Felshampo
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Posts posted by Felshampo
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14 minutes ago, IanD said:
The C rate is current divided by capacity, so of you charge or discharge a 100Ah battery at 50A the rate is 0.5C. It's this rate that determines how the battery behaves on both charge and discharge, especially lead-acid batteries which don't like rates much above 0.2C.
As both me and Alan said, there's no simple answer to your question, the time to get tail current down to 1% of capacity depends on SoC, C rate, battery type/model, phase of the moon...
What's much more important with LA cells is having enough capacity to keep SoC mostly above 50%, fully charging regularly to avoid sulphation, and not using high C rates because this reduces capacity and life. LA batteries are usually rated at 0.05C (the "20 hour") rate, if you run them at 0.5C ("2 hour rate") you lose anything up to half the capacity.
I have 160 AH AGM batteries and after inheriting some old knackered ones never let their expensive replacements go below 90%.
The C rate is set by the battery charger?
I have a Leece Neville 140 amp alternator which I always thought was a good thing. If it's giving off 70A that's 0.43 C. Is this a bad thing then. Although it usually falls down to 30A quite quickly.
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26 minutes ago, Alan de Enfield said:
But - for discussion :
1) You have taken 100Ah from a 400Ah battery bank it is now at 75% SoC.
2) You have taken 100Ah from a 1000Ah battery bank, it is now at 90% state of charge.
We know that it is very difficult and slow to get the 'last 10%' into the batteries, so in example 1) we will get (say) 15% back into the battery comparitively quickly but the last 10% will take several hours.
In example 2) the battery bank is at a much higher SoC (90%) so we are not going to get any charge in quickly and it will a slow slog and take several hours.
Will the only difference be the (say) 30 minutes it took to get the 15% into example 1) ?
Will the 'number of hours' taken to get from 90% to 99% be the same for both banks irrespective af the actual Ah (40Ah in example 1 and 100Ah in example 2) being put back into the battery bank ?
Will it take longer but need the same amount of input or more input?
I presume all things being equal its about the chemistry. How far into the lead is the sulphation that has to be converted. If its all close to the surface then in the bigger battery bank it might use less energy.
The smaller battery bank might use deeper lead which uses more energy to remove the sulphation?
57 minutes ago, IanD said:2b (same time) is most likely, but battery charging like this depends on rate and capacity and tail current and battery type so it's not guaranteed.
For example if you take 100AH out and recharge at 100A the 4x100AH bank will be charging at 0.25C from 75% SoC to 4A tail current (1A per battery), the 5x100Ah bank will be rechargingat 0.2C from 80% SoC to 5A tail current (1A per battery).
The bigger bank is charging from a higher SoC at a lower C rate, both of which are good for efficiency and time needed to get to 100% SoC (1% tail current), so it's possible that this will take less time than the smaller bank -- but it depends on the exact battery characteristics.
Any small difference in recharge time will probably matter much less to you than the 20% difference in capacity... 😉
What's the C rate about?
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That's the one cheers!
That's two votes for b.........
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I have two questions about battery charging. I have tried to find the answer by searching the forums but can't find answers. If this has been covered before could you point me in the right direction please.
1. I remember someone had posted a very detailed article that explaned battery charging and chemistry. I think it was pinned somewhere but can't find it. If someone can tell me where it is that would be great.
2. If I use 100 AH from my batteries. I then want to recharge them back to 100% until the charging current is, let's say, 1% of battery size. Will it take (a) longer (b) the same or (c) less time to recharge a battery bank that has 4 x 100AH batteries compared to 5 x 100AH batteries.
Battery chemistry is still a bit of a black art to me.
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6 hours ago, blackrose said:
Yes, you are correct. While it it's best practice not to do it, some hydraulic gearboxes can handle rapid shifts from forward to astern and vice versa at high engine revs.
