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nicknorman

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nicknorman last won the day on July 3

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  • 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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Community Answers

  1. The clue will surely be to measure the input voltage to the B2Bs. If the alternator is keeping up, the input voltage will be up around mid to high 13s. If the alternator can’t keep up then surely the B2B will just shut down due to low voltage at the input. It then takes 5 seconds to restart again. So you would see large slow fluctuations in the charge current on the BMV.
  2. Yes. My alternator controller displays field current. When I have it set to “fast charge” the maximum field current is not limited by the regulator. It is around 4.25A to start with. As the alternator gets hot it decreases to about 3.7A with the same voltage across it. The clue will surely be to measure the input voltage to the B2Bs. If the alternator is keeping up, the input voltage will be up around mid to high 13s. If the alternator can’t keep up then surely the B2B will just shut down due to low voltage at the input. It then takes 5 seconds to restart again. So you would see large slow fluctuations in the charge current on the BMV.
  3. is it just because you have the same cupboard, but twice as much heat generated? Something seems not quite right! You should just be able to connect both alternator outputs in parallel. If they have the same or similar regulated voltage they should share the output in proportion to their respective sizes.
  4. Pedant mode - a regulator produces a pressure related to ambient barometric pressure, so variations in atmospheric pressure are not relevant. The absolute output pressure of a regulator will track ambient pressure.
  5. Ah yes I'd forgotten about that. Dog poo in bins actually. However it seems a bit odd to permanently leave the forum as a result of just one thread, in which participation is not mandatory.
  6. So they say. Is there actually any evidence that it is a problem? Photos? Accident reports? Apart from someone down the pub saying they knew someone who knew someone ... And anyway, if you wash it off straight afterwards I really can't see how it can be a problem.
  7. Yes, I found it. It just shows the 2 B2Bs in parallel for both inputs and outputs with an isolator to allow one to be disconnected (to avoid overloading the alternators I think). No not heard from him. It does seem odd that such a prolific poster should suddenly cease. Something about Li battery safety upset him IIRC, but I think there must have been more to it than met the eye.
  8. Presumably it would zero if the stop solenoid was pressed, then the ignition was turned off after the engine stopped, which would be the normal way of doing it. Doing it the way round you say, would be expected to give the results you give.
  9. I would not daisy chain. You don’t want the voltage drop from the first device affecting the second. Take 2 wires from each of battery positive and negative, one to each B2B. Same for the B2B outputs, separate wires to the distribution bus bars.
  10. Ed Shiers, four counties marine. Not far away. once he’s worked out what the problem is, do tell us, it’s intriguing!
  11. 5%. Don’t forget we are talking about lithium batteries.
  12. Did you screw the dipstick in, or just offer it up? Pretty sure you’re supposed to screw it in.
  13. Obviously the B2Bs are fairly inefficient and that lost energy goes as heat, which has to escape somewhere. Are they located in a well-ventilated area? Improving the supply of cool fresh air might be an easy improvement if say they are located in a cupboard.
  14. If the alternator stopped working I’d expect the tacho to fall to zero. If the alternator was slipping I’d expect the tacho to under-read, but that is not the same as “frozen” ie completely unresponsive to changes in rpm. “Frozen” tacho implies loss of dc electrical power to the tacho so I’d suggest measuring the tacho 12v dc supply with a meter whilst the belt slipping/ tacho freeze is happening. You don’t mention the type of alternator but with a 9 diode one, switching off the ignition once it’s running should have no effect. Since it does have an effect presumably it’s a 6 diode machine? I’m struggling to invent a scenario that explains the behaviour but wondering if it’s something along the lines of a temporary (maybe partial) loss of battery supply to the panel and with that same supply being used as voltage sense. The low sense voltage could be forcing the alternator output to maximum and that maximum load causing the belt slip. So in addition to the above measurement of tacho supply voltage, I’d also measure the alternator output voltage at the B+ alternator terminal whilst the fault is happening.
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