Solar panel on B28

Yannis · Post by **Yannis** » Oct 27th, '13, 04:54

I'm planning to install one solar panel on my 28, which together with a small Honda type generator (that only weighs 13 kg) will most probably suffice for all my electricity needs. I figure I need 70-80 Ah per 24h. All this, in the attempt to not have to moor in organized marinas so as to be connected with a cable to the mains. This will allow me to choose my secluded beach and spend as much time I want in almost perfect peace...
In order for the solar panel to work efficiently, it has to be placed in an area where the sun hits it as much as possible; hence I thought either hanging on some sort of hinges vertical on the rails to be lifted horizontal when needed (like on some sailing boats), or, put it on top of everything - albeit I have no hard tops, just the two bimini soft tops. The dimensions of this panel are 104 X 52 cm (roughly 3 feet by less than 2 feet), so I recon it to be somewhat big for hanging it or just storing it downbelow and deploying it only when I need it. The flexible ones cannot supply the Amperes I need so I will need two flexible ones, that are already much more expensive. It also has to be somehow "invisible' or the boat will look like a Batman mobile !! Any thoughts on where i should install it ? Has anybody done this? Thanks.

jackryan · Post by **jackryan** » Oct 27th, '13, 21:20

I dont know anything about solar panels, but my brother knows a bit about them and I asked him about them today. He uses a small solar panel to keep the batteries on his boat charged up while sitting at the dock. The panel he uses is about 1'X2'. Sitting at the dock, there is very little draw on the batteries, so the solar panel does a nice job keeping the batteries topped off. He thinks to produce 70 to 80 Ah per day, you would need a very large panel, close to 10 times the size of the small one he uses to trickle charge his batteries. You may be able to use a small panel to generate some of your energy needs, and use your generator to make up the difference. Again, I am no expert, so if there are any solar experts out there, please chime in.

JR

Yannis · Post by **Yannis** » Oct 27th, '13, 22:56

Yes, Jack, I'm aware of this little panel, a variation of which you can even find for cell phone recharging.
And yes, your bro is right, the panel I'm talking about will be roughly 3 X 2 ft.
This panel will be generating about 40 Ah per day, so it will be keeping the fridge operating (my fridge consumes 30-40 Ah/day).For the remaining 30-40 Ah (which is lights, various pumps, stereo, fan, and toilet) just 30 min to 1 h of genny per day is enough. My cooking is all gas of course, no a/c of course, I also changed the 5 X 10 w cabin lights with 1.5w led ones, for 50 euros altogether. In this configuration you can stay away from marinas indefinitely. The only reason to go back to civilization is water, for which my next project will be a 12v operated desalinator (producing around 30 liters of fresh water per operating hour); you run it simultaneously with the genny and you're all set ! The sun never sets in the Bertram empire !

PS: To further ameliorate the electricity consumption, I'm planning to install a keel cooler. This will reduce my fridge's consumption by roughly 10 Ah per day. Somebody pls explain to me how I can attach a pdf file, in ... English.

Bruce · Post by **Bruce** » Oct 28th, '13, 07:23

Caution on using solar panels.

Most panels are rated at the maximum output in relation to its peak exposure to the sun. Since the earth is rotating the only way this can be achieved is to have a panels on a computer controlled rotatable platform constantly correcting for the rotation.
The additional problem with a marine application is a boat on the hook is constantly moving on its mooring adding to the problem of keeping the panel pointing in the correct position.

The way around this is to have more panel capacity than your load so when a fixed panel's peak is passed and the output drops, your still covered.

Your panel as you state does 40ah/day and your fridge does 30 to 40 ah/day. That's much to close to ensure your batteries are properly charged each day.

Trying hid a panel yet have it operate at is peak on 28' boat is near impossible.

Using a keel cooler for the condensing coil cooling rather than a fan can work to eliminate some of the load.
Not knowing what type of refrigeration system you have or its capacity or operating voltage, I can't make a determination.

Also you don't mention what type of charger run with the generator you will be using to charge the batteries. It makes a big difference what type of charger you use on a deep cycle system. Slow charging will always put the batteries back in their proper peak voltage for peak operation and life. High output, fast chargers will create heat within the battery and lead to much shorter life and lower peak voltages over time.

jackryan · Post by **jackryan** » Oct 28th, '13, 09:05

My brother just sent this email to me about solar panels:

Panels are rated in watts. My panel is 15W so it generates about 1 amp at about 14V. At best you can assume about 5 hours of full panel power per day so my panel will generate about 5ah. To generate 40ah I would need at least 120W panel (about 15 sqft. of panel). Also, generators are a very inefficient way to charge batteries, especially to "top them off". The generator should only be run 1st thing in the morning and on rainy days, otherwise those will be very expensive amp-hours it's generating.

