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RichardW
Joined: 24 Aug 2006 Posts: 8443 Location: Llyn Peninsular North Wales
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OtleyLad
Joined: 13 Jan 2007 Posts: 2737 Location: Otley, West Yorkshire
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Falstaff
Joined: 27 May 2009 Posts: 1014
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Hairyloon
Joined: 20 Nov 2008 Posts: 15425 Location: Today I are mostly being in Yorkshire.
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RichardW
Joined: 24 Aug 2006 Posts: 8443 Location: Llyn Peninsular North Wales
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RichardW
Joined: 24 Aug 2006 Posts: 8443 Location: Llyn Peninsular North Wales
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RichardW
Joined: 24 Aug 2006 Posts: 8443 Location: Llyn Peninsular North Wales
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Posted: Sat Jan 31, 15 7:58 pm Post subject: |
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Hairyloon wrote: |
1, I had not realised it did this badly. Perhaps you should say what you mean.
2, How do you know when you've got 30%?
3, Exactly so. Is that asking a lot?
4, It doesn't seem so to me, but I don't claim to know too much about batteries. |
1, If you had read all my posts you would have seen that I said Ah counting does not work well.
2, My meter accurately reads %SOC but then for me its worth spending more on the meter to protect a very expensive battery bank.
3, Yes it is. To do it well costs lots & lots.
4, |
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RichardW
Joined: 24 Aug 2006 Posts: 8443 Location: Llyn Peninsular North Wales
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Hairyloon
Joined: 20 Nov 2008 Posts: 15425 Location: Today I are mostly being in Yorkshire.
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Posted: Sat Jan 31, 15 8:26 pm Post subject: |
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RichardW wrote: |
Hairyloon wrote: |
1, I had not realised it did this badly. Perhaps you should say what you mean.
2, How do you know when you've got 30%?
3, Exactly so. Is that asking a lot? |
1, If you had read all my posts you would have seen that I said Ah counting does not work well. |
That is not the same as saying the data is bad, or indeed saying the data is useless. It is just saying that it doesn't do what you want it to do
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2, My meter accurately reads %SOC... |
How? What is it actually measuring?
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3, Yes it is. To do it well costs lots & lots. |
Why?
Chips that can accurately measure voltages, currents, etc things are cheap as, well, chips.
What is the difficult bit? |
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Falstaff
Joined: 27 May 2009 Posts: 1014
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Posted: Sat Jan 31, 15 9:11 pm Post subject: |
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Falstaff wrote: |
The point of connecting one of the terminals to earth is to tether the voltage. If you connect the +ve to earth, then the battery operates from 0v to -12v and if you connect the -ve to earth the battery operates from +12v to 0v. If neither is connected, then there is a voltage difference of 12v, but it's value is not identified and can "float about"
..........With simple dc stuff I don't think it would be critical to earth the system, but if you start interfacing with a domestic supply which IS earthed, it May become so.
More a matter of Good Practice I should say - but something which a Pro, looking at your circuitry would pick up on as looking "professional" and "when in Rome" eh ?
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As you can see Richard, I had picked up Both of the points you made in your most recent post, in my original one, before you wrote :-
RichardW wrote: |
Re the earthing, a lot of systems will be fitted in vehicles / boats & so not earthing can lead to galvanic corrosion. Also if fitting an inverter then it reduces the possibility of shocks. |
Which is entirely different and you are only now trying to move to a position which has some logic and which is trying to align with my original one !
a) However galvanic corrosion is a phenomenon which is entirely natural and unrelated to whether a boat contains any electrical equipment or not ! - There is now SOME concern that the use by some, of the hull as an "earth" actually exacerbates the process as you will see if you look up what galvanic corrosion actually IS !
b) You do at least seem now to understand that the "earthing" of the battery -ve does NOT in any way "Protect against shocks" as you originally thought and I'd be fascinated to hear your explanation as to how precisely coupling the neutral of the 230 V ac invertor output to the -ve terminal of the 12v dc battery in a boat as you suggest, is anything other than a potentially dangerous proposal ! |
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RichardW
Joined: 24 Aug 2006 Posts: 8443 Location: Llyn Peninsular North Wales
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RichardW
Joined: 24 Aug 2006 Posts: 8443 Location: Llyn Peninsular North Wales
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Hairyloon
Joined: 20 Nov 2008 Posts: 15425 Location: Today I are mostly being in Yorkshire.
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RichardW
Joined: 24 Aug 2006 Posts: 8443 Location: Llyn Peninsular North Wales
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