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Theo

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Posts posted by Theo

  1. I am sure that this subject has been discussed before but I can't track it down using the search function.

     

    Can anyone give me a lnk to a supplier?

     

    LA is sensitive to misuse and degrade in proper use anyway.  If I get second hand, are they going to be any better value than new since they are bound to have lost some capacity.

     

    What about 2nd hand lithium?  I know that there are lots of issues to be addressed if I go for lithium but is it likely at this state that 2nd had will be better than new.

     

    I look forward to reading more...

     

    TIA

     

    Nick

  2. On 06/11/2021 at 11:25, booke23 said:

    Agree with all the above. Remember you can have multiple cassettes to give you much longer intervals between visiting Elsan’s if you want. 

    But if you go the PortaPotti route then you might not be able to buy a spare tank.

     

    We have a PP 365.  We had to replace the supeerstructure bacause the flush pump wwent wrong.  Faced with the awful dilemma of having to buy two complete PPs to get a secont tank we dedided to get a replacement 365 from EBay and get a tank from the old one so now we have three tanks.  The bigger tanks last us about 3 bottom-days so we have plenty of flexibility regarding elsan emptying.

     

    Please try to avoid using blue chemicals to kill the bacteria and reduce smells.  We use nothing most of the time and get no smell.  When we decide that we need to use something we use Odourlos which is biodegradable.

     

    Nick

  3. On 06/11/2021 at 11:14, mrsmelly said:

    A cassette is ideal for a continuous cruiser. As you are moving about all the time, you will pass an elsan point most days ;)

    And they are free to empty...

     

    Usually.

    #

    N

  4. On 18/10/2021 at 18:25, nicknorman said:


    Well something is wrong there, maybe the batteries are knackered or your estimation of SoC is incorrect. 2% of 810Ah is 16.2A which many people consider to be 100% SoC.

     

    But other factors such as thin alternator and battery interconnect wiring designed for a 50A alternator, voltage lost in battery isolators etc may be at play. Is the 14.4v actually at the battery terminals, or somewhere else along the way?

    Just rereading the thread, I noticed that I had not replied to this post from nicknorman.

     

    The 14.4V is read off the SmartGuage which is connected directly to the battery terminals.  I believe the batteries to be pretty well knackered.  I have had them living aboard for 3 years  and 4 years not living aboard being looked after by the solar panels but for a period they were abused at the boatyard by being left without the solar panels connected.  So they don't owe me much and I should really be thinking of replacing them.

    • Greenie 1
  5. It's not working at the moment so I have unshipped it, taken it home and am investigating.  I think that it's the flame sensor plus some stiffness of the air blower from lack of use over a lengthy period.  I can't buy any more gaskets.  Mikuni have stopped making spares and MV Heating in Eastliegh have none left.  Not necessarily a problem I can create my own from some 2mm gasket paper.

     

    I got this news from the nice man at MV Heating who told me that the replacement for the MX40 is an MV MX50 which they will mount on the same plate that the MX40 was mounted on if I send it off to them,  cost £595 + VAT plus carriage.

     

    Question: is the MV MX50 a good buy?

     

    My inclination is to have a go with the old one and see if I can get it going for a few more years (months? weeks? not at all?)

     

    Opinions/advice will be gratefully read.

     

    N

  6. On 29/09/2021 at 15:29, _Catherine_ said:

     

    This is my first post, but don't want any going off at tangents as to why I wish to change and don't want composting toilet.

     

    Sensible advice much appreciated.

    Please be aware that one of the lasting benefits of this forum is the fact that there are many and various tangents that have been explored.

     

    The advice offered is usually good, often brilliant and always free.

     

    If you understand and can work with this you will have a very rewarding experience.

     

    Nick

  7. On 17/10/2021 at 11:25, agg221 said:

    I would say evolved rather than fundamentally changed.

     

    The swing to the Conservatives in North East since then has seen a shift in emphasis from Liverpool and Manchester towards Teesside which is now both a Freeport and a Hydrogen Hub. A new site has also been added in South Wales.

