Starting from Scratch

[Pblais]

For the solar panel my external voltage regulator can accept an alternator and a solar panel input. The solar panel really needs regulation just like the alternator.

With 6 golf carts you may have more power than you really need. Once you get to more than 400 AH you need to start thinking about how you can recharge them all fully once you suck out say half the amp hours. Once they get charged beyond bulk charge the input is going to drop and it may be the case where there isn't a practical way to get them all recharged full except on shore power. Having more batteries than you need really costs a lot of money and may be such that they don't last as long since you never get them fully charged.

If you went with a 12 volt fridge with lots of insulation I'm sure the 4 golf carts would be just fine. The money spent on the fridge would be saved in battery cost over the years. While the thruster is a big user you are only talking about very very short periods of use. Bigger boats may use a separate bank to reduce wire sizes from the battery to the devices but they still need to be charged. Your boat isn't that long so you don't get into the issues of really fat wire cables where it might be better.

I don't see any problems until you sort out just what the Inverter is going to eat up from the bank. You should be able to stay out on the hook a couple nights with 4 golf carts (like the Trojan T105's). Making AC power is just a lot of amp hours wasted so that would be the one place to sharpen the pencil and work the numbers tighter.

[knottybuoyz]

Minor revisions

Shadowed second set of 6 volts for future expansion if req'd.

Listed most likely Inverter & Charger so can now begin to sharpen my pencil as Paul suggested and work on the power requirements.

[knottybuoyz]

Started fleshing out Bill of Materials
Started to catalogue all the lighting fixtures and will continue with all the other elec. fittings and appliances so I can start to figure the total load budget.

Added the PV array and controller. Not sure if it's wired correctly but I've led the main feed from the controller to the input side of the battery combiner. Thinking is that the combiner will distribute charge current where required. Don't know if there'll be feedback to controller to allow it to function properly. Maybe thinking I'll need some way of switching charge current to indidivual battery banks manually unless someones already invented a gizmo I don't know about.

It's getting more complicated as I work through this. I can appreciate the people who do this for a living.

Rick

[knottybuoyz]

Selected what will "most likely" be the types of equipment I'll use for the thruster and windlass (based on price and availability here). Fleshed out the BOM some more with US prices, which are "retail" following the "Worst Case Scenario" to estimate building costs. I'm sure we'll do better as we go.

Still looking for some input from the electrical guru's out there. Would particularily like some feed back on the overall system, inherent flaws etc. I know I still have some work to do on wiresizing and current protection. I'll do another dwg of the lighting system but want to move onto plumbing right now and get back to the elect later.

Any feedback on the make & model(s) of the equipment I've chosen would also be appreciated, don't hold back, the good bad and downright ugly are what I'm looking for.

Any help appreciated.

[knottybuoyz]

If cost isn't a factor, are there any drawbacks to using oversized wire? For example a run calls for 14 ga and I run 10 ga.

Physical dimensions might be a consideration but are there other electrical issues I might not be aware of?

I suppose weight would might be a consideration on a performance boat but on a displacement hull'd 30 1/2' trawler a few extra pounds of cable shouldn't hurt.

[Pblais]

If cost isn't a factor, are there any drawbacks to using oversized wire? For example a run calls for 14 ga and I run 10 ga.

14 or 10 isn't that big an issue but 8 vs 6 is a huge cost factor. Tinned copper isn't all that cheap these days. I just bought some 6 guage to redo my shore charger run to the batteries one per bank. The wire was plenty expensive for 2 duplex runs of 12 feet each. Get some local prices before you just go bigger.

[knottybuoyz]

Thanks Paul

Guess I should have mentioned I have a line on some end-of-roll surplus stock that's going cheap so I'm stocking up early. The smaller sizes 12 + up are gone but there's lots of 6-10 ga primary, duplex & triplex as well as a lot of battery cable left. And NO I ain't tellin'!

Rick

[Pblais]

Rick,

Buy it all and maybe use it to finance the rest of the construction. I was amazed what it costs at the local West Marine.

