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Old 10-10-2015, 11:26   #31
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Re: Amps v Amp hours v Amps/Hr

Stu, glad you created a new thread. The "residential reefer" thread was totally hijacked by all the above. Thanks for you explanation of the SI standard. But one of the things that I think people get mislead by is the difference between the amp hours as measured by a battery monitor meter is not equivalent to the amp hours stored in a battery - necessarily. Correct me if I am wrong on this. The intent is for it to be for sure, but that is an approximation at best.
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Old 10-10-2015, 11:47   #32
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Re: Amps v Amp hours v Amps/Hr

Perhaps Abbott and Costello said it best?


Abbott & Costello - Who Done It - Watts Are Volts - Video Dailymotion


A classic Abbott and Costello routine, in the style of Whoís on First?, where Bud Abbott tries to explain electricity ó Watts and Volts ó only to have Lou Costello think that heís talking about Whatís and Votes. From their movie, Who Done It? Interestingly, it was improvised on the spot as they were filming, and reportedly has the other cast and crew in stitches.
Cop: He got 10,000 volts.
Lou Costello: Thatís enough to elect anybody, he should be president.
Bud Abbott: No, not that kind.
Lou Costello: What kind?
Bud Abbott: Volts.
Lou Costello: Thatís what I said, he got 10,000.
Bud Abbott: You know what volts are?
Lou Costello: Theyíre what?
Bud Abbott: Thatís right.
Lou Costello: What I say?
Bud Abbott: Volts are watts.
Lou Costello: Go ahead and tell me.
Bud Abbott: You just said it.
Lou Costello: I just asked you to tell me what I said. What I said?
Bud Abbott: Volts are watts!
Lou Costello: Volts are whats?
Bud Abbott: Yes.
Lou Costello: Iím asking you whatís volts.
Bud Abbott: Thatís right.
Lou Costello: Donít try to twist me now, what are you talking about, a dialect?
Bud Abbott: Watts! Watts! Watts!
Lou Costello: Whatís whatís whatís whats?
Bud Abbott: Volts!
Lou Costello: Whatís volts?
Bud Abbott: Thatís right.
Lou Costello: Well, go ahead and tell me.
Bud Abbott: Well, thatís it.
Lou Costello: What are volts?
Bud Abbott: Thatís right.
Lou Costello: Iím asking you.
Bud Abbott: Watts are volts.
Lou Costello: What?
Bud Abbott: Thatís right.
Lou Costello: Next thing you know youíll be telling me Watts on second base!
Bud Abbott: Now, donít start that!
Lou Costello: Thatís enough!
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Old 10-10-2015, 14:43   #33
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Re: Amps v Amp hours v Amps/Hr

Quote:
Originally Posted by Maine Sail View Post
.........
Amps per hour, amps/hr, nuc-u-lur, real-a-tor and RPM's are all equally is incorrect...
Dear Current Time CF Police,
What unit am I allowed to use when referring to my rate of change in current flow say when monitoring the current from my solar panel as the sun rises or sets?
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Old 10-10-2015, 15:32   #34
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Re: Amps v Amp hours v Amps/Hr

Quote:
Originally Posted by Factor View Post
What is a dozen, sounds like a silly old english concept.
Two less than a stone?
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Old 10-10-2015, 15:40   #35
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Re: Amps v Amp hours v Amps/Hr

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Originally Posted by Factor View Post
What is a dozen, sounds like a silly old english concept.
Stay tuned, the answer will be forthcoming but in another thread ( to be advised). I have drifted Stu's excellent topic too far already - sorry mate!
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Old 10-10-2015, 16:00   #36
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Re: Amps v Amp hours v Amps/Hr

I will never forget when we moved to Chile the carton of eggs never seemed to last as long as back in the USA. The carton looked the same but it held 10 eggs! A dozen is a peculiar English unit.
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Old 10-10-2015, 16:38   #37
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Re: Amps v Amp hours v Amps/Hr

Nice work Stu! Thanks.😀
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Old 10-10-2015, 17:12   #38
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Re: Amps v Amp hours v Amps/Hr

Quote:
Originally Posted by colemj View Post
Also:

"When at idle, the tach shows a range of RPM's between 500 and 1000. Do I have an air leak somewhere?"

