Robin2
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Posts posted by Robin2
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The problem was that some of the bolt holes had been partly broken away and I am happier with my solution in so far as the studs are no longer required to screw into the aluminium casting. Putting nuts on the studs just involves steel on steel rather than steel on aluminium.
I was surprised that the original fitting seemed to have neither spring washers nor threadlock.
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In case anyone is interested ...
A few weeks ago as I was mooring just before Blackburn I lost all drive from the engine. Luckily the boat was close to the towpath. When I lifted the engine cover lo and behold the PRM 120 gearbox had parted company from my Isuzu engine. Obviously the last burst of reverse was the straw that broke the camel's back.
The six bolts that hold the gearbox to the engine had worked loose for some reason. Someone suggested the propshaft had been misaligned but at that stage I had no means to check it.
Most of the threaded holes in the gearbox housing (where the missing bolts should have been) were damaged and it looked like a replacement gearbox would be necessary. However after thinking for a while about the potential damage to my savings I remembered that, in my trusty toolbox, I had some J B Weld epoxy that I had bought a few years ago "just in case". This is a high temperature epoxy intended for fixing engines etc.
I cleaned out the damaged threads (with my Lidl tap and die set) and epoxied studs into the gearbox. When it had hardened I fixed the gearbox back in place using nuts, spring washers and threadlock.
And I made sure that the propshaft is properly aligned - and checked it again two days go.
So far so good .......
A very helpful engineer called Gary Walker called to look at the gearbox on the evening of the problem and could have fitted a gearbox the next day but later I concluded that a DIY repair was possible. If anyone would like Gary's phone number send me a PM.
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I rather fancy a BMW 3L straight 6.
Biggles
Isn't it 2 weeks to April 1st ???
I can't conceive of any boat on the canal that would need the power of even the smallest BMW car engine - never mind a 6 cyl engine.
My 57ft boat has a 35hp Isuzu engine and I rarely exceed 1200 rpm - which might be 10 or 12 hp at full throttle but is clearly a long way short of that. Because of the way propellers work they are usually sized to match the engine horsepower at maximum engine power but then at lower RPM they absorb a lot less power than the engine can produce at that RPM.
Putting in a too large engine will just waste fuel and probably cause premature wear of the engine from under-use.
...Robin
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My biggest problem at the moment is that every time I boot up for the first time the cursor dances away from me, opens random windows, etc. I chase it around, so far I've always caught it and re-caught it long enough to restart the computer, after which it behaves impeccably.
I think I read about this somewhere else and as far as I remember it is because the operating system confuses something plugged into a usb port as a mouse. I think the problem was caused by an internet broadband dongle. Try starting the pc without USB things connected.
I'm very fond of Ubuntu - it deals with my broadband dongle and my freeview tv dongle much better than Windows.
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Thanks again for the replies, the gas conversion looks very apealing, will probably go for it.
I don't see how LPG can be 50% cheaper than petrol if you buy it in the usual 13kg cylinders. lpg has a much lower energy content per kg than petrol. I have spoken to Edge Technology about this nd they did not have an answer.
And you would buy a lot of diesel for the price of an EU20
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Fuel injected cars can do this easily by knowing the injection duration and fuel rail pressure.
It'd be possible to do it by using two flow meters, one each in the flow and return lines to and from the engine - then doing the difference calc with a PIC or some simpler method.
PC
I have thought about something like this but I have been unable to find a source of suitable flow meters - have you any suggestions?
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Exactly. I did it over about three tankfills with the Avon & upstream on the Severn in the middle of the three fills. Thats about four days hard motoring with between four and six hour days.
I was hoping you had some means of getting instantaneous fuel consumption data - such as is common on modern cars. I would like to be able to measure fuel consumption at different throttle settings.
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I have a DV36 (the three cylinder one) in a 54ft boat and having recently fitted a new prop I did a short stint of consumption recording and can tell you that on river work, much close to or at full throttle, it returned about 1.5 litres per hour and on canal work I would expect less than this unless I were to try to maintain a speed that is too fast for the particular canal.
