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nicknorman

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nicknorman last won the day on March 4

nicknorman had the most liked content!

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Profile Information

  • Gender
    Male
  • Location
    Aberdeen
  • Interests
    Electronics, gliding, motorbikes

Previous Fields

  • Occupation
    helicopter pilot - retired
  • Boat Name
    Telemachus
  • Boat Location
    Fazeley Mill Marina, Tamworth

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  1. Of course the problem is that this is an integrating process, and when you integrate - in this case current - over time, the error is cumulative and can increase without limit over time. This applies no matter how accurate the current measurement is, unless the error is zero which it can never be. So it is inevitable a compromise of how long the device is expected to run without being reset. That is, unless one can include some sort of automatic resetting of SoC based on some other factor. Battery fully charged is of course the normal way of doing this but as we know, one of the major points of lithiums is the absence of need to fully charge. Trying to do it via measuring the rested voltage might be possible, but difficult bearing in mind the flat voltage profile.
  2. I think you have hit the fundamental limitation of an open loop Hall effect sensor. In fact 5% is quite good, considering! Hall effect sensors usually have quite a temperature coefficient both in terms of offset and gain, so I wonder if measuring the temperature of the sensor and applying some compensation in software might help improve it (unless of course it already has such compensation built it). You also have the issue of the differing charge efficiency factors of the LA and the Li batteries, the former of which will vary according to state and rate of charge. Anyway, if the 5% is fairly repeatable it would be easy to build compensation into the code. That would likely improve things. But ultimately I think you should consider using a more conventional resistive shunt.
  3. Just the usual NBTA nonsense. I think they should be sued for misrepresentation because "Travelling" is the last thing they are interested in.
  4. Because they don't know any better? FLAs are only any good if your idea of a large electrical load is one LED in amongst the candles.
  5. Red engine might be raw water cooled as opposed to skin tank. Worth checking anyway, raw water cooling can be problematical on muddy plastic-strewn canals.
  6. Welcome back! Yes modding seems to have settled down now, nothing contentious for ages, ever since the moment you left in fact. Oh! Hang on...
  7. We have a sealed for life CO detector that has a pin that when inserted, turns the power off. When we leave the boat we turn it off to prevent any risk of annoying neighbouring boats. Clearly the battery will thus last longer than the calendar time of the design spec but it an interesting point about the sensor life. I think the latter is affected a lot by its environment and as said earlier, it does get “poisoned” by exposure to CO. But hopefully, when we are not on the boat there is no CO production! I have a mains powered CO alarm in my rental flat that nevertheless has an expiry date, 7 years I think, so it is not all about battery life. Our Boat CO alarm is probably approaching its calendar life so I’d better think about it!
  8. As said, domestic systems like to use header tanks because they are cheap and easy and safe. However it is perfectly possible to get a mains-pressure hot water tank installed, but you do need a means of disposing of any water coming out of the pressure relief valve. But quite expensive and need to be installed properly. Not rocket science, just follow the manufacturer’s installation instructions. Trouble is, some plumbers aren’t good at doing that!
  9. The point is that it gets you a notification without your post being quoted. So if for example you wanted to bring someone into a thread they weren’t participating in because, for example, they were considered an expert in the field, that would be a convenient way to do it. You are right, @ does mean at - ie you are directing the comment or whatever “at” someone. You will notice that if you type @ followed by a letter or two, it lists the matching member names allowing you to select the exactly correct user name. Let’s try it @Athy
  10. I might have agreed with you before we had a house with one. But no, our shower works great. Much, much better than an electric shower. Mains pressure hot water is always going to be better than a loft tank. The only downside of a Combi is that if it packs up, there is no backup such as an immersion heater.
  11. I know what you mean, but I have it turned off (ditto for quote notifications). Can’t recall doing so but maybe I did.
  12. It’s a Twitter thing! However, not sure it works on this forum. I haven’t received any notification but there might be a setting to turn notifications on somewhere. edit: Ah yes there is, I have it turned off. So no point in @-ing me!
  13. Our Combi is fairly old so your modern one might be different but.... Firstly is the maximum hot water flow set correctly at the boiler? With the bath hot tap on, does the water still come out as hot as it does if the tap is only 1/2 on? Normally there is a restriction tap on the boiler cold water input to restrict the max flow rate to that which the boiler can heat. Could it be that when the shower mixer is moved to hotter, actually the increase flow through the boiler causes the temperature to drop even though the boiler is flat out? Secondly yes I think a thermostatic shower mixer will make things much easier. We have that on our home and boat showers, wouldn’t want to be without them! With a combi system you are effectively taking one supply of water from the mains, sending part through the boiler and part direct to cold and thus there is some interaction - increasing the flow of one can have the effect of decreasing the pressure on the other, so manually regulating it can be a bit fiddly. With a thermostatic shower mixer, you don’t really need to adjust it once you have it in the right place. You just turn it on. Did you go for a Vaillant?
  14. No, not being flippant. I think the size depends on the number of parameters and volume of data. But within the size of a PC, definitely. Maybe not for an arduino, depends. At least there is no need for fast processing as batteries don’t change second by second. But I don’t think a Kalman filter is relevant. That is for processing several dimensions of data in the presence of noise, and predicting the outcome. It should be possible to measure the necessary parameters with very little noise.
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