dmr

Too much polishing? Alternators are like fuel injectors and even engines, the manual might tell you how to rebuild them but skilled men don't come cheap these days so unless its something special its usually cheaper just to get a new one. A while ago I asked a local a local garage if they could put some new bearings into my alternator, "are these inside the alternator" they said, "we've never looked inside one." ..............Dave

Big padlocks on the doors indicate an empty boat, a big steel bar across the front door with a padlock either end certainly indicates an empty boat, but yes, slowing down for occupied boats is what matters. ...................Dave

Just off the landing for the swing bridge, or even on the landing as long as somebody stays with the boat to help just in case another boat turns up. ..............Dave

Thanks, I would even say a boater who needs to stay reasonably close to his kids school, but still moves as much as he can, goes cruising in the school holidays, and plans to travel extensively once the kids have left home, is probably just about bone fide, but that is not clear cut. I've been thinking about this, for a month or two over winter our limited movements were driven by my wifes need to be close to her grandchildren, and my desire to be near a pub that I like, so we were actually not really bone fide even though we were compliant in CaRTs eyes. Since then we have been bone fide because the driving force is to be cruising. Its complicated, think I need beer. ................Dave

and if you do find a Hall device that can measure 150 amp and do a resolution and accuracy of say 0.1 amp then please do PM me, I always think with electronics that whatever you wish will turn up if you wait long enough. I believe some sensors work by supplying an equal and opposite current (through many turns) to balance the measured current and so the Hall sensor only needs to detect zero current. These have a better spec but then have the penalty of higher current consumption. Maybe using one of these and only turning it on to make a measurement once every second or so would be the way to go. .............Dave

If a Hall effect sensor can meet the required spec. then they would be the obvious choice and as you say the isolation makes everything so much simpler (and safer). I did think about using two sensors, one for higher currents and a much smaller one for the low current discharges, but even though they are electrically isolated devices it is still not possible to subject them to gross overload. Don't worry about all the op-amp stuff and voltage rails, just have a look at the data sheet for something like the INA219, its all in there, the zero drift differential amplifier, variable gain, filtering, and an I2C interface. They even work out power if you don't want to do that yourself in software. One of these, an Arduino, and a little LCD display and you have all the major building blocks of a good amp-hour meter. I suspect this is exactly what is inside the Sterling device

Its a very complicated situation and that's why it would be very sad if CaRT had to specify an exact cruising pattern to satisfy bone fide navigation. A boater who has a full time job but wants to explore the system may well leave his boat moored on the towpath and use it for one day once every 7 or 14 days. I would say this is bone fide navigation. A boater who takes his boat out of a marina only to save money and leaves it on the towpath (a dumper) and moves it once every 14 days is not using his boat for bone fide navigation. A liveaboard who moves his boat backwards and forwards once every two weeks and resents that move is not bone fide, but a liveaboard who moves over a 30 mile range and enjoys boating probably is. .............Dave

I got the 1000W version a couple of weeks ago. I have just tested it and it appears that the earth and neutral are totally isolated (not bonded). I will phone Sunshine next week to see if they know if an external bond is allowed. ............Dave

That looks like a pretty impressive plan. I assume you mean BondaPrimer (which is good stuff) If you can get back to 99% bare shiny steel then that plan makes sense, but if its still rust with just the loose stuff removed then I think that Red Owatrol might be better than BondaPrimer. ps.... Have just (10 minutes ago) painted a gunnel in BondaPrimer using it as a top coat over Craftmaster Raddle, I like the colour of BondaPrimer a bit better than Raddle, and its more non slip in the wet. Useful Tip BondaPrimer is very volatile/fast drying so all the time the tin is open its evaporating making the paint stodgier and stodgier, which is no good as BondaPrimer brushes so nicely when its thin. Buy a big tin of BondaPrimer and decant into lots of Jam Jars then use them one at a time. ................Dave

I did spend a little time looking at the specs of these things and I concluded that a shunt was still the better way to go. Can't remember the details but I think it was the zero offset that let the Hall effect devices down, though linearity was a bit iffy too. The active ones have the better performance but there is a current consumption penalty. Its a Tall order, need to cope with the heavy charge current (150 amps?) but also accurately handle a long slow discharge. A 1% zero offset is an error of 1.5 amps. .................Dave

That's your shortest reply ever??? So, lets say the op uses a 10 ohm resistor between the shunt and the "219", with a worse case voltage spike which transorb should he use to limit voltage to 26 volts without self destructing? (I have an interest myself here as its still on the todo list). .........Dave

The INA219 is only good for 26volts which is a bit low (and I assume you are a 12volt rather than 24volt boat). The data sheet does say that you can use 10 ohm resistors and a capacitor at the input to reduce noise. Maybe you could even go a bit higher than this (100 ohm?). Rather than the capacitor you could use a pair of transorb type things down to ground for protection. Its not an easy subject as you really need to have an idea of the size and duration of any spikes to know how much energy you will need to dissipate. I reckon there is at least one proper automotive electronics engineer on this forum (I am just a sort of electronic/mechanical/automotive/acoustic jack of all trades) so maybe they will help. I think NickNorman knows about this stuff too. A bit of help from someone with hands on experience is a whole lot more fun than working through the data sheets and guessing at the spikes. ..............Dave

