MoominPapa
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Posts posted by MoominPapa
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Grants lock bottom gate was warped and only just opening enough to get a boat past when we went south last week and when we returned a couple of days ago. It's possible someone go a bit too enthusiastic trying to push a slightly fat boat past, or had too many people leaning on the balance beam to get the last half inch of opening. Or someone failed to stop whilst entering the lock when full and just hit it. Given the level of fuckwittery I've witnessed going to Oxford and back, nothing would surprise me.
If this one doesn't get you, Pigeon Lock probably will. One top paddle in action; takes 30 minutes to make a level.
The pound between Slat Mill and Bourton locks that was empty last week is still low, probably because the cill at Bourton is basically blown and the bottom gates leak so much that it still leaks down fast, even with the blown cill filling it.
On the other hand, ignore the closure notice for Duke's cut. The top paddle is US, but the top gate leaks so much that it makes a perfect level in 15 minutes. Twice as fast as Pigeon!
MP.
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Melaleuca is at our new mooring at Shuckborough, which is a bit short of depth. We got the boat last night and found her sitting pretty much flat on the mud with the level maybe four inches lower than the tide mark on the hull. Hoping they fix this otherwise we're going to need a snatch to get off the mud into the channel. Unexplained low pounds does seem to be a bit of an epidemic. I suspect the number of people on the ground sorting stuff out is much reduced.
MP.
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1 hour ago, Mike Tee said:
Between Minworth bottom lock and Curdworth top, the level was down at least a foot yesterday. Basically tickover all the way and the only place I could get in close enough to moor was on the end of the top lock bollards. Naughty but by the time we arrived I'd had enough!
Again? End of Feb, we were stuck for a day on the shallow lump downstream of Curdworth tunnel and then had to spend an hour running water down Curdworth top lock to get enough in the next pound to grind under the bridge. CRT told us the problem was a pump down, but nobody here can see how that pound is supplied by a pump. Looks like the problem is ongoing.
MP.
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6 minutes ago, TheBiscuits said:
Although I should specify it was the Sterling B2B which is rated at what it takes from the system, delivering around 45 amps of charge. I understand the Renogy 60A delivers 60A so probably takes 90A and would cook a 100A alternator in fairly short order.
Those are really dire efficiency figures for a DC-DC converter. Better than 90% is easily attainable.
MP.
ETA of course you're talking current and not power, if the B2B lets the alternator output run up to 16V or 17V and is charging at 13.6 then it's doing pretty well. Has anyone measured that?
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5 hours ago, StephenA said:
I see a lot of posts about how charging LiFePO can burn out the alternator as it will take the max output of the alternator for as long as it needs it and they're not designed for that sort of load.
Which is fine - but what is the sensible long term max load you can put on say a Lucas 70A alternator without it burning out?
In my experience a 70A A127 can handle max load indefinitely* if it (and therefore its fan) is spinning fast enough and it's in reasonably cool ambient air.
*longer that the time taken to reach thermal equilibrium. If it's not gone pop by the time it has stopped getting hotter, the time is no longer important, except possibly for second-order reliability effects.
Conversely, and again from experience, there's a reason which the electric windscreen demist in Fords has a timer. If you don't have a functional heater and keep switching the demist back on when it turns of so that you can see where you are going, the alternator will go supernova.
MP.
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53 minutes ago, ditchcrawler said:
Didn't @nicknorman have fun down there
We got stuck in a 2'10" deep boat with the pound on weir last month. The boat was pivoting on the stone at the stern so it was fairly easy to slew the bow around and get crew off to dump another lock full of water down to lift the boat. It's mostly OK, but if you're deep and pick the wrong line it will still bite.
MP.
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Not very original. A boat got several years out of the same strategy on Peterborough embankment.
MP.
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As a data point, my home system: 6kWp, 60% south facing 40% west facing, has been doing 15-20 kWh during the nearly full sun days this week. Based on that, I tend not to believe the top line of the table and I'm dubious about the second, but the others look pretty feasible.
MP.
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That bloke looks just like me, only with less gut and more hair. Uncanny!
MP.
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14 hours ago, nicknorman said:
I’d be interested to know if the sheet is still in the water, whether there are now any warning signs for boaters.Looks pretty much as you described it. There are "men working" signs either side on the towpath and orange buoys next to them in the water, but no explicit signs. The sheet is still flapping about in the water; one end is weighted down with rocks on the offside bank. Rothens boats are on site, but no sign of Rothens doozers. Pound stayed up fine overnight, so the culvert leak may be fixed.
MP.
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8 minutes ago, nicknorman said:
I’d be interested to know if the sheet is still in the water, whether there are now any warning signs for boaters.Will report back. The only sign I can see from here is a "men working" road sign on the towpath.
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36 minutes ago, nicknorman said:
Surprising. We went from Fazelely to Star City last Tuesday, and back down again on Wednesday. All levels were normal. Just some Rothen guys doing something silly above lock 7 - ie installing a huge sheet of plastic right across the canal on the bottom, to seal a leak into a culvert. Well that was the plan, but the plastic sheet was floating to the surface probably buoyed up by methane from the rotting vegetation on the bottom. When we went up they advised us to pass in neutral to avoid getting the huge sheet round the prop. But on the way down there was nobody there and no notices, and as we passed (in neutral) we could see the huge plastic sheet lurking just below the surface. I did suggest to CRT that it wasn't a great idea and perhaps there should at the very least be some warning notices, but I don't think they "got it".
