Boat rewire: Am I going to die

[rwidman]

"Boat rewire: Am I going to die "

I see lots of replies on your number of batteries and how many "banks" you may have. What I don't see and what cannot be seen on a wiring schematic is your skill in wiring and terminating your wires and your knowledge and ability to install appropriate circuit protection as specified by the ABYC and good electrical practice. Also knowing and installing the appropriate wire and cable sizes.

These are the things that are important to your life or death.

At the very least, get yourself one or more books on boat wiring and study them until you understand them. Get a copy of the ABYC electrical specifications as well, understand and follow them.

[barnakiel]

Sometimes not drawing the black wires makes life simpler.

Cheers,
b.

[rwidman]

Originally Posted by barnakiel

Sometimes not drawing the black wires makes life simpler.

Cheers,
b.

To be fully ABYC compliant, the "black" wires would be yellow. At my age and with a lifetime in electricity and electronics, it's hard for me to see yellow as negative but that's what they call for to distinguish DC negative from AC hot.

[CarinaPDX]

As long as you are operating in salt water it may not be too important, but in fresh water you should have all thru-hulls and metal underwater fittings bonded together, and usually to an anode such as a large zinc. ABYC calls for this for a very good reason: protection against Electroshock Drowning (ESD). Our local ABYC rep lost his son to ESD because he was swimming near a boat with a leakage path between Line (hot) AC and an underwater fitting. The propeller/shaft isn't a good ground, and any anode would be small and needing constant replacement. Step up and put in a proper ground plate.

Greg

[IdoraKeeper]

Just dont forget to pull the bilge pump fuses when ever you go up on the hard. You dont want to those to run when dry. You never know when a float switch will get jostled.

[jeepbluetj]

I'd replace that one big fuse for the house bank with three MRBFs on the battery posts themselves. As long as the battery compartment is reasonably accessible I'd lose the isolation switches - for maint or emergency it's not too tough to just remove a cable.

I'd fuse to the starter. I do that on every boat I've rewired - even power boats with big engines.

I'd take all negs to some bigass blueseas buss bar and only one wire from there to the engine block.

[smac999]

Your always on fuse block is after the house switch. So it's not always on.

[billknny]

Originally Posted by newhaul

and you base this opinion on what? Perhaps the op is a marina hopper with no more that 3 or so days off shorepower.

It just makes no sense to have 30 or 40 amps of charging and a 600+ amp hour battery.....

Either a bigger charging system is needed OR the battery bank is way bigger than needed.

The battery bank can only store power, it makes none. if your charging capability is 40 to 80 amp hours a DAY which the OPs system seems to be, then why have so much battery? What's the advantage? Unless you need the weight as ballast...

Of course if wieght on money are no object, just add more batteries until...

[boatpoker]

Originally Posted by billknny

It just makes no sense to have 30 or 40 amps of charging and a 600+ amp hour battery.....

Either a bigger charging system is needed OR the battery bank is way bigger than needed.

The battery bank can only store power, it makes none. if your charging capability is 40 to 80 amp hours a DAY which the OPs system seems to be, then why have so much battery? What's the advantage? Unless you need the weight as ballast...

Of course if wieght on money are no object, just add more batteries until...

Sounds like you don't understand the difference between amps and amp hours.

[newhaul]

Originally Posted by billknny

It just makes no sense to have 30 or 40 amps of charging and a 600+ amp hour battery.....

Either a bigger charging system is needed OR the battery bank is way bigger than needed.

The battery bank can only store power, it makes none. if your charging capability is 40 to 80 amp hours a DAY which the OPs system seems to be, then why have so much battery? What's the advantage? Unless you need the weight as ballast...

Of course if wieght on money are no object, just add more batteries until...

ok so personal opinion then got it.

Technical: 400 watts solar is about 20ah x 6hours there is 120 ah
50 amp alternator so 50ah times however long you run the engine say 2 hours a day
Another 100ah now we are at 220 ah per day.
675 ah house bank so figure on 300ah usable. With 200+ ah charging there is just enough capacity to carry the vessel through a couple days of low solar output .
Does it now make sense to have 675 ah house bank. ( side note the lower dod the longer the bank will last)

[Colin A]

Originally Posted by smac999

Your always on fuse block is after the house switch. So it's not always on.

Yeah I noticed that too. Going to want to move that before the house battery switch.

[mikedefieslife]

Ah yes, thanks for pointing that out. I was debating to whether to put them before or after, the switch, since the switch would always be on anyhow.

I've seen it's practice on charter boats to have bilge pumps and VHFs even as 'always-on' obviously you can turn the VHF at the on device switch. Of course on these vessels you have a large number people on them who might inadvertently turn the batteries off. Still, probably worth the change.

Currently the boat (being old) has all of these on the breaker panel which seems a waste of panel space since I never turn the bilge pumps off to begin with.

[rwidman]

Originally Posted by CarinaPDX

As long as you are operating in salt water it may not be too important, but in fresh water you should have all thru-hulls and metal underwater fittings bonded together, and usually to an anode such as a large zinc. ABYC calls for this for a very good reason: protection against Electroshock Drowning (ESD). Our local ABYC rep lost his son to ESD because he was swimming near a boat with a leakage path between Line (hot) AC and an underwater fitting. The propeller/shaft isn't a good ground, and any anode would be small and needing constant replacement. Step up and put in a proper ground plate.

Greg

It would be a bad idea to design a boat's electrical system for either "salt" or "fresh" water. A boat will typically travel in both at some point in its life and often will travel in both on a single cruise (such as the AICW from VA to FL).

Bond the fittings and be done with it.

[roland stockham]

Couple of ideas for you to think about.
1 grounding there is no need to have an external DC earth, simply set up a big bus bar from the battery neg. The starter and engine electrics will be grounded to the block but not house supply. Radios, especially SSB do need immersed grounding for the aerial.
2 depending on you machinery it may be worth having a separate electronics batt. Loads such as fridges, inverters, pumps etc create lots of electrical noise which can cause radio interference and drop out on GPS and navgear. A separate battery for sensitive gear isolates them and also means you don't loose essentials if your hose bank runs down or fails

[CarinaPDX]

Originally Posted by rwidman

It would be a bad idea to design a boat's electrical system for either "salt" or "fresh" water. A boat will typically travel in both at some point in its life and often will travel in both on a single cruise (such as the AICW from VA to FL).

Bond the fittings and be done with it.

No disagreement. Still, there are folks that resist bonding and the resulting need for a zinc and regular replacement in salt water, and given that ESD is much less of a problem in salt water that may not be too crazy of a position (not acceptable to ABYC for sure). But the great safety hazard of ESD in fresh water, and the liability associated with it, argue strongly for bonding. I think that once installed it is more effort to keep changing it for conditions than just replace the zinc on a regular basis. I just note that I have known many cruisers who are against bonding, whether sensible or not, and I have seen boats where the bonding systems were undone. I want them to know of the greater danger in fresh water.

Greg