Fred: The existing battery location in the engine compartment can hold 2 batteries--one can be the starting bank and the other part of the house bank. Then if I make 2 or 3 batteries located somewhere forward, they could be dedicated to the house bank (and I could somehow isolate them from starting loads) through switching.
Bob Bob Boyer S/V Rainy Days / Annapolis MD 1983 C&C Landfall 38 - Hull #230 email: dainyr...@icloud.com blog: dainyrays.blogspot.com "There is nothing--absolutely nothing--half so much worth doing as simply messing about in boats." --Kenneth Grahame > On Nov 19, 2015, at 11:59 AM, Frederick G Street via CnC-List > <cnc-list@cnc-list.com> wrote: > > Bob — I would consider sizing the wiring aft from the forward batteries to > allow at least 100 amps, with a maximum 10% voltage drop. This would require > at least 4AWG cabling from under the v-berth to the electrical panel aft; > better would be 2AWG, which would allow you to pull 30 amps with a 3% voltage > drop. Don’t forget that you’ll need a battery switch located very close to > the bank under the v-berth; and I would also put a 100-amp breaker (a > 285-Series surface mount would do the trick: > https://www.bluesea.com/products/7187/285-Series_Circuit_Breaker_-_Surface_Mount_100A) > after the battery switch to protect the long wiring running aft. > > The biggest issue with doing this is that trying to start your engine by > switching over to the forward bank is most likely not going to work, as your > starter wants more current than your wiring would be sized for. Trying to > upsize the wiring to accommodate this would be VERY expensive, and not ideal > in any case. If you move two batteries forward and keep two aft, basically > splitting your house bank into two banks, you’d have a better chance using > the aft bank as an emergency engine start source; but your wiring for > charging and selection is going to be more complicated. > > Does this help at all, or just set you up for more questions? :^) > > — Fred > > Fred Street -- Minneapolis > S/V Oceanis (1979 C&C Landfall 38) -- on the hard in Bayfield, WI :^( > >> On Nov 19, 2015, at 10:24 AM, Robert Boyer via CnC-List >> <cnc-list@cnc-list.com> wrote: >> >> I am equipping my boat for 8 months per year of cruising in the Bahamas. I >> have added a 19-gallon auxiliary diesel tank where my holding tank was >> located (under the navigation seat) which adds weight aft. I currently have >> 4 group 27 batteries which will be eventually upgraded to Group 31's--these >> also are located aft. >> >> I have been considering moving 2 or 3 batteries from the aft cockpit locker >> to some dead space under the v-berth. This would take some weight from the >> aft and add it forward. (My boat currently sits about 2" high at the bow >> and maybe 1 inch low at the stern with no one aboard but full fuel tanks.) >> >> I could configure the batteries such that the new forward bank could be the >> house bank and the starting bank (which I could probably reduce to 1 or 2 >> batteries) could remain aft. My problem is sizing the cables that would run >> from the forward batteries to the aft controls. As I see it, these cables >> would never carry more than 30 amps (maximum charging from my solar panels) >> unless I needed them for starting (in the event of a dead starting battery). >> >> Does anyone have any comments or suggestions on this matter? >> >> Bob >> >> Bob Boyer >> S/V Rainy Days / Annapolis MD >> 1983 C&C Landfall 38 - Hull #230 >> email: dainyr...@icloud.com >> blog: dainyrays.blogspot.com > > _______________________________________________ > > Email address: > CnC-List@cnc-list.com > To change your list preferences, including unsubscribing -- go to the bottom > of page at: > http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com >
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