Those works are just in front of us. The sheet is visible on the offside bank, so that may have it place now. I shall be sure to pass in neutral if there's any water left in the pound to float in in the morning. Thanks for the heads-up.
MP.
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2 hours ago, David Mack said:
There is a backpump up Garrison and Camp Hill, although I don't know how much it is used (or even whether it is still in use). But if it has failed that should result in more water not less for the Fazeley cut.
Maybe I've been bullshitted.
Anyway, the activity running water down Minworth did yield a marginal increase in levels and I managed to redistribute enough mud to be able to slither over the remainder and get to Curdworth top lock without further problems. The long pound between Curdworth Lock 1 and Curdworth Lock 2 was 18 inches down. We had to fill it up to about 8 inches down to be able to grind under the A446 bridge, which definitely reversed the level increase in the Minworth-Curdworth pound. Since we've seen only one other moving boat in the last week, and he will be away up Minworth long since, I didn't feel too bad.
After the top pound, the rest of Curdworth is fine (so far). Moored for the night between 6&7.
MP.
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6 minutes ago, David Mack said:
Surely this section is fed by water from Perry Bar, Aston and Garrison locks. So why should any pumping be involved?
I'm just repeating what I was told.
There are definitely pumps at the top of the Garrison flight, so maybe the problem is water supply in Birmingham, which has resulted in less water coming down those flights. The bywashes around the bottom three locks at Aston are almost completely blocked and the pounds are flooding the towpath, so that's one source of water lost for a start.
MP.
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The entire 3 miles pound is down a foot or so, and pounds at Curdworth are also low because there's no supply from the top.
More specifically: Melaleuca is sat on the ridge outside Curdworth tunnel and going nowhere until the level goes up. The canal is therefore blocked unless another boat turns up and can do a snatch.
CRT are aware: apparently they have a pump down which is the cause of the problem. They are allegedly running water down Minworth now, but it could be a day before there's a significant improvement.
MP.
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13 minutes ago, Alan de Enfield said:
What the relevant ISO standard says :
In normal operation, different battery chemistries should not be connected in parallel or in series.
Combining/automated charging relays should not be used between systems using different chemistries.Does that read as if there should not be 'different chemistry' batteries anywhere in the system between the charge source and the Lithium batteries ?
I don't think it necessarily reads that way. Ignoring the series aspect (that's obviously a crazy thing to do) it says that different chemistrys should not be connected in parallel, either permanently or via a relay. Connecting them via a diode is not connecting them in parallel by that definition. As an example, a possible failure mode of parallel operation is the rapid discharge of the high energy, low resistance lithium pack into a faulty LA buffer battery. The blocking diode precludes that.
MP.
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1 hour ago, nicknorman said:
But you do say "I expect to replace the diode pack every few years". You are capable of doing that, many people aren't. So for most people that would be a replacement alternator every few years.
And what about the BMS disconnect / alternator transient thing? Or do you have the (frowned upon by the establishment) lead acid battery in parallel?
I have a lead-acid battery (the engine start battery) permanently connected to the alternator and the lithium pack is charged from that circuit via a BMS-controlled contactor and a high current Schotky diode which stops the lithium pack from back-feeding the engine system. I'm not sure if that counts as frowned-upon parallelisation, or not.
In my experience alternator life in boats is less than (say) in cars. They work much harder under all circumstances. I'm happy with the lifetime I achieve, and A127 alternators are cheap-as-chips. It may be possible to achieve alternator life comparable to that in car by installing a larger or more heavy duty alternator and de-rating it. I doubt doing that would reduce lifetime costs.
MP.
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11 hours ago, IanD said:
Unfortunately for most boaters, those two things that make your system work -- well ventilated and running alternator at high rpm -- don't apply to them... 😞
True, but I wouldn't like the fortunate few to suffer under a misapprehension.
MP.
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It is not a given that running an alternator at 100% of rated output will cook it. I charge a lithium bank with a 75A A127 and it runs at full capacity for hours. What allows it to do this without burning out is two things. 1) It's in a well ventilated engine room, not below deck boards. 2) It's run at high speed so that the fan moves plenty of air. In my case the speed is achieved buy running the drive belt on the outer circumference of the engine flywheel.
I expect to replace the diode pack every few years, but otherwise the alternator lives a long and happy life.
MP.
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1 hour ago, matty40s said:
Expect Ireland as a whole to be several miles nearer to Wales after Friday lunchtime.
Lol. I wonder if the ferry prices will drop?
The forecast peak gusts here are going in the right direction and now less (just) than 100 km/h.
MP.
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1 hour ago, Jonny P said:
Although if you take it at face value it didn’t apply a week ago.It reads to me it’s an easement of the situation as work progresses.
In this case, it's the lack of advance notice that's caused the problem. If I'd know that this was going to happen I could have made plans to use the T&M as an alternative to the Shropshire Union, which was due to reopen at Woodseaves on the 8th, now postponed until the 24th and with such a low probability of delivery that I can't make plans until I see it's actually open.
MP.
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CRT stoppages notices drive me spare. Having that information a week ago would have been really useful to me.
Stoppage reports either omit useful information, are out-of-date, or just plain lies.
MP.
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Rich on Roach the fuelboat covers that manor.
MP.
Lithium High Temperature warning
in Boat Building & Maintenance
Posted
Battery charging is a chemical reaction, and (most) chemical reactions get exponentially faster as the temperature increases. See: the Arrhenius equation.
MP.