Sailboat Power

[Sunking]

Dennis seriously what you want is not possible no mattery how much money you throw at it. You will need another boat to hold everything. .

[ChrisOlson]

I really see no problem with any of the DC loads. That is all normal stuff on a liveaboard cruising yacht. I mean, you are not going to go thru the boat at night and turn on every freaking light you can find. At least experienced sailors don't. You switch to your red night lighting after dark because if you are a husband/wife crew one of you is on watch 24 hours a day at sea. If whoever is on watch goes on deck to trim sails or something at 2:00 AM you can't go on deck blind from your pupils not being adjusted to the poorly lit conditions on deck in rough seas. It is a good way to end up dead.

The problem is the AC stuff. It all has to go. That is only doable on shore power or onboard marine generator at sea. And even then it cannot be done with a 12V system. Doing a complete refit on the boat for 24 or 32/36V and fitting a marine generator would make it possible. But a marine generator also requires fitting additional tankage for diesel. I don't recall what the diesel tankage is for a Columbia 50, but our H-R 54 carried 238 gallons of diesel, and that is primarily for the generator and not the propulsion engine. Boats without a generator are usually lucky to carry 75 gallons of diesel tankage.

Compounding the problem with the Columbia 50 is that they are a relatively slow boat with a short LWL, heavily ballasted and small sail area/displacement ratio. On a passage where we can make 200-220 nm in a day, a slower boat is going to make about 150-160. So 10 days at sea for us ends up being 14-15 days at sea for a slower boat. That means you have to carry 150% more supplies and tankage than a faster boat would on the same passage.

I really suggest getting on as crew on a boat making a passage. Or hiring an experienced captain to take you out on your boat for a passage to get an idea of what you have to look forward to. I'm detecting the "dream" that a lot of folks have here, but maybe not quite enough time spent at sea to realize the limitations of living onboard a sailing yacht several days out to sea. You are not going to have all the comforts and conveniences you have at home. And the first time you sail in a storm for two days in 20-30 foot seas you are going to wish you were enjoying the comforts of home instead of being up for 48 hours straight on a sailboat to keep it from becoming a statistic lost at sea.

On the other hand, if you plan on living in a slip most of the time and island hopping in the eastern Caribbean where you are never more than a day from the next island - then you can get away with more stuff. All depends on what your goals are.

[ChrisOlson]

Say, Dennis,

One thing I do not see in your DC loads is your windlass. I guarantee you that you are not going to armstrong a Danforth or Buegel and 50 feet of Grade 100 rode into the anchor well on a 50 foot yacht. The windlass draws a LOT of power. Usually enough so that some installations have a separate battery by the windlass to help minimize voltage drop in the wiring.

[Mike90250]

Dennis seriously what you want is not possible no mattery how much money you throw at it. You will need another boat to hold everything. .

Exactly what I was going to say. I'll let Chris continue

[Sunking]

Holy crap - jumped off that huge boat onto a harbor pilot boat !!! Dude is c-r-a-z-y !!!

I think that is SOP for all Cruise Jails, err Cruise Ships

[D_e_n_n_i_s]

Chris, I think you are closest on with the analysis. The Origo electrical stove is also a non-pressurized alcohol stove so the alcohol could be stored onboard and used instead of running it off electrical - The hope there was that electrical power is renewable indefinitely whereas fuel requires stops at ports that can provide provisions.

The Skyworth TV is also D/C so I'll look up the D/C specs, but obviously TV isn't critical, but a nice-to-have for information when I'm near ports broadcasting useful info or just entertainment.

I'm not hung up on the George Foreman grill, but again the line of thinking with all of this is that electrical power is replenishable whereas alcohol or propane (I do have a Magma Marine grille) are not. That having been said, I also agree that A/C power is hugely inefficient and I'm not disagreeing that the A/C equipment needs to go in favor of D/C appliances. There are additional D/C devices for heating/cooking that I haven't added to the list, but that would be used instead of the A/C power. Yes, I need to get you a more accurate, updated list, but that's a pretty decent list for starters.

75-80 gallons of diesel is all I can hold so you again are spot on in regards to fuel to run a generator. That's just not feasible when you consider my sailing time at sea. I'm going to be on the seas for many weeks if not months for some voyages so the thought of using non-replenishable supplies (unlike electricity) to do these things doesn't make a lot of sense.

