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Really weird electric issue


ANarrowEscape

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On 27/12/2020 at 16:33, ditchcrawler said:

I just wondered if it tripped your electric ? or even shut the gas off.

If I recall correctly the one I have fitted can be upgraded to disconnect gas (with the appropriate kit). Given that I turn mine off when leaving the boat for any length of time I didn't explore the matter. Going back to my lumpy water days it was normal practice to turn the gas off from the bottle when not actually cooking.  

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59 minutes ago, ANarrowEscape said:

The charger has an auto-turn off when batteries reach their limit, and I also have a volt-meter. So should be able to gauge some kind of capacity. Volt wise at least. 

It should only need to be on for 12 hours or so, as I will go back each day until I work out what the hell is going on. I might do a test at home to see how long it can run for. As long as it's over 12 hours I will be fine.

Battery voltage has NOTHING to do with CAPACITY. All the RESTED voltage will tell you is the percentage of charge the battery has at its PRESENT capacity. The actual capacity will be less that 100ah but how much less no one can tell without doing the discharge over time test and working it out. I alluded to it and @Alan de Enfield told you how. There is every chance the cam will work fine for 12 hours on the battery as it is but no one can guarantee it will.

 

That is RESTED voltage, not the voltage as soon as it comes off charge. It may be over an hour after charging stops or after a load has been put on the battery for a sort while.

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1 minute ago, Tony Brooks said:

Battery voltage has NOTHING to do with CAPACITY. All the RESTED voltage will tell you is the percentage of charge the battery has at its PRESENT capacity. The actual capacity will be less that 100ah but how much less no one can tell without doing the discharge over time test and working it out. I alluded to it and @Alan de Enfield told you how. There is every chance the cam will work fine for 12 hours on the battery as it is but no one can guarantee it will.

 

That is RESTED voltage, not the voltage as soon as it comes off charge. It may be over an hour after charging stops or after a load has been put on the battery for a sort while.

I'm bringing the battery home to charge it first.

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10 minutes ago, ANarrowEscape said:

I'm bringing the battery home to charge it first.

 

What they are trying to explain to you is that the rested voltage only tells you that the battery is charged to a certain percentage of it's actual capacity.

 

It tells you that the glass is half full, but you don't know if it's a shot glass or a pint glass.

 

If the battery is knackered, it might only have 11Ah left usable out of the 110Ah it was originally, and the voltage on it's own won't tell you this.  

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Just now, TheBiscuits said:

 

What they are trying to explain to you is that the rested voltage only tells you that the battery is charged to a certain percentage of it's actual capacity.

 

It tells you that the glass is half full, but you don't know if it's a shot glass or a pint glass.

 

If the battery is knackered, it might only have 11Ah left usable out of the 110Ah it was originally, and the voltage on it's own won't tell you this.  

Yes I understand what's being said, and that it could be knackered. That's why I'm bringing it home to charge it, then running the dashcam here as a test.

 

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1 hour ago, Tony Brooks said:

Unless you discharge it at a known rate and time it you will have no way of assessing the capacity.  

The number of times I have posted that, people still think the magic meters will tell them what's left in their batteries or because they charge to 14.4 volts they are fully charged

1 hour ago, Tracy D'arth said:

Is the Finch out of pokey and flying around again?

https://braunstonmarina.co.uk/wp-content/uploads/Finch-The-Remorseful-Day-II-20-11-03.pdf

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2 minutes ago, ditchcrawler said:

The number of times I have posted that, people still think the magic meters will tell them what's left in their batteries or because they charge to 14.4 volts they are fully charged

I'm pretty new to narrowboats, and to the world of 12v electrics, so very sorry for making you repeat yourself. But as I stated, I just wanted to know if a spare battery would run a dashcam for about 12 hours. I don't really need to know how much amperage it has, or how good the quality of it is. I just need to know if it will do the job required. Which I will find out with tests. We're not all experts. 

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23 minutes ago, ANarrowEscape said:

Yes I understand what's being said, and that it could be knackered. That's why I'm bringing it home to charge it, then running the dashcam here as a test.

 

 

That's the bit we weren't sure you understood - many don't get it.

 

If you are only going to use a small charger (5A ish) then the time it takes to charge from one known state to another can give a vague indication of capacity. 

 

If it takes an hour at 5A to go from from half charged (12.2V ish) to fully charged (12.8V ish) it's only got 10Ah left.  If it takes 10 hours it's got 100Ah left.  It's not very accurate, but it's a clue.

 

 

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Just now, TheBiscuits said:

 

That's the bit we weren't sure you understood - many don't get it.

 

If you are only going to use a small charger (5A ish) then the time it takes to charge from one known state to another can give a vague indication of capacity. 

 

If it takes an hour at 5A to go from from half charged (12.2V ish) to fully charged (12.8V ish) it's only got 10Ah left.  If it takes 10 hours it's got 100Ah left.  It's not very accurate, but it's a clue.

 

 

Okay ta. I've opted for a 10 amp charger, so should be a bit quicker. I'd say double the time, but I can guarantee someone will correct me over it.

So roughly the same equation as you've stated but roughly half the time? So 5 hrs to charge means it would be on the good side.

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2 minutes ago, ANarrowEscape said:

I just wanted to know if a spare battery would run a dashcam for about 12 hours. I don't really need to know how much amperage it has

 

They are the same thing really.  If all you want to know is can it run a camera (power unknown) for 12 hours then just try it. 

 

If you know the power used by the camera and the capacity of the battery you'll know how many days the camera will run for, or indeed if this battery is worth keeping on the boat.

