moomba
N/A
not bad , but your are still on the picking holes in very small matters , which are irelevant then this spate will end:encouragement:
Battery advice?
- Thread starter Quandary
- Start date
not bad , but your are still on the picking holes in very small matters , which are irelevant then this spate will end:encouragement:
Blue Sunray
Well-Known Member
You are correct that Q=It thus in terms of units C=As, but the Ampere is an SI base unit - one of several whose definitions were changed last month. This thread illustrates why dumbing down to trying to give formulae in terms of units rather that quantities can give rise to more confusion than clarity.
moomba
N/A
I think I have already explained myself and my disability and politely asked that they are now ignored , your post is therefore inappropriate
Hydrozoan
Well-Known Member
Thanks - I missed that type.
RichardS
N/A
That might, or might not be the case, I guess, depending upon the context .... but it is clear that that charge cannot be made against Paul Rainbow because he gave a concise "dumbed-down" explanation without giving any formulae whatsoever, which accords with your hypothesis.
Richard
Mistroma
Well-Known Member
Nigel is technically correct. You only have to tilt a narrow oblong container full of water to demonstrate the difference. A significant amount of plate would be exposed in one direction and almost nothing when tilted in the other as long as you start with electrolyte just level with the top of the plate .
However, you are correct that it doesn't usually matter and it's easy to top up when level. I couldn't fit my T105s with plates parallel to the centreline and did a few tests after setting the electrolyte level. I usually fill the electrolyte at the max. allowed level and top ups usually take 20-30mls per cell, rarely 45-50mls. I have to tip a filled cell above normal angle of heel to get a little of the plate above the electrolyte. I doubt 50mls less makes much difference. A little guesswork was involved as I could only estimate the position of the top corner of each plate. However, it's a box, with lots of right angles in the design and I shouldn't be far out. The normal motion of my boat through waves will also help splash electrolyte around to keep plate top edges wet.
I also checked how far the boat could heel before electrolyte would leak for an open fill point. I think it was well in excess of 45 degrees as far as I can remember.
I don't spend days sitting at a high angle of heel in flat water. I might move and rebuild the battery box if I was doing a non-stop round the world trip. Not really worth the effort when most of my sails are not that long and the boat must spend about 80% of the time fairly upright. I would have fitted the T105s differently if it had been an easy job as that would have made the orientation ideal. It just wasn't worth the large amount of effort for a relatively small (if any) gain in battery lifespan.
PS
I have an HRC and several mega-fuses on my boat. Never had to use one of my spares but that's mainly because I have plenty of spares (sod's law dictates they only blow when there are no spares). I like the mega-fuses but they would take a minute or two to replace. I hadn't seen the other type you mentioned but probably not so well suited to tags on T105s. I just went with mega-fuses for engine and domestic.
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PaulRainbow
Well-Known Member
240/250 amp is fine, but i'd fit the same to both banks, in case you need to use the domestic bank to start the engine.
Nope.
PaulRainbow
Well-Known Member
I don't recal giving any formulae, doing so would not acheive the aim of trying to get simply explain the difference between amps and amp hours. I beleive my explanation was simple enough for someone with little or no electrical knowledge to grasp a basic understanding of the differences.
Anyone frequenting these forums for information isn't interested in fancy formulae, all they want is an understandable description of how to deal with their issue. They don't come here for an education in electronics.
Hacker
Well-Known Member
+1 (in the absence of a like button)
awol
Well-Known Member
I absolutely agree with you Paul.
If Awol thinks that "So a 600 amp battery can deliver 600 amps, maximum." is you "conflating CCA and Ah" then he really needs to read your simplified explanation a lot more thoroughly himself because he's way behind the curve. :ambivalence:
Richard
And you, Richard, need to read what I wrote. The quote is an example of an idiotic statement from Paul, nothing to do with conflation.
Blue Sunray
Well-Known Member
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RichardS
N/A
That's interesting ..... in my post #86 I assumed that you were complimenting Paul so I said "That might, or might not be the case, I guess, depending upon the context .... but it is clear that that charge cannot be made against Paul Rainbow because he gave a concise "dumbed-down" explanation without giving any formulae whatsoever, which accords with your hypothesis."
However, from your latest post it now appears that you were, in fact, criticising him.
Which means that your understanding of things electrical can, as confirmed by your user name, be summarised by the term "glitched". :encouragement:
Richard
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RichardS
N/A
Paul's simplified "idiotic statement" is perfectly correct and/or you think that he's conflating CCA and Ah which he has not done.
Either way, the prosecution case, as they say, rests M'Lord.
Richard
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PaulRainbow
Well-Known Member
Idiotic statement ?