     

    There are several different aspects to hydrogen. Hydrogen goes by various colour names depending on source. Brown hydrogen is made by heating water and coke together, forming a mixture of carbon monoxide and hydrogen (the old towns gas) and is still industrially significant, particularly on Teesside. Green hydrogen is made by electrolysis of water and is seen as clean and sustainable, so long as you are using surplus renewable electricity to make it. Blue hydrogen is the same but specifically made using offshore wind turbines.

     

    Leaving aside the challenges for the moment, and they are considerable, the planned applications are where you need a higher energy density than can be delivered with battery storage. Current areas of interest include rail, flight and shipping, and possibly heavy road haulage. The question is how you use it, which is in part a matter of semantics but it is actually at the heart of one of the current areas of debate. If you burn hydrogen, either for domestic heat or to run an internal combustion engine, it is very simple and cost-effective at point of use, but whilst it creates no carbon emissions it does emit nitrous oxides as the oxygen and nitrogen react at temperature. This NOx is nowhere near as significant a greenhouse gas as carbon based gases but it is still there. The alternative is to use a fuel cell for motive power and rely on electrical heating but this has major technical and commercial barriers - the fuel cell uses enough platinum for this to be infeasible to scale to the current requirements (my first job was developing fuel cell catalysts for Johnson Matthey). Therefore, what it comes down to is whether targets are defined as 'net zero carbon emissions' or 'net zero emissions' and if the latter whether offsetting the NOx emissions is deemed acceptable. It's a political debate and I personally have little interest in what the decision is, but I will probably be part of working out how to implement it so I do take a significant interest in knowing where the thinking ends up.

     

    Alec

    Coming late to the discussion: Blue hydrogen is made from natural gas and is effectively a fossil fuel.  Hydrogen made using elecricity from renewable energy of whatever variety is Green.

  8. 1 hour ago, MtB said:

    Is there any mileage in cilling the stern in a lock, for better access?

    Absolutely not.  As soon as you get lift from the cill on the bottom of the boat the stability is all shot to hell and the boat tips over to one side or the other.  This could be mitigated if you managed to get to the forward end of the cill and then the boat would be like sitting in a drydock.  The problem then, if you have not already submerged the bow, is that the boat could easily slip off.  Please don't try this.

     

    You could always try a staircase where you could sit the boat down on the invert.  Nice and level.  But then you have the possibility of damaging the bottom of the boat by putting lots of wieight on a small pointy object.

     

    N

  9. "It’s to do with the regulation curve of an alternator’s rather basic regulator. The current supplied by an alternator is related (inversely) to the terminal voltage. So if we presume for example that the regulated voltage is 14.4v, at 14.4v it is producing no current. At 14.39v it is producing  maybe 1% of its output. At 14.3 maybe 10%. At 14.2v maybe 25% You have to get right down to perhaps 13.7v before it is producing 100% of its output. (Figures made up, but the principle is right)."

     

    I have quoted the bit from nicknorman's post that I can't get me head around.

     

    Lets forget that we are using an alternator for a moment.  If we were to use a true constant voltage source where the voltage is entirely independent of the current drawn, then the current delivered at, say 14.4V, would be entirely dependent upon what the battery bank would accept.

     

    Now take the case of nicknorman's alternator.  The battery bank is at 14.4V so the current delivered is zero as controlled by the alternator electronics.  Now let's say that some charge is drawn from the bank so that its voltage drops to 14.39.  In the case stated by nn the alternator immediately delivers its 1% which, with a 70A alternator is 0.7A or a 140A alternator is 1.4A.  If we take the load drawn out of the equation by assuming that it is switched off the moment that the voltage drops to 14.39V then the alternator will continue to charge the battery until the voltage reaches 14.40V and then stops.  Ah! It is becoming clear what nn is saying even as I am typing the reply.  What he means (and says clearly) is that, assuming the same alternator controller characteristics, a 140A alternator will charge the battery more quickly even at the low tail currents.

     

    My old alternator is a Bosch to which I fitted an adjustable controller.  I originally found that it would charge reasonably rapidly at the beginning of the day's cruising but the current would drop off far to early.  I got around this with an Adverc which made a huge difference...