JR

Yannis · Post by **Yannis** » Oct 28th, '13, 10:17

Bruce and Jack (and brother of Jack), thank you for your input.

First of all, Jack, the solar energy companies in Greece do their calculations on 10 hours of usable sunlight, so as to be on the safe side; consider this, the sun rises at 6 am and sets after 8:30 pm. Out of those 14+ hours of scorching sunlight they calculate just 10. So, yes, it will be big, but not as big (thank God). The panel I'm talking about is 100 X 50 cm and if I recall correctly, it is 80 W.

Bruce, yes, the conditions will not always be optimal, that's why in my calculations I deduct a 20% for "not perfect sun direction" and/or clouds (if you ever see a cloud in Greece during the summer ...pls. take a picture of it!). And, yes, you're right, it has to be placed fixed, I can't play around with mounting and removing it or I'll eventually break it.
My fridge is a Vitrifrigo C 75 L NA / with a Danfoss compressor / at 12 volts / 42 watts / input current at 3.6 A (minus 10 Ah if Keel Cooler). My Battery charger is a Quick, model SBC 500 ADV / Max. output 40 A.

I believe that the combo of this solar panel with a small 1000kva Honda-type genny should be enough (for my 70-80 Ah daily needs ). It puzzles me, however, when you start talking about charging time. I have ordinary batteries, not gel, so its not deep cycle (am I wrong?) Shall I move to gel, at least for the house? Shouldn't the solar energy (at least) be considered slow charging ?
In this context, Jack, what do you mean by "expensive amp hours"; the cost of gas for 1 hour of genny operation, that is 1 liter or 2 euros a day (that is for the remaining 40 or so non-solar amps, which with my 40 A charger I replenish in an hour) ?

PS: Bruce, for some unknown reason, the earth rotates at a lesser pace over here !!

Bruce · Post by **Bruce** » Oct 28th, '13, 12:15

Your system is considered deep cycle or should be considering since your removing power from the batteries, maybe not so much during the day when the sun is out, but certainly at night. This power consumption without a charge being put right back in, in the case of an engine start and then the alternator charging back what the starter took out and covering any running current, is referred to as a deep cycle operation and should use batteries required as such either lead acid, gel or AGM.

The plates are much heavier and will take the constant charging and discharging. While engine start batteries have been used also, they are not the optimum style battery.

High amp chargers will shed plate material. That plate material over time falls to the bottom and then builds up to the point where it will short out the cell and render a battery useless on lead acid.
Gel batteries will not take high output charging without killing them. Same for AGM. If one looks at the manufacturers charging specs on the last two batteries it will show it. If you use slower multi stage chargers, that just means more generator run time.

I suggest you do an experiment. Hook up your panel, lay it in the sun and do some output measuring throughout the day. You'd be surprised how little a change in sun will affect output.

I have a 12"x18" panel on an out building hooked directly to a exhaust fan(no battery) to keep the heat down in the summer(in Florida lets face it all year round).
Its interesting to listen to the rpm of the fan change with a passing cloud, change in time of day, change in time of year. With a battery you don't see or hear those subtle changes that can grossly effect output.

I would have double the panel output for load needed for a reliable system as I don't know the quality of the panels you have there but the ones I've seen for decades here, and they are better now than they were, still have issues with individual cells.

The type of panel you have, Mono or Poly crystalline, makes a difference in output also.

Yannis · Post by **Yannis** » Oct 29th, '13, 01:14

Thank you Bruce.

I guess I have to consider doubling my solar output; now that I come to think of it, it's not so terrible; where one single panel would go, now there will go two, so as to minimize genny time which is harmful to my batteries.
I was thinking of the location to install them: Either on top of the fb bimini (if I don't put the bimini canvass back on and let those two panels do the work of shading), or perhaps on the front surface of the fb, over the salon front windows ( but it's so ugly there).
It would be ideal to install them over the deck canvass, but this would prohibit me from folding it (as I do) in bad weather. Tough life !

Bruce · Post by **Bruce** » Oct 29th, '13, 07:33

I'd make another bimini type frame that would go over the canvas and allow any tilt that might be needed yet keep close to canvas as not to stick out like bad hollywood plastic surgery and mount the panels to that.

Make the frame so it could tilt down and secure in front of the windows for storms.

You might look into a wind turbine. I had much more success with those on systems that required continuous power inputs back into the batteries and the solar was just backup to that.