[GordMay]

Under the circumstances you describe - bigger is BETTER!

[Rick]

Sorry to wait so long to offer a few suggestions and challenges:
The first challenge is to seriously question the philosophy of using batteries separate from the main house bank for thrusters/windlasses. This question has been discussed with intelligent arguments against the use of separate batteries since the 80's. The argument boils down to the concept that with your proposed system design the weight of cabling from your house bank to the windlass and thruster will be less than the weight of your added batterys. If you have the room put the extra batteries into your house bank thereby decreasing the source resistance and increasing the voltage under load of the bank for all uses. In addition, the cable weight will be distributed rather than lumped into a place which will probably add to the pitch moment of the vessel.

The necessity of using a manual ac switch to select between shore and inverter power is obviated by the selection of an inverter/charger which is capable of internally (and automatically) transferring the entire 30A shore power. With a good remote control for the inverter/charger you can choose to enable or disable either "auto-invert" or "auto-charge". With "auto-invert" disabled if the vessel is unattended and the shore power is removed then no heater loads will deplete your battery bank without your knowledge.

Do you have the ability to mount a large frame (9inch dia.) high output alternator in addition to the existing one?

What is the stall current rating of your starter motor? This determines the selection of a fuse rating from the battery. I am opposed to the inclusion of a fuse between a start battery and the starter. Any nuisance opening of the fuse is potentially dangerous when you need to have that engine in an emergency. ABYC allows for no fuse with short cabling distance and good wiring practices. Yes, you would still fuse a cable from the start battery to any other switch or item other than the starter.

Yes, you should have a "real" battery monitor for your house bank.

Consider designing in either an isolation transformer preferably the new "switch-mode" light-weight one that Mastervolt has introduced for the US market or at least one of the torroid transformer types that are lighter and smaller than the old technology non-torroid types (new winding machines have enabled the production of high power torroids that did not exist several years ago thereby making them more affordable as well as more efficient). We need to realize that ABYC may "dictate" that existing galvanic isolators are not acceptable without so much internal electronics for monitoring the integrity of the device that the cost of such a product will approach that of an isolation transformer. In addition, with the inclusion of an isolation transformer the necessity of ground-fault monitoring may be simply accomplished with branch circuits like in the galley and head. Any consideration for external ground-fault monitoring only needs to be between the dock and the end of the shore power cable at the boat, and in the future dock power boxes may be required to have them built in.

Before commenting on any other details regarding your system design it is necessary to make decisions about these basic considerations because the details beyond these basic ideas will follow from them.

Design attributes which make automatic power transfer and switching (ac as well as dc) when done properly removes the requirement of anyone having to be schooled about when and where switches must be thrown and under what conditions. There will be a lot of comments about this philosophy, especially that "KISS" thing which I hate to hear anymore as though one equates "automatic" or "more involved" with a lowering of reliability which innately is untrue. In fact the concept of "KISS", as is generally interpreted, is actually a logical fallicy.

An an example, I have set up a few boats so that someone relatively uninitiated with the electrical system can connect or disconnect the shore power cord at any time with or without throwing any breakers and have no problems result. They can use the microwave, toaster, hairdryer, 120V TV/DVD tied into a 120VAC sound system and not be concerned about throwing switches with or without shore power. If the owner is not aboard and there is no shore power available she can tell a guest aboard to use the conveniences at will merely noting an illuminated bar on the battery monitor/inverter/charger controller. If the "bar indicator" turns from green to amber turn on the engine and let it run until the bar turns green again and then turn off the engine. No swiches have to be changed,nothing else has to be done. If the shore power returns or goes away it not matter. No one has to understand what is an "Amp-hour" or what voltage means what. Think about it.

[Pblais]

will be a lot of comments about this philosophy, especially that "KISS" thing which I hate to hear anymore as though one equates "automatic" or "more involved" with a lowering of reliability which innately is untrue.