1.5 Litres per hour is right in the middle of the 1 to 2 litres per hours that most diesels return on inland work.
How do you measure your fuel consumption?
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My take on that is that you need to maximise the time on bulk phase yet still keep the bank in good condition. I would have the largest bank size, charger / alt & suitable genny set up I could fit & then cycle it 100-50%. At least weekly do a FULL charge. I would be looking at getting 4 days min out of the bank (but if you always move / heat water more often than that will affect that).
How much power do you use per day?
Are you live aboard?
Do you move often? How long?
Do you heat water via the engine? how long?
Do you have room, budget or want solar PV? (in the summer you would /could not need ANY other power source dep on size & usage)
I reckon I need to get about 150 Ah per day from my batteries, and I don't move often in Winter.
As soon as you talk about "alternator & suitable genny " you are fast moving away from cheap electricity. Ditto solar and windpower.
I do agree with your idea of maximizing the time on bulk charge. However that requires a deep discharge - so either I have a modest battery bank and bulk charge it daily or a larger bank that only needs a bulk charge every few days. And the size of alternator is also relevant. If I got a bigger battery bank I may also need to get a bigger alternator to reduce engine run time which, effectively, makes the extra batteries even more expensive - and we are back to the choice between spending on hardware or diesel.
Why do you say the battery needs a full charge weekly. One of the deep cycle battery manufacturers sent me a document that said a full charge every 4 weeks would be sufficient, and I was thinking of once every three weeks to be safer.
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I've just had a thought. I'll give you some examples of just how difficult this problem is........................
You have a fixed installation: A battery bank of a certain size, a charger of a certain size, you do not use any equipment whilst charging. To determine the state of charge you shake the batteries up then use a hydrometer. Ok so far?
On monday you discharge to 50% SoC then immediately recharge to full (as per the hydrometer). You time it. It takes 7 hours.
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I'm not making this up. That is what you are up against.
I'm afraid that to ask "How long will it take" and then get angry when someone who knows what they are talking about tells you it can't be answered just shows your lack of understanding of the subject. The very fact that I tell you it cannot be answered does not show that I cannot answer the question. It shows that I know enough about the subject to know that it cannot be answered. Whether you believe that or not is your problem not mine.
Progress at last ...
Inevitably if one were to do enough of these tests one would be able to produce an average and a standard deviation. One would then have a pretty good idea how much it would cost to charge the batteries. The examples using extra equipment are just a distraction - they are the equivalent of having a smaller generator or charger.
If the figures you have quoted are approximately correct - i.e. 7 to 9 hours to fully charge the set-up in question - it is then possible to assess what would be the optimal charging regime over a two to three week period. It is not too hard to demonstrate that a full charge every day is much less economical than a bulk charge every day and a full charge every two weeks. Even if the actual times are different for a different battery /charger set-up, the relative behaviour should be similar.
I have a practical problem to solve - finding the most economical way to have electricity on board. I cannot allow 25 alternative solutions to get in the way. So far your focus seems to only be on the battery part of the equation, but I will spend far more on diesel in a year than I do on batteries so the objective must be to reduce diesel consumption without increasing the cost of batteries so much that it negates the saving on diesel. The ideal seems to be a regime that makes efficient use of diesel (i.e. short daily runs) and keeps the batteries in good condition (full charges at appropriate intervals).
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You want someone else, for no charge, to analyse your system, test your batteries, check your charge system, monitor your electrical usage during your charge cylce then someone else to collect all the information together and analyse it to tell you how long it will take you to charge your batteries.
You expect someone else to do this, something that will be of no benefit whatsoever to anyone else, because their system will never be identical to yours.
I'm afraid life doesn't work that way. If you want to know all about your charge system and how long it will take to charge then that is down to you to learn enough about the system to do so yourself or for you to put your hand in your wallet and pay someone with the knowledge to do it for you. It is not reasonable to expect someone else to go to that level of work just for you.