The most important thing is to keep your batteries at their peak during usage as when voltage drops, current is going to increase using more watts of energy. Anything below 11vdc is considered a dead condition and where most inverters will shut down to protect themselves from an over current condition.

With increased current also comes higher heat which can also affect equipment being utilized and shorten its life.

The type of compressor you are using is used in a popular dc reefer system here called Adler Barbour which was real voltage sensitive especially the module.

Yannis · Post by **Yannis** » Oct 29th, '13, 10:20

I thought so too, in what refers to the frame for the solars.
The frame you propose should be somehow pivoting so that it can fall fwd onto the front deck against the windows. Not a bad idea. I was thinking more of securing the existing frame on the front side by SS vertical (or so) rods (actually I only have rear SS rods,almost vertical, so I can't really fold the frame down - I can only remove the canvas and stow it away - the retracted frame rests aft on the aft rods). Then, on this totally stable frame, attach externally (with SS joints) two upside down U's that will hold the panels; with a 10 cm space between the U's and the canvas, to allow for canvas' vertical slack... I'm a bit worried about the weight though.

The wind turbine has, I suspect, 3 drawbacks; One, there are times it's complete calm for days..., Two, it's much more expensive for the same output, and, Three, it makes noise. I haven't, however, ruled it out completely and thank you for bringing it up.

You also gave me the idea to break down my electric consumption pattern into time zones. After sunset, all I have is the reefer (less consumption though, cos its not as hot outside), the cabin lights (minimal), and the shower pump (10-15 mins max if the boys are there too, or any other company).
What's your opinion on common showers to minimize fresh water pump usage?

PS: Correct me if I'm wrong but I think you meant "... current is going to increase using more Amps of energy" not watts.

Bruce · Post by **Bruce** » Oct 30th, '13, 07:34

What's your opinion on common showers to minimize fresh water pump usage?

Anytime a man and any number of women can shower together, I'm all for it. Thats where the environmentalist in me really shines.

A number of times where the structure was there to support the weight, a 10 or 15 gallon painted black tank or heavy bladder above the head works well. Wet down, water off, soap, rinse. Its amazing how little water you can use.

Pat has told me his required bathing technique during his sub duty from a sink.
You just have to do it in the right order otherwise brushing your teeth could be foul tasting.

Current is amps, one in the same. watts is power used as in volts times amps.

Two formulas to use if you don't have them are E=IR, E=voltage, I=current(amps), R=resistance and for power in a dc circuit P=IV, P=power in watts, I=current(amps), V=voltage.

If you have two quantities you can always find the third by changing the equation around.

Also when figuring numbers remember that manufacturer published data is almost always off. Once installed, wire size, length of run, voltage can make a difference in what the battery sees both in draw and charging.

Also don't forget while minute in time function, start up current both on DC, AC and inductive and capacitance loads will spike at start up using more power. An Item that cycles quite a bit during a 24 hour period can make a difference in power consumption.

Thats why when figuring generator kw capacity is essential to know this. While this probably doesn't apply to you, its just general post information. I've seen numerous instances where gen sets won't start required multiple loads because its kw capacity was figured using run current. Even though its a pretty instantaneous spike, the genset won't take it. Large capacitors can help such as in hard start kits for air cons.

I think your very smart for trying to figure peak usage during peak sun hours. I would have if it were me a quality volt and amp gauge in my system. Both calibrated to read fractions of whole numbers. The amp gauge should be one that uses a buss bar, not one that goes in series with the load.

My ham shack is set up to run either on AC or DC with solar charging on a bank of gel batteries. Those meters when on DC are very important when transmitting on HF because of the power usage. Low voltage will reduce transmitted output power.

Once setup, a non electric grid backup solar system will take a bit of time to get used to and adjust your usage habits.

Yannis · Post by **Yannis** » Oct 30th, '13, 11:04

Bruce, I'm in tears with your vivid descriptions !!

Here's my experience on how to take a shower, without almost any fresh water!
First you jump into the water to get wet.
2. You climb back onto the boat, bringing with you a bucket full of sea water
3. As you are wet, you grab the shower gel (I tested it with Badedas and Fa, but really any such gel will do/no kitchen liquid/no bar soap) and start applying it onto your body with a little help of water from the bucket to make foam. You apply and wash.Its better to avoid windy spots cos the foam dries out fast with the current.
4.When you're done and foamy, you jump back into the water to rinse. You have to be meticulous in rinsing because the shower gel does not come off by itself. You have to use your palms and go over all parts of your body to get rid of it.You check you haven't forgotten any difficult spots; ears, between toes, etc
5. You come back on the boat and you dry with a clean shower towel that has not salt on it
6. You are clean, and what's important, there is not a single grain of salt on your body. The little fresh water you will use is for the areas that you could not apply soap on; your eyes and perhaps other areas too.
7. Finito.

