Small Boat Electrical for Sail

[rgleason]

Attached are

Schematic Wiring Diagram 8-15-2018
Schematic Loads & Notes 8-15-2018
Wiring & Hull Section 8-15-2018

These drawings are being used to review and consider the actual installation in terms of dimensions and practicality, cable runs, space available, access, etc.

In a nutshell, I am not happy with it and I think it will be very difficult to make this a neat installation. Particularly with all the wiring that enters the engine compartment at the bulkhead at the port side cockpit seat. It is already a nest there.

[rgleason]

I'd be interested in what other people who have dealt with these kinds of installations think about this one!

For me, if it has to be like this, I might just change a few alternator wires and just leave it. It is not worthwhile doing a whole rewire, without a major improvement in wire handling. This is somewhat disappointing after all the planning.

I am considering eliminating a drawer we use for projects in the cabin and using that area under the settee for batteries. I like the following aspects:

1. Battery weight is more towards the center of the boat, away from the ends.
2. Batteries are are more protected and away from wet areas.
3. Wiring and busbars should also fit in the same area away from the wetter lockers.
4. The port sail locker no longer contains a battery box so I can now access the prop shaft and stuffing box & packing more easily.
5. More storage for sail area. Will have to find a place for lines.
6. Wiring layout must be much better or it is not worth doing this.
7. The installation must be acceptable for future LiFePO4 too.

Possible issues/problems:

1. This new location is not appreciated by my wife who has had her silverware in the drawer closest to the engine.
2. We loose other storage under the drawers.
3. The seats are not high enough for the batteries when the hull curvature is involved.
4. The wiring is more distant from the engine with greater voltage drops.
5. The AC panel is also quite far from the engine.
6. Distance from the engine to the Port side seat location is shorter, but requires wiring under the cabin sole or in the lockers above the refrigerator.
7. Port side wiring under the cabin sole might not be able to turn up along the hull and access the under seat area.
8. Starboard side is further due to the oven, but it might have better cable access. Also the seat is a little higher.
9. Access to the batteries will disrupt our storage of charts under the seat cushions.
10. For the new T105 we will need at least 11" clearance.

[john61ct]

Sorry couldn't resist
http://youtu.be/rTMxZxI7-SQ

[rgleason]

Pretty funny!


It ain't going to happen. Its the first and last boat I am told by the admiral.

Who knows what I am going to do? Got to measure more and look at conditions again. I think that 3way Switch is going to have to move if the batteries go under the cabin seats, otherwise the runs get way too long. Do I just put the switch in the battery area? Cables are going to get maybe 3-4' longer (6'-8' total) with this total rewire. Why is this so complicated?



It would be cooler, but
How much venting from under the seats is required?

[Stu Jackson]

Originally Posted by rgleason

>>>>>>>>>>>>>>>>>
Why is this so complicated?>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>

rg,


Because.


Really, it was no more complicated 20 years ago, it's just that none of us who cared to learn, as you have, had the handy resources that are now available. While we were inventing the wheel back then, we made the effort to document what it was we were doing and why. Electrically speaking, rg, you "got it." You have no idea how many hotel and restaurant notepads I used up sketching wiring diagrams until I finally had that "aha!" moment and understood routing the AO to the house bank and the proper use of the 1-2-B switch.


YOUR current (pi!) problems relate to physical space on YOUR boat and the limitations imposed by that fact and your partner.


There is literally nothing any of us can do to help you out in that regard.


Unless you run into an owner with an identical boat to yours who has done so. And I'd be willing to bet they'd do something different than you would.


Good luck.


PS - I'm still out cruising, so I haven't looked at your latest wiring diagram. Yet.

[rgleason]

Thanks Stu, John and Rod and all the other contributors for your observations and experiences. At some point I'll make a decision about this and let you all know.
It's a pretty sure thing I should get new alternator and a healthy amount of solar. As far as how the wiring is laid out that's my problem, but I have a good diagram now. Thanks!

[rgleason]

Peter Kennedy's blog about lithium system , components and quantitative comparison to AGM is quite helpful too. https://shop.pkys.com/lithium.html
Lithium is expensive! I think if I can find a good place for the batteries and wiring, get enough solar and a better alt, and plan for some upgrades later, FLA is going to be fine.

Bruce Schwaub Regarding Li:

I have a simple rule of thumb:

1. If you have enough solar to cover your loads and condition your batteries, Pb will be fine.
2. If your loads are such that you have to charge with fuel, then you should consider Li.

John

1. Solar is only needed for the long tail if the bank is lead.
2. The smaller the wattage, the higher SoC you need to do with dino juice. Insolation weather latitude are big factors.
3. Yes most cases 300W is plenty, cloudy days morning dino juice run 2-3 hrs rather than 1-2 when you need the high-amp boost.
4. And yes if LFP, all a bigger alt does is reduce runtime.
5. Smartgauge is for lead only.
6. For future LFP, just ensure wiring is robust and all charge sources are user-adjustable setpoints. What is LFP acceptance rate, generally? If you have the amps can refill under an hour.

Newhaul.