To say "Introducing all sorts of esoteric options is just a way of avoiding the issue" shows quite clearly that you do not know even remotely close to enough about the subect to even be entitled to make the statement. If you did know enough to make that statement, you would know that it is complete sh*t. It is also offensive to those who do know about the subject.
The fact that you think it is a simple subject doesn't make it so. It actually just shows your inability to comprehend the depth of the subject. Further, those who do know it to be a rather complex subject tell you so, but you still refuse to accept it and instead throw out accusations of "Introducing all sorts of esoteric options..............". This shows quite extensive arrogance on your part. You admit you don't know enough about the subject to answer your own question, yet you believe anyone who tells you the question cannot be answered is just making it up. Ridiculous.
The fact that you thiink the question can be answered does not mean it can be answered. It simply means you don't know enough to realise that it cannot.
I have never asked you to express any opinion about my specific equipment. I have asked you to provide additional supporting information about the two examples on your web page. All I want is for you to tell me what equipment you used and how it performed. I will then make a judgment about how relevant it is to me.
How can it be complex to know how much diesel you use to charge your battery - I presume, since you are a professional in this subject area, that you have all the necessary test and measurement equipment.
If, for whatever reason, you don't want to publish your data just say so. Don't disguise it by telling me I'm stupid.
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And so on and so on. The question connot be answered!!!!!!!!!!!!!!!!!!!!!!!
:lol: Of course the question can be answered. I don't want all the possible variants - just one example with the details specified.
Introducing all sorts of esoteric options is just a way of avoiding the issue. If everyone took that approach nothing would ever have been invented.
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Not that simple I'm afraid. Batteries are a complex subject................
http://www.smartgauge.co.uk/sga_faq.html#flat
http://www.smartgauge.co.uk/sga_faq.html#how
http://www.smartgauge.co.uk/chargesize.html
http://www.smartgauge.co.uk/surf_chg.html
etc etc etc
It sounds like a simple question. It isn't. The subject is hugely complex and there are so many variables involved that it simply isn't possible to answer it concisely. It relies on the person wanting to know the answer to read loads about the subject. You can't hope to find a little paragraph that answers the question.
I wonder if the emperor has no clothes
My original question related to the examples on your web page [ http://www.smartgauge.co.uk/50percent.html ] Since it was you that prepared the examples I assume you know how long the charging cycles take for the set of equipment on which the examples are based.
Once we know how long the charging cycles take (and ideally we should have a graph of current flow during that period) we can calculate how much diesel we need to charge the batteries. Then, and only then, can we make an informed decision about how to design and manage our battery banks. All the rest is guesswork or blind faith - and in case you haven't guessed, I'm an atheist.
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although this seems to be going off topic/ a topic of its own - I just gotta laugh - if you think anything about boats is cheap especially electricity well... do let me know how you manage it!
I am surprised by your comment. You started this thread because of what appeared to be your concern about spending a lot of money on poorly performing batteries. Surely that puts you in the same camp as me - hoping to spend as little as possible on electricity so that more money is available for spending on interesting things - real ale, perhaps.
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Yes it does
Was this a deliberately unhelpful answer? How about a link to the relevant page?
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In the meantime I will try to do some "back of the envelope" calculations myself.
I now have a basic spreadsheet that suggests that two battery banks are slightly more economical than occasional long charges on a single battery bank, and require significantly less annual engine running hours.
Is there any way I can upload it so that others can see it and comment on my assumptions?
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The optimum economic solution is to follow the 50% rule..............
Your website only deals with part of the economics - summed up in the last line "Discharging deep cycle batteries to 50% results in the most economical use of the batteries in terms of battery life and monetary outlay."