Now, in what concerns the electrical issue we are discussing,I think I will come back to you once I've re-read it and somehow digested it. Just one thing though. I think the reefer as a device falls into the category you mentioned of multiple start and restart sequences, I guess I'll have to take this into account too.

I'll come back, thank you for your time and kind assistance.
Yannis.

Yannis · Post by **Yannis** » Dec 26th, '13, 02:53

Happy holidays everyone !

My technician told me that, given my needs, I will finally need 2 X 100 watts solar panels measuring 2 X 3+ ft each. What's more, he's VERY hesitant of my idea to install them on the top bimini, albeit with certain structural amelioration ( a new SS frame on top of everything, binding the existing frame together on top of which the panels will rest). He says he's not afraid of this construction, rather he fears that with a typical Aegean gust the whole thing will dismantle and ...fly away, for reason of the rivets (and/or small hex screws) that actually bind the steel pieces together.
I don't want to install this huge metal (alu ?) construction onto which there'll be a hardtop - too much weight too high + very expensive, so I thought of a butane refrigerator to cut down on electrical needs = a single, perhaps flexible panel will then suffice.
Question: Is a gas/butane fridge compatible with boating? Isn't there always a pilot flame which is a potential fire hazard ? I know of off the grid homes that use such fridges but in a boat ?
All suggestions and ... wild guessing welcome !

Bruce · Post by **Bruce** » Dec 29th, '13, 14:00

Most of the gas powered frig units left boating in the 80's. They are widely used in the RV industry though. They will have to be properly vented to the outside for the burner exhaust and if installed correctly should be no problem.

One of the reasons for them disappearing was insurance companies dropping coverage for open flame units on boats. If you insure your boat, check with your insurer first to make sure there are no exclusions to that type of box.

I was a dealer for Norcold, yet my liability insurance forbid me from servicing open flame boxes that I got a call from time to time on.

You'll have to factor in the cost of the butane though. The one in my RV, a separate fridge and freezer would burn through some gas. A smaller cubic foot box will be better. The other issue is they are absorption type coolant systems that are charged with ammonia, not freon and ammonia is very deadly and corrosive if leaks occur in an enclosed area.

At this point I'd be looking into a wind generator if the solar is out.

Yannis · Post by **Yannis** » Jan 1st, '14, 02:46

Thank you Bruce.
Despite the limitations, butane can at least be considered as an alternative.

Another thing; a friend lent me two wonderful books, "Sailboat maintenance manual" by Don Casey, and, "Boatowner's mechanical and electrical manual" by Nigel Calder.
Just in case any of us here are not already aware of these books and their authors, they make great X-mas gifts.
As you're about to celebrate the new year (here its already 2014), may you all have a fruitful 2014.

BCBertie · Post by **BCBertie** » Jan 1st, '14, 16:42

Hello Yannis,

I, too have a 28 with Yanmars and most of the same desires as you have. Here is what I have considered…

Propane would be great, but I don't think it can be easily done. ABYC (and good sense) requires that you keep the tanks in a locker that vents from the bottom to overboard and with all the hatches that have to be accessible, that pretty much leaves out the cockpit unless you are wiling to seriously remodel the gunwales. I have a late model flybridge that would allow for a locker for the small bottles under the starboard seat, but then you would still have the problem that the connector to the refrigerator would be at the bottom of the interior cabin, lower than the water level. I could make it work for a stove, but I wouldn't want a propane leak at the bottom of the cabin.

I don't really want a generator because there really isn't enough room, they are noisy, and if affordable use gasoline.

That leaves (for me, anyway) an engine-driven AC generator. I bought a two-sheave crank pulley from Yanmar to drive a SeaPower unit form MEPS, which outputs very-high quality AC. I will wire that to a inverter/charger to power DC loads and charge the house bank. Calder's book explains the concepts very well and for me they make a lot of sense. EddyG has a setup like this and he told me he was very happy with it. This approach allows for quality charging and very simple to use systems. Size the battery bank appropriately and you have silent power while you're on the hook!

Best wishes,

John

Yannis · Post by **Yannis** » Jan 2nd, '14, 00:05

Thank you John,

Do you keep the boat in California or in Canada ? It is my dream from childhood to one day visit Canada and its beautiful scenery, only its so far-far away !
I'll look it up again in Calder and revert, as I'm not so familiar with what you're proposing.

My original thought was to just not let so much sunshine be wasted, if I could only find a place to put those panels...