Yet another valid use of "RPM's"

Mark
RPM's what?

I really should start another thread on the misuse of apostrophes
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Old 10-10-2015, 17:16   #39
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Re: Amps v Amp hours v Amps/Hr

Quote:
Originally Posted by Maine Sail View Post
CCA (0F) or MCA (32F) is not about how much current can "safely be drawn". It is about how much current can be drawn at a specific battery temperature (0F or 32F), for a specified time (30 seconds) while remaining above a terminal voltage of 7.2V.
A valid point. I plead guilty to grossly oversimplifying there.

(where gross is dimensionless )
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Old 10-10-2015, 17:24   #40
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Re: Amps v Amp hours v Amps/Hr

Quote:
Originally Posted by jcapo View Post
Two less than a stone?
Nope. Stone is a dimensional unit of weight (mass). Dozen is dimensionless.

So a dozen pounds is two less than a stone, but a dozen is two less than 14.
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Old 10-10-2015, 17:27   #41
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Re: Amps v Amp hours v Amps/Hr

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Originally Posted by Wotname View Post
Dear Current Time CF Police,
What unit am I allowed to use when referring to my rate of change in current flow say when monitoring the current from my solar panel as the sun rises or sets?
Congratulations, you have got it. That is indeed one of the very few situations where you could appropriately use amps per second or whatever time unit you want to measure the rate change over.
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Old 11-10-2015, 00:42   #42
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Re: Amps v Amp hours v Amps/Hr

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Originally Posted by exMaggieDrum View Post
Stu, glad you created a new thread. The "residential reefer" thread was totally hijacked by all the above. Thanks for you explanation of the SI standard. But one of the things that I think people get mislead by is the difference between the amp hours as measured by a battery monitor meter is not equivalent to the amp hours stored in a battery - necessarily. Correct me if I am wrong on this. The intent is for it to be for sure, but that is an approximation at best.
No they are the same units.

The only issue is you need to account for inefficiencies in the system.

This is similar to filling a 5gal jug. In reality, you have account for the accuracy of the measurement lines on the jug, you have to account for temperature expansion and other variances. It doesn't change the units.
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Old 11-10-2015, 00:46   #43
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Re: Amps v Amp hours v Amps/Hr

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Originally Posted by Wotname View Post
Dear Current Time CF Police,
What unit am I allowed to use when referring to my rate of change in current flow say when monitoring the current from my solar panel as the sun rises or sets?
We already discussed this in the fridge thread.

amp/day is a valid unit of measurement but just doesn't have much use in terms of a cruising boat and to use it as a measurement of battery storage is flat out wrong.

In what context would you care about the amp/day?
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Old 11-10-2015, 01:50   #44
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Re: Amps v Amp hours v Amps/Hr

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Originally Posted by valhalla360 View Post
We already discussed this in the fridge thread.

amp/day is a valid unit of measurement but just doesn't have much use in terms of a cruising boat and to use it as a measurement of battery storage is flat out wrong.

In what context would you care about the amp/day?
Not sure why you have quoted amp/day?
I haven't
Stu has provided a suitable guide suggesting amp/second although amp/min would also be good IMO.
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Old 11-10-2015, 02:15   #45
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Re: Amps v Amp hours v Amps/Hr

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Not sure why you have quoted amp/day?
I haven't
Stu has provided a suitable guide suggesting amp/second although amp/min would also be good IMO.
amp/day, amp/sec, amp/min, etc... essentially the same thing being measured. Same as feet and meters are both measuring distance.

I saw the comment about seeing the change in amps as the sun sets but what value does it provide? What would you use it for?

Examples:
- Amps: Allows you to determine appropriate wire or circuit breaker size or select a starting battery that can produce enough cranking amps.
- Amp-hr: Allows you to select appropriate battery bank size.
- Amp/time period: ?????
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