A full economic optimization will also take account of generation costs - both fuel and the capital cost of the generator. What we should all be aiming for is the lowest cost electricity when all of the costs have been taken into account. It may be that 50% discharge is ideal, or it may mean being less careful with the batteries, or being more careful with them. If you have any information about the total cost of generation I would appreciate it if you would share it with us.
In the meantime I will try to do some "back of the envelope" calculations myself.
However your website does not say how long the charging regimes in the examples would take, or whether they return the batteries to a full-charge specific gravity each time.
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I didn't realize "SG" meant SmartGauge. I had seen that site before, but I can't see anything on it about the optimum economic solution.
As it happens its not expensive I just bought wellVictron £500
Genset £600
Alternator £60
8 x 200Ah 6v Batteries £400 ( 5 years ago, they are now double that )
Which is better to have a system that works or to have one the doesn't
If that is a quiet diesel genset it was a very good price, and I don't know where I could get one at a similar price. In any case power generated by a genset is not substantially cheaper than power from my engine/alternator, so I'm not sure it would make sense to buy a genset even at £600 - that would buy a lot of diesel.
The trick, as in all aspects of life, is to get a cheap solution that works
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I hate saying this but its been done to death on here. Check out the SG web site & read all about it.
How do I find the SG website ?
Not evidence as such but I operate the following ( figures converted to 12v to make it easy) regime :Equipment
800Ah battery bank
140A charger Victron multi
100A Alternator. 14.6v internal regulator
4kVA genset
Starting from where I am this would result in VERY expensive electricity
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One battery bank, keep it as highly charged as you can. Nothing more you can do. But having looked at this idea (the current one) more closely (Pete first mentioned the idea a year or more ago) it just doesn't hold any water.
Edit: PS. Giving them a full charge every couple of weeks will be better than not doing so. Giving them a full charge every week will be even better. But taking the power out of the other batteries to do so is not going to achieve anything other than, perhaps, reducing the life of the bank as a whole.
It is not my idea to take power from bank A to charge bank B, but to charge bank B over successive days whenever the alternator is operating for the principal purpose of charging bank A.
As you say, charging the batteries fully from time to time will help. The question I am trying to address is what is the most economical way of doing this and I had been hoping you would provide some evidence for your advice "one battery bank, keep it as highly charged as you can".
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This is where people seem to be going wrong.
Yes it does. Discharge a battery, recharge it, Some sulfate is left on the plates. It is impossible to get rid of it all.
No. The process of sulfation starts immediately the battery is discharged.
Therefore he is!
Fundamental error. It is impossible to bring it back to full charge. It simply cannot be done.
Incorrect I'm afraid. If it really was that simple no one would ever have problems with sulfated batteries.
So if the battery is does not get back to full charge, how close does it get? If well maintained batteries last several years the loss of capacity must be very gradual, and the error between my assumption that all the sulfation will be removed and the actual situation will not matter for practical purposes.
And your remark that "no one would ever have problems with sulfated batteries" is not at all the same as saying that "everyone has problems with sulfated batteries" or "no one NEVER has problems with sulfated batteries"
So what is your recommendation for most economically meeting a requirement for (say) 120 ah per day from the batteries? taking account of fuel costs, and battery cost and battery life?
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In brief, say you split a bank into parts A, B, C, D.
You then use parts A, B, C and charge daily from 50% to 85% each day, and charge part D from 85% to 100% over 3 days.
I think this notion of "splitting" a battery bank is confusing the issue. What I have in mind is investing in a second battery bank that is the same size as the first one. So having a second bank won't result in either bank being discharged more than the original bank would have been.
Of course, after buying more batteries I could build them all into one bank and that large bank would be discharged less than the original bank. But ... batteries accept large charge currents when they are below about 85% capacity. Making the bank bigger means that there will be more batteries continuously undercharged - because it will still require several hours of charge time to bring the specific gravity back to full charge.
My thinking is that having a second battery bank that can be brought up to full charge over several days is the most economical way to get the battery to full charge when you don't have access to shore power. If the time required to achieve full charge exceeds 12 hours then it will never be possible to fully charge a single battery bank because you may only run your generator for 12 hours per day. Whereas a second battery bank could be charged for 50 hours or more over several days.
