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10-10-2015, 10:26
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#31
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Registered User
Join Date: Mar 2014
Location: Anacortes
Boat: previous - Whitby 42 new - Goldenwave 44
Posts: 1,835
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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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10-10-2015, 10:47
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#32
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Registered User
Join Date: Aug 2011
Location: New York, New York
Boat: Dufour Safari 27'
Posts: 1,909
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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 Who’s on First?, where Bud Abbott tries to explain electricity — Watts and Volts — only to have Lou Costello think that he’s talking about What’s 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: That’s enough to elect anybody, he should be president.
Bud Abbott: No, not that kind.
Lou Costello: What kind?
Bud Abbott: Volts.
Lou Costello: That’s what I said, he got 10,000.
Bud Abbott: You know what volts are?
Lou Costello: They’re what?
Bud Abbott: That’s 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: I’m asking you what’s volts.
Bud Abbott: That’s right.
Lou Costello: Don’t try to twist me now, what are you talking about, a dialect?
Bud Abbott: Watts! Watts! Watts!
Lou Costello: What’s what’s what’s whats?
Bud Abbott: Volts!
Lou Costello: What’s volts?
Bud Abbott: That’s right.
Lou Costello: Well, go ahead and tell me.
Bud Abbott: Well, that’s it.
Lou Costello: What are volts?
Bud Abbott: That’s right.
Lou Costello: I’m asking you.
Bud Abbott: Watts are volts.
Lou Costello: What?
Bud Abbott: That’s right.
Lou Costello: Next thing you know you’ll be telling me Watts on second base!
Bud Abbott: Now, don’t start that!
Lou Costello: That’s enough!
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10-10-2015, 13:43
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#33
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Moderator and Certifiable Refitter
Join Date: Jan 2008
Location: South of 43 S, Australia
Boat: C.L.O.D.
Posts: 20,305
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Re: Amps v Amp hours v Amps/Hr
Quote:
Originally Posted by Maine Sail
.........
Amps per hour, amps/hr, nuc-u-lur, real-a-tor and RPM's are all equally is incorrect...
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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?
__________________
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence
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10-10-2015, 14:32
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#34
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Registered User
Join Date: Mar 2007
Location: Rocky's Boat Yard
Boat: Tayana V42 - Passages
Posts: 611
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Re: Amps v Amp hours v Amps/Hr
Quote:
Originally Posted by Factor
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Two less than a stone?
__________________
You can make more money but you can't make more time.
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10-10-2015, 14:40
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#35
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Moderator and Certifiable Refitter
Join Date: Jan 2008
Location: South of 43 S, Australia
Boat: C.L.O.D.
Posts: 20,305
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Re: Amps v Amp hours v Amps/Hr
Quote:
Originally Posted by Factor
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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!
__________________
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence
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10-10-2015, 15:00
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#36
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Registered User
Join Date: Aug 2007
Location: on the boat. Gulf Coast
Boat: C&C 38'
Posts: 351
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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.
__________________
Jerry and Denver
Happy Old cruisers!
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10-10-2015, 15:38
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#37
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Registered User
Join Date: May 2015
Location: Florida
Boat: Kadey-Krogen 38 Cutter
Posts: 36
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Re: Amps v Amp hours v Amps/Hr
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10-10-2015, 16:12
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#38
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Senior Cruiser
Join Date: Nov 2013
Location: Port Moresby,Papua New Guinea
Boat: FP Belize Maestro 43 and OPBs
Posts: 12,888
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Re: Amps v Amp hours v Amps/Hr
Quote:
Originally Posted by colemj
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
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RPM's what?
I really should start another thread on the misuse of apostrophes
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10-10-2015, 16:16
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#39
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Senior Cruiser
Join Date: Nov 2013
Location: Port Moresby,Papua New Guinea
Boat: FP Belize Maestro 43 and OPBs
Posts: 12,888
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Re: Amps v Amp hours v Amps/Hr
Quote:
Originally Posted by Maine Sail
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.
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A valid point. I plead guilty to grossly oversimplifying there.
(where gross is dimensionless )
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10-10-2015, 16:24
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#40
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Senior Cruiser
Join Date: Nov 2013
Location: Port Moresby,Papua New Guinea
Boat: FP Belize Maestro 43 and OPBs
Posts: 12,888
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Re: Amps v Amp hours v Amps/Hr
Quote:
Originally Posted by jcapo
Two less than a stone?
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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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10-10-2015, 16:27
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#41
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Senior Cruiser
Join Date: Nov 2013
Location: Port Moresby,Papua New Guinea
Boat: FP Belize Maestro 43 and OPBs
Posts: 12,888
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Re: Amps v Amp hours v Amps/Hr
Quote:
Originally Posted by Wotname
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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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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10-10-2015, 23:42
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#42
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Registered User
Join Date: Apr 2013
Posts: 11,002
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Re: Amps v Amp hours v Amps/Hr
Quote:
Originally Posted by exMaggieDrum
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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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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10-10-2015, 23:46
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#43
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Registered User
Join Date: Apr 2013
Posts: 11,002
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Re: Amps v Amp hours v Amps/Hr
Quote:
Originally Posted by Wotname
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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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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11-10-2015, 00:50
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#44
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Moderator and Certifiable Refitter
Join Date: Jan 2008
Location: South of 43 S, Australia
Boat: C.L.O.D.
Posts: 20,305
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Re: Amps v Amp hours v Amps/Hr
Quote:
Originally Posted by valhalla360
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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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.
__________________
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence
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11-10-2015, 01:15
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#45
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Registered User
Join Date: Apr 2013
Posts: 11,002
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Re: Amps v Amp hours v Amps/Hr
Quote:
Originally Posted by Wotname
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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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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