RobinJ

Reading the various threads about anodes, galvanic isolators and isolation transformers started some of my rusty grey cells twitching! Thoughts: Magnesium is used as opposed to Zinc on inland waters because there is less ionisation? it has a more negative potential? therefore provides better protection? Many blame sizzling anodes on poor AC protection? Galvanic isolators work so long as they don't conduct? A lot of AC equipment produces RFI which turns galvanic isolators on? Didn't I read somewhere there can be as much as 30V difference between ground and the earth lead? So best solution is isolation transformer despite cost? Many boats are now chained to the bank (to stop them getting nicked!). So we need tyres (for the piling), isolation trasnformer (for AC), a non conducting chain!

Actually there are quite a few reasons to have one! - Emergencies, middle of nowhere you try getting police, ambulance or fire brigade to find a puddle! - Accurate speed measurement, it is surprising how the optimum speed varies between canals and even in different directions, but probably more useful on rivers where there is some flow. - Also gives you the time and sunrise or sunset, so you now how long you've got left before you have to tie up in the dark. Mines waterproof too!

Yep, don't get owt for nowt! Can't see why, its running for the same amount of time. So long as it can handle any extra heat and load. May be (mine slips a bit on full whack) you have to change the belt more often?

I know mine charges at constant current (many do at least in part), admittedly by pushing up the voltage limit. Is not the benefit charge time. Voltage regulation reduces current as the voltage rises, but some external ones maintain current at a high level so the voltage rises quicker? What effect do larger battery banks have? Are not on board controllers designed to work with one batery? Not necessarily ideal for multi bank operation, especially if they are differentially discharged?

This would make perfect sense if a NRV was fitted between them?

I always carry at least one spare (hence the box of bits). Since I upgraded to the Bosch I haven't had to use the only working one I have left! The first failure was as a result of the starter battery going short in a lock. Other failures were probably related to staying overnight close to tunnels (I believe more drain than charge - the other reason I upgraded). Here the external controller saved the day (always a bank holiday!), as I was able to continue running without the internal alternator controller working! (hence no spare diodes!) Incidentally, as a result, I now start with my external controller switched off, allow the starter to recover at least before switching it on to boost the domestic and inverter batteries. Normally it only takes about fifteen minutes running to fully charge, but after a heavy inverter session it can take hours.

Not having a calorifier I'm probably confused!What is the difference between this and having one near the water pump? Everything works until it goes wrong!There should be an NRV between any 'fresh' water and heated or foul areas, this includes both hot water and toilets! I assume this is looking down towards the floor, so the pump is horizontal?Many installations I have seen mount the pump vertical with the 'head' at the top.Having crawled in a number of boats to repair pumps, I decided to mount mine with the pump body below the 'head', then if the seals ever go, the motor doesn't get drenched!

Argh! (gone bald) Now I know why everybody's so chummy. I suppose technically the engine maintains the charge current!

The trade!I have a box of bits somewhere all without diodes I think? Actualy some maintain the charge current up to a voltage limit!But the trick is to keep the voltage below gassing point.

Last time my A127 regulator failed (dazzling in the tunnel!) I was told that parts were no longer available. I found the problem with the older Lucas alternators was cooling (but that depends on the engine compartment). Now have a Bosch 70 amp with big fan, but does burn the belt more! If you are cruising or spending time on the boat a lot or using loads of power, then they are probably worth the money (eventually). With leisure batteries, it is difficult to keep them at maximum capacity without a decent charger, and in the absence of shore power or a generator, the easiest way is probably a clever alternator controller. (Not sure about finacially - red diesel versus electricity?)

Most accumulators have an inflation valve on the top, which can be pumped up with a car type foot pump. When the system is pressurised, the pressure in the 'air' side should be the same as the water pressure. If you know your pump pressure (e.g. 30 psi), when the system is unpressurised, you can set the accumulator pressure to about one third of this (i.e. 10 psi), this theoretically gives the maximum capacity (up to about two thirds of the accumulator) when the system is pressurised (since a third volume should give three times the pressure). You must have sufficient pressure to expel the water from the accumulator as the pressure drops (so 10 psi is about the lowest useful), this will allow for those high volume situations like showers.

After discussion with hire boat engineers I moved away from using splitters in favour of charge relays, as it eventually prevents the batteries working to their full potential in high charge/discharge situations. In theory there is no reason why you could not fit two diodes (each way in parallel) in the warning light connection to the alternator to compensate. The first one enables the current to flow from the warning light to energise the alternator, the second allows the current to extiguigh the warning light when the alternator is running. This should work as it drops the alternator vaoltage by the extra 0.6V that the batteries are not receiving!