Gibbo introduced some maths to calculate sulfation days, but from what I have read sulfation damage does not occur just because a battery is discharged - only if it is left in a discharged state for a period of time. Therefore he is not comparing like with like when he contrasts the days at low charge with the days at high charge. My understanding is that, provided the battery is good to start with, bringing it back to full charge removes all "sulfation" and it is sufficient to achieve full charge about once every 2 to 4 weeks.
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Most of us work out the amount of power that we need to consume over a 24 hour period, then put into place a battery bank & charging systems sufficient to put back in enough energy to maintain our consumption.
The issue is not simply a balance between what you take out and what you put back each day. For example if my daily demand is 120ah and I charge my battery from 50% to 85% (i.e. 120 = 35%) the battery bank capacity must be 342amp hours. However the life of the battery depends on it being charged from 85% to 100% periodically - at least once a month, as far as my research has discovered.
The point about having 2 separate battery banks is that the bank that is "resting" (to use the theatrical term) can be charged up to 100% over a period of days without having to run the engine (and consume diesel) for many hours. And it is no good running the engine for 12 hours today, getting a single battery bank to, say, 95% and then discharging it overnight to run the fridge, lights etc. Then you need another 12 hours engine run the next day, and the next ...
As far as I can see the proper measure of a fully charged battery is when the specific gravity of the electrolyte is 1.266. My starter battery shows that, but my present single bank of house batteries is well below it.
I have a portable mains battery charger that can be set to a maximum charge rate of 2, 4, 8 or 16 amps. By using one of the lower ranges it won't draw too much from the in-service battery bank, and the battery is only going to accept a low current while it is charging from 85% to 100%.
Yes it's inefficient to charge a battery through an inverter - but you could buy a lot of diesel with the price of a better battery charger.
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the charging routine is not suspect - you just all made up your minds that you consider it to be! it worked fine for the forklifts - I thought a couple of days running on batts was pretty cr*p but you all seem to think that is great! I should have just stuck with them...
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you think I should just chuck yet more money at it?
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god I'm just fed up of it all now (throws toys out of pram...)
Have you considered operating two separate battery banks as mentioned in one of my earlier posts on this subject? I think it is the only practical way to ensure that each bank is alternately charged to 100% without excessively long engine hours. However I am interested to hear everyone's view.
I guess you have, yourself, come to the conclusion that the diodes would not help. As far as I can see all they would do is prevent a charged cell from discharging into a less charged cell. But if the cells were all collected together to start with they should all have the same charge. And the diodes will waste power.
I think a hydrometer is the best tool to identify a dodgy cell - it should show a different specific gravity reading compared with the rest of the cells.
You do raise an interesting question which has not been addressed yet - how should you test a battery when it is delivered to prove that it is up to specification?
And, from the research (on the web) that I did there should be nothing wrong with discharging a deep cycle battery well below 50% as long as you are prepared to live with the reduction in the total number of discharge/charge cycles it will survive. Presumably discharging only to 75% would be even better than a 50% limit. But what the "never go below 50%" brigade do not acknowledge is that the battery will take a faster charge when it is more deeply discharged and that makes much better use of your generator fuel. After all, the whole thing is a balance between the cost of batteries and the cost of diesel.
My idea, with two battery banks, is to use one bank in the range 40% to 80% (or 30% to 70%) for (say) a week and then charge it up to 100% during the subsequent week when bank2 is being used for "house" duties.
I don't profess to be any more than a competent amateur, so all other comments ae welcome.
Gear box fell off
in Boat Equipment
Posted
The boat was new in 2004 so I presume that is also the age of the engine and gearbox.
The bolts that originally held the gearbox on included a washer as part of the bolt head and the underside of the washer had grips on it. However I'm not sure how much grip they would have got on cast iron.