By the way, I've been through a 3-day hurricane and it was absolutely miserable, but survivable, albeit with some damage to the vessel. I get being in rough seas.

I had to laugh at your accurate, but funny post that you're not going to turn all the lights on at the same time ... Spot on, again !! It was a quick list of what's onboard, not what is going to run all night. I'll be single-handing the vessel so I'll probably only have a couple of lights on at most - Yep, using the red bulb while I'm at the helm, of course !!

Looking at the numbers, I still don't see why the Norcold frig has to go while using it's D/C power side. Seems fine to me. It really doesn't use nearly as much power as I initially thought before I started running numbers. Where to get ice at sea? OK, I've actually got some thoughts on that, which should only require minimal electricity, but I'll get into that another time.

Definitely right about the watermaker. Just me (at least current plans) so running time should be minimal, but it's a power hog as things go onboard a sailboat.

I noted that I need to buy radar, but don't have specs on it. VHF isn't something I'm going to leave on all the time ... um, did I put that in print ... uh, scratch that. Anywho, radar is a beast for power and I'm not sure that I will go with HAM/SSB given its power consumption. Radar is nice not just for navigation double-checks (I don't rely on electronics for navigation), but especially in heavy fog. I guess if you had tons of electrical power you could also use it as an anchor alarm, but I don't see that happening realistically.

Sunking - I've actually done the measurements for those huge batteries and I can make them fit. There's a lot of space aboard a 50 ft boat, but it is tight as it is on any boat.

Again, I don't want to spend any time in marinas so I'm going to be out there by myself without a charging system other than what I put onboard. It's not good to run the motor to use an alternator for charging, but it can be done in an emergency, but I don't want to rely on this regularly. I'm in discussions with Wells Marine for a radar arch, that will also mount the D400's and solar panels as well. My goal is to not create an electrical danger, but to be able to store sufficient power that I can have some comforts onboard, store food in the frig and have lights, etc. with enough battery storage that I can recharge a days' worth of electrical use in a day ... Replenishable energy !!

To re-wire the entire vessel for 24/36 volt power is a major refit. I get that the higher voltage will decrease the size of my wires, but they sell some pretty large wire so I do think I can throw money at this ... yeah, a lot of money, but that's what I'm trying to figure out. Keep in mind that it's not going to be cheap to change out the main panel and most everything else to use a different voltage scheme. Money is money so I'm willing to put a pen and paper to anything. We'll see ..

My windlass is mechanical - no power required other than a strong arm ... All chain rode and a pair of CQR anchors. You get used to it. It's just like the Groco head that I had powered by D/C. When I pulled the single bolt to disconnect the electrical pump arm and just used my own arm to pump it, it was very easy and I actually prefer it now. No power consumption other than food.

Guys, if there is an electrical issue with how I'm connecting things or a danger that can't be resolved with the high amperage, I get those things. I also believe in facing those dangers and trying to come up with a safe way to hook things together. After all, rotating small banks of batteries throughout the day and hooking each bank of two batteries to a pair of solar panels (hooked in series) connected to the battery bank through an MPPT controller already sounds like it is very do-able. What exactly am I missing that makes this whole thing so scary to everyone that they think I can't fit it on my boat or that it will, quite literally, explode? Come on, give me numbers or specific problems, but not a gloom and doom run-away prediction. I'll look at the amperages to run equipment, but perhaps two batteries hooked into the main panel at any given time will be sufficient for the loads. Perhaps two banks of 2 batteries will need to be hooked to the panel at the same time as a worse-case scenario. Yeah, I was looking at switching panel power around to charge depleted battery banks and I appreciate the feedback I've received that showed me the dangers of charging dissimilarly charged bank of batteries and that is the feedback I'm hoping for to educate me and keep me from harming myself. I really do want to be safe, but I believe that for long voyages replenishable energy is the way to go. Sorry for the rant ... I truly do appreciate the sage advice I've received, but do confess that I am dreaming a dream, but I think it is achievable. If I'm wrong, then I'll fall on my face trying.

