nicknorman

February 10

9 hours ago, rogher said:

I saw a boat with the waste outlet installed on the roof.

A good idea, perhaps, if needing to pump out from the 'wrong' side, but the seal would need to be good to get that extra lift...

We have cabin top pump out fitting. Within the fitting is an O ring, so the seal is always good. It’s never been a problem.

February 9

Grade B cells. There is only grade A and grade B.

February 9

3 hours ago, blackrose said:

Ok thanks. Hopefully I'll have time to fit it next weekend. Yes it's a 712.

Do I need to get both batteries up to 100% on the Fogstar app? They're about 35% out of sync now. One's at about 85% and the other at 50%

I'm kind of regretting not buying a single 560ah Fogstar now. I didn't realise they'd go out of balance so readily. I've got a feeling it's just that the BMS is wrong and the batteries themselves aren't really that out of sync.

I think there might be some confusion between being “in balance” for cells in series (very important) vs being “in balance” for batteries in parallel (of zero consequence).

I think it’s likely that most of this SoC difference is to do with the BMS rather than an actual state, however it doesn’t matter. If you fully charge the batteries, by the time they are approaching fully charged they will in reality both be at more or less the same SoC (regardless of what the BMSs might say), and when the first battery is fully charged, the other battery will also be fully charged. Once the voltage is up around 14.2 or so, and the current has decreased to perhaps 5% of capacity, both batteries will fully charged.

This is an important point - cells in series don’t “automatically balance” (the BMS has to engineer that state), whereas batteries in parallel do automatically balance where it matters ie approaching high or low SoC.

2 hours ago, blackrose said:

I've spoken to Fogstar who say that the BMS disconnect can be used and can be relied on. I'm not going to do that regularly as I'd rather stop charging at 80% SoC to ensure longevity of the batteries. However, to calibrate the BMV and balance the batteries there seems to be no other option.

I don’t think you should be too shy of fully charging from time to time. As the other “faction” mentions, plenty of people do this and it’s fine. Although ultimately it shortens the battery life, the life is still very long and there isn’t an alternative to occasional (every few weeks) fully charging, if you want to know the SoC (ie to synchronise the Ah counting battery monitor).

I sometimes fully charge our batteries if eg I know we aren’t planning to move for a couple of days, it saves having to run the engine when moored, which I rather dislike. So I think the point is to try to avoid getting close to 100% (or 0%) as a matter of routine, but doing it occasionally when necessary is fine. What people struggle to get their heads around (due to decades of lead acid mindset) is that hitting 0% is not as bad as hitting 100%. But neither is in any way catastrophic.

February 8

2 hours ago, Onewheeler said:

It's a few years since we used one but they used to give ten minutes of pump time, so if you paused it you could get longer in real time. I often found that one ticket was enough for two boats, and always left it on pause for the next one in line.

Unfortunately with the new ones, the "Pause" expires after quite a short time, 3 minutes I think, so the days of arriving at a pumpout and finding it on pause with enough "free" time left, are over.

February 8

28 minutes ago, blackrose said:

Sorry another basic question:

I haven't fitted my BMV-702 monitor yet, but is there any way to know when I'm up to about 80% charged by looking at amps going into my 560ah of Fogstars from my 70A charger using my BEP shunt meter? If I switch off charging when the current drops to 56A (10% of my 560ah bank) does that mean I'm already at 90% SoC, or doesn't it work like that?

It doesn't really work like that. Best thing to do is to fully charge the Li, and then connect the BMV712 (Hopefully it is a 712, not a 702?) and set it to 100%. Or fit it, and sometime later fully charge the Li so that Li and the BMV will be at 100%

February 7

Just now, blackrose said:

Thanks, I hadn't seen that one. I was using this one from Google. They all seem to vary a bit.

Someone with lead acid mentality drew that one! Green for fully charged, amber below 50% -shock horror, and red below 20% PANIC!

In reality it should be green from 20 to 80, amber 80-90 and 20-10, and red below 10 and above 90. Or something like that!

February 7

9 minutes ago, TheBiscuits said:

Charles Sterling the younger told me exactly the same in person about the AMPS/Sterling LFP batteries. He pointed out that the BMS can either do it's job or not, and if it can't you should not be relying on it for emergency cutoff.

