Fuse between Battery(s) and Selector Switch

[GordMay]

Originally Posted by Topazken

” ... The ABYC guidlines are great but realistically, a direct connection from the alternator to the battery has virtually no chance of failure. Millions of cars are wired like that
If we did everything as per all of the safety guidlines we would not even leave the dock. ...”

Which is why ABYC says you don’t require fuses/breakers on Cranking Motor conductors, of any length. See diagram, preciously posted.

If we did everything as per all of the safety guidelines we would live at and leave the dock in relative safety.

[Topazken]

Originally Posted by GordMay

Which is why ABYC says you don’t require fuses/breakers on Cranking Motor conductors, of any length. See diagram, preciously posted.

If we did everything as per all of the safety guidelines we would live at and leave the dock in relative safety.

I am not picking a fight but... How many crew are suggested be aboard for watch standing? Almost all crusing boats are too short handed to comply.

[GordMay]

Originally Posted by Topazken

... How many crew are suggested be aboard for watch standing? Almost all cruising boats are too short handed to comply.

Suggested by whom, and for which boats?
The only recommendation/requirement I'm aware of is for all boats to have someone on watch at all times.

[never monday]

Topazken,
There have been recorded cases where a wire down stream from the panel. Has been overloaded and overheated to the point of catching fire. The breaker did not trip. The only way to stop this would be to disconnect the batteries. Do you want to unbolt the batteries with the cabin filling with toxic smoke? or flip the battery switch off on your way out?

On your own boat do what you feel is in your best interest. Please don't advocate processes that are not approved.

[Topazken]

NeverMonday

In the sintuation you site, the fuses between the battery and alternator would not blow unless you are talking about an extremely high load like a windlass which should have its own fuse/breaker.

Please read my post. I did not advocate getting rid of fuses. I advocated getting rid of the bank selector switch. I specifically said the fuse is OK.

[never monday]

A fuse between the alternator and battery has no effect on a discharge from the house side of the bank. AND has no part of this conversation. The original question was regarding putting fuses at the battery terminals.

My statement above is in regard to battery switches. ya know 1-2-all-off type of switches.

I'll restate my position
Please do not advocate to others modifications of factory installed safety systems

[Topazken]

Never Monday

A factory installed electrical system will not serve a world cruiser properly. They are intended for absent minded dock dwellers.

You can type your demands in caps and bold type but it does not give you any more authority, knowledge or experience.

[never monday]

We as a board have always advocated ABYC standards. at this moment there are about 60 members and over 250 guests reading the board.
If one of them were to follow your plan of no battery switch and have a fire as I suggested. What would your comment be then?

There are hundreds of commercially produced boats floating around out there with factory electrical system Or systems rebuilt to ABYC Standards.

[Topazken]

Never Monday

This seems to be some kind of weird test of wills thing. I think you misread or misunderstood the point of my post. Perhaps I was not clear.

Even though you might be talking about house load fuses, I was talking about having two banks versus one. I was also only discussing the connection between the alternator and the battery.

I also very clearly stated that a fuse between the battery and alternator was OK.

I think that it is important that a crusier understand all of the implications of the choices they make. Most people do not know that turning the battery selector switch will kill their alternator. On many boats, the switch is easy to accidentally bump.

There is nothing wrong with adhering to ABYC standards but they are not the end all nor will they prevent every eventuality.

The fact is, more cruisers will endure difficulty and hardship because of a failed alternator than any kind of batttery switch/fuse related fire. If one turns off all of the house loads (except bilge pump & anchor light) when away from the boat, this is even more true.

Again, I never advocated what you seem to think I did. I mostly want people to be able to bake informed decisions.

[never monday]

Originally Posted by Topazken

Get rid of the selector switch. Having two house banks is one of the silliest things ever done aboard a boat.

Have one house bank wired directly to the alternator (fuse in-line is fine).

A solar charged, back-up starting battery is suggested in the event that you foolishly discharge your house bank below 12v.

In the above referenced quote you state. "Get rid of the selector switch" I don't know how I could have miss read that.

Even if you go to a single bank set up you still need a battery cut switch.

[MidLandOne]

I go with you TopazKen. The 1,2, Both,Off type switches are a poor solution for an independant cruising boat. In fact in my view any new boat should not be built with them.

In our own case we have 2 alternators each directly cabled to its own battery (in one case the cranking battery and in the other case the service batteries) with no switch at all between alternators and batteries ie the alternators are always live on the batteries regardless of whether the batteries are isolated from their distrubution or not. There is a paralleling switch for emergency use.

If only one alternator but two batteries then there are much better ways of distributing the charge than using 1,2,Both,Off type switches eg by VCR's.

Perhaps Never Monday is getting confused by incorrectly thinking that if there is no 1,2,Both,Off switch that there is no way of isolating the batteries from their distribution. One, of course, always has a correctly rated switch, preferably 2 pole so both negative and positive switched, for such between the batteries and their distribution (ie between service batteries and panel, and between cranking battery and engine).

PS We don't use fuses at batteries, but I won't get into that discussion .

[Topazken]

At the risk of even more angst...

If you feel you need an emergency cut switch between the alternator and battery bank.. fine. I do not really understand the point. It is only protecting you from a direct short inside the alternator (not sure it is possible) and a short between the wiring upstream of the cut switch. This also assumes you are there to turn off the switch.

I am all for the ability to disconnect all house loads. A switch between the alternator and battery bank, no.

Just my humble opinion...

[Topazken]

Midlandone

That is how Topaz is set up. Two alternators directly wired to their own bank. One was just a starting battery and the other the house bank.

And yes, the distrubution side needs switches and fuses/breakers.