The fact that it eliminates the need to have proper manual sitches may not be more simple but it is more stupid resistent. The downside of failing to flip the switch has it's drastic outcome. It's nice when you can't shoot yourself in the foot.

You can interpret the STUPID part of KISS two ways. It really is easy to forget to flip a switch when you need it done before something else should be done. Elimination of that step makes it more simple to operate and avoids the potential problem.

[knottybuoyz]

Back at you Rick.

Wow, thanks for all that info. Still trying to digest it all. I'll have to contact the US agent for Nanni diesels to get the specs on the alternator and starter. Until then I doodled this sketch to illustrate the relative positions of the equipment. The main battery bank will be located under the steps in a ventilated compartment just ahead of the engineroom bulkhead. This will put the tops of the batteries at just about the DWL. I was thinking of building an shallow enclosed "electrical closet" in the companionway just above the battery storage compartment. This would result in very short cable runs.

I was debating the "Kiss" principle and the requirement for a combination unit like a charger/inverter and the decision came down to 1: ecomomics (I chose less expensive) and 2: single point of failure (lose one function as opposed to losing both). As much as I'd like to make the whole thing idiot-proof for the next owner, it's not beyond my ability to toss a switch or two and understand the consequences of doing just that.

I will investigate the inverter/charger and isolation transformer options. I have to be able to "wrap my head around it" to be able to understand and include it in the plan.

Wow, back to the drawing board......

Rick

[knottybuoyz]

I'm going to try to tackle Rick's observations one at a time. I think I'm getting the picture.....

Originally Posted by Rick

The first challenge is to seriously question the philosophy of using batteries separate from the main house bank for thrusters/windlasses.

Physically all the deep cycle batteries will be stored in one central location as I illustrated earlier. Separation into two banks was suggested earlier although it sort of makes sense to have a single large bank instead of a second sitting virtually idle for the most part until a thruster or windlass gets operated.

Originally Posted by Rick

The necessity of using a manual ac switch to select between shore and inverter power is obviated by the selection of an inverter/charger which is capable of internally (and automatically) transferring the entire 30A shore power.

Great suggestion. I totally overlooked the options available illustrates my inexperience. I've done some quick research and the Xantrex MS2000 would fulfill these requirements and includes the battery monitoring mentioned below. The cost of the combi unit is virtually the same as the three components originally planned. A good choice in equipment?

Originally Posted by Rick

Yes, you should have a "real" battery monitor for your house bank.

See above.

Originally Posted by Rick

Consider designing in either an isolation transformer.

Again some research turns up the Charles Industries Iso-Guard 93-IXFMR3/6N-A 3.6 kVA (30 amps) Isolation Transformer which seems to be just the ticket. A good choice? About twice the cost of a galvanic isolator. I can't seem to put my finger on pricing for the Mastervolt equivalent.

Originally Posted by Rick

Think about it.

I can't stop thinking about it! This and the plumbing! There in lies the problem. So many choices and so few boats to build!

I do greatly appreciate your help!

Rick

[GordMay]

Rick:
I think you are getting the picture, as (so eloquently)painted by Rick.

ABYC Technical Committees are currently reviewing electrical standards, including those for Galvanic Isolators and Isolation Transformers.
I don’t know what, if any, impact their discussions will have on current standards, and respective equipment prices.
Goto: http://www.abycinc.org/committees/callForComments.cfm

And: http://www.nmma.org/certification/te...hnicalupdates/
http://www.nmma.org/certification/te...icalupdates/?y

[knottybuoyz]

Ok, here's the latest including most of the comments from the last 24 hours or so.

I've removed the separate Inverter & Charger and replaced with a combi unit a Xantrex MS2000 auto AC source selecter as suggested and plugged in the Isolation Transformer. Documentation from the web on both is pretty poor. I've got an extra wire hanging out of the Inverter/Charger that I have no idea where it goes!!!

Anyhow these few changes have simplified it a bit (I think!). I'm still waiting to hear from the engine people on the other specs that Rick asked for.

Thanks for the input fella's.

Rick