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Old 19-06-2009, 05:06   #31
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Just an FYI -- below is a picture looking up at my masthead VHF antenna after the lightning strike. (Note stainless melts at 2,781 degrees F). Note also that the VHF RG8x cable and screw-on connector were blown off.... how did it unscrew???? The connector went missing, presumably in the water. My Windex wind indicator literally exploded and pieces were found on the deck.

This is a carbon-fiber mast that the prior owner bonded at the base-plate to a Dynaplate directly beneath the hull. There was no hull or mast damage, determined after hauling and careful inspection/survey. (That is one data point to refute the urban legends about C-F masts and Dynaplates not being able to dissipate lightning without total destruction). There was damage to electronics, best described as "random" without going into detail. All electronics that were not connected to a wire were undamaged. Those items connected by wire were OK in some cases, totally or partially dysfunctional in others.... even if they were on the same wire (such as Seatalk bus) there was no pattern as to which survived OK.

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Old 19-06-2009, 17:46   #32
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Just an FYI -- below is a picture looking up at my masthead VHF antenna after the lightning strike. (Note stainless melts at 2,781 degrees F). Note also that the VHF RG8x cable and screw-on connector were blown off.... how did it unscrew???? The connector went missing, presumably in the water. My Windex wind indicator literally exploded and pieces were found on the deck.

This is a carbon-fiber mast that the prior owner bonded at the base-plate to a Dynaplate directly beneath the hull. There was no hull or mast damage, determined after hauling and careful inspection/survey. (That is one data point to refute the urban legends about C-F masts and Dynaplates not being able to dissipate lightning without total destruction). There was damage to electronics, best described as "random" without going into detail. All electronics that were not connected to a wire were undamaged. Those items connected by wire were OK in some cases, totally or partially dysfunctional in others.... even if they were on the same wire (such as Seatalk bus) there was no pattern as to which survived OK.
Very interesting. Good to hear that you mast took it with stride. Contrary to your experience ABYC deals with CF mast as if they were made of wood and calls for a 4 AWG conductor to carry the strike to ground via a rod and dissipator plate. They assume that epoxy resin is not a conductor and although carbon fiber is the heat generated may destoy the fiber bonding and the mast. Maybe you should let them know that is not always like they assume.
Your experience proves the only thing certain about lighting. There are no rules about it. The intensity varies considerably and probably in case of very powerful ones there is nothing that can take them without major damage. Many thousands volts and amps will destroy anything. Here in the Pacific northwest I have seen gigantic trees (3+ m dia) burned to the core by lighting.
The debatable conductivity of CF mast is one of the reasons I want to go with aluminum. Of course the cost is the primary. Do you know how much is your mast? how tall is it?
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Old 19-06-2009, 18:24   #33
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Do you know how much is your mast? how tall is it?
Cheers
I don't know the cost. My mast is deck-stepped and 17.2m (56.4 feet) from the deck.

A few years ago I priced a 15 meter mast at $45k USD for another boat but that included all fittings and sheaves, etc. pre-installed. I assume it wasn't a competitive bid (knowing the provider is not a company that competes on price) but it was enough to make me decide not to pursue it further.

Also a possible factor for lighting conductivity is that it has Andersen metal sail track almost the entire length, and steel jumper stays from approximately 7/8 of it's length that terminate at the metal base where the bond wire is attached.
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Old 19-06-2009, 19:27   #34
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I don't know the cost. My mast is deck-stepped and 17.2m (56.4 feet) from the deck.

A few years ago I priced a 15 meter mast at $45k USD for another boat but that included all fittings and sheaves, etc. pre-installed. I assume it wasn't a competitive bid (knowing the provider is not a company that competes on price) but it was enough to make me decide not to pursue it further.

Also a possible factor for lighting conductivity is that it has Andersen metal sail track almost the entire length, and steel jumper stays from approximately 7/8 of it's length that terminate at the metal base where the bond wire is attached.
I budgeted 50K USD for a complete 19m mast and 3 sails. CF is probably at least 40% more expensive compared to aluminum. I doubt I'll ever own one.