You're the one that made the "conflation" claim.
How many boats have you re-wired this week ?
Perhaps you'd like to offer a better explanation of the difference between amps and amp hours that the average person (with little or no technical electrical knowledge) can easily understand ?
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Mistroma
Well-Known Member
Paul explicitly said that he was trying to keep it basic. He did jump from what probably was CCA to Ah a little confusingly. I'm certain it was a small mistake in what he meant to say. However, the post was a generally useful simplified explanation. He doesn't claim to be disabled or dyslexic so I guess that means he is fair game for criticism of spelling ("resulated" and in such a short post, shocking!! ), leaving out CCA and jumping to Ah.
However, I can't really get worked up about it. When I saw "deliver 600 amps, maximum" my brain pretty much filled in CCA because that made sense and I accepted that wasn't an actual theoretical maximum. If someone didn't understand the subject I imagine they'd just read it as "possibility for a lot of amps" or something similar.
CCA is simply a measure of current draw over 30 seconds when it's cold. It doesn't represent what you will actually get instantaneously in a short circuit. I'd guess that you'd get 6,000A or more for a very short time from available surface charge on a 600CCA battery. Paul will certainly know that 600CCA does not mean that's the absolute maximum you can ever get. The absolute figure isn't really that relevant unless you drop a 2 sq. inch bar across the terminals. Any wiring likely to be fitted will have vapourised well below the maximum theoretically available short circuit current.
Just me, but I couldn't really get worked up about it. Doesn't mean that others shouldn't post a clarification to help explain the point further.
), leaving out CCA and jumping to Ah. However, I can't really get worked up about it. When I saw "deliver 600 amps, maximum" my brain pretty much filled in CCA because that made sense and I accepted that wasn't an actual theoretical maximum. If someone didn't understand the subject I imagine they'd just read it as "possibility for a lot of amps" or something similar.
CCA is simply a measure of current draw over 30 seconds when it's cold. It doesn't represent what you will actually get instantaneously in a short circuit. I'd guess that you'd get 6,000A or more for a very short time from available surface charge on a 600CCA battery. Paul will certainly know that 600CCA does not mean that's the absolute maximum you can ever get. The absolute figure isn't really that relevant unless you drop a 2 sq. inch bar across the terminals. Any wiring likely to be fitted will have vapourised well below the maximum theoretically available short circuit current.
Just me, but I couldn't really get worked up about it. Doesn't mean that others shouldn't post a clarification to help explain the point further.
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Lon nan Gruagach
Well-Known Member
CCA, A, Ah... lets face it, you are on a hiding to nowhere in a world where people consider household electricity consumption in kilowatts per hour.
cpedw
Well-Known Member
Or should that be kilowatts times hours, also known as kilowatt hours. That's what I pay for my electricity in.
Derek
Lon nan Gruagach
Well-Known Member
Thats what it should be, but if I had a quid for every time I've heard kilowatts per hour, I'd be quite drunk.
PaulRainbow
Well-Known Member
I obviously didn't dumb it down enough for you. But Googling irrelevant details doesn't help at all, most of your post above is just a cut and paste from the 'net. To remove any doubt, here is where you got your post from https://www.google.com/search?clien...gws-wiz.......0i71j0i131j0i20i263.aPiOlpw4kG0
I specifically did not mention CCA, because CCA was not relevant to the point i was making, it does nothing to help explain the difference between amps and a/h. Neither did i mention MCA or any other such labelling. To make the simple point, i don't need to quote formulae, amperes law, ohms law, protons, electrons or coloumbs. This is PBO, posters simply want to know how to do some DIY work on there boat.
An amp is a unit of electric current, CCA is an entirely different thing. If we subject the battery to a 5a load, a 5a current will flow. There won't be any CCAs flowing, or MCAs or anything else you might care to Google.
An Ah is a measure of capacity. If it's a 50ah battery it will supply a current of 1a for 50 hours, or in the case of the above 5a, it will supply the load for 10 hours.
We will, of course, not allow our batteries to become completely discharged, so the run of the mill 50ah battery would only be useful to supply 25ah. This figure would additionally vary with temperature and battery age, but a simple explanation does not require formulae for such things.
PaulRainbow
Well-Known Member
I read on another forum recently, something that went like ;
"The average internet forum contains enough "experts" to drown out those with real knowledge."
An interesting comment, i thought. Perhaps that's why there is a noticable lack of industry professionals posting on PBO ?
"The average internet forum contains enough "experts" to drown out those with real knowledge."
An interesting comment, i thought. Perhaps that's why there is a noticable lack of industry professionals posting on PBO ?