     

    Thanks, nicknorman.  I believe that I now understand but will not be fitting a bigger alternator because of the issues of fitting new pulleys etc.  I will live with what I have.  (And keep the belt tensioned properly.)

     

     

  10. Just now, Alan de Enfield said:

     

    He has all sorts of electronics overiding the alternator.

    But at safe voltages you can only put so much current into the battery bank.  At 80% charge and 14.4V my nominal  810AH (very old) battery bank is only accepting in the region of 18A.  This will, of course be due to surface charge, but can such chemistry be overcome by lots of electronics?  I am using an Adverc, and very excellent it is too, but I can't see how I would manage to keep my alternator working flat out any more than it is now.

     

     

    • Greenie 1
  11. 9 minutes ago, David Schweizer said:

    One thing that hs occured to me, a 1005 alternator belt is quite short for a BMC1.5, unless you have misquoted the size in your original post. A larger crankshaft pulley wheel would increase the revs of the alternater at a slower engine speed. Does yours look this size ?

     

    984465237_25EngineGearbox02.JPG.bef6f0277bdd487a6bd3744950dc9b16.JPG

     

     

    I would guess that it's about that size.  There is the added pully on the crankshaft.  It's a small one and is used for the pelt drive to the raw water pump.

     

    Edited to add:  An extension to the maths will show that the force on the drive belt to the alternator does not change as the pulley size on the alternator changes.  I find that quite interesting.

     

    N

  12. 28 minutes ago, Theo said:

    Thanks for all the useful advice.  All the advice had already been followed except Tracy D'Arth's "There should be about 10mm maximum deflection on the longest run between pulleys with firm thumb pressure."

     

    It is embarassing to admit that I had not got it tight enough.  I had been testing the tension on the shortest length from the water pump to the alternator (Theodora has a BMC 1.5) The longest length is from the alternator to the crank shaft.  Tightening it with a little assistance of the jemmy should have done the trick but I can't test it properly until tomorrow when we will have run the batteries down a bit.

     

    David said "Have you always had a 70amp alternator, or is it a recent more powerful replacement? I replaced the original 35 amp alternator on Helvetiia with a bigger 70 amp one, still using the original 10 x 1050 belt, and experienced a lot of squealing under load. After tolerating it for a while, I arranged for Jonathon Hewitt at UCC to open out the crankshaft pulley V groove, fit a wider alternator pulley, and fit a 13.5 x 1050 belt - problem solved. "

     

    Actually, the alternator might be 100A.  I fitted a new one when we first had Theodora.  The old one, the original Lucas, IIRC, was not working at all when we bought the boat.  And in my ignorance I thought that a bigger alternator had to be better.  A few years later I got around to fitting an ammeter in the alternator output.  What a worthwhile investment!  I have never seen the output go higher than 85A and that was when we collected the poor old boat from where they had been painted.  The soc (Smartguage) was reading 25%.  I never let it go below 50% normally and usually get concerened when we approach 60%.  I rarely charge the batteries with the engine when moored but when I do I run the engine just fast enough to give maximum current.

     

    I observe from the alternator current that at the beginning of the day the alternator output might go as high as 45A, falling back to 25A within five or ten minutes and gradually reducing over the rest of the day's cruising.  Who needs a high powered alternator?

     

    N

    I should add that there is good and simple mathematics behind the advice to run the alternator fast:

    Power output of the alternator at any instant = VI.

    Power input ( just a bit more than power input)  = Torque (in N-m) x angular velocity (radians/second)

     

    So for a given power input increasing the angular velocity (think RPM) the torque will reduce.  So running the engine faster will reduce the force on the alternator belt.  However running the engine faster means that it is wasting more power in overcoming friction so you will use more fuel.  That's why I run the engine as slowly as possible consistent with maximum current.

     

    N

  13. 1 hour ago, harleyj said:

    While travelling the canals this year we have met some interesting and wonderful people and made some wonderful new friends. But yesterday I met someone completely lost. This gentleman had just bought his boat from Nantwich and on his first day out I met him at the bottom lock at Hurlston. Nothing strange in that, but when I asked him where he was heading, he astounded me by saying he was heading to "Ripon". I said I think you are going the wrong way, but he assured me someone had told him that the shortest way to get there was via the Llangollen. I eventually convinced him to turn around. I was laughing so much when I caught up with my wife at the bridge that I didn't even get the boats name. Made my day!