[ChrisOlson]

I think that is SOP for all Cruise Jails, err Cruise Ships

Yep, that's SOP on any boats that require a pilot with specialized licensing and training. Same thing on the Great Lakes. Ocean freighters on the Great Lakes have to be piloted by a licensed Great Lakes Pilot. On the Great Lakes, pilots have different levels of certification depending on which part of the lakes they pilot the freighters on. I've seen the switch made on 1,000 foot freighters in the middle of the night, steaming at 15 kts. The skiff pulls up alongside the freighter and the pilot climbs a 50 foot rope boarding ladder hanging off the side the ship.

The USCG cutters Alder and Mackinaw are busting ice up here to get the ships moving again. I seen Alder leave Duluth Harbor the other day and that's pretty impressive to watch. 6,000hp in a 235 foot cutter busting 3-5 foot ice at 4-5 kts with the props throwing water all over hell and grinding ice. Gotta admire those USCG guys and gals- crewing one of those cutters on ice breaking duty is like living in constant Richter Scale 5.0 earthquake for a two week tour of duty.

[ChrisOlson]

Chris, I think you are closest on with the analysis. The Origo electrical stove is also a non-pressurized alcohol stove so the alcohol could be stored onboard and used instead of running it off electrical - The hope there was that electrical power is renewable indefinitely whereas fuel requires stops at ports that can provide provisions.

Dennis, you have to realize that a cruising yacht is NOT a sustainable environment. The boat can be equipped and provisioned for a limited time at sea, usually not exceeding 19-20 days. It is not a cruise ship or nuclear aircraft carrier. You make a passage to get one from port to the next where you can take on fuel, fresh water and supplies. Your watermaker should be run to replenish your fresh water tankage every single day. It is not something you can count on. Watermakers plug up the membrane, the brushes go out of the motor, etc.. It is a safety cushion because if something happens at sea - you get caught in a storm and the boat gets dismasted and your radios are all out - you might end up being at sea longer than you expected.

You can survive on catching fish or without food for a long time. But when the fresh water runs out you are on borrowed time at sea. And once you set off your EPIRBS and launch an international rescue mission to save your a$$ the expense will end your cruising career. So be prepared for it. The ocean is a very big and beautiful place. But it is deadly at the same time and even in this modern day and age of technology you can be lost at seas and never found.

So make sure your head and shower is plumbed to use seawater, make sure your galley is plumbed to use seawater, etc.. Use seawater where ever you can in the boat at sea and only use the fresh water for the things you need to use fresh water for.

I highly doubt your boat is fit properly for blue water cruising. You need to fit things like circulating valves on the hot water so you can circulate the water until there is hot at the tap before you open the tap to get hot water out. This saves on water and doesn't waste a single drop. All these little things make the difference between a weekend cruiser and an ocean crossing boat.

I would highly suggest fitting an electric windlass for single handing the boat. I have the advantage of having a wife that is a licensed captain as a First Mate (actually she wears the white hat at sea and is in command, and I wear the blue one). What's going to happen is that you're going to get an anchorage, the wind switches and picks up in the middle of the night and your anchor alarm goes off on your chartplotter and wakes you up. You go up on deck and find that you are dragging those CQR's and you got minutes to get the problem fixed or you're going to be on the rocks. There is no way in hell you are going armstrong 400 lbs worth of anchor and chain rode on a 7:1 scope being pulled on by a 18 ton yacht into the well and get your boat out of there before you're grounded. For us, when that happens neither of us have to say anything. My wife springs into action and gets the diesel started and the transmission in gear while I go forward and start winching in rode. You don't have the luxury of a First Mate (or Captain, as it is) that knows what to do to save the boat. So spend the money on that windlass. You won't regret it.

When you are single handing you're going to need things that replaces crew. For instance, we prefer hank-on headsails because of the reliability and repair-ability at sea of a hank-on headsail system. For single handing you'll need a roller furled headsail and probably add an inner forestay for the storm jib. You won't have anybody to rotate with to be on watch on night and you need to sleep. Buy a radar with an alarm. The last you want to do is hear a big crunch in the middle of the night and wake up to water coming in the boat because you crashed into the side of a cruise ship.