Rick
At cruise-anchor 80amp/24hr, at sea 130ah/24hr. I've been studying and helped by some of the best, on this forum. You may not have seen it. Small Boat Electrical for Sail Energy budget and existing system are at the beginning.

Newhaul wrote:
ok with those numbers you will need about 300ah of Lfp and just about 300 watts solar to be independent of your engines( after several days of bad weather you may need to run it A stock 120 amp alternator will likely put out about 70 amps so a couple hours running will get you another couple days for the weather to clear.

[rgleason]

There are two possible locations for the batteries:

1. Existing port cockpit locker, with a bigger new box to turn batts in proper orientation. New busbars, fuses, solar controllers, combiner will be subjected to possible seawater from seat lid in the event of a pooping wave also not much room for these. Access to stuffing box requires removal of batts, not great. Larger batt box will make getting sails in and out of locker harder.

2. Cabin under seat battery location, taking over a drawer. 5' from engine to batt area not including cables in engine compartment and batt box. Cables may be 10' longer.Checking lead acid soc condition with new cushions in cabin a big negative with the admiral. Two T105 fit in proper orientation. I could fit oasis firefly. I would like to fit 4 T105 but only 3 will fit in proper orientation. The 4th would have to be turned 90 deg to fit the height under the seat. Is this a big problem if topped up with H2O fluid a lot? These batts will be awqy from engine heat and possible seawatet. There should be room for busbars, fuses and 24hr panel. It requires rewire of everything. Also location of 3way switch no longer makes sense. Where would the 3 way switch be located now, in the batt box? Also longer run for solar panels. Questions about venting, battery heat and fumes under the seat.

Which choice of batt location would you make. Why?

[john61ct]

Where they are more certain to remain dry in any scenario I consider more than half a percent likely to happen.

10' copper runs are not a significant factor.

Loss of lower-priority storage space not a factor.

[rgleason]

Thanks John,

Under the cabin seat, I would like to fit 4 T105 but only 3 will fit in proper orientation. The 4th T-105 would have to be turned 90 deg to fit the height under the seat. Is this a big problem if topped up with H2O fluid a lot?

I can probably get the reserve battery in there.

Where do I put the 3way switch now? It is now many feet away.

[Stu Jackson]

Hi, welcome back.


#2, heavy lower.


Switch? It's only wire and should be, as we've previously discussed, sized for the distance, which John & I know for sure YOU know how to do, right?

[john61ct]

Originally Posted by rgleason

The 4th T-105 would have to be turned 90 deg to fit the height under the seat. Is this a big problem if topped up with H2O fluid a lot?

Depends on time spent heeling, angles involved. Exposing plates is the problem, not just water levels getting low.

Choose the voltage cells that fit the space, 2V to 12V plenty of choices.

Or maybe go sealed?

> Where do I put the 3way switch now? It is now many feet away.

Again, why the aversion to wire? Boats routinely run 50' to put infrastructure in the right place.

These are your decisions as captain to make, you have all the info needed.

[rgleason]

I just got another chuckle about the Jaws link, ...needing a bigger boat. Thanks John.

I guess I'll draw this option up and size the wiring and price it. The % voltage drop is going to go up a little because I don't want to pay too much for copper, which is going to prove quite expensive anyway.

I'll just stick with (2) T-105 or (2) Deka GC2 for now, as 4 would exacerbate another little problem.
The boat already lists to the starboard a little and the (2)64lb=128lb batteries are moving from the port to the starboard side. That is a total change in weight of 256 lbs. The port side settee is not as high, starts at 12" but ends up at 9" clearance at 11" in from the drawer opening, it is a shorter distance to the engine, but the batteries won't fit. It might fit Firefly batteries, but I want a battery box big enough for various size batteries.

So I've got to rearrange storage on the boat, making it more inconvenient. My tools and drawer of parts which weigh about what one battery weighs will have to move from starboard to port. I'll have to move the pile of manuals for the boat from the starboard cupboard shelves over to open shelves on the port. I'll have to find some other heavy items to relocate. .... Maybe those lighter firefly batteries would be nice to have sometime....It is never simple on this boat.

[Stu Jackson]

Originally Posted by john61ct

>>>>>>>>>>>>>>>>>>>>>

Again, why the aversion to wire? Boats routinely run 50' to put infrastructure in the right place.
>>>>>>>>>>>>>>>>>>>>>>>>>>

I agree. rg, In your next post you talk about the expense of wire. Yes, if it gets twice as long, it costs twice as much, more if you have to go up a gauge. But in the overall cost I'd bet it's less than 1-3%. Only you know that.


And, if anything don't ever UP the voltage drop to save a few pennies. Oversize the wire not the voltage drop.

[john61ct]

Yes, skimp on things you'll be replacing anyway, but IMO not on copper.

Of course possible for us OCD types to go overboard, but to me that's below 1% V drop.

2% may be OK, but 3% is too much.

Now if the fatter wire adds say $500+ then I may consider a Sterling DCDC instead, since they add versatility and charging precision, let me use whatever "rough" charge sources, which can save a lot of money down the road, including going to LFP later.