nicknorman
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Posts posted by nicknorman
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1 hour ago, Jen-in-Wellies said:
I have mentioned this before, but it has been a while, so time for a repeat. My dip stick is calibrated from the top of the tank to the diesel surface, rather than from the bottom of the tank filler neck to the diesel surface. That way, the stick doesn't have to be dipped to the bottom to find the volume of diesel in the tank.
To use it, I slowly lower the stick in till I see it just touch the surface, then read the volume from the stick. In my case, this is the litres needed to fill up to the top. Subtract from 225l and that gives the volume in the tank. This way means only a tiny drip of diesel is on the tip of the stick. The rest remains dry. In this picture, the tank is nearly full. Perhaps 30l from the the top.
Never thought of that before, it’s a great idea. Well it would be if you have a tank like yours. Our tank is under the engine with a long flexible and slightly curving filler pipe from gunnel to the tank. Which is why we have an electronic gauge! -
9 hours ago, dmr said:
There is also a difference between ignorance/poor workmanship, and making an informed decision to deviate from the rules.
I like to solder things, but I know how to solder. I have some 240volt and 12volt cables running next to each other under the gunnel (previous owner stuff), but I know they are there and would turn the 240 off before messing with the 12. We have a sink drain very close to the waterline, so the hose is all done correctly inside the boat etc etc.
My point was not to tell you that you must comply with the letter of the law. You are a big boy (so they say) and have a good dollop of experience and common sense. My point was that when giving advice to questioners on here, it is advisable to stick with best practice. Best practice being designed to cope with a low common denominator. Someone coming on here to ask questions is doing so because they don’t have the experience / competence to know the answers and we can’t know what other factors might be present to turn some minor bodgery into disaster.
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Even though failing to meet the ISOs and then stating that the boat is RCD/RCR compliant is most likely a very common issue that has probably never been prosecuted on canal boats, IMO people on the forum should not be advocating ignoring best practice as per the ISOs. It is irresponsible. Just because one has done something that contravenes the ISO and has “got away with it” - ie not had a problem as a result YET, does not give that experience any credence in a world with thousands of people and boats. Accidents usually happen due to a combination of unfavourable circumstances, and reducing safety margins in one seemingly trivial area can have unintended consequences when combined with other unanticipated factors.
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I think you might struggle to install it low enough so that shower water reaches the manifold by gravity in order to activate the pump. Most shower waste outlets are virtually on the baseplate.
And if it fails, sink water may flood the bathroom.
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20 minutes ago, Alan de Enfield said:
Maybe I'm totally misunderstanding, but that reads to a simpleton such as myself, that a (say) 600Ah bank could increase by :
2x 600 = 1200 degrees C per minute.
I doubt that is correct so could you show a calculation, as an example, of what that formula means in real life ?
Yes I am not clear about this and it is a bit late to get my head around it but anyway I see I mis-wrote. What was actually written was degC/min-Ah. I'll edit my earlier cockup.
But that little detail aside (!) my point was about the differences between LFP and the more energy-dense chemistries, around a factor of 100.
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I've recently gained access to British Standards online, giving me access to the latest version of "small craft - lithium-ion batteries. Most of it is pretty sensible and I am compliant eg with things like
"Charging sources shall be operated/controlled to meet the charging profile recommendations
provided by the lithium-ion battery or cell manufacturer."which I would take to mean that relying on the BMS cutoff to ensure safe charging, is not acceptable.
But relevant to the discussion about battery abuse, the BS makes reference to a paper "Investigating the Role of Energy Density in Thermal Runaway of Lithium-Ion Batteries with Accelerating Rate Calorimetry" which is freely available on line.
There is a graph of thermal runaways with different chemistries. First of all it is interesting that thermal runaway only really "takes off" when the temperature gets over 200C (or 180 for LiCoO2). Which is quite hot. But once thermal runaway is in full swing, LiFePO4 suffers a rate of (adiabatic) temperature rise of around 2 or 3 degC per minute-amphour. Whereas the likes of LiCoO2 is around 400 and NMC around 170. So there is a massive difference between the rate of energy released by LiFePO4 vs these other chemistries. I know that we knew that, but it's good to see the hard data.-
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2 hours ago, Ronaldo47 said:
Our 20 year old electric bikes use SLA batteries. We used to leave the chargers plugged in when not in use, as the chargers would provide a trickle charge once fully charged. One of the chargers developed a fault, outputting more than 50V instead of the circa 42V charging voltage specified for the 3 x 12V SLAs. It must have been like this for the several days that the bike was not in use, and when it was next needed, the battery box was quite hot to the touch. Inspection showed that the cases of the batteries (Varta I think) had swelled significantly, making it difficult to remove them, but no liquid was lost, and they would not hold charge. The charger was the one originally supplied with the bike, and after buying a fresh set of batteries and a new charger, I now use a plug-in timer where you can set your own number of ON/OFF sequences, and programmed it to charge in three periods of 2 hours, well spaced apart so that the charger does not operate continuously. We normally only do short trips, and 2 hours is normally long enough to fully recharge.
