Sailboat Power

[Sunking]

Sunking - "Cannot interconnect batteries that way" ... Do you mean having certain banks and/or all batteries connected to a main panel to supply power and have each bank also connected to all MPPT controllers through a secondary panel?

No Sir that is not what I am saying.

If I understood you correctly it sounds like you plan to take batteries off line, or disconnect and rotating batteries in and out of circuit. If that is what you intend to do you are playing with fire. In other words let's say for example you are going to use two 12 volt batteries. One off-line, and the other on-line. When you connect two batteries together in parallel that are at different state of charge, you will have massive amounts of equalizing current flowing between the two batteries. The battery with a higher state of charge will try to equalize and pull up the lower state of charge battery. With the size of batteries you are using that can be up in the thousands of amps, and if there is no over current protection devices (like fuses) on each battery there is no way to break the connection and the wiring will act as a fuse by bursting into flames and melting the copper wire. It is bad enough if that happens on dry land, but really bad on boat and planes.

So please don't get offended, I just care about folks safety.


On a different subject what are you going with 12 volts? Why not 24 or 48?

[Mike90250]

Whoa. The big problem is, you are on a boat. Even worse, a sailboat, with masts, stays, lines, shrouds and all that. The shadows from even a small stay, will shut down a PV panel. 200w panel. 15 watts coming out. ARGHHH!!

You cannot build a infinite bank of paralleled batteries, especially AGM. Their internal resistance is low enough that the differences in the parallel cables, will imbalance the bank. Regular flooded batteries have a bit higher internal resistance, and using buss bars to parallel batteries becomes feasible, unless you are on a boat, then everything has to be tin or nickle plated. Stranded wire in the cables, buss bars, breaker terminals. Everything. The moist salt air will turn plain copper to swiss cheese in just a couple years.

A boat full of expensive batteries, needs to have a backup charging source, not wind, but some kind of reliable ICE generator, or aux alternator on the drive motor.

If you plan to have Air conditioning and electric heat, it's NOT going to happen with solar on a boat, unless you tow a raft with a huge solar array (that is not in your mast shadow). Just food refrigeration will be a problem (all those pesky shadows).

And there are ways to deal with gasoline issues, you can't just write off a whole line of portable power like that.

This is going to need a major rethink, of what your critical uses are, and how to get power to them. Conserve, conserve, conserve.

[Naptown]

switching will become a real issue trying to switch controllers between batteries.
Mostly because you will have very high voltage from the panels if in series and you need to connect in order. battery first then panels so if you disconect a battery bank you will need to disconnect and reconnect the panels to the controller which is at higher voltage and requires a whole different flavor of switch.

[ChrisOlson]

Plan on buying a new set of batteries every year.

At night you have to have running/anchor lights, and in a cloudy week with no solar, you will murder the batteries.
Please consider even a small honda eu1000 to power a backup battery charger. Yes, there are gasoline storage issues, but they can be dealt with. At some point dead batteries will not boot up the solar charger, and then you are goner.

Doesn't this boat have dual battery banks? We have solar on our sailboat with a MidNite KID controller. But we also have two battery banks, selectable with a switch (can be seen to the right of the controller in this photo):



Also Mike, most cruisers run the propulsion engine once a day for hot water onboard on passages. Sailing yachts typically have 90 - 200A alternators on the propulsion engine (depending on the size of the boat) for the express purpose of charging batteries.

NEVER use a portable generator on a yacht. Your Mastervolt equipment has neutral switching, depending on whether you are on shore power or at sea. Plugging the shore power cord into a portable generator does not take the place of the neutral ground bonding that you get on shore power when connected. If you want to cause lots of galvanic corrosion on your boat and eat all your zincs off running a portable generator onboard is a good way to do it. But I only ask one thing - stay the hell away from my boat when you come into an anchorage and drop hook, then run your portable generator. I don't care if you want your rudder post to get ate off. But I'd like to keep mine intact, thanks.

[Naptown]

No Sir that is not what I am saying.

If I understood you correctly it sounds like you plan to take batteries off line, or disconnect and rotating batteries in and out of circuit. If that is what you intend to do you are playing with fire. In other words let's say for example you are going to use two 12 volt batteries. One off-line, and the other on-line. When you connect two batteries together in parallel that are at different state of charge, you will have massive amounts of equalizing current flowing between the two batteries. The battery with a higher state of charge will try to equalize and pull up the lower state of charge battery. With the size of batteries you are using that can be up in the thousands of amps, and if there is no over current protection devices (like fuses) on each battery there is no way to break the connection and the wiring will act as a fuse by bursting into flames and melting the copper wire. It is bad enough if that happens on dry land, but really bad on boat and planes.

