nicknorman

I think the problem is that JBD sell the BMS and obviously the end user needs to be able to configure it. They are probably not fussed that their end user is Fogstar whilst Fogstar's end user is the hapless boater. That is Fogstar's problem!

I used to be a Mastervolt fan, and we still have Mastervolt kit. But if it died I’d go for Victron for a few reasons. The kit seems well built and is reliable. They have a lot of “open source” information which allows connectivity with other stuff. Their Apps and Bluetooth connectivity are pretty good. They have a good concept of an overall system as opposed to individual items, eg their Venus Gx /Cerbus GX systems. No other manufacturer offers all that. But it depends on what you want. In my caravan I have a stand alone sunshine solar inverter. It is quite good really, and cheap. But if you want a Combi inverter charger, battery monitor, solar controller etc all talking to each other and to an App, Victron has cornered the market. As to the going on fire thing, hard to quantify but some cheap Chinese stuff is fine, some other cheap Chinese stuff is dangerous, hard to know which is which and that is the problem.

I’d say blacking the baseplate is money better spent than on zinc priming.

The chip I use also has a phase input, it’s used for various things including rpm awareness, keeping any tacho drive alive (by not reducing field current too much) and it’s state machine ie when power is applied to the “turn on” terminal, just a small field current is supplied until rpm is sensed and only then is full field current (or whatever the programmed limit is ) authorised. I did see the circuit, it was very complicated with lots of analogue stuff, op amps etc. as well as the microcontroller. Seemed a huge lot of hassle when you could get a single chip device to do all that and more for £8, hence my strategy (mainly because I’m not great at analogue electronics) On the ripple thing, I find there isn’t any. The BMS chip reads cell voltages to 3 decimal places and the sample time is tiny compared to alternator frequency. There is no detectable ripple. Which is perhaps odd but then again the Combi has chunky electrolytics. But probably mainly because the BMS AtoD cell voltage inputs have 0.1uF and 10k ohm time constant, which is 0.001 seconds / 1000hz. The alternator chip has similar (no time constant specified, it just says “low pass filter) and one needs to remember that the inductance of the field winding means the field current can’t change quickly and so one might as well have a similar time constant on the voltage measurement.

Yes I think the BMV relay turning off the wakespeed would be a fairly effective system. You would lose “float” ie keeping the alternator working at a reduced voltage, but that is not a showstopper. You would just have a switch to break the signal, ie stop the alternator shutting down, when you wanted to charge to 100% to sync the BMV

Who knows what the BSS might end up with! They don’t seem particularly well up on the issues. But I would have thought your proposal was a reasonable compromise. The batteries would not be directly in parallel. The issue originates from various Li manufacturers who say “do not mix with batteries of a different chemistry” as an arse covering comment in the installation manuals.

There is talk in the Wakespeed manuals about the use of avalanche diodes (similar idea to zener diodes) on modern alternators. Our Iskra 12v 175A has such diodes. This should result in no more than about 36v transient from a full output load dump. Still, 36v is quite a lot hence why I fitted the tranzorb bank. Or Sterling do a similar thing for more £££s. I would caution against the hybrid system (lead acid in parallel) since it seems that for some reason, BSS are dead against it and at some point in the future this might become problematic.

Wakespeed advertise compatibility with the Cerbo GX which is one of Victron’s “data concentrator” (aka system integrator) devices along with the Venus etc. so I would hazard a guess that with a BMV712 connected to the Cerbo connected to the Wakespeed, you could set it up to stop charging at a specified SoC. You would need some means to fully charge to 100% from time to time, to resynchronise the BMV.

Well you can of course do PID with analogue electronics, it’s just so much easier to do it with digital. The chip I use only starts to decrease current when within about 100mV whereas a conventional alternator regular the same thing is more like 0.5v or maybe more. I would imagine that both the wakespeed and Alpha Pro have digital regulation at their hearts.

Might be worth looking at a Victron smart shunt and the Venus GX or raspberry pi equivalent. Victron smart shunt sends SoC data to the Venus and that can be set to operate a volt-free relay. I don’t know if the wakespeed has a digital input to switch from charge to float, but it’s quite clever so probably does. And maybe it understands the victron VE.Direct protocol, not sure. If so you wouldn’t need the Venus. Incidentally I made a load dump absorber with 12 fat Tranzorb diodes, as a fall back if my battery emergency disconnect went open circuit for some reason. I have spare PCBs if you are interested (supply your own tranzorbs).