In their Owners Manual PRM state:
Gear Shifting (Except PRM60/90/125)
PRM Newage Ltd hydraulic marine gearboxes have been designed and tested to ensure rapid shifts from ahead to astern and vice versa at full horsepower ratings and speeds if necessary. However, since full-power shifts do place abnormal, even if short lived, loads on the gearbox and if used indiscriminately as it will reduce the operating life, they should be reserved for emergency use only.The point is why would you want to do it unless it was an emergency situation anyway? You're clearly not in control of the boat if you're slamming the gearbox from one direction to the other at high engine revs, although I've seen people do it unnecessarily.
Is this connected to the pressured change when going into neutral, if only briefly, when changing gear. On my hydraulic gearbox the pressure drops from around 275 psi in gear to 50 psi in neutral. This I understand was only introduced by prm in 2010.
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12 hours ago, matty40s said:
A better bet is sticking a coat or two of gloss first then your chosen non slip surface. This guarantees non porous finish under whatever you need for walkability.
Thanks for your advice.
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32 minutes ago, matty40s said:
We have used International granules for most of our roof paints, easily the best to use for even coverage and after painting cleanability.!!
You have to stir it, and stir it, and stir it, every time you either pour it into a tray or dip a brush into it.
I've done back cabin in raddle now and had no issues in last 3 years with using roof in dey or wet conditions.
We did a roof today with the owners explicit instructions on how to apply, mixed the International paint with the instructed quantity matting agent, applied with roller as instructed, and its ended up looking like a ploughed field. A good sanding and doing it our way on the next coat should rescue it.
I will be using a 1/2 inch brush. I will stir it a lot more. Is it a good idea to put a coat of plain Raddle on top after you've got the texture right?
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34 minutes ago, dave moore said:
Resolute’s cabin top was simply painted in raddle red, another Norton Canes. I was happy to use it when locking and never had an issue with slipping. Perhaps I was lucky.....
I don't really have an issue with it but the gunnels are textured and give that extra grip.
Just thought it would be a good idea.........
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33 minutes ago, Mike Tee said:
I could well be wrong, but if the textured roof looks really good, it was probably done as per 'Higgs' suggestion, with dried sand and thinned paint. That was the only way I ever got a good effective result.
Oh..........
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36 minutes ago, Bee said:
This can be a problem. Most 'non slip' paint has a grit added, this can grow green mossy stuff and look a mess, especially under trees - well that's what I find anyway. Lots of stirring will help but I don't particularly like gritty paint - it seems a bit too permanent somehow. I think its OK on the side decks as safety is everything there. I use Black Country Paints deck paint, a sort of semi gloss without grit and its pretty good but to be honest I have not found the perfect answer and anyway some shoes are lethal on any surface.
Yep, I wondered if I hadn't stirred it enough. I'll try that. I have seen a couple of boats with textured roofs that looked really good which is what gave me the idea.
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As someone who walks on the roof of the boat to get in and out of locks I thought it would be a good idea to use a textured paint when I did the roof.
I have got some Craftmaster textured deck paint which appears to have a fine material in it.
I have tried a sample patch on the roof and it doesn't look too good. Some parts are fine but others seem too textured.
Am I being too optomistic? Is this one of those jobs I should have left to a professional and just used ordinary Raddle red?
Has anyone any expert advice to help me do a better job. If you have used Craftmaster textured deck paint on the roof and it turned out alright what are the tricks of the trade.
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4 hours ago, gatekrash said:
You are correct about the W&B, according to my Pearson's Severn and Avon book
"Two aspects of this canal were remarkable. Boats kept left when passing each other and pairs of donkeys were widely used in place of horses"
2 hours ago, magpie patrick said:You are not making it up - Tom Rolt reported this in Landscape with Canals
Edited to add - he arrived on the Worcester and Birmingham from the Northern Stratford and asked before entering Wast Hill Tunnel
Thanks for that confirmation. Maybe the dementia isn't progressing as fast as I thought.