A lithium battery subjected to the same period of severe overcharge would no doubt have have resulted in a very different outcome. The chargers supplied by the bike company are also used for their current models that use 36V lithium batteries, but having experienced the safe behaviour of SLA batteries when the charger malfunctions, I am not inclined to swap our SLA batteries for lithium ones.
What very different outcome do you envisage? For a LiFePO4 battery it would have been a much better outcome- the BMS would have isolated the battery with no damage occurring. This is the thing with Li batteries, there are two levels of protection, the charger’s regulation AND the BMS. With lead acid there is only one.But even with the double failure of charge regulation and BMS, chances are the LiFePO4 battery would have suffered a similar fate to the LA - been badly damaged. But not gone on fire nor risked spraying boiling sulphuric acid around.
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Oh dear! Can’t say I’m too surprised though.
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5 hours ago, Bargebuilder said:
So no actual data or evidence, just hearsay and someone’s opinion. -
I would strongly recommend reviewing the BSS inspection criteria before starting. https://www.boatsafetyscheme.org/media/299451/bss-complete-ecps-private-boat-public-version-2023.pdf
For example the boatyard is quite correct, the starter must go through the engine battery isolator ditto the alternator. It is not that one needs to isolate the battery from the engine, it is the other way round ie isolate the engine electrics from the battery (source of a lot of energy). If someone is working on the engine they don’t want an accidental touch of eg a spanner on the starter stud and the engine casing, to short circuit the battery, melt the spanner and spray molten metal in their eyes.If you just rewire it your way, it may fail the next BSS check and you would have to redo it.
Most boats have 2 isolator switches, one for the domestic and one for the engine batteries.
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12 minutes ago, MoominPapa said:
There's a subtle misunderstanding here. It's not that boat insurance policies don't cover third party liabilities (they have to, in law) , it's that they don't cover third party liabilities if the insurer breaks the contract of insurance. Examples may make this easier to understand.
If I get into my comprehensively insured car pissed as a fart, set off down the M1 and crash into another car, the insurance company will not pay out for the damage to my car, even though it's comprehensively insured. That's because the accident was caused by my negligence and there's a clause in the insurance policy that covers that eventuality. It will, however, still have to pay out for the damage to the car I hit, because the road traffic act says it must.
If my boat sinks because I haven't maintained it and there's a rust hole in the gas locker floor, the insurance company will similarly not pay out, because there's a clause in the policy that says the boat must be maintained and it wasn't.. The difference to the car example is that if the sunken boat leaks the contents of the diesel tank and strips the blacking off the waterlines of marina full of boats, the same clause atill renders the policy void, and the insurance company will not pay for the third party owners of those boats to get them re-blacked.
The first example is hypothetical, the second definitely happened to me (I was one of the third parties).
The clause in the British Waterways act analogous to the one in the road traffic act that says BW and it's successors can insist on third party insurance is the same as the one in the road traffic act, except that it misses out the stipulation that third party cover must be unconditional. To the best of my knowledge
all marine insurance policies take advantage of this. When I was affected it was certainly the case that the sunken boat's insurance did, and I asked my insurers and the same was true of them.
MP.
Interesting. It’s hard to think of a reason why a boat would sink that didn’t involve some negligence of the owner. Perhaps this is why boat insurance is so cheap! -
Surely it is mandatory to have 3rd party insurance to get a CRT licence?
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1 hour ago, Bargebuilder said:
The concerns may be, rightly or wrongly, that the above dangers can be almost eliminated by certain actions by the boats owner/crew, whereas there are reports of modern electric vehicles spontaneously combusting whilst sitting on the driveway, not even on charge, and in no way avoidable by the owner.
Yes but the REALLY KEY POINT is that the cars have a completely different and more volatile battery chemistry.