Cheers,

Yannis.

BCBertie · Post by **BCBertie** » Jan 2nd, '14, 15:29

Hello Yannis,

Well, that's the problem. I couldn't figure out where to put them that wasn't incredibly ugly (not that there is much sunlight as far north as BC anyway...)

My 28 is currently on the hard here at my house, and the 26 is on the trailer. Since my wife and I got new jobs, we don't have enough vacation time to make it worth trailering either Bert up to BC, so I have a little C-Dory I use as the SUV to get to my place in Canada. I'm slowly re-habbing the 28 with the plan of taking the wife up the inside passage to Alaska, and we still have a little time before our jobs will let us.

The relevant part in Calder's book is where he describes the "inverter-based boat." My plan is to use the engine-driven AC generator to feed a Xantrex (or similar) sine-wave inverter. The input to the Xantrex will have a transfer switch to select from either the engine-based AC generator or shore power. The Xantrex offers pass-through AC, so it will automatically charge the batteries when it sees input, and provide inverter power when it doesn't. A big advantage of this setup is that the engine DC systems stay separate, only responsible for charging their individual starting bank, and the engine-driven AC generator is then responsible for the house bank, with high-quality charging coming from the Xantrex. Simple to wire, and simple to understand.

Just carry jumper cables for when one of them fails.

Calder shows you how to do the load calculations so that you can size your house bank adequately. The only load hog I see is the refrigerator; the microwave uses a lot of power, but only for a short time. Everything else (TV etc.) uses very little power (and won't really get a lot of use). Since I expect to be largely cruising when I use the refrigerator, I'm only planning for three days on the hook without an engine running. I also rarely have access to shore power, so the boat needs to be self sufficient.

Well, that's the plan, anyway...

Cheers!

John

Eddy G · Post by **Eddy G** » Jan 3rd, '14, 09:05

The SeaPower unit from MEPS is great for A/C power while under way or for short periods at anchor, but the best addition I made for cruising was a Honda EU2000i generator. It only weighs 45 lbs, I stick it out on the swim platform when in use and connect it directly into the boat's 30 amp inlet by means of a heavy cord I made. On days that I don't move very far between anchorages, I run it all night on econo mode and it runs the fridge, fans, etc. while charging the batteries through the on board charger. On econo mode, it will run 10 hours plus on a gallon of fuel and is nearly silent. After the coffee is made in the morning, I shut her down for the day. It stows away nicely on a B28 behind the fly bridge ladder in its custom cover. Two group 27 deep cycle batteries should be enough to last between charges.

Eddy G.

BCBertie · Post by **BCBertie** » Jan 3rd, '14, 13:37

Hi Eddy!

Long time no type… <grin!>

That's why it's so important to accurately assess your needs when you pick a system. I only need a fridge when I am cruising, which means I'm running the engine 6-10 hours a day. I don't need aircon in Canada and Alaska, while I'm sure it would be pretty useful in Louisiana! And I am never in conditions where my swim platform isn't wet, so the Honda on the swim platform won't work for me.

So for me it is more about minimizing the load; and for my wife it is more about minimizing the noise. When we do get somewhere isolated, she really wants the quiet. On the 26 she would refuse to use the fridge and just make do with two coolers.

So, instead of a Norcold-type fridge, I'm thinking about building a hyper-insulated chest-type. We'll see.

Anyway, Happy New Year!

John

Eddy G · Post by **Eddy G** » Jan 3rd, '14, 15:11

Hey John
It has been a while. I do as you do and minimize my power needs. Pretty much everything is 12 volts except the air conditioner and microwave. The big draw is the old Norcold. I do the ice chest thing for weekend trips, but when we go for a week or two, I use the fridge. I only use the Honda at anchor and never had any splash issues. As for the ice chest, a few years ago I had an aluminum open top container made to fit inside of the ice chest. It is a little less than half the size of the ice chest and maybe an inch shorter. It is welded on all corners and is watertight. I put the food in it and fill the ice chest around it. The food stays cold and dry and when you remove something, the frickin' ice doesn't cave into its place. By leaving the plug out and letting the ice chest drain, the ice lasts a long time.

Eddy G.

BCBertie · Post by **BCBertie** » Jan 3rd, '14, 16:43

Eddy -

Yep, that's a great idea! Up north coolers make great sense anyway, as the ambient temps aren't too warm. Even Calder cautions to think long and hard about adding refrigeration instead of an icebox in cooler climes. Still, a fridge makes a boat seem more grown-up and would definitely make the wife happier.

But ice is so cheap...

Cheers!