So please don't get offended, I just care about folks safety.


On a different subject what are you going with 12 volts? Why not 24 or 48?

Marine battery switches are mad in two flavors. Most are make before break so one can switch banks with the engine running and not fry the alternator.
In this case house loads should be isolated with a battery isolator and starting bateries always connected to the alternator.
switches between battery banks (very normal on a boat to allow combining batteries) in this case should be break then make

[D_e_n_n_i_s]

Sunking - Aha, light begins to dawn. OK, yep ... You not only don't want to charge dissimarly sized batteries, but also wouldn't want to charge banks of batteries with dissimar states of charge. Keep in mind that I'm talking about using a switch so I'm not physically disconnecting batteries AND that I want to take a bank out of production when it gets very close to 50% charge (or sooner). That being said, I do see your point that it will be a rare day when you get two banks of batteries discharged down to the same % charge, even taking them off at 50% because as soon as I hit 50%, I want to throw it into the charging mix. If they are within 5% of charge and all the same batch of 8D batteries, would something like this work or just too dangerous to even try?

Oh, and I am definitely not offended and appreciate you keeping me on the boat rather than swimming in the sea when the sailboat is fully ablaze ...

Reason for 12 volts ... That's easy. Everything on the boat is 12-volts so I would have to step up voltage and step it back down to use anything else from the panel, change gauges, change how things are wired, hope I never make a mistake with wiring connections ... I don't want to become a sequel to "All is Lost" .... though slow action caused most of Robert Redford's problems - He is actually a real sailor and that film must have driven him nuts

So far, I now know that I want to hook two solar panels in series and place the MPPT controller very close to one bank of batteries so I run smaller gauge wire to the MPPT controller and a shorter run of heavier gauge wire to the batteries. At some point I'll ask for recommended gauges for monitoring battery charge so I can watch all this magic happen and know when to break out the dinghy for escape ...


Speaking of real sailors, Mike ... You must be sailing to Catalina Island !! Soooo true, metal just dissolves in salt air ... I was planning on using class 3 stranded tinned wire of greater than recommended sizing to allow for some threads to bust loose without causing a fire ... Stuff that keeps you up at night even with the gentle rocking of the boat ...

Thanks for the info on the AGM batteries. I think AGM is definitely the best way to go, but I need to find the safe balance of bank size. Figuring 6-8 AGM 8D batteries, I was thinking it best to go with smaller 2-battery banks, but I could go with banks of 3 batteries if I'm not pushing it. Of course, we have to go back to my thoughts of hooking them together. I really envisioned cycling banks to use for power after doing some take-offs for the amperage I'll need when running a watermaker or some other higher amp draw device. I also haven't even gotten into how to hook up the A/C side to be powered from the batteries and that is a huge concern. Do you know at what point I would have too many 8D AGM batteries hooked together to no longer be safe?

Oh yeah, first thing I figured when calculating power was that there is no way to run air conditioning or heat on any kind of D/C system and hot water is dicey at best even with some D/C options. I have some ideas on all of these subjects, but I need to order and test some equipment before I'm ready to expand on that topic. In the meantime, there's always the black bag for hot water and latitude adjustment for heat/cooling ... lol

By the way, running a Norcold frig with its D/C side is surprisingly efficient. D/C is about 3 times more efficient than A/C with an inverter so that's clearly the way to go. I think that one surprised me that it was really quite do-able.

My outboard is gas so I'm stuck with having some explosives onboard, but I do try to minimize it whenever I can. Shaking that gas can up in high seas, then settling down to a hot calm ... just sayin' ...

Amen to conservation !! Absolutely necessary regardless of the route I get there with power. That's the thing about being onboard a boat - You know where every drop of fresh water and every amp of power goes ... You control your world out there on the sea. That's why I really do want to be completely self-sufficient if I can make it happen.

Do the Kyocera 300 watt solar panels really lose that much power with minor shadowing? I'll have to go back to my earlier research, but if you can recommend a different brand that can handle shadowing better, please let me know !!

Thanks guys for the terrific education that I'm getting !! I really do appreciate your time and feedback and please don't think for a minute that I'm dismissing any of your ideas ... I'm just trying to fully understand my options because I really want to set this up right and it's a long swim to shore !!

[Sunking]

Marine battery switches are mad in two flavors. Most are make before break so one can switch banks with the engine running and not fry the alternator.
In this case house loads should be isolated with a battery isolator and starting bateries always connected to the alternator.
switches between battery banks (very normal on a boat to allow combining batteries) in this case should be break then make

Not a boat person. My only experience with boats is Bass Boats and U-Boats and everything on a U-Boat is electric. Well except for Auxiliary diesel if the reactor fire goes out.