Yes, the track would explain the conductivity. It was probably designed with lightning in mind. Smart, you save the cost and weight of the 4 AWG wire.
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Old 19-06-2009, 21:56   #35
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snip.

Yes, the track would explain the conductivity. It was probably designed with lightning in mind. Smart, you save the cost and weight of the 4 AWG wire.
Cheers
If that is what saved the mast it was pure serendipity. I seriously doubt lightning conductivity was a design consideration from the maker, as I think the Andersen sail track sections are joined with non-metallic "keys" and the bottom of the track ends near the goose neck without bonding.

However, since the goose neck area is so accessible and so close to the mast base, it would be simple to devise a bonding arrangement, and it now seems like a good idea. The base is already grounded. Thanks.
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Old 21-06-2009, 10:24   #36
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I am designing the systems for a 50' performance cat with live aboard amenities for tropical cruising. I would love to hear more details on the solar array set up you have and also on the Frigoboat fridge and freezer problems.

Here is the preliminary spec. Being a performance cat, weight limitation is a major concern.

I'd think a 50' would give you signficant carrying capacity! We have a 37' with all the cruising gear, it is not a great sailer. When we removed lots of it, I was VERY pleasantly surprised at our sailing performance. Also, it is relative. Even in a cruising configuration (heavy weight) we sail as well as all cruising mono hulls up to about 44 foot.Cheers

*250 Ah 24v AGM house batteries.

If you're cruising, the weight difference between 250 and 400 Ah should not be that much of a concern. IF you're going to be away from shore power for extended periods, you'll appreciate the flexibility the extra capacity will give you. Four (4) Fullriver DC400-6 is certainly a configuration I'd seriously consider. Although, Surrette is coming out with an AGM product shortly, I am waiting to see the specs on these.

*2x1500w 230/24v stackable inverter charger (35A) combi

I'd think one is usually better than 2 from a complexity stand point, otherwise the wattage seems very appropriate.

*1 high output 24v 75A belt driven alternator (port)

I have at length stated I don't believe engine driven alternators are a cost effective method of generating electricity. I'd keep what was there and allocate the dollars to something else. Oh, if you get one, you should probably get two. One for each engine.

*1 Yanmar AC generator (between one main engine block and gearbox) 230V 6Kw (KMG65E) (stbd)

What is the weight of a genset? I like the gensets from a conceptual stand point, my only issue was the weight. But, I don't think weight is as much a concern to you as it is for me.

*3x210w 24v Kyocera solar panels in series and MPPT controller (Outback 60 may be too big)

Yes, on the solar panel side. I'd think the Outback 60 would be ideal for your proposed configuration. I don't understand the big. It is not physically that large, it doesn't weigh that much. The 60 is maximum amp it will handle, sort of. With MX60, the voltage of running the panels in series is the concern. In very cold weather as an example it would probably not handle 4 210 24 watt panels in series. LOVE mine.

* Separate fridge and freezer: 2 x Frigoboat Danfoss BD50 compressors, keel condensers and bendable evaporators.

I love the concept of the Frigoboat units. The execution was/is my only issue. If I were going to do them again, I'd go through them and marinize them myself.

* 2x16500btu air conditioners

I am slightly biased here. I couldn't support the weight of a genset, so couldn't consider air conditioners. We use window mounted units on hatches when we are in a marina. But, if you have the carrying capacity. Great!

* 120 l/h, 230 v, 1600 w watermaker (energy recovery Spectra like systems no needed, too expensive and more complicated)

An AC based system will be more cost effective at purchase time than a DC system. I am not certain about the overall running cost however. You'll have to be running your genset to make water. Inverters and the battery capacity you're planning probably won't do it. I'd make certain I had enough other things I was going to do while running the genset and making water. Like baking bread, or doing the laundry. Make sure you check the operating cost of your genset. At $5.00 a gallon, it gets surprising very quickly.