    That, to me, seems like a really horrible person telling him lies to mislead him.  Mind you, he should have bouhg some maps!

  14. Thanks for all the useful advice.  All the advice had already been followed except Tracy D'Arth's "There should be about 10mm maximum deflection on the longest run between pulleys with firm thumb pressure."

     

    It is embarassing to admit that I had not got it tight enough.  I had been testing the tension on the shortest length from the water pump to the alternator (Theodora has a BMC 1.5) The longest length is from the alternator to the crank shaft.  Tightening it with a little assistance of the jemmy should have done the trick but I can't test it properly until tomorrow when we will have run the batteries down a bit.

     

    David said "Have you always had a 70amp alternator, or is it a recent more powerful replacement? I replaced the original 35 amp alternator on Helvetiia with a bigger 70 amp one, still using the original 10 x 1050 belt, and experienced a lot of squealing under load. After tolerating it for a while, I arranged for Jonathon Hewitt at UCC to open out the crankshaft pulley V groove, fit a wider alternator pulley, and fit a 13.5 x 1050 belt - problem solved. "

     

    Actually, the alternator might be 100A.  I fitted a new one when we first had Theodora.  The old one, the original Lucas, IIRC, was not working at all when we bought the boat.  And in my ignorance I thought that a bigger alternator had to be better.  A few years later I got around to fitting an ammeter in the alternator output.  What a worthwhile investment!  I have never seen the output go higher than 85A and that was when we collected the poor old boat from where they had been painted.  The soc (Smartguage) was reading 25%.  I never let it go below 50% normally and usually get concerened when we approach 60%.  I rarely charge the batteries with the engine when moored but when I do I run the engine just fast enough to give maximum current.

     

    I observe from the alternator current that at the beginning of the day the alternator output might go as high as 45A, falling back to 25A within five or ten minutes and gradually reducing over the rest of the day's cruising.  Who needs a high paowered alternator?

     

    N

  15. I have had a squealy alternator belt three times in the course of a three week trip with few running hours (often less than 4 hours per day.

     

    Each time I have tightened it a boit more.  The belt was new at the beginning of the trip so I would expect to have to retighten it once after the initial tightening, but three times seems a bit excessive.  It is a 10mm x 1005mm belt in the correct pulley width.

     

    This morning the battery soc was down to about 70% and as soon as the split charge relay connected the domestics the alternator delivered about 55A.  Its a 70A alternator.  As the battery voltage built up and the current delivered by the alternator reduced to about 40A the squealing stopped.

    What I don't want to do is to overtighten the belt.  I was told years ago that the alternator would stand lots of lateral force on the bearings but not so the water pump.  So I want to keep the tension as low as I can consistent with not shredding the alternator belt and scattering bits of black dust over the engine.

     

    Advice please?

     

    Nick

  16. 8 hours ago, Tony Brooks said:

    If you are stopping charging at 20 amps charge or higher, then you are destroying the batteries by sulphation. You need to go on charging until the current has stopped dropping over about an hour at 14.2volts plus or when the current has dropped to 1 to 2% of batery capacity, again at a voltage of 14.2V or higher

    I'm getting confused, Do you mean that the charging current is 20A?  I think you must mean that and I would agree that it would be at far too low a soc...

     

    I am no longer confused. I see exactly what you mean.  I just needed to allow my aging brain to catch up and finish processing. 🙂

     

    N

  17. On 25/09/2021 at 12:53, Alan de Enfield said:

    If you are staying moored up for the rest of the year it may be worth changing, if you are planning to cruise then you will have problems getting your cylinders changed as the FloGas network is but a fraction of the size of Calors distribution network of retailers.

     

    Make sure you are comparing like-for-like (13kg not 12kg etc) and do not use 13KgFLT cylinders these are to be used 'lying down' on fork-trucks and use 'liquid propane' rather than 'gas'.

    What's liquid propane?  All propane in bottles starts as liquid then boils off to gas.

     

    N

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