In fairness, it's mostly those who "rolled their own" from bare cells that suggest this, which is reasonable. Especially as the early adopters didn't have the range of simple BMS systems available.

However as I understand it, the ISO standard for installing Li batteries in small craft, requires the charging source to be controlled so it doesn’t try to charge a battery under inappropriate circumstances. It considers the BMS to be backup safety, as I do. Lots of unqualified people know better than the people who wrote the ISO, and good engineering design practices, but eventually they may come unstuck.

February 7

1 hour ago, Tacet said:

Did you connect the heating exchanger in series or parallel with the skin tank? If in series, there is a prospect of restricting the flow of coolant to the engine.

I connected mine to the calorifier circuit partly because the engine and heating circuits were in convenient proximity near the calorifier. And as the engine has twin thermostats, it can't be desperately over-cooled.

In series, but with a bypass that I could open if necessary. However it has never been necessary, including during hours of high rpm operation on the tidal Trent.

February 6

19 hours ago, JoeC said:

Is there a way to calculate what size heat exchanger is required? Apart from physical sizing, I see they come in the amount of plates it is built. Is there a kW heat rating?

I know what is required depends on boat length and how many and radiators installed but I don’t know how to calculate what is required.

Thanks

These plate heat exchangers do have a kw rating but it is misleading. Bear in mind that the rate of heat transfer is proportional to the temperature difference between the hot side and the cooler side. In a Combi boiler doing hot water, the incoming water is very cold, and the circulating boiler coolant is very hot (80c or so) thus there is a big temperature difference. Therefore a given size of heat exchanger transfers a lot of heat and thus has a high kw rating.

Use the same heat exchanger for central heating where the circulating CH water is already quite hot, and there is much less temperature difference and hence much less heat transfer. So you need a heat exchanger with a nominal rating much greater than you might at first think.

Put it another way, the bigger the heat exchanger the less difference there will be between the engine coolant and the radiators. Since the engine coolant on many engines including Betas is only around 75C, you want to drop as little temperature as possible across the heat exchanger, and therefore you want a big heat exchanger rated at what seems like far too much kw!

The bottom line is that the bigger the heat exchanger, the hotter the radiators will be and since the maximum temperature is only about the same as you would get with a diesel boiler, the rads can’t really be too hot. Diminishing returns though, so no point in being absolutely huge but I’d suggest around 30 plates would be a good compromise.

Incidentally, I would advise connecting the heat exchanger to the main flow to the skin tank (which is what I did). Lots of people do it to the calorifier circuit but IMO this is sub-optimal.

If you have another heat source such as a diesel heater, you can use 2 low opening pressure one way valves / flap valves, so that hot water from one source doesn’t back-flow into the other source and waste the heat.

February 6

39 minutes ago, blackrose said:

Can the single shunt on the BMV monitor 2 banks or were you talking about it monitoring the voltage of the starter battery?

You just get the voltage of the starter battery. The shunt is only connected to the domestic, therefore only domestic current, SoC etc.

February 6

4 minutes ago, blackrose said:

I have 2 battery monitors connected to my domestic batteries: a BEP 12v DC meter which has a shunt and gives me amps in/out of the domestic bank and voltage on the start, BT and domestic banks. It also does SoC but I ignore that as it drifts and isn't accurate. I also have a Smartgauge which gives me an accurate SoC during discharge.

I recently installed lithium domestic batteries and plan to fit a Victron BMV 712 which I'll use alongside the BEP meter.

The Smartgauge is now useless as the voltage algorithms it uses don't work with lithium so I'm wondering what to do with it?

Should I fit it to the BT batteries, start battery or to the hybrid sealed LA battery that I'm using between my domestic alternator and B2B charger/lithium bank?

Or should I just sell it?

The BMV712 can monitor the starter battery. I would just sell it. Or in my case I just gave it away to a good home!

February 6

Fitting out a narrowboat (all the interior woodwork etc) can be very expensive and cost a lot more than a bare hull / engine etc. The cheap boat has a very basic fit out, it’s mostly just empty space with some movable furniture, and what fittings there are look cheap and amateurish in the photos. The more expensive boat looks to have a better, more professional fit out. Although I think it’s a bit over-priced for a boat of that age and quality.