* 24v SSB radio (if I can find it!!)

I'd not do 24v. You're wiring for 12 anyway, it is going to be less expensive and much more mainstream when you have issues.

* 24/12v 60A converter for the 12v system (cabin lighting and stereo)

24 volt is definitely more efficient, but you will probably need the converter.


With this system I hope to achieve the following.
*Minimun weight by using main engine driven 230 AC generator (only 40Kg for 6 Kw) a 24v system (less than half wiring weight), small house battery in conjunction with large solar panels.

*The rather small battery house bank and 630W solar should be enough to sustain the equivalent of a 12v 200/250 Ah per day consumption. Most sunny days at the anchor or undersail in the day should not be necessary to run the engine.

Don't take as much beer! small house bank would not be where I'd save weight. Wiring is probably not it either.

*Triple level of redundancy. The solar, AC gen/inverter/charger, 12v alternator provide 3 power supplies.

I am a fan of redundancy. Consider a wind generator also. But, if you're really going to do the Air Conditioner and AC watermaker, I'd not bother with the wind generator.

*Air conditioning can be run on shore power or when the main engine AC gen is running (at the anchor under way).

Is the air conditioning already installed? If so, I'd definitely leave it. I don't know about running it only periodically. Seems to me it is addictive. Once you take it, you have to keep having your fix! If you can kick the habit, you don't miss it as much.

Are you taking lady's aboard? kids? They tend to shift some of the priorities. I'd didn't see things like a microwave? Bread maker? what kind of cooking/oven you'll need. How about sail inventory? Do you have powered winches? (don't change whatever you have!
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Old 21-06-2009, 18:34   #37
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*250 Ah 24v AGM house batteries.

If you're cruising, the weight difference between 250 and 400 Ah should not be that much of a concern. IF you're going to be away from shore power for extended periods, you'll appreciate the flexibility the extra capacity will give you. Four (4) Fullriver DC400-6 is certainly a configuration I'd seriously consider. Although, Surrette is coming out with an AGM product shortly, I am waiting to see the specs on these.
Thanks for your valuable comments.
I would love the extra capacity, but adding 150 Ah at 24v will result in 84 Kg weight increase which in my case is a lot. I am working on the specification of a 48' performance cruising cat with a max fully loaded displacement of 7 to 8t, I am already few hundred Kgs out!
I agree 250Ah 24v is small so I will probably go for 300Ah (extra 30 Kg ). My reasoning is that in the tropics with a powerful solar array (675w) the required battery autonomy is more for just about 12 h, not 24 as it is usually used for period between charges calculations.
I am completing the energy budget and it looks like that as long as it is sunny I will not need to run any engine for electricity (except for watermaking).

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*2x1500w 230/24v stackable inverter charger (35A) combi

I'd think one is usually better than 2 from a complexity stand point, otherwise the wattage seems very appropriate.
I thought of two for redundancy and also to reduce the stand by draw (3Kw will be hardly ever needed). In the end, if too complicated I may just get one big.

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*1 high output 24v 75A belt driven alternator (port)

I have at length stated I don't believe engine driven alternators are a cost effective method of generating electricity. I'd keep what was there and allocate the dollars to something else. Oh, if you get one, you should probably get two. One for each engine.
As I said I am at the drawing board so I can chose what to get. For the sake of weight savings, on port engine I may just go for the high output alternator only and charge the starting battery with a 24 to 12 V converter/charger. I am even considering only one starting battery for both engines charged from a 24/12 converter/charger, no small alternators installed but one stashed away for emergency (lightning damage). The 24v 70A will be a small frame alt. with external regulator. The cost and weight implications are small and that alone can run the boat electric load if the other 2 sources fail (with a little one I would be in a bind otherwise). I will have only one belt driven because the other engine will have a 6Kw 230v AC gen that will charge the bank at the same rate (70A) trough the inverter/charger.

