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nicknorman

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nicknorman last won the day on May 17

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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. If you object to them holding your data ref. the GDPR, that is absolutely your right. But you won’t be allowed in for a pint!
  2. Yes but none of that is relevant to a long-standing installation that doesn’t normally suffer from that problem but is currently having a problem.
  3. Blimey someone’s been on the sauce!
  4. Yes, however one would presume that this boat has been in use for a while and hasn’t suddenly had an additional header tank surgically removed. If so then a fundamental issue with the design of the system (insufficient header tank volume for the total coolant volume) is a red herring.
  5. Beta would disagree with you. This engine is designed for keel/skin tank cooling and no additional header / expansion tank is deemed necessary, according to the installation instructions. We certainly don’t have one on ours and when I changed the coolant a couple of years ago, bleeding it was not an issue.
  6. Yes I agree which is why I put the stat at the end of my list, but on the other hand it’s an easy thing to check / eliminate. Beta 43s have an integral header tank so all installations should have the same volume, it’s fairly large. Of course the other thing we haven’t thought about is whether the engine is actually getting hot, or whether it just thinks it is. Confirmation bias. The oil seemed hotter than expected but that is a bit vague. And that is then linked to the overheat alarm to mentally confirm its activation. Is there any evidence that the engine is in fact overheating, other than the alarm? Yes I know the gauge shows hot but is there just the one sensor for gauge and alarm? (Off to check the schematic...) Edit... looks like there is just one sensor to feed the gauge and the warning light / alarm.
  7. Check the small alternator drive belt that also drives the water pump isn’t very slack or bust. Check level of water in the header tank (built into the top of the engine). Presumably there isn’t some kind of shutoff valve for the skin tank circuit? Feel temperature of pipes in skin tank circuit - obviously the feed should be hot all the way from the engine to the skin tank. If not, the water isn’t circulating. If no joy, undo the 2 bolts that hold down the thermostat housing and remove thermostat, replace housing/bolts. Try running the engine again without the thermostat.
  8. So not that much cheaper than new from China, which would be about £1400 for similar.
  9. This brings up a point that I don’t think has really been discussed. Which source of LiFePO4 cells (without BMS) for a boater? By which I think I mean Jeremy (as per quite a few on here) or new, direct from China (as per Dre). I can see the cost of the new Chinese cells but have no idea what people have paid for Jeremy’s second hand cells.
  10. I use RS a lot. They do have some trade counters where you can collect from, depends where you are.
  11. Point of order, it is matching the Vmp that is relevant, not the Voc, although to be fair if one is matched the other is not likely to be too far off.
  12. A bigger bank is one solution, obviously. But Li batteries are expensive and long lasting so it may not make sense to spend a lot of additional money on a large bank that is going to massively outlive the owner! For us as leisure users it seems unlikely that Li batteries bought now and used fairly hard would be at risk of approaching their useful lives before I become unable to boat any more (due to being dead, etc).
  13. 2nd para - well, it’s been discussed extensively before but which thread, no idea! This is why I am developing my own BMS system that can control the Combi charging voltage and do automatic balancing, and why it will be linked to my alternator controller. The lower tech alternative is simply to get the cells balanced and then keep the charge voltage low enough to avoid one cell running up the knee (with some safety margin), which is what everyone else is doing. 3rd para yes it doesn’t matter that much, it is just to get an idea of how much charge you’ve taken out for future reference. Not critical at all, but then not hard to implement. Ideally you want 3 resistor systems, you switch them onto the 3 highest cells and turn them off (probably at different times) when those cells reach the voltage of the lowest cell. You can of course do it with 1 resistor but it will take a lot longer and be more faffy as you will have to bring 3 cells down to the level of the lowest one, one at a time.
  14. Your first para - this is exactly the problem and why you need individual cell monitoring and the ability to stop charging or at least reduce the charging voltage to prevent any one cell from being over charged. The alternative, as promoted by Peterboat, is to leave a large margin and never charge the batteries near to 100%. 2nd/3rd para. No there is nothing magical about 10A it is just a convenient figure to make it easy to work out how many AH you have extracted. But if you have no idea what current you are taking out you risk either overheating the resistor or having to spend decades discharging the cell! If you want to top balance the cells during charging then it would be advisable to be able to dump more current into the resistor than the charging device is providing, otherwise the cell voltage will continue to rise. Final para. Provided the discharging device is isolated, as a resistor would be, you simply put it across the cell with the battery assembled. No need to disassemble. The cell discharges through the resistor without any current flowing through the other cells. Of course this is passive balancing where the excess charge is wasted. If you want to do active balancing where the excess charge from one cell is used to charge other cells, that is a lot more complicated to achieve. And not necessary IMO.
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