pvb
Well-Known Member
Just a note of caution - if you have a separate battery in the bows, the cable linking it to the main bank needs fuses at both ends.
Battery for Bow Thuruster and Windlass
- Thread starter AndrewPalmer
- Start date
Chris_Robb
Well-Known Member
By using a sterling Battery to Battery charger you keep the amps to a known max - about 25 amps I think, but even then the wires are the size of a fountain pen.
Norman_E
Well-Known Member
So yours connect via a VSR (is it a split charge relay like this? http://www.ebay.co.uk/itm/Durite-12...ervan_Caravan_Accessories&hash=item35d4688dd9 ?). I think mine are just connected together via a pair of heavy cables, so perhaps I should insert a relay into the positive cable at the house battery end, making the forward battery effectively third in line for charging. I am still trying to think up a system whereby I can connect the Nasa BM2 battery monitor to keep tabs on the two house batteries without its results being compromised by current drawn off when the bow thruster or windlass is used, or is taking charging current. The problem there is that for the BM2 to work properly all current must pass through the shunt, but bow thruster and windlass currents will not because the shunt will be on the house battery negative, and in any case the thruster draws more current than the shunt rating. Its not actually much of a problem as I mainly want the BM2 to show me the charge or discharge current and am not really concerned about its state of charge percentage display. If I was really concerned about that only the Merlin Smartgauge would be likely to be any good on my setup, but because it works without a shunt it only displays battery voltage and state of charge, not current..
maxi77
Well-Known Member
Yes it was something like that though I used a 30 amp vsr to switch a big automotive relay, today I would use something like your one. Using a vsr you only connect the two systems when you reach charging voltage. This means that your BM should record discharge accurately
Storyline
Well-Known Member
Several times when I have seen bow thrusters being used on modest sized yachts I have seen all mighty cock-ups. Recently in Tobermory one situation became quite comical when as Vonasi points out, gusts of wind overcame the power of the thruster. The skipper must have tried a dozen times to get the bow alongside the pontoon and just as it was looking good a gust blew them off again. Think the boat was around 35' long and quite modern, definitely not a long keeler. Eventually the guy must have been so embarrassed with several people watching as he reversed away from the pontoon and gave up. Felt quite sorry for him as some people (including his wife) were shouting advice and the whole operation became doomed to failure.
My theory was that he probably had got used to having the bow thruster and not learnt how his boat behaved properly. Trying not to be big headed (there by the grace of God etc.) but I reckon I could have easily berthed Storyline in the place he was trying to get into.
My theory was that he probably had got used to having the bow thruster and not learnt how his boat behaved properly. Trying not to be big headed (there by the grace of God etc.) but I reckon I could have easily berthed Storyline in the place he was trying to get into.
Norman_E
Well-Known Member
Just an update. I bought the BM2 from Amazon, and as I have not used it I was able to return it. I have done so because after drawing out all the possible battery wiring diagrams it was clear that whilst it would show charge and discharge currents to the main batteries it could never be made to show state of charge, so the Merlin Smartgauge is a much better option. The boat has separate ammeters for charge and discharge, the former is disconnected due to the alternator being too big for the shunt and the range of the meter, but I think I can solve that problem. The discharge ammeter works but I think it has the wrong shunt because it never shows much of a reading. It will need investigating.