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*1 Yanmar AC generator (between one main engine block and gearbox) 230V 6Kw (KMG65E) (stbd)

What is the weight of a genset? I like the gensets from a conceptual stand point, my only issue was the weight. But, I don't think weight is as much a concern to you as it is for me.
A stand alone 6 Kw gen set weights about 200 kgs. The 6Kw Yanmar KMG65E about 50kgs (21Kg in the engine room and the remaining further forward). This solution will save 150 Kg, quite a bit of money of initial cost, simpler installation, much less maintenance and space saving. I am planning to use the main engine with the AC Gen while I am motoring and at the same time I can make water and charge the batteries. Even with 6 Kw taken by the generator in a windless situation I should be able to cruise at 7 knots on one engine.
Given the very lightweight design and the large solar array I expect to run the engines rarely so putting hours on the main engine is not an issue.
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*3x210w 24v Kyocera solar panels in series and MPPT controller (Outback 60 may be too big)

Yes, on the solar panel side. I'd think the Outback 60 would be ideal for your proposed configuration. I don't understand the big. It is not physically that large, it doesn't weigh that much. The 60 is maximum amp it will handle, sort of. With MX60, the voltage of running the panels in series is the concern. In very cold weather as an example it would probably not handle 4 210 24 watt panels in series. LOVE mine.
The Outback 60 can put out 60A at 24v. 3x210W=630W=26A at 24v. With this scenario the Outback 60 will work at less than 50% capacity. That's why I said "too big". The max input voltage is 600v so it can handle a lot of panels. I think that in the end I'll go for 5x135W 12v in series which will result in a max input voltage of about 100v. I have to make sure I do a good wiring job.
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* Separate fridge and freezer: 2 x Frigoboat Danfoss BD50 compressors, keel condensers and bendable evaporators.

I love the concept of the Frigoboat units. The execution was/is my only issue. If I were going to do them again, I'd go through them and marinize them myself.
I love the concept too and I read your story with them. Hopefully I'll be one of the lucky user. I'll have an isolation transformer and syntetic thruhulls so with the zinc installed I expect the keel coolers to last. I am a bit concerned by the drag though. I'll put the 2 fore and aft with fairing before and after. I am plannig a 3 Cuft freezer and 11 Cuft fridge.
In my energy budget I estimated the daily consumption of 90 Ah/day (for 2 BD50 units and keel coolers) at 12v. On Frigoboat site they indicate that with top isolation you can get even a lot less consumption. What is the consumption you have experienced in your installation?
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* 2x16500btu air conditioners

I am slightly biased here. I couldn't support the weight of a genset, so couldn't consider air conditioners. We use window mounted units on hatches when we are in a marina. But, if you have the carrying capacity. Great!
I really don't have a lot of carrying capacity but I thought I would make an exception with the air con. I may get away with 2 smaller units (12000btu?) so I should be able to install both for about 70kg. In the future I may get in the occasional crewed charter so I am afraid I have to have them.
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* 120 l/h, 230 v, 1600 w watermaker (energy recovery Spectra like systems no needed, too expensive and more complicated)

An AC based system will be more cost effective at purchase time than a DC system. I am not certain about the overall running cost however. You'll have to be running your genset to make water. Inverters and the battery capacity you're planning probably won't do it. I'd make certain I had enough other things I was going to do while running the genset and making water. Like baking bread, or doing the laundry. Make sure you check the operating cost of your genset. At $5.00 a gallon, it gets surprising very quickly.
As long has one has an AC 6Kw generator already in mind, the AC watermaker is a better solution in my view especially because can produce way more water and offer short running times. So in my case the only problem I see is redundancy if the generator fails. Most 120 l/h watermaker (about 2Kw) will probably not run on a 3Kw inverter unless there is a soft start feature or a recovery system. The solution could be a Danfoss system http://www.idswater.com/Common/exhib_301/5.pdf but it is very pricey. The solar in the best hours of the day and the high out belt driven alternator can produce about 90A at 24v which equates to 2.1KW which should be enough to power the watermaker without taxing the battery. The limiting factor would be the 3Kw inverter that can only sustain a peak load of 6Kw and a constant of 2.5Kw. There would be an high risk of tripping.
While the AC gen is on for making water the batteries can also be charged and other loads can be put on.
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* 24v SSB radio (if I can find it!!)