John

Yannis · Post by **Yannis** » Jan 5th, '14, 23:58

John and Eddy,

I agree that apart from the solar panel issue (how many, how big and where to put), is the minimization of loads.
For me the only load, really, is the reefer (no aircon, no m/w oven, no coffee machine, just the various water pumps, a fan and very little lighting),and I recently purchased a portable, folding oven from Cabelas which sits on my gas stove and should be an alternative to when I'm not in the mood to start an open fire, or when the food is not appropriate for the gas driven cast iron skillet, or the pot.
So, the trick is how to insulate the fridge and freezer to obtain the best result. I contacted a local coolbox maker to get an idea of the costs and I gave him the exact dimensions of the two separate boxes. He proposed a two box combo (75lt fridge, 25lt freezer) to be placed laterally against the head bulkhead, under the galley counter top with the shallower freezer outboard. Plenty of room for the two compressors on the floor.
I'm wondering whether, instead of constructing this custom double box combo, it wouldn't be cheaper to buy two YETI coolers and turn them into refrigerators by connecting the machinery to them. If their insulation is not already thick enough to guarantee the load minimization necessary, I could even consider putting them both together into a larger custom made glass or plywood box filled with foam (or whatever else material is best), the objective being to obtain an overall 10cm insulation all around. My technician is telling me that with such a thickness, the compressors might have to live a very relaxed life, and I could perhaps be able to power the lot with one (larger perhaps, but just one) fixed solar panel and maybe another flexible one, that will not turn the boat into a Bat Mobile.
In the process, I'm left with the original Bertram 28 galley top sitting outside, waiting for somebody to pick it up !

Eddy G · Post by **Eddy G** » Jan 6th, '14, 14:11

I have chartered several sail boats that use the cold plate technology. In the earlier years, the aux engine had a compressor just like an automobile A/C that froze the plates. There were two very well insulated boxes, one a freezer and the other a cooler. The later years had a 12v compressor. Either one only had to run an hour or so to keep the boxes cold for a day or two. Older Grand Banks trawlers still have them and they work really well if you anchor out a lot. You may be able to combine your Yeti idea with cold plates to get what you are looking for.

Eddy G.

Bruce · Post by **Bruce** » Jan 6th, '14, 16:13

Top loading boxes and cold plates, either glycol or salt water is a great way to go.
If you have to buy all the components or have them made, it will be the most expensive of several ways to go.

Cold plates aren't cheap, but with a little skill one can make the boxes.

I have a bunch of technical data if you decide to go this way. I made custom boxes at one time, but the cost was prohibitive for many.

Yannis · Post by **Yannis** » Jan 7th, '14, 03:25

The type of the power source to be used for refrigeration has to be appropriate for one's life pattern on board.
In my case, except for the initial trip out, which may last 3-4 hours to my first destination, subsequent cruising time is anywhere from zero (even for several days), to max 1 hour if I take short trips to go swim elsewhere, or, 1-2 hours max if I want to change islands. So, really, I cannot have an AC source, either by shore cable or by motor driven systems; it has to be a 12 volt DC system. This is the way I understand it and, having read your comments, I realize that for different reasons (climate, engine running time, shore power availability, etc) I'm not in the situation of John and Eddy. If it proves totally impossible to install two panels, I will consider the one panel plus some Honda juice. Butane, although ideal in smashing loads down, I think I'm finally very reluctant too of open flames on board.

Bruce, do you know of anybody having turned a Yeti cooler into a fridge/freezer by adding evaporators and compressors? The question is not so much if the system is efficient because I will make it efficient with addl insulation IF need be, rather, will the cooler's walls sustain drilling and the weight of the machinery and the abuse necessary for the conversion. If not Yeti, can anybody suggest any other durable brand? Otherwise I'll have it custom built by my technician.

Thanx,

Yannis.

Eddy G · Post by **Eddy G** » Jan 7th, '14, 11:46

It sounds like the combination of cold plate technology and a 12 volt compressor is best suited for your use. You can charge your battery bank via solar panels, portable generator or propulsion engine depending on what you are doing that day. Bruce would know better than I as to how long the compressor would need to run and how often. I do know this from experience that once those plates are cold prior to leaving the dock, it doesn't take much to keep a well insulated top loading box cold. The one's I am familiar with had small hatches on top so you don't let much cool out when opening it. Plus, cold air sinks, so it doesn't escape as bad as a front loader.

Eddy G.

PeterPalmieri · Post by **PeterPalmieri** » Jan 7th, '14, 12:21

You can get coolers already converted by a number of manufacturers

https://www.engel-usa.com/products/fridge-freezers" onclick="window.open(this.href);return false;

Yannis · Post by **Yannis** » Jan 7th, '14, 16:37

Thanks Peter.

