Battery isolation

[vyv_cox]

I just checked the current draw on my Standard Horizon GX 1500, for interest. 4.8 amps on transmit.

I guess that like most boats our batteries would be almost the first things to flood, so without a dedicated VHF battery the radio would fail well before the boat sank. Our VHF was wired through the instrument panel by Sadlers and I have not changed it.

 

[ghostlymoron]

Is it not recommended that a VHF be wired directly ( via fuse) to battery?

I've never come across such a requirement and I've had a few makes of VHF - are you confusing with a radio/cassette/CD which are often coded to deter theft?
Two further comments:-
1. It's not strictly necessary to have a further isolator for the VHF as it has it's own on/off switch built in to the volume control (usually)
2. There was a 'readers project' recently in PBO mag on installing an emergency battery for the VHF which could be used if your main batteries were flooded.

 

[rosssavage]

Answers the original question, but probably superceded by previous answers:

http://www.gaelforcemarine.co.uk/42184/Index-Marine-Commoning-Post-with-8mm-Stud.html

 

[noelex]

I've never come across such a requirement and I've had a few makes of VHF - are you confusing with a radio/cassette/CD which are often coded to deter theft?
Two further comments:-
1. It's not strictly necessary to have a further isolator for the VHF as it has it's own on/off switch built in to the volume control (usually)
2. There was a 'readers project' recently in PBO mag on installing an emergency battery for the VHF which could be used if your main batteries were flooded.

I dont think there is any confusion. There is a resonable argument for having the VHF and bilge pumps wired directly from the battery with everything else wired via the switch panel.
There are pros and cons, but I do not feel its too critical.
Personally my bilge pumps are wired direct, but the VHF is via the switch panel. I do have a small emergancy battery above the waterline. I also use this to power the anchor lights and gps if there is lots of lightning around although in many strikes it won't make any difference.

 

[Graham_Wright]

Without thinking it through (as usual), would a 1,2 and both switch wired backwards do the trick?

 

[rosssavage]

I dont think there is any confusion. There is a resonable argument for having the VHF and bilge pumps wired directly from the battery with everything else wired via the switch panel.
There are pros and cons, but I do not feel its too critical.
Personally my bilge pumps are wired direct, but the VHF is via the switch panel. I do have a small emergancy battery above the waterline. I also use this to power the anchor lights and gps if there is lots of lightning around although in many strikes it won't make any difference.

Bit of both for me. Flybridge VHF run through Nav instruments breaker fed from domestic distribution through battery isolator, 3x bilge pumps from the domestic system too - each independently fused from the domestic bus.

I have a separate hot battery bus permanently connected to the engine battery, this supplies unswitched power to the lower helm VHF and engine room BIG bilge pump. No isolator (removes a point of failure) but fused where the supply is taken from the hot side of the engine isolator and fused locally for VHF wiring.

So two independent supplies for the two radios, and a separate supply for the engine room emergency pump.

 

[lw395]

Nothing in the current ORC regs:

http://www.sailing.org/tools/documents/OSR2012Mo1240112-[11793].pdf

 

[Fantasie 19]

Is it not recommended that a VHF be wired directly ( via fuse) to battery?

Ah - so that's why it's wired that way on my boat... you learn something new every day...

PS Not being sarcastic - I really didn't know! Mine has the bilge pump directly wired as well... all makes sense when you think of it.....

 

[rob2]

You don't give a reason why you wish to isolate the battery. If the existing system is otherwise acceptable (individually fused direct connections) then on the odd occasion you just whip one of the battery connections off..

I suspect that you actually want to be able to isolate when the boat is unattended, so you either need to revise your refusal to rewire or get one of those post mounted isolators shown in the earlier posts.

Rob.

 

[lustyd]

The reason is that the engine and auto tiller both connect via sockets at the stern. Any moisture in these and the metal connectors in the sockets are eaten away. Removing power would remove this problem.

The problem is solved now though, I'm going to put a second isolation switch into the locker next to the battery. This will avoid a rewire of the whole boat and give me a way to cut power.
Cheers
Dave

 

[fisherman]

Since 1974 I have understood that it was at least good practice to wire one VHF direct with minimum connections, and have always done so.