No. At 80% the battery voltage curve is still very flat, and there is some hysteresis and effect of previous activity (charge or discharge at varying currents). However one could argue that you don’t need to stop charging at a specified SoC. I know people talk about not going over 80% etc but IMO this is probably overkill. The thing is to avoid “going up the knee” so by setting a charge voltage of say 13.7v you will get to 90-something percent without stressing the batteries. I think! It’s got to be massively better than charging until the BMS emergency disconnect triggers. The only thing is that if you have conventional analogue “soft” regulation with a limiting voltage of 13.7, the current will be falling off for a long time as the voltage creeps slowly up, which rather defeats the object. You want a charge source with PID regulation so that the current doesn’t start to decrease until 0.1v or so short of the limit. Pretty difficult to do with analogue.

In my opinion float for Li batteries means an accurately set charge voltage such that no current flows into the battery, but when a load is turned the charge source provides most of the current, rather than it coming from the batteries. I suppose it depends on how often you use a big load when cruising, but in our case we have electric kettle, washing machine etc that can be fed from the alternator after the batteries have gone to float. Float, for Li, is certainly not trickle charging.

I think they are good. No direct experience but reputationally ok.

I have to admit my sins, it is cathartic. Before we got Telemachus we used to borrow my mate’s boat for a couple of weeks a year, for about 15 years. And of course Rule 1 of descending a lock is always to keep an eye on position of boat vs cill. I knew that since I was a kid. Only a fool would catch the rudder on the cill. Except on this one occasion I did. Banbury lock, I still remember. Rudder lifted up, but worse it got lifted up because the skeg got bent up. Mucho embarrassing! I had to pay for a dry docking to fix it. Served me right! Although of course if it had been a Hudson, it wouldn’t have bent the skeg!

Condensation.

Fewer blue signs and lower executive pay. Surely if it’s been beaten to death many times that means it’s likely to be correct? But actually the main thing is the dissolution of the primary asset - the skilled people and the plant. And the switch to near sole reliance on contractors. A model that had been discredited at least 10 years previously. The better model being the retention of the majority of skill and plant, with the use of contractors limited to massaging the peaks and troughs of demand.

it is annoying. But unfortunately IMO CRT have historically not spent their government money wisely. And the government have noticed. And so they have reduced the payments as punishment. And we suffer and have to make up the shortfall in order to minimise the decline in services and navigation infrastructure.

yes the removal of services is a concern. However there are still quite a lot around our way and one should bear in mind that in some cases, CRT pay marinas to provide the service eg when Peel’s Wharf was abandoned, CRT made an agreement with Fazeley Mill Marina to provide elsan, water and rubbish to boaters FOC. From Peel’s wharf and apart from FMM there is still Fradley and Bradley Green, both within a days cruise. Atherstone top and Gt Haywood a couple of days. And up B&F whilst it is a bit more limited, there is the pound below D&D, then Cuckoo Wharf, then Cambrian Basin. So that doesn’t seem too bad to me. Compared to our excursions onto EA waters this year (Nene and Gt Ouse) where rubbish and elsan were extremely limited.

I think we should remember that currently, most boats with a home mooring pay more to CRT than boats without a home mooring. And as a generalisation boats without a home mooring usually generate more CRT direct costs - more rubbish disposal, more elsan disposal, more tap water, than someone with a home mooring. Well, a home mooring in a marina anyway. I am thinking of the 10% of mooring fees that most marinas have to pay to CRT. So I pay about 25% more to CRT - directly and indirectly - than someone without a home mooring. This seems an obvious anomaly.

Video will definitely help. Picture worth 1000 words etc. Often when people (with the best of intentions) try to describe something, they know exactly what they mean. But other people reading it, can form a different interpretation!

If the point of rotation is more or less at the top, which it sounds like from your description, then the rudder has probably been lifted out of the bottom cup (on the skeg) and is dangling by the top bearing. Typically caused by catching it on a lock cill going down, or on some underwater obstruction. Rudder would need to be lifted a bit and the bottom relocated into the cup on the skeg. Which is possible to do in the water, but not easily as it is very heavy (as you’ve noticed!) and you can’t see what you’re doing. If you can find some clear water, have a look down the weed hatch to see if the rudder is moving sideways at the bottom.

It depends on the engine it’s fitted to. And there could well be some variation according to when the engine was built, whether it had the TP from new etc.

Yes just because they showed 13v after a period of no load, doesn’t mean they are ok. Knackered batteries can often behave like good batteries that are 100th the nominal size, But first perhaps check that they are being charged properly in case there is some issue with the charging. What means do you have for monitoring battery current and voltage?

Not answering your question but the zanussi works fine on our Mastervolt 2500 Combi. There is no flickering of the lights etc - which suggests it isn’t struggling. I mean, how hard can it be to turn a small washing machine drum? So I would have thought something else other than sheer max current. Do you have power saving modes disabled? It would certainly be interesting to put a dual channel scope on it, to catch the voltage and current (current by means of voltage across a small series resistor). Possibly just some momentary voltage glitch is upsetting the motor controller in the zanussi.

So what you are saying is to use pipe that is imperial in diameter but metric in length. Good stuff if you can find it. By the way that was a joke