I do not know what your experience level is. But you have to realize that single-handing a 50 foot yacht on ocean passages is only for very, very, VERY experienced sailors. I would strongly consider trading down to a smaller boat. The bigger they are, the harder they are to handle in rough seas. Even with the experience my wife and I have, a 54 footer was too much for us to handle. I would not even dream of myself trying to single-hand a 50 foot yacht on ocean passages. Cripes, the headsail alone is a 165 lb wad of Dacron and if you break a sheet and suddenly your sail is being shredded in the wind, or have any problems at sea which is more the norm than the exception on sailing yachts, you are going to be in trouble. Even our 37 foot yacht has room in it that rivals our house. A 50 footer has quite comfortable accommodations for four.

So those are all my thoughts on it. My gut feeling is that you are biting off more than you can chew. Scale things down a little and then I see your dream as being more of a practical reality. We met a young couple in Ambergris Caye, Belize that sailed a 25 foot MacGregor there from Germany. And they were having the time of their life and were setting sail for Panama to go thru the canal and to Hawaii. That sort of puts things into perspective.

[D_e_n_n_i_s]

Being prepared is so very critical and we are both on the same page with the emphasis on essentials for life. One of the things I liked about my specific vessel is that it had less volume of diesel, but had water tanks that will hold 300 gallons of water. I can run with no motor, but hard to live without water. The watermaker extends cruising and is a safety addition to water catchment. It is best to run it daily, which I plan to do. I will also have a water catchment system in place - As you wisely point out, you can't go very long without water. And yes, I do plan to supplement onboard supplies with fish, caught through various means. Yes again, you never know how long you will be out at sea because disasters will strike ... Amen, brotha !!

EPIRBS ... No stinkin' EPIRBS ... Dang electronics !! If the weather is that bad for my boat, they're not gonna launch a chopper or boats for me ... You're better to bring repair/emergency supplies to save yourself. And turn off the dang VHF as the noise will keep you from rest and a tranquil mind ...

Head plumbed to use seawater --> Check, both Groco heads. One of the easiest choices of "best" equipment to buy was a Groco head. Usually it's a hard comparison between competing lines, but Groco stands out.

Galley sink plumbed with a spout hooked to foot pump to use seawater - Check

Shower plumbed to use seawater ... Um, that's what a bucket is for, right? Got many of those fancy plastic shower bags to heat up on deck and take below - Even show temperature on the bag, but the black bags with no fancy temp gauge work better ...

Great advice for all about saving your freshwater - So very true and that is life-saving advice for anyone that doesn't recognize it as such.

Circulating valves on the hot water ... No A/C power to heat it up, but I do have the lines to the motor for heating. Not a great choice and always put your diesel motor in gear if you are using the alternator or heating water with it. Highly inefficient either way, but putting the engine in gear will help keep the engine walls from glassing ... Not sure exactly what you mean by the circulating valves, but it sounds interesting. I did have a Taylor Diesel heater that had lines around it for heating water, but it almost killed me once (my fault for not keeping it cleaner and running it too hard) so I yanked it out. Carbon monoxide poisoning sucks ...

Wife a licensed captain ... Dang, I can't compete with that level of preparedness ... lol - I'd make her captain of the vessel too; You are a VERY wise man ... Yeah, but for the consumption an electric windlass has on the batteries, I'm willing to make things a bit more tricky weighing the anchor. Typically, put up a jib only and slowly come up on the anchor and crank it up once it breaks loose from positioning the boat. It's a bit tricky, but not that bad. Yep, so true about the middle of the night anchor dragging - I only plan to put out the single, heavier CQR and be prepared to drop the second in case the anchor starts to drag. Both will hold the vessel unless I'm in a hurricane. I also have a large Danforth for additional emergency need. Preparation for quick action is the key. You've got to have the lines ready to go before you hit the sack. 400 lbs of anchor ?? Dude, design ... not weight !! Using the motor is a great way to deal with the huge forces that the wind puts on a boat. I found out quickly that I had to use the winches to move the boat in hurricane winds, I don't care how strong you are ... Watch those fingers !!

You get better roach with henked on sails and better repair-ability than you do with the snarler furling system I have, but there is a serious convenience with my Harken roller snarling system for the jib for single-handing. A knife will take it down in a pinch if things are totally lost. If you've ever seen a jib in hurricane winds whipping about, they only whip for about 5-10 minutes before they start to rip and they rip apart in another 2 minutes ... No, not mine ... a neighboring boat.