The problem with reading books is you often think that's really interesting and then six months later have no idea where you read it or if you are misremembering.
Any votes for returning to that system, just for the W&B, maybe starting on the 1st of April.
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I was asked today why boats pass each other on the right. This made me think I once read of a canal that had the opposite rule, historically, of passing on the left. Have I made this up?
The Worcester and Birmingham came to mind for some reason.
I'm probably making it up but don't mock its my age.
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2 hours ago, Athy said:
This reminds me of the time, when I was a boy, that Dad tried to teach Mum to drive. You could guarantee that within five minutes of setting off from home he would become stentorian and launch accusations of low mental capacity and of bovinity, and she would become shrill. After she burst into tears and came within an ace of driving our Hillman Minx into a drystone wall, he gave up.
But we live in enlightened times and I'm sure that nothing similar would happen these days.
That's sort of it. We don't end up with an argument more of a "your better at it than I am, you do it"
I'm sure if I wasn't there and she had someone else to show her she would do far better. That was certainly the case when she came to an outdoor centre I worked at in a previous life.
1 hour ago, Tracy D'arth said:Could your OH's lack of confidence (but not ability) be due to your presence on the boat? Not intending to be sarcastic but its like teaching the kids to drive.
I think your right.
Although funnily enough I did teach the kids to drive but they refused, point blank, to go out with their mum.
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52 minutes ago, MartynG said:
The RYA Helmsman training covers the basic principles. eg how to throw a rope, tie a boat up, go through a lock, check the oil etc. Steering/handling a boat and man overboard . It is quite basic. The way trainers work you may as well do it with your OH on your own boat . I did the helmsman course before I bought a boat .
I learned how to handle a boat only by later experience with my own boat.
What do you hope to learn? You already seem to have that experience ?
I want the qualification for the insurance but we mainly want the training to give my OH more confidence.
9 hours ago, IanM said:Our boat has a morse control. I also steer a boat with a push/pull throttle and a rod gear change. I have also steered a boat with a speed wheel and a rod gear change, and one with a speed wheel and a gear wheel. From the discussions above it seems I shouldn’t have been able to have used more than one type in my life without my head exploding.
It really isn’t difficult to get to grips with the idiosyncrasies of each type and as long as you take each as they are and relax, everything is fine.
Try telling that to my OH!
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13 minutes ago, David Mack said:
If you haven't learnt how to use your controls in 3 years boating, why do you think a day or two with a trainer will make a difference?
I've been using trad controls for a lot longer than three years. I think you have misunderstood my post.
Thanks for all the replies.
I think it went off topic from the start which always seems to happen.
If anyone knows of an instructor who can use trad controls then please dm me.
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2 hours ago, David Mack said:
If you are happy to take your boat to the furthest flung part of the system, by the time you get there you will have enough experience of using your trad controls not to need any training.
We have had the boat for three years and have lived on it for most of that time, experience is not what I'm after.
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5 hours ago, dmr said:
Do the course on the trainers boat with a morse single lever control and likely a cruiser stern. 99% of what you learn will also apply to your boat and some experience of handling a different boat will be a very good thing.
Many single lever boaters are rather scathing of, or intimidated by, trad controls. By trying both you will soon find that trad controls are actually much nicer to use and with a little practice give you much finer control over the boat.
If your engine is a JD3/BD3 it will not have the Huge flywheel of a vintage job so the handling with trad controls is really easy. Just a shame they don't sound quite as good as a proper a vintage jobby.
I agree that trad controls are more sensitive especially with a large prop. Getting used to the prop effect allows you to control mooring and entering locks but it doesn't always work. Also the ability to go quickly into reverse with a hydraulic gearbox can be a great help in an emergency.
I am sure we would learn a lot of other things from using a trainers boat.
However I need the trainer to use our boat to give my OH the confidence to steer our boat on her own.
We have a Gardner 2LW by the way and I love how it sounds, sorry.