1 hour ago, Alan de Enfield said:The difference being (possibly) that all of those are checked on the BSS examination - if - the examiner does his job properly.
Yes they are checked, but there are still fires…
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But how many boats have gone on fire due to their LiFePO4 batteries catching fire spontaneously? Vs how many have gone on fire from solid fuel stove installations, curtains over gas stoves, gas leaks, petrol fumes etc?
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There are a few possible different technologies for flame failure detection, one is a thermocouple that gets heated, a small voltage is produced that keeps the gas valve open. It takes a few seconds for the thing to be heated enough. If the flame isn’t really playing on the probe, or the probe is generally “tired” then it can be slow or malfunction. As mentioned, if the flame isn’t playing on the probe this is usually because something is upsetting the flow of gas and/or air. Dirt or corrosion in the jet and burner.
Another technology is a flame conductivity check - an electrode is bathed in the flame which also reaches the metal of the burner. The flame is a plasma which is highly conductive and the system detects low resistance and keeps the gas valve open. This type of system needs a power supply (battery or supply from the boat) , whereas the first I mentioned doesn’t. The latter generally uses the sparking (lighting) electrode as the flame probe, and the flame shape is more critical than the thermocouple as the flame has to touch both the electrode and the burner metal. But again, dirt and corrosion in the jet and burner are usually at the root of the problem.
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2 hours ago, AJLElectronics said:
Thank you. I put in what I assumed is impossible, Bidford to Fradley and as expected got a lot of fails. However there was one which failed for a reason that makes no contextual sense...
Possible route: River Avon - Warwickshire (Upper Avon Navigation) -- River Avon - Warwickshire (Lower Avon Navigation) -- River Severn (main river - Worcester to Gloucester) -- River Severn (main river - Stourport to Worcester) -- Staffordshire and Worcestershire Canal (Stourport Basins: Broad Route) -- Staffordshire and Worcestershire Canal (Stourport Basins: Narrow Route) -- Staffordshire and Worcestershire Canal (Main Line: Stourport to Stourton) -- Staffordshire and Worcestershire Canal (Main Line: Stourton to Aldersley) -- Staffordshire and Worcestershire Canal (Main Line: Aldersley to Autherley) -- Staffordshire and Worcestershire Canal (Main Line: Autherley to Great Haywood) -- Trent and Mersey Canal (Main Line - Fradley to Great Haywood)
The Staffordshire and Worcestershire Canal (Stourport Basins: Broad Route) from Severn - Stourport Broad Locks Entrance is on the list of optional waterways for the following reason: narrow boats should normally use the narrow locks
If you want to plan a route along this waterway, turn it on from the "Exclusions" tab in your preferences
You can lock up from the river to Stourport basin using either the wide locks or the narrow ones. They are in parallel. Narrowboats should use the narrow locks to save water. But the Staffs and Worc after Stourport basin is narrow only so you can’t go beyond the basin.
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1 hour ago, Gybe Ho said:
When you assembled your lithium bank did you measure the internal resistance of your new cells and use the readings to average out the IR in your 3P4S cell matrix?
p.s. I do not know how to measure cell IR but I have read that hardcore lithium bank DIY assemblers mix & match cells according to IR results.
No I didn’t. The IR is very small and I can’t see that there’s much variation. Probably more variation in the interconnect / connection resistances. And also IR is made up of at least a couple of things, one being the ohmic resistance and the other being the “chemical resistance” ie the reaction rate. Even if the former is fairly static, the latter won’t be - varying with temperature, and non-linearly with load.
Possibly it might be relevant if one was operating the cells at 1C rates or higher, but the max I get to is about 0.35C and that only for short periods (electric kettle), so I can’t see that slight variations in IR are going to be consequential.
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At a loose end on the boat today in the marina so I thought I’d take the battery up to 100% again to see how the balancing is. And also to demonstrate that balancing is only appropriate right at the top. The following pics taken of the BMS display during the very late stage of charging. In the first pic you can see the cell voltage order is 1,2,3,4
And so you might think that cell 4 needs a bit taking out of it. Also of note is that the battery is now 99.7% SoC and yet the voltage is not that high yet - see other screens from BMS.The last bit of voltage gives very little extra charge…
But right at the end, the cell voltage order is quite different at 4,2,3,1. So the lowest cell from before is now the highest, and vice versa.
So if anything cell 1 needs a bit taking out, although the split of 11mV is below my threshold for activating balancing.
