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Craig Shelley

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    51
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  • Gender
    Male
  • Location
    Birmingham

Previous Fields

  • Occupation
    Engineer
  • Boat Name
    Pretty Amazing Grace
  • Boat Location
    here and there

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  1. Hi, The link below is to a ZIP containing the HTML document and Javascript files. I was a little reluctant to share this via google drive as I cannot guarantee how long the link will remain live. Also I'm not too sure about the licencing terms. I'm aware that the Leaflet library is distributed under a BSD permissive licence. Since this off-line page loads its data from the feeds published by IWA, if ever those feeds change it will stop working. https://drive.google.com/file/d/1KaBVmV8ua3Le-KHoSwlUvdTBAtwso7hQ This is exactly the same map as is published on IWA
  2. This map is great. I've had it on my wall for several years now. We also have one on the boat, but had to cut it down to a more practical size. It's possible with a bit of snipping to get it down to A2, whilst still having the enlargement sections not obscuring anything. One thing that makes this map particularly useful is the inclusion of major roads. Also, it is possible with a bit of script modification to use the very nice map that the IWA publish via their website as a full-screen webpage with scroll-wheel zooming. Unfortunately, it is not possible to attach the .html .css and
  3. Had another letter through the door today, stating that the policy expires on 4th of December 2021. Starting to get a bit confusing now.
  4. Hi, Sorry to reignite an old thread, but it looks like my dad has ended up being caught out by this trap. The letter (attached) arrived today 04/02/2021, saying that his car insurance had been cancelled yesterday 03/02/2021. With the poor weather recently, I though perhaps the letter had been delayed in the post? ... but the envelope was franked on 01/02/2021. Some weeks ago, my dad had to phone his car insurers for a completely unrelated reason but ended up mentioning that he was living on his narrowboat. He's been staying on the boat permanently recently because his g
  5. After digging back through the photos.. (memory not as good as it used to be) I can vaguely remember cutting through the transparent surface film with a scalpel. I can also remember it being possible to thread the wire in from the ends alongside the copper foil. I think the copper foil is only adhered to one side of the transparent film. I remember cutting a hole in the film part way along, to allow the wire to be soldered, either to the foil or back onto itself. You can see on the photo that I did a staggered cut of the sheet so that the connection point wasn't located directly beneath t
  6. I've tried to implement this, but due to various effects our long-term Ah counting has turned out to be not good enough. I'm hoping to make improvements over the next few weeks, but there's no guarantee that will overcome all of the long-term drift error which is inherent with this method. Charging to 100% periodically to reset the meter is one obvious solution, but you might not want to do that as often as is needed. The problem we found when using estimated SoC to stop the charging was that the numbers ended up looking too trustworthy and we lost our mental reference of SoC. We o
  7. That is an impressively low idle power consumption. Is that also counting Ah in/out of the battery? I always wondered how the BMV achieved zero-drift. It's very difficult to achieve the required dynamic range i.e. being able to measure 300-400A at the top end whilst accurately measuring sub 10mA at the bottom end. The zero calibration can be thrown out by a few microvolts at the shunt resistor - easily created by a thermocouple junction given the different metals involved. This makes my RPI solution look rather laughable at 80mA!
  8. Attached is a "zoomed in" view of the charge profile from yesterday. I agree that the voltage we are tripping the alternator off at is a little low. It would be nice if the alternator controller could benefit from some of the monitoring improvements which are currently going in. I might add a comms link back to the Pi to enable a proper CV/CI charging profile. If it's useful, I can export the data from google sheets, or provide a link to the live sheet. From experience, increasing the alternator cut-off voltage further doesn't tend to lead to a great deal more charging time because t
  9. Its nearly been a month since the new battery monitor was switched on. Still some work to do to move the current measurements to the new monitor so that the prototype system can be switched off. The graphs are relatively self explanatory. and are beginning to show the effect of temperature on performance. The near vertical steps on the blue Charge trace show when the alternator was used. This charges initially at about 100A, before dropping back to about 80A as it warms up. The charge current is engine RPM dependant, and quite possibly not consistent between charges. The more gr
  10. LOL the back bedroom already looks like a time machine from the '80s. The main interface to this is currently via smartphone/tablet, it's still undecided if we'll ever install a fixed display. The representation is a little experimental to see what works best. My father prefers to interpret an analogue dial over reading digital display. He finds the existing 7seg readouts need a lot more mental effort to understand. As for the 12 rather than 3 (I'm assuming you mean 4). Some of the decision is a little historical in how the battery packs have been assembled and installed. We've end
  11. We're starting to get some interesting data from the new monitoring system. There are a few interruptions on these graphs where we disconnected cables to tidy up the installation, paint the boxes etc... The temperature graph shows some of the batteries leading/lagging, i guess due to differences in the physical locations of the enclosures. Interestingly, the effect of internal heating due to charging can be seen quite clearly. Engine was run on the 4th and 6th Nov. My understanding is that the linear(ish) portion of the heating is caused by resistive/chemical heating of/within
  12. Ah yes, i forgot about those. So that's 8 chunky rectifier diodes, and 3 little ones for the 100A iskra.
  13. Sounds right to me. You should be getting more than 30A - not sure what your alternator rating is. As with most things in the automotive world, the specifications are usually overstated. We have a 100A iskra (though some sources rate it as 90A) It only gives this current when stone cold, soon dropping down to about 80A as it warms up. This current is RPM dependant, so it is possible to compensate for the drop-off, to some extent, by increasing the revs. Failed diodes can also cause a drop off in available current. As most alternators usually have at least 3 phases, with a rectifier c
  14. We just turn them on before charging with the alternator. Even when below zero C, as a domestic supply they perform quite adequately whilst discharging. From memory the solar controller is configured not to charge below zero C. A few years back, the recommended charge cut off temperature was zero C but that has been revised upward to 5 C more recently. If I remember correctly the winter of 2017/2018 dropped into sub zero temperatures for several weeks. At that time we didn't have any heaters, insulated enclosures or even temperature sensors. I'm sure we would have charged with t
  15. I always find the term ”loss of capacity at low temperature" a bit of a curious conundrum. If the capacity of a charged battery goes down, where does the energy go? Even if the voltage at the terminals is lower at low temperatures, the energy stored cannot simply disappear. The main thing I have observed at low temperatures is the apparent increase in internal resistance. I.e. pulling a heavy load causes the terminal voltage to drop more when the batteries are cold. Likewise, our charger which charges until a voltage threshold is crossed, trips out notably earlier when the bat
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