Their are some "rules of thumb" around, but calculations get complicated. Some say the bigger the better, but then you get more expansion! If you are just using it normally on canals, about 0.5 square foot per 100cc is a good guess. Personally, I would try to get 9 square feet even if it means one either side. A lot depends on the length of boat, average cruising time, gear ratio etc. Baffles are important as it increases the 'travel' through the tank, some install vertical ones which makes it more difficult to flush, I think horizontal ones are better. I came up with an idea that hasn't been tested - measure the length of 'heating' (quickly, twice the length/width of the block plus length of exhaust/heat exchanger). If this is less than the 'cooling' distance through the tank (distance to go round all the baffles from inlet to outlet) you should be ok? When I put the 1.8 in the boat, I had to switch back to raw water for the oil coolers as it was cooking the gearbox. Generally BMC's don't like two much head (water pump is impeller type) and have a tendency to boil suddenly under load (like weed etc.), so its nice to have a margin of error.

I have come across a wide variety of 'swicthed mode' type power supplies (although I am including DC-DC converters too)including discrete sine wave, digital psuedo and new 'electronic' transformers. Many of the modern low current ones use an IC with at least a capacitor for 'integration'! I am assuming these chargers are DC output and not AC!

Three sources of leak! Around the frame - have to remove each one and reseal! Rubber seal around the glass - may have problems getting rubber and you have to take them apart! Joints around hopper bar - these can be sealed with silicon, but take the hopper out first! Caldwells (up north) supply some good solid windows in varous styles including hoppers and sliding, with round or square corners. If they are not standard sizes it could be expensive - not sure if there is a good supplier nearer to you. Does anybody know who supplied Black Prince?

I switched from BMC 1.5 to 1.8 last year for more power! Friend has been installing a rebuild (instead of his Lister), new injectors, shells and rings, overhauled fuel pump, had to replace timing chain. When fired up, boat dissapeared in white smoke - obvious timing problem. Thought it was likely to be fuel pump timing, but after stripping down, found crank pulley was half a tooth out. This is strange as it fits on the woodruff, if it had moved, teeth would not line up anyway! Now running beautifully. Has anybody found timing marks not to line up before?

Oh water pumps, so many hours of fun - usually under the bunk or the cratch! Probably one of three things; microswitch failure (pressure switch bit) - they tend to arc and wear out with all that switching on and off, now difficult to find a replacement and not easy to fit; seal leak on the pump - water leaks into motor and it gets rusty, need a service kit but can usually be cleaned up if its not gone too long; finally brushes, but then you say it did't stop so discount that one! If its been there for more than five years simplest is to replace.

Can someone explain to me why somethings trip the inverter one day and not the next, I suspect its to do with battery state! The problem is there are different types of inverter and different types of switched mode power supply. A good switched mode power supply will work on a bad inverter (i.e. square wave), this is because they 'integrate' the pulse to produce a lower voltage. Cheap switched mode power supplies work simply by chopping the sine wave at the right voltage, so if they don't get one they tend to produce spikes, which the inverter doesn't like and not give out much voltage as they switch off very quickly! Flashing rope light contollers tend to have cheap switched mode power supplies in them, so either blow up or don't light. The same will be true of cheap universal phone charges etc.

You don't say which engine it is? The small pulley is for fitting the Jabasco water pump for oil cooler (usually raw water). The Alternator normally fits on the side of the engine next to the thermostat, secured with a hinge bolt at the top and an adjuster at the bottom. These normally include spacers which allow the alternator pulley to be lined up with the crank and water pump (the right size of washers can be used if necessary). The hinge bolt is normally fixed directly to the block, but it sounds as though in your case it is not - modification? It is important for long service that the alternator is secured by its rear mounting hole, this may be what is causing the failure, as the alternator will tend to wobble if not! Many BMC's are fitted with oversize crank pulleys to increase cooling at low revs., this means belt sizes can vary! I upgraded my alternator to a 70 after a few of the Lucas A127's failed, needed new belt, spacer adjustment and change to electrical connectors (3 pin plug to eyelets).

Two reasons gnerally why BMC's do this:- 1) Sucking oil - excessive back pressure, fumes from oil filler - kink in breather or blocked filter, condensed oil blown into intake. What sort of valve seals are fitted? Setting the valve clearance properly may help, but it could be a sign that either the valve guides or the rings are getting worn. 2) Sucking fuel - usually leaky lift pump, but can also be air leaking into fuel pipes. Does the oil level go up when it is left standing with the fuel on? The diaphragm can split, but sometimes fuel just leaks past the rivet in the middle!