My experience of using Arduino libraries is that some of them really are plug in and go, and some need a LOT of effort. The Arduino library system is all a big tricky and non intuitive. Arduino is promoted as an easy to use system for non engineers; maybe non engineers are a lot cleverer than engineers because I don't find it easy at all. How anybody can describe "C" as a beginners language is beyond me. .................Dave

That's not so easy. If you put the shunt in the negative battery lead (as most commercial systems do) then there should not be an issue with spikes, though not sure if the chip that I linked to does negative sensing, have a look at the data sheet. If you put the shunt in the positive lead then there might be a problem. One advantage of using the positive lead is that the system will measure volts as well as amps. These things are quite cheap so I would be tempted to try it and see how it goes. Its not easy to filter the shunt output as its all low impedance. You could possibly use little series resistors and capacitors or transient suppressors after the shunt. A better approach might be a small resistor in the ground line and then a transient suppressor to the positive. Another winter has gone without finding the time to do any work on this project, paid work rather took priority, and now its cruising time. .............Dave

That link don't work for me. 2000 at 80% is only twice as good as Trojans, and because Trojan appear to concentrate on the T105, aiming at golf carts, off grid installations etc etc they must have a huge economy of scale and so will likely provide much better value than any alternatives. Looking back at the Trojan cycle life (link above) I note it says "Stationary Applications", I wonder if Trojan know something here? maybe they do less well if they get shaken up quite a bit. ..............Dave

Spencer and Victoria have two coal boats and also own the canalside "boatyard" at Hilperton. They run a very tight business and appear more interested in providing a good service to boaters than getting rich. FAME free diesel at 55p and coal cheaper than driving to the local coal merchant. No realistic chance of any new business getting a look in. They do the River Avon, Western end and long pound. Another smaller boat does whats left; the Kennet and Eastern end. ..............Dave

Universities are very big businesses who charge students extortionate amounts of money, but everyone of them is a charity. A major aim of CaRT, like most charities, is to raise money to spend on the things they are there to do, it is NOT to give money away. ..............Dave

It would be worrying if a judge had to decide, though a few have already tried. The law says "bone fide navigation" and it really should be CaRT, the navigation authority, who decide what this means. Judges specialise in interpreting the law but are not equipped to understand matters of navigation. .................Dave

A small pumpout tank combines the worse features of pumpouts and cassettes. We try to use ours carefully and with two people can just about go 6 weeks. I usually pump out every 4 weeks which leaves a good safety margin; a full tank is no fun. I also find the tank can get a bit whiffy as its gets fuller so a 4 week pumpout is about right. If you need to pump out more often than maybe every two weeks then a cassette starts to look attractive. ...............Dave

You are totally correct and there is still a good selection of interesting boats on the Western K&A, plus a fair few neglected bland ones. For this diversity of boats and boaters alone it is worth trying to preserve communities like the K&A, its rather sad that their (non elected) representatives have chosen a route of conflict with CaRT rather than getting CaRT to understand that they have value. It does sometimes appear that the NBTA is an organisation that enjoys conflict as much as it enjoys representing boaters. .................Dave

CaRT do turn a blind eye, but I think that they have stated its not their problem, it would be up to a local authority to prove that a mooring was been used as a residence without planning permission. As long as everybody is discrete its fine, that is why I am concerned that the protesters are drawing attention to the shortage of residential moorings and so if pushed may well draw attention to the leisure mooring vulnerability. Its a lot like caravan parks though, as long as you don't use it as a postal address and spend at least a few of nights away each year its hard for a council to prove its residential. .............Dave

My recent experiences confirm that Sods Law is still a powerful and malevolent force. If you spend time fixing something then other totally unrelated components will feel neglected and so break to get their share of attention. ...............Dave

Its really not that simple. Many boaters could afford a mooring, their argument is why should they pay for something that they believe they can have for free, and indeed have had for free for many years. Also I suspect many do like to move but only over a limited range. CaRT can not easily create residential moorings, its needs planning permission. If CaRT create leisure mooring and try to force boaters on to them then there is a strong possibility of the NBTA pointing out that living on leisure moorings is illegal and wrecking that lifestyle for many boaters all over the country. ................Dave and I forgot to say, I am pretty sure that there are several vacant leisure moorings available in that area. .............Dave

A long time ago I was part of a co-operative housing association and we had a number of residents (wealthy upper middle class students) who said that having a good time and overseas holidays was more important to them than paying rent. Maybe paying rent was just a thing for the working class members??? .......................Dave

Yes, I already have these (and more) stashed in the battery folder on my hard disk. Its interesting that, for example, the US and Trojan specs are a bit different for what are similar batteries. Does this reflect real battery performance or just how the data is measured? I suspect these curves are based on a mixture of measurement, prediction and extrapolation. The Rolls do look seriously good. I have seen a curve for some True Tractions that are no better than Trojans, not sure if I saved that one. What would be interesting is the equivalent curve for some cheapo leisures. Would the curve have a similar shape and slope, or would cycle life fall much more steeply at deeper discharges???? ...............Dave