I'd not do 24v. You're wiring for 12 anyway, it is going to be less expensive and much more mainstream when you have issues.
The problem with SSB is that it needs a very good power supply. The Icom converter to supply it from 24v costs an arm and a leg. The alternative would be to buy another brand but I would prefer have as much gear as possible directly at 24 v.
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With this system I hope to achieve the following.
*Minimun weight by using main engine driven 230 AC generator (only 40Kg for 6 Kw) a 24v system (less than half wiring weight), small house battery in conjunction with large solar panels.

*The rather small battery house bank and 630W solar should be enough to sustain the equivalent of a 12v 200/250 Ah per day consumption. Most sunny days at the anchor or undersail in the day should not be necessary to run the engine.

Don't take as much beer! small house bank would not be where I'd save weight. Wiring is probably not it either.
Sure, beer can add a lot of weight and energy demand . So does wiring weight. I have estimated 150 Kg of copper for a 24v sytem like mine. The simple law of copper losses is: if you double the voltage the diameter of cable becomes 1/4. In practice at 12v the weight would probably double if not triple. The saving in weight and cost are substantial, not to mention the simplicity of running smaller wires.
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Are you taking lady's aboard? kids? They tend to shift some of the priorities. I'd didn't see things like a microwave? Bread maker? what kind of cooking/oven you'll need. How about sail inventory? Do you have powered winches? (don't change whatever you have!
No kids and ladies (at the moment). For the time being no need to worry there . Propane for cooking, no bread maker (I plan to stock up and freeze good bread when I find it) and no microwave (I have never had one, I don't like the molecular abuse of my food ). I will have either a toaster or a small convection oven to make the frozen bread crunchy again. Weight permitting I will have one power winch for mainsheet and davits. 3 headsails on furlers (Asymmetrical, genoa, staysail) and fully battened main. Maybe a symmetrical spinnaker.
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Old 22-06-2009, 05:07   #38
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... I am working on the specification of a 48' performance cruising cat ...
... In the future I may get in the occasional crewed charter...
Is cruising is your objective, and high-performance your preferred mode; or are you designing a less Spartan racer?

Iím certain that everyone is aware of the trade-offs inherent in trying to marry the ideal cruiser and the high performance boat.

An adequate energy supply is one of the prime requisites of a comfortable cruising boat; and should be ranked very high on your trade study analysis.

If performance is your prime criteria, then youíll probably be limited to day charters.
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Old 22-06-2009, 13:46   #39
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Is cruising is your objective, and high-performance your preferred mode; or are you designing a less Spartan racer?

Iím certain that everyone is aware of the trade-offs inherent in trying to marry the ideal cruiser and the high performance boat.

An adequate energy supply is one of the prime requisites of a comfortable cruising boat; and should be ranked very high on your trade study analysis.