[Naptown]

[QUOTE=ChrisOlson;103273

I don't care if you want your rudder post to get ate off. But I'd like to keep mine intact, thanks.[/QUOTE]


Rudder? We don't need no stinkin rudder.

[Sunking]

Rudder? We don't need no stinkin rudder.

Last ship I was on, Oasis of the Seas, had no rudders.

[D_e_n_n_i_s]

U-Boat - Very cool ... Now there's some electrical experience you don't see every day !!

Oh the virtues of zinc !! Ya'll are crackin' me up !!

No rudder ?? Do those Royal Caribbean boats angle those large screws or just use side thrust ??

[ChrisOlson]

Do the Kyocera 300 watt solar panels really lose that much power with minor shadowing? I'll have to go back to my earlier research, but if you can recommend a different brand that can handle shadowing better, please let me know !!

When you're under sail you'll have constant shading issues on the panels. Most folks with solar on a sailing yacht use separate MPPT controllers on each panel to minimize the shading issue and maximize solar harvest. We have two Kyocera 160 watt panels on the arch along with GPS, SSB, VHF, and radar. We have our Rogue WiFi antenna on top of the mast.

Your daytime loads at sea are going to be chartplotter, autopilot (unless you have a windvane), maybe depth sounder if you're not in deep water, radar, VHF, SSB (if equipped), watermaker, and maybe some misc cabin loads if your wife goes below deck to cook dinner or something. Some folks will have a PC running with OpenCPN for navigation, and the PC is tied to the autopilot. I don't see the value of using a laptop for navigation at sea anymore with modern chartplotters and/or tablet computers that run marine nav apps. OpenCPN on a PC is nice for planning a passage when you're dangling on the hook, or have shore power. But at sea, shut it off and don't use it.

At night add running and masthead lights, cabin lights, ventilation fans, and maybe red cockpit lighting (if equipped). Total power consumption is usually in the neighborhood of 4 kWh/day on a 40-50 ft class cruiser, or about 350ah. The autopilot is going to consume the most power, and the watermaker is going to be #2.

We can get by with just 320 watts because we have a Monitor windvane autopilot on our boat. The Monitor is a bit more expensive than like a Ray Marine electric over hydraulic, or wheel drive, autopilot. But it's worth the money because you will work the snot out of your electric autopilot in 15-20 foot seas. The higher the wind and the bigger the seas, the better the Monitor works. We also have an electric autopilot for motoring, but we dis-engage it under sail and don't use it.

It is best to split your battery bank and have an isolator for the starting battery on the diesel. For one, the isolator prevents huge voltage drop to your onboard electronics during engine crank. And it disconnects the house loads from the starting battery to prevent discharge of your starting battery when under sail. It will reconnect your starting battery and charge it when you have a charging source available. During the day you run on Bank 1 and when nightfall comes if Bank1 isn't fully charged, then switch to your fully charged Bank 2 for the night. Bank2 has charging priority the next morning, and if you have adequate charging power, you can combine Bank1 and Bank2 and change them both.

You're going to need onboard hot water for showers, unless you want to take showers with seawater drawn on your seawater intake seacock. Most men can get by with this just fine. But I cruise with a woman and she doesn't like the "sticky" feeling after taking a seawater shower. So that means you will run your diesel at least once a day anyway. Factor in how many amp-hours you're going to get from the alternator on the diesel when you're producing hot water with it, and that reduces your need for solar panels. Using an inverter at sea cannot be done unless your boat is equipped with an onboard marine generator to recharge the batteries, or you plan on running the propulsion engine a lot more for charging. Forget anything to do with inverters onboard a sailing yacht unless you have the equipment to charge those batteries. And a sailing yacht cannot carry enough solar panels to make that happen.

You don't mention whether your boat is a ketch or a masthead or fractional sloop. That makes a BIG difference where you are going to mount the panels. On a sloop, mounting them on the arch (if equipped) works good, and mount them flat. Tilting panels on a sailing yacht does not work. On a ketch you're going to have to get creative because most of the deck is partially shaded most of the day with the addition of the mizzen.

Most of your ocean passages are going to be sailing on a reach. So on a sloop having those panels near the stern is going to provide them with the most insolation thru the day. Do not mount them low. Especially if you have a hydraulic swim deck or Monitor windvane on the boat. Spend the $10 Grand on a custom stainless arch and put them on there. You will get by with half the panels you would otherwise need.

