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IanD

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Everything posted by IanD

  1. As a serious question, have you ever had to actually design an SMPS including analysing how the control loops (voltage/current) work and are kept stable? I can assure you that though the current (inductor and/or input/output) can be measured -- and used as a secondary factor in the control algorithms, for example feedforward compensation -- there is no way to directly adjust current by adjusting duty cycle, which is the fundamental way the loops work. Changing the switch duty cycle changes the voltage conversion ratio, and the load current then changes as a result depending on SMPS output impedance, source output impedance and load input resistance. This is the case for all the standard hard-switched SMPS topologies like boost (step-up), buck (step-down) and buck-boost (step up or down). Soft-switched/resonant converters like LLC are a whole different kettle of fish and much harder to analyse and control, because the output voltage doesn't just depend on duty cycle, but these are very rarely used because they're a total PITA to design. DAMHIK... πŸ˜‰
  2. Your last paragraph is unfortunately wrong... πŸ˜‰ All SMPS -- buck, boost, or buck-boost -- produce an output voltage (low impedance) which depends on the input voltage and the switching duty cycle. So if you drive a low impedance load like a battery, a small change in duty cycle causes a big change in output current, which can of course be sensed by the controller -- but this then changes the duty cycle which changes the output voltage, the current then changes as a consequence of this.
  3. All of which is true, if that's how you use your ebike. If like me you go out for an hour's ride at lunchtime, an electric bike means you work less hard and go further and faster -- which is not helpful if you're on a towpath... πŸ˜‰ So as usual, it depends how you use it.
  4. Hasn't Marple been fragile and prone to stoppages for many *many* years (*long* before CART, or maybe even BWB...), partly due to inadequacies in design/construction as well as inadequate maintenance? Though that wasn't why we got stuck in Marple last time... πŸ˜‰
  5. I hope the "you" wasn't aimed at @LadyG who ignores trolls, and is a paragon of (somewhat eccentric) reason and friendlyness in comparison... πŸ˜‰
  6. Or maybe all the Igors on the Discworld -- though perhaps better at corporeal reuse/reassembly then the one in (Young?) Frankenstein... πŸ˜‰
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  10. If you mean at Dukinfield then we've often moored there overnight too, pleasant and quiet and we've had no problems. There are (towpath side) mooring rings along the wooded bit just north of the swing bridge but last time I was there these had got buried in the mud/grass over the years so they're not always easy to find, you might need to dig a bit -- OTOH the maps photo looks like the towpath has been redone so maybe better now. There's a footpath up to the road, you can walk up to the Chapel House pub (Holts) where we've had some enjoyable evenings in the past, sadly no real ale any more but the beer is still fine -- and *very* cheap, here's a round with the change from a tenner, though admittedly in 2019... πŸ˜‰
  11. All of which is pretty much what I said -- if you want to go further or with less effort they're great πŸ™‚ Not at all, that was one of the excellent uses I listed πŸ™‚ Indeed, possibly an electric bike for longer distances/harder hills/less sweaty cycling, and a manual one when you just want to get fitter or don't need the electric one. If I was still commuting into town and doing 20+ miles a day every day like when I was at Imperial, I'd have an electric bike like a shot. But I only use the bike here at home (full-size) for exercise/enjoyment (towpath cycling) and the one on the boat (Brompton) for lock-wheeling and short trips, and for both these a manual is absolutely fine -- and of course since you exert more effort, gets you fitter faster... πŸ˜‰ The point is that cycling is one of the best ways of getting around if you can do it, whatever type of bike you're on, and if an e-bike encourages you to do this instead of using other less environmentally friendly forms of transport then so much the better.
  12. You mean like the one above with several similar posts on this thread, with not a scrap of useful content between them, all sniping at another poster? 😞
  13. The other gotcha for naive selective-reading boaters who think they can just drop-in an LFP, like some of the adverts and people on Facebook say... 😞 Now they have @MoominPapa to blame for all their other blown-up 12V gear that didn't like 90V being shoved up it, as well as a fried alternator... πŸ˜‰
  14. There's little doubt that a G-line will be an even bigger favourite of tealeaves than the other Bromptons at half the price -- and the electric version worth another 50% even more so... 😞 Electric bikes aren't for those who want to improve fitness, they're for those who want to use them as a less sweaty means of green transport, or where a trip on a traditional bike would be too long or too slow, or where they simply don't have the youth or energy to propel themselves. And for all those purposes they're an excellent solution... πŸ˜‰ If you want to bike mainly to improve fitness then you might as well get the maximum benefit by pedalling yourself, that's what I do... πŸ™‚
  15. Useful/relevant content: 0% Provocative/troll content: 100% CWDF needs more posts like this, it would be a much better place... 😞
  16. Agreed, but you know the way the internet works -- someone will half-read your post, selectively see the "it's not a problem" bit (while ignoring the caveats), and then burn out their alternator after installing dead-easy drop-in LFP batteries. And it'll all be your fault... πŸ˜‰
  17. Given they cost Β£3500 I'd be surprised if anyone on the canals has one, far too expensive for poor boaters who can't even afford a small license fee increase... πŸ˜‰
  18. 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... 😞
  19. No comment needed... πŸ˜‰ P.S. Don't mention it...
  20. Surely only a pirate can be arrrticulate? πŸ˜‰
  21. The frequency of the vibration is set by the rate the prop blades pass the rudder (engine rpm x number of blades), it's nothing to do with the tiller length. More amplitude is always worse for comfort. A four-blade prop gives less tiller vibration than a three-blade one because one prop blade is passing the top part of the rudder blade left-to-right at the same time another is passing the bottom part right-to-left, so the two forces tend to cancel out. With a three-blade prop the forces alternate left-to-right top and right-to-left bottom which tends to shake the tiller. Not just theory, demonstrated in practice... πŸ˜‰
  22. The NBTA "Conclusion and recommendation" shows exactly which particular axe they have to grind -- and as usual misuses their favourite word... 😞 "Taken together, the inconsistencies in the Review’s ToR suggest that CRT is pre-emptively seeking to obtain legislation that would endanger the existing rights and protections for itinerant live-aboard boaters, making this way of life unviable. This is in spite of the fact that this community of boaters contributes significantly to the vitality of the canal system, pays substantial licence fees to enable CRT’s operations, and has historically played a crucial role in maintaining the waterway network since the decline of its industrial use." And of course they don't have an "existing right" to both stay essentially in one place without a home mooring, that's exactly what the CC exemption forbids but the NBTA pretends otherwise... πŸ˜‰ Also this "community of boaters" has played no such historical role, that was down to the volunteers/boaters who helped restore the canals and the CCers who actually cruise around them, not the CMers who do no such thing... 😞
  23. Like the one in "Vengeance Most Fowl"? πŸ˜‰
  24. And I'm sure the actual report/recommendations -- as opposed to a document like this recording what was said at a meeting -- will have lawyers run their (expensive) eyes over it...
  25. Though that's not true if the rudder axis is tilted back at the top (to help with centering?) and the tiller is horizontal, which is the case for many boats including mine... πŸ˜‰
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