When North Sails sent me a quote for replacing all of my sails, including adding a spinnaker, and after I caught my breath again at the $32,000 quote, I saw that they included a storm jib that doesn't require a second stay to change out quickly. It's called an ATN gale sail. I'll have to read up more on it. I'm not sure how links are viewed in this forum so I won't post it, but I'm sure you can Google it quickly enough.

That was the other thing a radar is particularly useful for and that is as an alarm for other vessels. The power consumption will probably not result in its use as an anchor alarm (The weather will usually wake you up anyway), but it must be used for safety in this scenario and will add to my power consumption significantly while underway. DuoGen is coming out this year with a water generator that doesn't serve dual purpose (not a wind/water generator) so I think will be better sealed and something to consider for being underway. That may be how I provide the additional power for running a radar for this purpose. If I can hook it up correctly Without radar you have to wake up every 15 minutes and I REALLY don't want to do that ...

I talked to one sailor that lost an eye because he had an inexperienced landlubber take the helm while he went forward to fix a problem with the jib. The jib snapped in his face and he held his eye in his hand until they got to shore. Huge forces on sails are not to be underestimated. Sometimes, it's better to rely on yourself .... Just sayin'

Hawaii - Awesome ... Canal - Forget it !! Read up on all the small boats that get sunk going through the canal beside floating monsters ... OK, not gloom and doom, but not as safe as you might think ...

Thanks for your thoughts .. Maybe I've sparked some other commentary. I'm hoping for electrical guidance because like most things, when you get into outfitting a vessel for circumnavigation, you get into details you never thought you would. Like that alcohol for my Origo stove/oven and Origo stove - If you want alcohol without poison (not denatured), you have to pay a hefty excise tax because it can be consumed. Go with anhydrous alcohol and you get rid of the moisture issue in winter that these can cause ... Devil is in the details ... Thanks again for everyone's input !!

[D_e_n_n_i_s]

Just to focus things a bit ... I'm very easily derailed with sailing conversation

1. Hook up 2 solar panels in series to an MPPT controller, placing MPPT controller close to battery (OK, I added the 2nd part myself)
2. Hook MPPT controller to battery bank of 2 batteries (This should balance the pair of 300 Watt Kyocera panels with a matching pair of batteries)

To repeat one of my earlier posts:
What happens when I connect multiple banks of batteries to the main panel? They will all be interconnected at the panel through ... a switch or secondary panel ?? ... How should this be handled and will I get to toast marshmallows when I flip the switch(es)? Thoughts ??

To expand on that previous post, let's say that I just hook 2 banks of batteries, each with 2 8D batteries, to the main panel. I wouldn't think that kind of amperage is going to cook anything, right? What happens with the MPPT controllers? Do they sense the now "shared" load and freak out or continue to work as usual? Remember, the way I currently have this hypothetically designed here in the forum, the 2 solar panels, hooked to an MPPT controller are hooked to a bank of batteries directly - whether or not the particular bank is connected to the panel is a matter of flipping a switch. Would this cause an issue? Do I need to have a switch between the MPPT controller and its bank of batteries to switch it off:
a. When the bank is fully charged (Unless the MPPT controller manages that for me)
b. Before connecting the bank to the Main panel to power stuff on the boat

[ChrisOlson]

Circulating valves on the hot water ... No A/C power to heat it up, but I do have the lines to the motor for heating.

The engine is your primary method of heating water at sea. The electric is only for shore power (or onboard generator).

The water recirculating system plumbs in a simple circulation valve on the hot water line to the tap. When you need hot water you open the valve and let the water circulate back to the tank until you have hot water at the tap. When you open the tap you get instant hot water and not a single drop is wasted. Otherwise the line from the tank to the tap is full of cold water and if you need hot water you waste all that water in the line running it down the drain before your hot water gets there.

We had an ATN storm jib on our H-R 54. They are OK. Not near as convenient or strong as a removable forestay though. The storm jib can put pretty severe load on the forestay with the weight of a roller furling system.

