MoominPapa

Battery charging is a chemical reaction, and (most) chemical reactions get exponentially faster as the temperature increases. See: the Arrhenius equation. MP.

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.

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.

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.

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?

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.

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.

Not very original. A boat got several years out of the same strategy on Peterborough embankment. MP.

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.

That bloke looks just like me, only with less gut and more hair. Uncanny! MP.

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.

Will report back. The only sign I can see from here is a "men working" road sign on the towpath.

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.

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.

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.

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.

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.

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.

True, but I wouldn't like the fortunate few to suffer under a misapprehension. MP.

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.

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.

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.

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.

Randall understands..... https://xkcd.com/3038/