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8 minutes ago, Gybe Ho said:Narrowboaters will no doubt appreciate the following advice from His Majesty's Government...
Well, government docs intended for the masses have to be specific and unambiguous. If they didn’t define “battery” some people would think it was a posh name for a fish and chip shop.-
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9 hours ago, blackrose said:
And you sound like another one with a large mouth if I'm being honest.
There's no more a "typical wide beam attitude" than a typical narrow boat attitude. That's just a figment of your own prejudice and bigotry.
So you intentionally insulted someone because you didn't like their boat and then you got offended when they returned the favour? Can you spot the hypocrisy?
There are plenty of instances of conflict and insults thrown around between owners of lots of different types of boats including narrow boat vs narrow boat. But if you really want to try to negatively characterise people on the basis of the boats they own it really says much more about you than it does about them.
It goes with the territory of being a human being evolved from cavemen when anyone not in your clan was the enemy as they competed for your food and women. Some people struggle to move on from their ancient ancestors! We got the same kind of prejudice about our choice of boat builder, even though he made great boats and I have never encountered an “up themselves” owner.-
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44 minutes ago, GUMPY said:
I still don't understand why anybody would use those posts when there is a perfectly good M8 bolt that fits M8 lugs perfectly.
Exactly what I was thinking.
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20 minutes ago, Gybe Ho said:
Thanks. This suggests it is possible to get through half the adjustment range over a 2 or 3 year period between haulouts. All depending on cumulative prop revolutions and not overtightening the pusher.
Possible yes, but not normally unless very high usage. I’d say more like 10 years between repacking as an average with moderate use. I think you over-analysed my thinking a bit! If you have 2 pack blacking as we do, the boat comes out every 5 or 6 years. But my point was really that repacking is a trivial expense unless you also have to get the boat out of the water to do it.
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58 minutes ago, Gybe Ho said:
Ok thanks now I can picture the setup. Does this sound right?
- Once a day turn the greaser.
- A few times a season refill with grease. The frequency of which will be dependent on the degree of compression applied by the packer and the age of the packing wadding.
- Very occasionally nip up the packing adjuster to apply more compression on the wadding as needed.
- Exceptionally replace the packing wadding.
Having got that sorted in my head, I hope, my prelaunch obligations are (i) check the greaser is not empty (ii) inspect the packing adjuster to ensure it is not at its limit.
Happy to edit this post if I am using the wrong names for the parts involved.
Yes. Be aware that the packing comes in different sizes and you can get graphite-loaded or normal. Check the position of the pusher/stud length protruding and make a judgement call as to whether to repack. Since it is much easier to do this out of the water, and cheap, I’d suggest doing it anyway if it’s more than about 1/2 worn.
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1 minute ago, dmr said:
I posted a bit more info that might be relevent, but it got added to my previous post rather than as a separate post.
This is a sort of forum bug.
I make a post, somebody gives a greeny but does not reply, I make another post which just gets added to the previous post, it might be utter rubbish and no longer deserve that greeny 😀😀
No I don’t think it was rubbish, the point about the castellated nut (or its absence) was cogent. I think the point is to try to avoid the nut being able to rotate a bit, which could cause fretting especially in an application where the direction of rotation / load reverses. Whether the tangs are bent circumferentially or radially is not significant since the bending is only to stop the pin from sliding out and there is no significant force trying to make that happen - in fact the offset mass of the pin is only going to pull it in when rotated fast.
But locking things subject to heavy load only by means of a split pin isn’t great design, the primary means should be friction and bolt stretching, which admittedly is tricky with a fairly short “bolt” and dissimilar metals (with different thermal expansion coefficients). But fortunately the tapered shaft adds plenty of friction!
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Tank senders
in Boat Equipment
Posted · Edited by nicknorman
We have the MCS fuel gauge, top entry onto the tank. It does rely on not losing any air pressure ever, but of course it does, slightly. I have to pump it up about once a year but it only takes a few minutes.
In the OP’s case I have no idea what sort of input the Cerbo needs. The sensor for the MCS device is a pressure sensor which is a bridge, so the output would be very small and some amplification would likely be needed to get it into a range suitable for the Cerbo. Or just steal the principle and find a low pressure sensor with a suitable output, the rest is just plumbing.
https://www.mcsboatproducts.co.uk/our-products/fuel
Edit: looks like they’ve changed the design. Ours had a Schroeder air valve to top the pressure up in the down-pointing pipe, and it was much narrower than the type shown.