If performance is your prime criteria, then youíll probably be limited to day charters.
Yes, performance and comfort are the most difficult things to marry in a cat.
However, especially with some Australian designs I believe it is possible to find a good compromise. As I have mentioned before I am happy not to have some very common stuff found on 50' cats: Washing machine, dishwashers, big generators, dive compressors, electric stoves, microwave, side opening refrigerators, ice machine, house entertaining systems, incandescent lighting, etc.
I have completed the energy budget and with a conservative estimate I will be using the equivalent of less than 200 Ah (at 12v) per day at the anchor and close to the double on a passage. In the tropics the solar array will cover all the energy need at the anchor. On a passage I may have to fire up one of the engines for one to two hours every day. Every 2/3 days I will make water running the AC gen off the main engine.
As somebody else has suggested I may end up using a 400 Ah 24v house battery bank. Just to allow for the performance decay over time. I still hope I can get away with 300 Ah though. I have done a cost and weight budget for every item on board and I am at 8t fully loaded, about 500kg higher than the design figure.
I will commute to the cat every month and live on it for about 5 months per year to cruise in the tropics. Besides being fond of easily driven crafts and enjoy speed, performance is also a necessity considering that my cruising windows are barely one month each. I need a performance cat to increase the cruising area, to be able to sail to windward if needed, to move the boat to a new area and make the best of the available time in general. When I retire I may start loading her up......
I am one of the few believers that light weight is synonymous of seaworthiness and that for tropical cruising light displacement crafts are a better choice. That is my conclusion after cruising for a long time on a performance mono engaged in a round the world cruise.
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Old 23-06-2009, 06:34   #40
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I may have an older Outback MX60 AND, I am getting old and the memory is not as it used to be. But, I seem to recall that the maximum voltage the MX60 would take was something on the order of 140. I recall (subject to the memory thingy again) that there were rather strident warnings in one of the installation docs that came with the unit. They even went over things like how cold weather increased the voltage output of the panels. I believe they said a 24 volt panel could put out up to 34 or so volts? and that got me to the 140 volt max. I'll have to dig into my ships systems book and re-read that section. But, in any case, you would be okay even if you found you wanted to add an additional panel. The real operative is the efficiency of the units in the conversion. They are renowned as one of the most efficient in the industry, when I looked. I did more of my research from the solar home sites than boating. It seems to be the preferred solution for there.

With the ICOM SSB M802 I have, I mount the control head up in my nav station, the electronics are mounted in a compartment between the engine room and breaker panels (Under some steps of all places!). The operative here is that there is a 12 foot run (6 from 6 to) from the breaker panel to the unit. You could mount the electronics next to your converter and minimize the length of that run. So, it is only the increased weight of that run. I'd go with 24 volts every where else I could, although it is going to be more expensive.
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Old 23-06-2009, 13:56   #41
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I may have an older Outback MX60 AND, I am getting old and the memory is not as it used to be. But, I seem to recall that the maximum voltage the MX60 would take was something on the order of 140. I recall (subject to the memory thingy again) that there were rather strident warnings in one of the installation docs that came with the unit. They even went over things like how cold weather increased the voltage output of the panels. I believe they said a 24 volt panel could put out up to 34 or so volts? and that got me to the 140 volt max. I'll have to dig into my ships systems book and re-read that section. But, in any case, you would be okay even if you found you wanted to add an additional panel. The real operative is the efficiency of the units in the conversion. They are renowned as one of the most efficient in the industry, when I looked. I did more of my research from the solar home sites than boating. It seems to be the preferred solution for there.
Your memory is not bad at all; the VOC is 150v Max. The Outback 60 can take up to 750W 12v array. http://www.wholesalesolar.com/pdf.fo...ax60_specs.pdf
The advantage with 24v panels is that you can use a smaller charge controller. The same controller can handle twice the power at 24v. If the space and weight available is enough I could even try to fit 4x210W 24v.
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With the ICOM SSB M802 I have, I mount the control head up in my nav station, the electronics are mounted in a compartment between the engine room and breaker panels (Under some steps of all places!). The operative here is that there is a 12 foot run (6 from 6 to) from the breaker panel to the unit. You could mount the electronics next to your converter and minimize the length of that run. So, it is only the increased weight of that run. I'd go with 24 volts every where else I could, although it is going to be more expensive.
Yes, that would be the best set up with ICOM M802 12v. I believe that there are 24v SSB radios. ICOM and Furuno make them for the European market. I'll have to evaluate the cost difference. I suspect that will be cheaper to buy a 12v and aftermarket converter than a 24V one.
For the rest of the gear (pumps, windlass, toilets, winches), I have not noticed a considerable difference in price. Most electronics run on both
voltages. Considering the price of copper I suspect that in the end it is cheaper to go 24v.