I do not agree at ALL on the ground tackle, man. Been there. Done that. Got the t-shirt. Seen too many boats end up on the rocks because the captain said he (or she) had anchors that would hold in a hurricane. I hope you got really good insurance on the boat.

Your deck knife is fine to save a sail that's getting shredded because of a broken sheet or failed car on the track. But guess where it ends up? Ever tried to pull a soaked sail out of the drink after cutting it loose? Been there. Done that. Got the t-shirt on that one too.

We took a Hallberg-Rassy 34 thru the canal in 2007, crewing on a friend's boat. It is not that bad. It costs a lot of money. But you are assigned an Advisor that comes onboard your boat for the canal passage and there is no sunk boats - they make sure of it. That canal is so busy that you are assigned a specific time of passage that you have to make. It requires minimum 8 kts motoring speed in the canal, as you cannot hoist the sails. If you cannot maintain 8 kts they will pull you out and assign you a Canal Tug to tow you thru at the minimum speed. That Canal tug will cost you $2,500/hr. If you fail to provide your Advisor with dinner on time he will call the Canal Authority on the radio and they will send a skiff out with food and water for him. That dinner for your Advisor will cost you $175. It requires a crew of four on board and you have to hire line handlers on the lock walls. Those line handlers will cost you a Grand. They have specific requirements for the lines, and since nobody carries those on their boats, you have to rent them from the Canal Authority at $250/line. All told, it will cost you $5 Grand to make the 90 mile passage thru the Canal. That's if you don't screw anything up. There are only two alternatives - turn around and sail the other way around the world to get to the other side. Or sail around Cape Horn. If you sail around Cape Horn be prepared to freeze your balls off. Been there. Done that. Got the t-shirt. Don't want another t-shirt. The canal is the lesser of three evils.

[D_e_n_n_i_s]

Chris - Thanks for the insight into the circulating system and fair enough on the ground tackle and jib in the water ...

I wasn't suggesting the smaller anchor would hold in a hurricane, just in nasty storms or current changes that can cause an anchor to drag - Usually, the anchor is pulled in a different direction and that causes the drag problem. Hurricane's are an altogether different subject, no doubt !!

Holy crap - $2500/hour, dinner, $250/line ... I'll have to see if the new motor will do 8 knots - Replacing a Pathfinder 50HP (marinized VW motor) with a Yanmar. Good move, but lots of bucks ... $5K - Gee whiz, man ... Why do you need to spend $5K to cut out sailing time ... Go around and enjoy the extra weeks of sailing free, untethered to shore !!! OK, short of the Antarctic, the Horn is the most challenging, but still ...

As far as the jib goes, I HOPE I don't have to cut it !!! Yes, retrieving any sail in the water is going to be a long, hard series of pulls somehow involving the winches ... Bad times ...


OK, I have to add something more to point so I will recap first ...

1. Hook up 2 solar panels in series to an MPPT controller, placing MPPT controller close to battery (OK, I added the 2nd part myself)
2. Hook MPPT controller to battery bank of 2 batteries (This should balance the pair of 300 Watt Kyocera panels with a matching pair of batteries)
3. Put switch between each bank of batteries and main panel ???
4. Put switch between each MPPT controller and its bank of batteries ???

One thing that kills me with assigning a pair of panels to just one bank of batteries (fixed, not dynamically) is that I'll end up with 2 or 3 banks fully charged during the day and the panels hooked to those fully charged banks are soaking up the sun ready to crank out power, but sit idle when they could be dynamically assigned to charge the 1 or 2 banks of discharged batteries ... What a waste !!

Yes, each bank would need to be isolated and not charged at the same time because charging banks of batteries at dissimilar states of charge would cause HUGE issues, but an individual bank could be assigned multiple banks of solar panels to charge it up more quickly. Same could be done for 2 banks of batteries if kept isolated from each other ... or so I'm thinking ...

[ChrisOlson]

1. Hook up 2 solar panels in series to an MPPT controller, placing MPPT controller close to battery (OK, I added the 2nd part myself)
2. Hook MPPT controller to battery bank of 2 batteries (This should balance the pair of 300 Watt Kyocera panels with a matching pair of batteries)

Sorry - sailing is just too much fun.