 

As was said upthread, if you consider this a spare battery for general use it's probably handy to know if it's knackered or not.

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5 minutes ago, ANarrowEscape said:

I'm pretty new to narrowboats, and to the world of 12v electrics, so very sorry for making you repeat yourself. But as I stated, I just wanted to know if a spare battery would run a dashcam for about 12 hours. I don't really need to know how much amperage it has, or how good the quality of it is. I just need to know if it will do the job required. Which I will find out with tests. We're not all experts. 

My comment was not aimed at you or any one else, It was  just a general comment about lots of peoples understanding of their batteries. I find it strange that someone will build a boat costing maybe over £100K and not fit an ammeter and volt meter as standard.

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Just now, ditchcrawler said:

My comment was not aimed at you or any one else, It was  just a general comment about lots of peoples understanding of their batteries. I find it strange that someone will build a boat costing maybe over £100K and not fit an ammeter and volt meter as standard.

Sorry to seem snippy, but I tend to get an array of answers on here that appear to be a little snotty at times. 

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Just now, ANarrowEscape said:

Okay ta. I've opted for a 10 amp charger, so should be a bit quicker. I'd say double the time, but I can guarantee someone will correct me over it.

So roughly the same equation as you've stated but roughly half the time? So 5 hrs to charge means it would be on the good side.

 

Depends on the rested voltage when you start and when you finish.  You said you think it was around 12.4V, so I just went for 12.2V (50%) to make the numbers easier in my example.

 

When you get the battery home, let it warm up from frozen, then take the voltage reading.  Then charge it, noting how long it takes to fully charge, then rest it for another hour or two and read the voltage again.

 

If you post those numbers here we'll do the maths for you - you'll probably get three different answers though :D

 

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5 minutes ago, TheBiscuits said:

 

Depends on the rested voltage when you start and when you finish.  You said you think it was around 12.4V, so I just went for 12.2V (50%) to make the numbers easier in my example.

 

When you get the battery home, let it warm up from frozen, then take the voltage reading.  Then charge it, noting how long it takes to fully charge, then rest it for another hour or two and read the voltage again.

 

If you post those numbers here we'll do the maths for you - you'll probably get three different answers though :D

 

Okay ta. Will do.

 

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21 minutes ago, TheBiscuits said:

If it takes an hour at 5A to go from from half charged (12.2V ish) to fully charged (12.8V ish) it's only got 10Ah left.  If it takes 10 hours it's got 100Ah left.  It's not very accurate, but it's a clue.

Thats not really quite true is it.

It could take 6 or 8 hours to get just the last 10% in

 

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1 minute ago, Alan de Enfield said:

Thats not really quite true is it.

It could take 6 or 8 hours to get just the last 10% in

 

 

Not on a 5A charger.  That's close enough to final tail current on a 110Ah battery, without getting into all the complications of what does "fully charged" mean.

 

On a 10A charger it will be even less accurate of course, but all we are looking for here is either weigh it in or keep it as a spare - the exact Ah remaining is irrelevant in this case.  The numbers I have asked for will allow us to say good battery, half gone or scrap it - which is all @ANarrowEscape wants to know.

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1 hour ago, Alan de Enfield said:

He was a bad man.

Homeless, he patrolled the canal towpaths, breaking into boats, eating and drinking whatever he could find, spending the night onboard, washing the pots, tidying up and then leaving.

 

Was doing this for many years eventually caught and 'locked up'.

He was an unfortunate man and a sad man, but I wouldn't describe him as a bad man. When broke into our boat he ate a few items from our food cupboard, he drank a half bottle of whisky but wisely ignored the Bristol Cream sherry, he tidied up, and he washed up (including washing up a couple of things we had forgotten to do ourselves). In doing so, for the £4.50 replacement cost of a small bolt, he performed a valuable security consultation for us by showing us a weakness - an easily forced sidehatch lid - that needed rectifying. Good value for money, I reckon.

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26 minutes ago, TheBiscuits said:

If you post those numbers here we'll do the maths for you - you'll probably get three different answers though :D

 

5 minutes ago, TheBiscuits said:

The numbers I have asked for will allow us to say good battery, half gone or scrap it

 

I can see a slight flaw here. 

 

I told him he'll get three different answers, then listed which three answers are possible.  If we give him all three of those answers he's not going to be any wiser!

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FFS

Knowing the actual battery capacity is irrelevant, charge the battery at home put the camera on it at home see how long it lasts, if over 12hrs then all's well and good recharge the battery and do the same on the boat, job done.

If it doesn't last 12hrs you will need a better battery.

 

Edited by Loddon
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... and does it really need to be tested first? Why not just charge the battery, then take it to the boat and connect to dash cam. Chances are it will power the camera for a day but if not, nothing is lost apart from the day, because the battery would be scrap. On the other hand if it does work (which it’s likely to do, because a dash cam doesn’t take much juice) then you are sorted.
Oh except that ghosts are mostly invisible, aren’t they?

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37 minutes ago, Loddon said:

FFS

Knowing the actual battery capacity is irrelevant, charge the battery at home put the camera on it at home see how long it lasts, if over 12hrs then all's well and good recharge the battery and do the same on the boat, job done.

If it doesn't last 12hrs you will need a better battery.

 

The voice of sanity, sometimes we get tooooo technical for the OP.

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Maybe if you take possession of the spare key or change the lock on the door it will solve the problem.

 

The small battery charger you asked about seems to perform the same functions as the charger I bought from Aldi a few years ago.

It has been very useful for maintaining batteries at home and as a approximate  means of testing a battery its okay .

 

I doubt  a dashcam consumes more than 0.5 A.

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