world would be a very different place. Lots of great ideas but no-one to get the nuts and bolts stuff done!

Love these sorts of discussions and if I pick up one extra valid piece of info it was worth reading.

Cheers
Muddy