So have you got any consumption figures for the Frigoboat SD50 with keel cooler? I really wonder if the estimates on their site are realistic. What level of insulation do you use? Top or front?
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Old 24-06-2009, 08:02   #42
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I did a great job of re-insulating my refrigerator. I basically followed Richard Kollman's recommendations on his refrigeration website. I used 4" of extruded polystyrene all around the box. It is an upright box. I used the largest evaporator plate put out by Frigoboat. I did rather extensive monitoring of this unit when I initially installed it. It used about 22 amp hours in a 24 hour period. I have the Smart Speed Controller and when it is on, it is always at the lowest speed (except when there is a system reset). Very good! My wind generator produced enough energy to keep up with its power consumption.

My freezer is another matter! I could not see how to pull it out short of ripping pretty much all the joinery in the cabin it is installed in. So, I attempted to insulate it in place. I used the same foam on the top, bottom and one side. (Tried to get to 5") I could not get as much on the back, and one side is pretty much just spray foam. I did not remove the prior insulation, did not use aluminum foil on all sides and did not put in any vapor barrier. It is an upright. I'll have to measure the sizes of both boxes again, I am not sure of my capacity. They are on the large size however. It is priority one on my list before going cruising again to rebuild this box.

This freezer uses about 95+ amp hours in a 24 hour period. It is pretty much always on the highest speed setting when it is warm. I keep the box at 25 degrees. I can go lower, but the compressor would run constantly if I did. In the winter and in cold water, I have seen it go down to lower settings, and the consumption is a lot better! This is not a function of the efficiency of the unit, it is due to the size and lack of insulation on my box! Case in point, when I had the boat out of the water this winter and was preparing to re-launch (April) I noticed there was condensation on the underside of my hull sitting up against the lower back of the freezer. This is an area that I was not able to get to for re-insulation. I am seriously leaking cold (Okay, so technically, I allowing heat into the box. exothermic, endothermic - hey, I was an econ/polysci major!)

When I get some spare $$$$$ I'll put in an entirely new box with a combination of Vacuum panels (VIP) and polystyrene. I wouldn't be surprised to see the consumption cut in half when I do.
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Old 24-06-2009, 17:07   #43
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I did a great job of re-insulating my refrigerator. I basically followed Richard Kollman's recommendations on his refrigeration website. I used 4" of extruded polystyrene all around the box. It is an upright box. I used the largest evaporator plate put out by Frigoboat. I did rather extensive monitoring of this unit when I initially installed it. It used about 22 amp hours in a 24 hour period. I have the Smart Speed Controller and when it is on, it is always at the lowest speed (except when there is a system reset). Very good! My wind generator produced enough energy to keep up with its power consumption.
22 Ah per day! That's outstanding. I hope that the performance has been recorded in tropical conditions. Your figures confirms Frigoboat website estimates. I think I'll have the space to go even thicker with the insulation. Nigel Calder books have also a good explanation how to make the ideal box.
I think I'll revise the energy budget estimate and to stay on the safe side lower the freezer and fridge comsumption total to 70 Ah / day.
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Originally Posted by Strygaldwir View Post
My freezer is another matter! I could not see how to pull it out short of ripping pretty much all the joinery in the cabin it is installed in. So, I attempted to insulate it in place. I used the same foam on the top, bottom and one side. (Tried to get to 5") I could not get as much on the back, and one side is pretty much just spray foam. I did not remove the prior insulation, did not use aluminum foil on all sides and did not put in any vapor barrier. It is an upright. I'll have to measure the sizes of both boxes again, I am not sure of my capacity. They are on the large size however. It is priority one on my list before going cruising again to rebuild this box.