I think I will let one of the experts on solar reply to this, as I do not fully understand what you are trying to accomplish here.

What happens when I connect multiple banks of batteries to the main panel? They will all be interconnected at the panel through ... a switch or secondary panel ?? ... How should this be handled and will I get to toast marshmallows when I flip the switch(es)? Thoughts ??

If the battery banks are at different SOC the higher charged one discharges in the lower charged one. That's why you don't do that. There is not going to be any toasty marshmallows. You see where it says 1&2 on your Battery Selector Switch? You only switch to that position when you have adequate charge power for both banks. Or in an emergency where both banks are low on power and you need everything you got left to operate some critical equipment.

To expand on that previous post, let's say that I just hook 2 banks of batteries, each with 2 8D batteries, to the main panel. I wouldn't think that kind of amperage is going to cook anything, right? What happens with the MPPT controllers? Do they sense the now "shared" load and freak out or continue to work as usual?

Those controllers hook to your DC panel bus. Not to the battery. Whichever battery is hooked to the panel with the Battery Selector Switch gets to use the controllers.

The other thing it sounds like you don't have is an auto-isolator or ACR. Buy one:

http://www.bluesea.com/resources/58/Battery_Isolators_and_Automatic_Charging_Relays

[Mike90250]

I'm not following why multiple banks of batteries, other than a backup for a bonehead screwup and you only drain half your power. Watts is Watts. If you need 50KWh of batteries, they ALL need the capability to be recharged at the proper rate.
And how long will you last with a couple cloudy days, without backup generator? This just seems like huge loads, huge battery banks, and a couple small PV panels (2, 300w panels only give 40a in the best conditions @ 15V charging voltage.)
Each controller needs the option to connect and charge each bank individually, and each controller needs to be powered up in the correct sequence, each time you swap things around, and it reboots itself.
I'd say all banks and all chargers connected at all times, except for a bank in reserve for a whoops moment, but you have to rotate the usage around all the banks, every day after a full charge.

[D_e_n_n_i_s]

Truly sailing is too much fun ... you stinker !!

Not sure myself ... Really, I just need to look at my power take-offs and make sure I have enough amperage to run everything I want to run at any given time. The only time I would need say 2 banks of batteries (each bank having 2 batteries at this point in theory), would be if I'm running the frig, taking a shower so the fresh water pump is coming on periodically and also flipped on the watermaker ... I dunno, need to do a max-amp-need takeoff.

I do want to keep the banks at different states of charge isolated. Sunking educated me on that - Thanks !! I do have a secondary panel with multiple fuses and switches and actually don't have one of those 1&2 battery switches on this boat ... lol That's what you get for derailing me !!!

OK to serious stuff now ... The MPPT controllers hook to D/C panel bus. OK, this is a huge thing that I'm not getting, but need to understand. Right now, I have a "House" input and an "Engine" input as the two D/C inputs to the main panel. I actually mounted a post for both of them on the hull, which besides taking the physical strain off pulling on the panel with the long battery cables, also gives me the ability to hook additional inputs if that is the way to go. I'm still not clear how I would connect multiple banks of batteries to my main panel. So sad ... so clueless ... I'm really missing some basics with this stuff, guys.

ACR's - Woah, now that's cool. Opened my eyes to another world ... an electronic check valve ... who'd a thunk it. Seems to be an auto-sensing device like you would have on a charger to know when the battery is charged or needs charging (senses voltage). Closes when voltage shows as charged (though voltage of battery is how it's guessing the battery is hooked to a charging source rather than sensing a load) ... The switch then closes and shares the charging current with the other battery ... hmmmmm ... opens back up when voltage shows battery needs charging.

Connected during charging and disconnected during discharge ... OK, that makes sense. So does this help keep two batteries in the same bank at a better charge equilibrium ?? No, this seems to do this between battery banks ... Also, helps to prevent one battery from being pulled down too low ??

I like a multi-stage charger, but how does an MPPT controller reduce charge as a battery's voltage shows it is becoming fully charged ?? I'm such an electronic newb sometimes ...

OK, I'm getting more pieces of the puzzle to set up a monitored, regulated system, but I'm still too clueless to be safe. Thoughts ?? No, besides this guy is an idiot about to kill himself ... Guide me, please ...