February 5

It can be difficult. I used a plastic scraper thing so as to try to avoid paint damage. A car trim removal tool might work.

i would recommend closed cell foam over sealant / butyl.

February 5

OK. One issue might be that they update the firmware in the device to add a new feature etc, but don't update the instruction manual!

February 5

Ah I see what you mean! I have two of these, unfortunately I am not near either of them, the nearest one being 85 miles away! Presuming this is not a synthetic image in some advertising blurb, I suspect it is either showing the setup menu or possibly the history menu. I can check at the weekend. In any case, it is not a display you would normally see in day to day operation.

February 5

It shows a number of things, you can scroll through them using the buttons on the display:

1/domestic battery voltage

2/ starter battery voltage

3/ current in/out of the battery

4/ Amp-hours taken out from the battery's fully charged state

5/ State of Charge as a percentage of capacity

6/ time to run to being completely flat at the present rate of discharge

Note that it is necessary to fully charge your batteries fairly often (weekly, or monthly if it is lithium batteries) in order to "synchronise" the meter to 100% State of Charge. And regarding 5/ and 6/, this is only accurate if you enter the actual battery capacity (not necessarily the capacity on the battery label) in the settings. Lead Acid batteries tend to lose capacity fairly quickly over time, lithium much less so. So for lead acid, if you don't update the capacity setting in the meter from time to time, it will mislead you into thinking you have more charge available than you actually do.

The meter also supports an App on a smartphone via Bluetooth, which is by far the easiest way to peruse the readings and adjust the settings.

It would be helpful to know the type of domestic battery you have (lead acid, or lithium) before giving further advice on the usefulness of these readings.

February 5

9 hours ago, Mac of Cygnet said:

To get back to the thread title, I have been wondering the same thing. At one time he seemed to moderate the Forums singlehanded, but he last visited on Jan 23, and last posted back in November. I have met Mike several times (he accommodated my boat outside his house twice for a few days), and hope he is OK.

I noticed this over a year ago so I asked him. Hopefully he won’t mind me saying that he had a sudden onset of a vision problem which made reading difficult/tiresome, hence much less active as a mod. Of course something else could have cropped up since then but that is what he told me at the time.

February 4

16 minutes ago, IanD said:

Ooh, nice bit of victim blaming there...

Some of the comments -- including the one he objected to -- had no useful content and were purely having a poke. As was yours about "why do we help these people?".

If you can't see the issue with posts like this from "long-standing members" to newcomers, I'm afraid you're part of the problem.

And before you have a dig at me for daring to point this out, you've both got form for doing this, as demonstrated multiple times... 😞

I’m confused. Are there two of me now?
You never fail to amuse by doing exactly what you criticise others for. You really don’t see it.

February 4

38 minutes ago, GDJones said:

These people? Would you like to elaborate?

Well, since you ask, I am referring to people who come on here not having contributed anything to the pool themselves, ask questions, and are very quick to get stroppy when someone posts something they don't like.

As an example, a couple of people made what you found rather irritating comments. You had two choices:

1) You could have simply ignored them in order to get the best out of the forum and not set an unpleaseant and therefore seemingly ungrateful tone, or

2) You could have vented your irritation straight away and without any restraint, making you come across as entitled and sulky. Which if you consider it dispassionately, is unlikely to encourage people to help you. You chose option 2. Own goal.

I have no idea what you are like in person, and the written word is very bad at communicating character, so perhaps you are a lovely person. But my impession so far is that I am not inclined to offer help.

February 4

Why do we try to help these people?

February 3

5 minutes ago, IanD said:

Indeed, but that's due to the "soft limiting" curve of an analogue regulator. For hours of charging before the voltage gets up that high (which I thought was what Mike was talking about), surely both could provide the same current?

In my experience a standard alternator starts reducing field current very early in the voltage rise. I never actually measured it but probably as low as 13.6v. What I did notice was a massive difference when I went to digital regulation but still had the LA batteries, max current right up to about 0.1v below regulated voltage. But as I said, not of consequence with Li where the voltage remains very low until the end. Who is Mike?