This freezer uses about 95+ amp hours in a 24 hour period. It is pretty much always on the highest speed setting when it is warm. I keep the box at 25 degrees. I can go lower, but the compressor would run constantly if I did. In the winter and in cold water, I have seen it go down to lower settings, and the consumption is a lot better! This is not a function of the efficiency of the unit, it is due to the size and lack of insulation on my box! Case in point, when I had the boat out of the water this winter and was preparing to re-launch (April) I noticed there was condensation on the underside of my hull sitting up against the lower back of the freezer. This is an area that I was not able to get to for re-insulation. I am seriously leaking cold (Okay, so technically, I allowing heat into the box. exothermic, endothermic - hey, I was an econ/polysci major!)

When I get some spare $$$$$ I'll put in an entirely new box with a combination of Vacuum panels (VIP) and polystyrene. I wouldn't be surprised to see the consumption cut in half when I do.
If properly dimensioned and executed the freezer should have similar consumption. Double seals, top loading and no drains also make big improvements in performance. If you have plenty of space and can go to 6" insulation, vacuum panels are not necessary. The vacuum panels are very expensive and may not last due to loss of vacuum. Vacuum panels are good for making the lids.
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Old 25-06-2009, 08:13   #44
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If properly dimensioned and executed the freezer should have similar consumption. Double seals, top loading and no drains also make big improvements in performance. If you have plenty of space and can go to 6" insulation, vacuum panels are not necessary. The vacuum panels are very expensive and may not last due to loss of vacuum. Vacuum panels are good for making the lids.
Okay, when can you come over and help with that freezer?

Just kidding, too big a job for me right now. But, let me try to describe a little bit of the issue. I don't know if you're familiar with the Privilege catamarans, but one of the things they were known for was the quality of their joiner work. When it is new, it is almost breathtaking. All this light polyeurethaned birch all over the interior. Now what the factory did is in the aft cabin off the galley, they took what would probably be a sink and cabinet and they built in a freezer. On the front facing side it is one continuous piece of birch with the freezer door. On part of one of the sides there is a birch access panel that can be removed by unscrewing it. On the bottom there is compartment (mounted portions of the water maker in there On the top, there is nothing. On the side with the access panel, the bottom is attached to a platform that forms the engine room on the bottom and queen berth on top of that. Once again, the engine access panel is done in this finished birch. Portions of the box are tab glassed in.

To get the freezer out, I'd have to cut this panel away from the fiberglassing and the joints to engine compartment. Then, I have to figure out how to get it through the cabin door. That was the show stopper for me! I am not sure it will fit? Big box, narrow door. I bet they put it in there when the top of the boat was off and didn't give too much thought to replacing it. I KNOW they did this for the heads. Great looking molded unit, but don't ever have to replace the fixtures!

So, my thought was, I will have to destroy the current box (reciprocating saws and boats, I shudder to think!) in the cabin build a new box, install it then put the facing on while it is in the cabin. I have a limited space. I have engine compartment on one side, facing on another hull on the back and bottom and a bulkhead on the side away from the engine compartment. Six inches on all sides is going to tough and I could never get it past the cabin door. I was looking at Building custom refrigeration boxes with BARRIER Superinsulation panels. I could build an insulated super box and then slide one of these units in that area, then put a removable facing/door back on. I'd use the VIP's because of the modular nature of the assembly and limited space in certain areas.

So, it is that "If you have plenty of space" part that seems to be a show stopper for me.
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Old 26-06-2009, 04:36   #45
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Okay, when can you come over and help with that freezer?
If you were near by I would certainly come by and assist somehow.
It is difficult to figure the challenge you are facing with the freezer upgrade but it seems complicated enough to understand the hesitation. However, I think your current consumption is way too high and you will have to do something about it. The issue is not just current consumption is also the constant load and wear of the compressor. BD compressors are nice but won't run forever.
So just get a chain saw and make room for a nice icebox
From the little I can understand I would suggest to build or modify the current freezer in situ. Forget about going through the door with a new one. If space is limited the vacuum panels will be very useful and get you the same insulation with half the thickness.
Sorry I can't help much. I am sure you'll find ways to solve the problem and get close to perennial ice.
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