Does anybody know why this Engel Swing Motor System that uses so few amps, doesn't drain batt's at surge, is so simple to fix compared to the Danfoss' likes, so suitable to boating shocks etc., only produce little fridge/freezers ? Is it that this swing system can only be very efficient for up to 50 lt (or 55-60 quarts) ?
I need 100lt and neither Engel nor a transformed ice cooler can do the job. The Yeti solution needs 2 more inches of outside insulation that it defeats the point...
Interesting. And costly may I add !

Bruce · Post by **Bruce** » Jan 7th, '14, 17:22

Those engels are the same as norcold using the same swing type compressor.
I have one. There is no hold over capability other than the food itself the evaporator is just wrap around aluminum plate extruded where the coolant charge runs.

Hold over plates are going to give you the absolute least run time hands down.
If your not sure what hold over plates are check out this link.

http://www.rparts.com/index.php?cPath=13_20" onclick="window.open(this.href);return false;

Yes I have seen people make coolers into refrigerant boxes. But power usage was not a concern and frankly they looked like crap. But one has to remember I built things that people paid good money for. I'm not an owner trying to cover a budget and be the most efficient. I naturally don't think that way. Old dog, new trick syndrome I guess.

Hold over plates in a well insulated poly foam top loading box is going to give you the absolute least amount of run time.
A real good thermostat mounted outside the box is a must, not inside if you want to control on/off run time.

The smaller the compressor unit, the longer run time to pull down and maintain the box but the least amount of current usage.
A larger unit, shorter run time but slightly higher energy usage may be better depending on what the total plate capacity is.

Yannis · Post by **Yannis** » Jan 9th, '14, 22:41

Thanks Bruce.

I'll probably have the boxes custom made. With all the hassle (and extra cost) that it takes.
The holding plates tho, are best suited for engine driven or shore power fed fridges, none of which is my case. I was told that they are not as efficient for freezer apps.
I'm working on the energy consumption of all alternatives and will let you know...
My objective is to have to use only one solar panel. And also, find a place to put it !

Hyena Love · Post by **Hyena Love** » Jan 10th, '14, 09:11

Install a small diesel powered generator.

Yannis · Post by **Yannis** » Jan 10th, '14, 09:21

Too expensive, heavy and voluminous.
What about a little Honda? I'll put it under the cabin sole or under the rear deck sofa !

Hyena Love · Post by **Hyena Love** » Jan 10th, '14, 11:10

Then you have to haul fuel to run it for any extended period. So, you need jugs or a tank. Not a major problem if only a bit of fuel needed or if you have a aux. tank for the gas.

Yannis · Post by **Yannis** » Jan 10th, '14, 13:06

You're right.
However, it will be just as a backup. So, very little fuel is required. A jug somewhere...
The whole difficulty here is how to totally rely on solar power; the gen will only be used in the autumn or spring when there's less sun, or if and when the boys or anybody else keep playing with the fridge hatch!
Today came the fridgeman(!) at the boat. Its true that this thing will be a bit bulky because of its 10cm insulation, but this is the price to be paid for not ever having to reach for shore power. I'll ask my son to come and shoot a few pics (my phone is a 2002 model and I dont have another camera either) so I will then try to post a few.

Tony Meola · Post by **Tony Meola** » Jan 10th, '14, 23:19

Yannis

When I was young and foolish I would carry fuel. But even with a diesel, carrying around a gallon of gas. A potential bomb.

Yannis · Post by **Yannis** » Jan 11th, '14, 03:03

Tony,

One sunny day, when I was younger, I left the pier in my little island to go skiing with some friends in my boston whaler. The sea was calm and as we were no more than a few hundred meters from the port we saw another boat behind us leaving the port too. Before we blinked our eyes, that boat was on fire, the panicked crew jumped overboard and then, boom, an explosion, smoke and a burning sea...
We rushed to save them and we were all very lucky to not burn too, as we approached almost into the burning area to lift them into our boat.
It was then that I swore that not only I wouldn't buy, but also never enter a boat with gas inboard engines.
Sometimes I wonder how can someone walk on 1000 liters of gasoline in a gas inboard boat and not be scared. Scared to death, that is.

I agree with you, but bear in mind that I already carry some gas for the dinghy's outboard, so a few more liters for the genny is not an additional problem.
Should I buy a diesel 3 hp engine for the dinghy? No.
Just keep those 20 or so liters in a well closed appropriate tank, in an appropriately aerated area... and hope for the best !