February 3

11 minutes ago, IanD said:

I'm pretty sure it can't, it's just a regulator down from battery voltage like the internal one -- once there's full battery voltage across the field coil (which either can provide, near enough) that's it.

No but what it can do is put full battery voltage across the rotor when eg the output voltage is 14.1v and the regulated voltage is 14.4v. An analogue regulator will already have started modulating the field voltage (and hence reducing the current) long before then.

February 3

9 minutes ago, Tony Brooks said:

It depends upon how deep you want to go, and I suspect the Alpha Pro is actually a computer, a bit like a car ECU, measuring things like temperature, voltage, and possibly current to compare with a digital map it contains. that map MIGHT (but probably not) be adjustable by the user. It might also measure RPM, so it does not run a full charge a idle and stall the engine.

In effect, the until keeps turning the rotor field current on and off (just like a normal regulator) while altering the mark space ratio. Long ons and short offs give a high magnetic strength in the rotor, short ons and low offs gives a weak magnetic strength in the rotor. The strength of the magnetic rotor field and the speed at which it is moving controls the alternator output voltage, so long ons = a high voltage and low ons = a lower voltage. It may pulse the higher voltage to minimise gassing as the Adverc does, and it may also time the phase of charge.

It probably just boost the voltage during the acceptance phase of charging, so a little more current is pushed into the batteries, just like the Sterling equivalent or the Adverc. It can't do anything during the initial bulk phase because the alternator is working flat out, so the high current automatically depresses the voltage by careful design.

The Alpha pro is reasonably configurable via Masterbus. It can do temperature throttling (if you add the optional alternator temperature sensor), throttling at low engine rpm to avoid stalling or belt slip, and you can set an overall percentage of maximum output, which I suppose would be useful for charging Li if you didn't want to do it properly and have an alternator temperatures sensor.

1 minute ago, IanD said:

It can't get any more current out of the alternator, but if the alternator has a temperature sensor on (recommended with LFP) and overheats (likely with LFP...) it can/should reduce charging current to protect it.

What it can do is get more out of the alternator when charging LA at a mid-charge point, when a traditional alternator would have entered the large "between bulk and absorption" zone where current falls off long before regulated voltage is reached, due to a traditional regulator having simple analogue first order regulation. ie increase the current when the voltage has risen a bit but still a long way from the regulated voltage. Which is mostly what eg an Adverc does. But for Li, this aspect is not useful because the Li keeps the voltage depressed, hence max alternator output, until the Li is very nearly fully charged.

February 3

33 minutes ago, Anonathy said:

Thanks! I've been trying to research how it all actually works at a fundamental level so I've got a better understanding of it but everything online just seems to be AI generated garbage that constantly contradicts itself 😑 I wasn't sure if it mattered which brush was which but that clears a lot up. I'll just cut the ring tab off so it's definitely not connecting. I should be fine with the rest, fingers crossed, thanks for your help it means a lot!

It doesn't matter which brush is which because the rotor windings just create an electro-magnetic. Once it is spinning round, the stator coils (in which the current is generated) don't know or care whether one particular part of the rotor was north or south pole. I can't remember if I cut off the ring tab off or not, but I did keep the bush and I bought a spare regulator / brush unit from ebay for about £20, just in case anything happened to my regulator and I had to revert to standard. But 4 years on it has of course never been used!

February 3

It doesn't really matter which way round you connect the wires to the brushes. The main thing is to ensure that the brushes are not also connected to anything in the alternator (apart from the rotor of course). So definitely remove the brass spacer thing. I would keep it somewhere safe just in case you ever want or need to revert to the conventional regulator.

The thing to bear in mind is that you are effectively turning a 9 diode machine into a 6 diode machine. ie the whole field diodes / D+ terminal bit is no longer relevant. I know that the Alpha Pro manual talks about a "D+ lamp" but they are just using that terminology to mean "alternator warning lamp" - rather confusingly!. So the warning lamp is connected to the Alpha Pro as per the manual, nothing is connected to the D+ on the alternator. You will need to connect the W to the regulator though and also the "reg on" to the ignition switch.

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