Rewire

[pappaecho]

I am completely rewiring my Evasion 32. Normal practice on cars these days is to have the main heavy duty feed cable wired directly to the starter motor relay from the battery +ve terminal. Do I do this, or wire via an isolation switch, which will isolate the rest of the circuits, in the same sort of way that the ignition switch would isolate all car circuits. The Perko switch is good for 200 amps, and has two switch banks whixh can be commoned in an emergency

<hr width=100% size=1>Def: Yachting - a way of spending the kids inheritance

 

[paulrossall]

I would wire it via an isolation switch. Why don't you just replicate the existing wiring. A car engine will require more electrical power than most saily boat engines. The rating of your existing switch is OK. Just replace the existing wiring like for like. Whats the saying? "If it aint broke don't fix it". Paul

<hr width=100% size=1>" there is nothing-absolutely nothing-half so much worth doing as simply messing about in boats".

 

[William_H]

It is an interesting question regarding isolation switch for the starter current. In cars it is not isolated however in light aircraft (essentially a car wiring circuit) they use an isolation switch ( a remotely operated solenoid) which isolates the stater current. (the stater current goes through 2 solenoids) (this may be a safety feature it is a big prop if it starts turning accidentally) In boats most people seem to isolate the starter current via switch and this may be dictated by various standards but I can't imagine why. The stater solenoid should provide sufficient isolation and it would have much less voltage drop not going through another switch. The whole question is made more absurd by the proliferation of circuits which are not switched off when leaving the boat. bilge pump solar charger clocks redio memory etc.
No I haven't an answer but I do understand the question. I suspect I would not isolate the stater if I had an inboard engine. will

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[pappaecho]

The rewire is required because the wiring loom is like knitted spaghetti. The original wiring diagram is in French! There are only 3 fuses, and with modern gagetry like autohelms, gps systems, electronic logs, vhf radios etc, the fuses have been replaced with 4 inch nails! hence a complete rewire with 12 switch -fused circuits. The car radio cassette is so old that it has no memory function, no security code, and hence can be switched off with out problems, but still gets the shipping forecast!

<hr width=100% size=1>Def: Yachting - a way of spending the kids inheritance

 

[Lance]

I have had previous experience of this which may give you food for thought!
A boat I owned previously was wired with the live feed to the starter motor wired direct.
All was well until one day a spanner (that yours truly) had left on top of the engine by mistake fell down and wedged between the + terminal on the starter motor and the engine block! The result was lots of smoke from the battery cable and burnt fingers for the afore mentioned Moose whilst trying to remove the + terminal from the battery as there was no isolator switch.
Had this happened whilst the boat was unattended there would have been a serious fire.

When I repaired the damage, I wired through an isolator switch and just for good measure fitted a 200Amp fuse right by the battery in case of a short between battery & switch.

When I changed boats, the first task was to re-wire to the above spec. The engines are 150 deisels started by single 110amp battery and there is always plenty of life to start.

Main battery fuses are the subject of some debate as should it blow whilst engine is running, it would almost certainly goose the alternator.
My personal opinion is that rarely do main battery fuses blow without good reason and I would risk the alternator every time considering what nearly happened to me.

Hope this helps
lance

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[DavidGrieves]

Try this:-

http://www.reading-college.ac.uk/marine/

then click "Maintenace course notes"

Good info...

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[Ruffles]

pappaecho

FYI I bought a new Sony CD car radio a month back and it does NOT have a key code. Just a removable front panel. It seems key codes are a thing of the past which is good news on a boat with a main switch.

Rob.

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[FullCircle]

Try looking at a Ford Transit Battery Earth cable - 350A fuse built in.

<hr width=100% size=1>Jeanneau 35 - only 13,272 lbs displacement, not even 6 tons,what a lightweight!!!