BCBertie · Post by **BCBertie** » Jan 11th, '14, 10:46

Yannis,

Calder talks at length about the difficulties of building your own box and the thickness of insulation required. Not easy to do it right...

BTW, have you seen the products from Webasto? They make top-loading refrigerator/freezers in Italy that you may find suitable:

http://www.indelwebastomarine.com/int/p ... i-92-dual/" onclick="window.open(this.href);return false;

Hope this helps.

Cheers!

John

Yannis · Post by **Yannis** » Jan 11th, '14, 11:56

Calder talks at length about the difficulties of building your own box and the thickness of insulation required. Not easy to do it right...

John, thanx.

I have not found anyone yet who makes fridges with 10 cm (4 inches) insulation.
And certainly nobody who makes fridges with a "step" underneath to fit the Bertram's port step !
So, I will have to custom make it, following Calder's advice as you well suggest.
If I had the courage, I would make the box myself, but it requires an inner and outer mold - separate for fridge and freezer (so, 4 molds); do you know why they are separate?
Simply because if they were both in one unit, they wouldn't fit through the door !! Ha !
The freezer can turn into a fridge with a switch, so that when there is not enough solar power I will economize around 20 Ah by turning the freezer to fridge mode.
In that case my ouzo will be drunk without homemade ice cubes...

Yannis · Post by **Yannis** » Jan 22nd, '15, 11:04

I decided to add a second solar panel, so that energy be sufficient until deep into September or when moored in a shadowy spot. Additionally, it will help power that 12v water maker that I might put in next year. With the bimini on you hardly see any panel(last pic).

PS: I never run out of battery juice last summer, everything worked as planned, it's just that you may have to resort to shore power on consecutive cloudy days as is the case in September.

luis · Post by **luis** » Jan 22nd, '15, 13:45

Why not to try something like this : MC4 Peel & Stick 136 watt Uni-Solar Laminate Solar Panel Flexible 24v Unisolar
Its a solar panel that we can walk on top and it can be glued on the top of the cabin, I think

All the best

Yannis · Post by **Yannis** » Jan 22nd, '15, 22:31

Luis,

The actual wattage of my panels is 2 X 130 = 260 watts. With normal summer sunshine (where you calculate 10 hours of usable light) this is 2.6 kilowatts per day. Theoretical alright, but as it proved out last summer, not far from reality.
To obtain 260 watts in flexible panels you need TWICE the area and 2X the cost. There simply isn't such space on a B28. The only space I can think of is on the bow, but this is usable space for other activities such as dinghy space, sunbathing space where you spread towels and cushions, plus, it is not as exposed to the sun as the top.
When I use the boat, the bimini canvass is always deployed, so you hardly notice anything, either from inside the boat or from the dock.
Last summer, with a single panel, I was offering home made ice cubes to all adjacent boats and I really never used shore power or gen. Cold beer, safe food keeping, lights, pumps, fans, cell laptop and ipad charging, music... without a single cable or gen noise.

luis · Post by **luis** » Jan 23rd, '15, 08:31

I check on the prices and maybe you're right. What takes me to rethink what I want to do.
Very similar to your approach. My fridger works on 12V underway and when I stop to spend the day or the weekend, I turn it to gas (with the small pilot always on) but I have a good ventilation and from time to time I vaccum the lower part of the caves. Only switch to 220 at the dock. But with sons and great childrens aboard , microwave, music, charger, xbox,tv, whatever... makes the 2 house batteries suffer big discharges so , I think I go more to what you have done.

Thanks and all the best

Luis

Yannis · Post by **Yannis** » Jan 23rd, '15, 13:14

Luis,

I'm glad someone out there considers solar. Of course Portugal lends itself to such a conversion, but keep in mind that you WILL have to make some concessions.
After a short while, however, you won't even notice they are concessions at all.
What you did by putting a gas reefer, I did with what you see in the pic; 10 cm insulation around the fridge and 15 cm around the freezer. TOP loading fridge. TWO motors, for economy (if you have a freezer).
Then, I have 4 X 100 amp batteries of which only the 3 are connected to the solar panel.
I changed the car type stereo to a portable speaker that connects by blue tooth to an ipod or cell. BIIIG savings in amps. Excellent sound, dancing volume !
No microwave, c'mon what do you use it for?
X box and tv I don't have, but those 2 should not make all that difference for a couple of hours a day. Now, if the kids stay in front of the tv so long,...perhaps they don't enjoy the boat as much.
No problem with all pumps, lights (led), fans, 12 v mosquito repellents, life is beautiful !

Supertooth it's called, around 70 euros if I recall..