4 hours ago, dmr said:They are really nice for a very slow gentle winding, set the revs to just above tickover and do every thing on the gear lever.
With a JD3 and a PRM box you can do forward to reverse at full revs in a real emergency but its not a good thing to do. Another big plus is that the controls are right where you need them, no leaning over and stretching to handle the morse control and tiller at the same time.
So true, especially the emergency stop, don't ask me how I know that.......
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5 minutes ago, Tracy D'arth said:
Correct, and Ford and John Deere share a common organisation and production facilities.
You seem too be contradicting yourself unaided there Felshampoo.
No but you are. You didn't read my original post where I said I had a boat with a trad stern and speed controls.
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16 minutes ago, Tracy D'arth said:
Nuts, you mean like a Beta Tug engine? Its only a John Deere tractor diesel. I used a 70' boat with a monster Ailsa Craig FR4 engine, 200RPM flat out, for years, rod and wheel, and moored it no problem. A big slow prop stops you faster and with less bank effect than a spinning egg whisk does.
Exactly
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24 minutes ago, Tracy D'arth said:
Sorry but I disagree, there is little difference when coming in to moor.
The same reduction of speed and precision of steering applies as does the allowance for the bank effect with any reverse applied. Perhaps you are trying to come in too fast and using lots of reverse? I moor with no reverse until parallel with the bank and close enough to step off, a little tick over reverse just as I leave, and stop the boat with the centre line by pulling it into the bank on the fenders I have flipped down.
I see no difference when using locks either especially as most with rod and wheel are full length trad boats where they fit the lock better in most cases.
Its just the same with rod and wheel, I have used both over the years.
Not sure why you think I am coming in too fast, surely it makes no difference.
Where it is different is that the prop effect is different on the left compared to the right. Also the depth of water with a deep drafted boat is different to a other boats.
I never use the centre line to stop the boat as it is already stationary when I step off, maybe you are trying to come in too fast...... 😁
9 minutes ago, Tonka said:Totally disagree. It is different with traditional controls but it is not because of the controls. It is because if the boat has trad controls it probably has a slower engine with a bigger prop and this causes the difference
Agreed the behave very differently.
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22 minutes ago, Tracy D'arth said:
There is no problem with rod and wheel, its just a different way and you have to remember to speed down before changing gear. You will soon get used to it.
That's easy for you to say but being my OH she ignores all my advice which is why I want someone with experience of these controls.
You have to be more subtle with trad controls, especially in locks and when coming in to moor.
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13 minutes ago, Tracy D'arth said:
The limitations of a trad stern for instruction will make this unlikely. The predominance of single lever control in boats will make it unlikely that any other system would appeal to the usual trainees.
There is no problem with rod and wheel, its just a different way and you have to remember to speed down before changing gear. You will soon get used to it.
Presumably you have or will have such a boat?
As they all claim to have years of experience I am surprised that none of them have any experience of trad controls.
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I would like to do a helmsmans course and my OH a beginners course. We want to use our boat as it has a trad stern with speed controls. Most companies that run courses seem to do them on their boats with morso controls. If they do offer courses on your boat they seem to either not do them if you have a trad stern or speed controls.
Does anyone know of anyone who will do them on our boat? We are happy to travel to them anywhere on the system.
Battery charging.
in Boat Building & Maintenance
Posted · Edited by Felshampo
I know this is a can of worms.
I have a mastervolt inverter with a mastervolt bm. It is supposed to be able to tell the amount of consumption and adjust as the batteries cycle (peukert numbers left me baffled).
You can cycle through a plethora of menus which supposedly tell you all you need to know. This had to be set up when I got the new batteries but after then, according to the manual, was self calibrating?
I know it probably tells lies but when ever I check the SOC with a multi meter it looks about right.
We are in a marina for winter and so get to fully charge the batteries. Its when we are cruising that the BM gets looked at most.