When it comes to marine electrical, it is VERY easy to screw it up royally. Your boat has two grounding systems in it - the bonding system and the electrical grounding system. If you combine them, or hook things up wrong, then lose your rudder at sea because the post corroded off from galvanic corrosion, it will turn into a disaster for you. Unless the boat is a ketch and you can steer it with the mizzen, in almost any ocean on earth you can figure on $10 Grand to get a tow into port from sea and 2-3 weeks and another $10 Grand spent in port to get a new rudder for it. I've seen it time and time again all because people cobbled the electrical system on the boat. If you have any doubts about what you are doing on a Class A ocean cruising yacht, consult a licensed marine electrician. Your life depends on it at sea.

[ChrisOlson]

Rudder? We don't need no stinkin rudder.

Well no, technically you don't need a rudder. I mean, if the sails are trimmed nice with a little weather helm and you lose the rudder she'll just round up and come to a stop. Then you spend the next couple months drifting at sea, very peacefully, and see how your supplies and fresh water holds out

Now, I've seen some very good sailors drop the main on a ketch and bring her into port steering with the mizzen. But if they were 10 days out to sea, by the time they get to port they look like they been dragged thru a knothole sideways and then beat up with a baseball bat after spending 240 hours straight on the sheets to steer the boat.

I've seen some people try it on sloops and finally call Mayday on the radio when it became apparent they weren't going to make it. That gets dicey in international waters under marine salvage law. You can lose your boat to salvage, depending on who responds to the Mayday call to tow you in. If it's a commercial fishing trawler that comes to your rescue you will have to pay not only for the tow, but also for their lost income both to port and back to their fishing grounds. The tow bill many times ends up being more than your boat is worth and it is impounded once you reach port until you pay the bill or release her for salvage.

Overall, I'm going to say that a rudder is a good thing to have.

[Naptown]

Well no, technically you don't need a rudder. I mean, if the sails are trimmed nice with a little weather helm and you lose the rudder she'll just round up and come to a stop. Then you spend the next couple months drifting at sea, very peacefully, and see how your supplies and fresh water holds out

Now, I've seen some very good sailors drop the main on a ketch and bring her into port steering with the mizzen. But if they were 10 days out to sea, by the time they get to port they look like they been dragged thru a knothole sideways and then beat up with a baseball bat after spending 240 hours straight on the sheets to steer the boat.

I've seen some people try it on sloops and finally call Mayday on the radio when it became apparent they weren't going to make it. That gets dicey in international waters under marine salvage law. You can lose your boat to salvage, depending on who responds to the Mayday call to tow you in. If it's a commercial fishing trawler that comes to your rescue you will have to pay not only for the tow, but also for their lost income both to port and back to their fishing grounds. The tow bill many times ends up being more than your boat is worth and it is impounded once you reach port until you pay the bill or release her for salvage.

Overall, I'm going to say that a rudder is a good thing to have.

I used to run a youth sailing program.
One of the things we made the kids do to learn trim and sail balance was to take them out and take away their rudders.

[D_e_n_n_i_s]

LOL - Chris, love the rudder commentary, but that is actually quite educational on the Mayday call ... I've never had anyone spell that out, but a third world country's interpretation of international marine salvage law, corrupt charges that can't be paid resulting in loss of vessel ... and pay for lost wages & fuel/time for transit to fishing grounds ... I just got schooled again - Thanks for the insight !!

I just bought an Aries windvane that should ship out next week - I like my sailing to be relaxing, but you do make a very valid point about using sails for steering. In fact, even to properly use a windvane, sails should be set up properly to make everything work together.

I don't have the experience to bring a 50 foot sailboat into a slip under sail, but might manage getting into port if those other boaters will just clear a mile path for me ...

Rich - That's an interesting training technique that should really put folks to the test. Force 'em to understand how the sails move the boat. I've heard of some sailors so good with using their sails that they actually prefer to come into slips using sails as it provides better control than a motor. Maybe one day ...

[ChrisOlson]

I used to run a youth sailing program.
One of the things we made the kids do to learn trim and sail balance was to take them out and take away their rudders.

Every sailor needs to learn balance and trim. BUT - sailing a dinghy without a rudder is a lot different than a husband/wife crew on a 22 ton 50 foot sailing yacht a week or more out to sea with no rudder. After the 2nd or 3rd day on the sheets, working 24/7, you because so exhausted that you simply cannot carry on. That far out to sea you are meeting a deadline to the day you run out of supplies and fuel. Instead of instruction under controlled conditions it becomes life or death with greatly increased chances of being caught in heavy seas, and running out of supplies.