Reengineer the electrical system

[MarkJ]

I agree with SkipMac... its unlikely you are using 250 ampshours per day.

Towing/shaft generators only work at sea but even on a fast circumnavigation the vast majority of the time is at anchor.

A wind generator does work well as it cuts the draw at night.

You may need to use your new boat a bit more before you settle on 250 amphour wdraw/day... unless you have air con...


Sent from a stupid phone that replaces words with weird stuff.

[AnchorageGuy]

Before considering anything, you might clarify your battery capacity. 4 gel batteries that provide 300 AH is 75 AH per battery. For 250 AH daily usage, you will need a minimum 500 AH bank. So the first step would be to get suitable sized batteries before anything else. Can you clarify? Chuck

[Bob666]

Hi!

I think all the laptops and iPads are taking lots of power. We need to have school aboard for the kids.

The AIS transponder (Seapikot Graphene + with WiFi) doesn't take much but I have to run the AIS software-I want something to beep if ships in vicinity. Either on a laptop via USB, they take around 2 Amps on average right? It has to run 24 h. Or via iPad software, so need to charge the iPad all the time.

The current Frigoboat is from 1994 and is currently using 6,5 A. Sometimes 4,7 A. Terrible. I currently have -5 degrees Celsius in the fridge. But I want +5!

Might have to replace the whole system. It's a McGyver solution.

Should I get water cooled compressor as we're heading for the tropics? The sea water intake is near the fridge, feeds the sink.

I think the sea water will not be replaced much and gets overheated eventually?

Or will a state of the art air cooled compressor do the job? It sucks in air from the cabin floor. Guess it gets hot in the tropics there.

[Bob666]

Originally Posted by AnchorageGuy

Before considering anything, you might clarify your battery capacity. 4 gel batteries that provide 300 AH is 75 AH per battery. For 250 AH daily usage, you will need a minimum 500 AH bank. So the first step would be to get suitable sized batteries before anything else. Can you clarify? Chuck

Hi!

I wasn't thinking so. If I also have a steady influx of power, why can't I have and outtake of more than 50% a day?

If I need to replace the Gel batteries, I am thinking to buy cheap batteries and connect in series. Perhaps 3 x 180 Ah (heavy Stuff!)

[Bob666]

Is there a max number of watts of solar panels it is useful to put on if only 300 E house bank?

Also got a battery for the windlass, doubles as an emergency start battery, that I want to charge. So need to charge 375 W.

[skipmac]

Originally Posted by Bob666

Hi!

I wasn't thinking so. If I also have a steady influx of power, why can't I have and outtake of more than 50% a day?

If I need to replace the Gel batteries, I am thinking to buy cheap batteries and connect in series. Perhaps 3 x 180 Ah (heavy Stuff!)

Here's the calculation for useful battery power. Unless you are connected with shore power, run a generator most of the day or have a great excess of solar it will be very difficult to charge your batteries completely. As you probably know, if you start with a battery that is at half charge, it will initially take a lot of charge but as the battery state of charge increases then the rate slows down a lot. With a good charging source it is very easy to get from 50% charge to 80% charge. But from 80% to 90% is much slower, even slower from 90% to 95% and from 95% to 100% takes much, much longer. So for practical use most cruisers use their batteries between 50% and 80% to avoid hours and hours running engine or generator to get from 80% to 100%.

So if you are using standard lead/acid batteries you will only be able to use about 30% of the capacity. If you need 250 amp hours per day then you need at least 750 amp hours of battery capacity.

This is the simplified, theoretical version. On a real boat the calculations can be more complex. You have charge coming in, power going out. Some days you have a lot of sun, some days none. Some days you use a lot of power, some days not as much. Still a good rule of th35umb is go with minimum 3X your expected usage.

There are lots of battery options and new technologies but unless you want to spend a good bit of time learning the new technology, my opinion is the easiest and cheapest option is to use standard flooded lead acid batteries in the form of deep cycle 6V batteries like the Trojan T105 or similar. My system is 6 batteries, 6 volts each for a total of 645 amp hours capacity.

Regarding refrigeration, I have a pretty large box, almost 10 cubic ft (0.25 cu meter). About 1.5 cu ft of the box is for freezer, the rest just refrigerator. In Florida in the summer with daily high temps of 35C low at night 25C I was using less than 50 amp hours per day, so average draw 2 amps. This is with a plain air-cooled Frigoboat system using a BD50 compressor. I did completely rebuild the box and increased the insulation to min 100 cm of foam board. There were a lot of problems in the past with the Frigoboat keel cooler systems and the air cooled is a simpler system which also influenced my decision.

[Bob666]

Hi!

Do you think I should replace only the controller unit and thermostat of my cooling system or change also the compressor and fan from 1994? They still work ok, but the controller and thermostat have gone havoc.

The fridge in the house, I put "5.0 degrees" and it becomes 5.0 degrees. Perhaps to much to wish for. Anyway, a rotatable knob as a thermostat, what a big step forward for me.

Regarding Ah of house bank. I cannot afford to replace the battery bank before ARC in 2018, unless it breaks. Need to buy life raft etc etc. A week after Las Palmas, what's the use of having the fridge running. Unless you catch a giant fish, but you can also hang slices of fish to dry on the rigging.

iPhones, iPads etc - might as well turn them off.

We'll bring some Kindle tablets to read with, not so power hungry I've heard. And normal books. 0 Ah.

I think we'll bring a 100 W foldable solar cell. Perfect in marinas, at anchor or when sailing in calm weather. I will also mount 2 x 50 W on the sprayhood, velcro mounted, easy to detach. I heard the MK4 connectors are not perfect for marine use?

We also have foldable 10 W for charging iPhone so if a crew member wants to listen to music from iPhone with headphones on, feel free, but charge it yourself...could buy more such devices. The one we got charges a battery pack as well. Works pretty good.

Not sure yet how many Watts of solar panels on the aft arch, we'll see soon enough.

We are currently mounting a Windpilot Pacific. So the Raymarine autopilot will be idling during passage, for sure.

But 300 Ah as it stands today. Does that effectively limit the max Watt of solar panels that would be useful for me? And should I wary what regulators to buy and how to connect them? I heard they can compete with each other and one might turn of charging for its array of solar panels because of the high voltage, when i would be better if it contributed to the charging. Is this an exact science? Can one not just buy the same brand and model for all regulators?

We got two regulators already, would be un-economical to scrap those of course. Hmm.

We could turn off VHF and AIS during calm day passages, but in the night the helmsman needs VHF, AIS and AIS receiving device (iPad or laptop) running. No need to have the plotter running during passage. Paper charts of the Atlantic will do.

We won't mount radar as it's expensive, power hungry and not necessary as prio 1 on this passage. ("Good to have" = not absolutely necessary).

Would anybody know the average consumption of a 2-3 years old laptop if running in energy saving mode? Working on a new energy budget, two in fact, one for passage, one for anchor.

Getting 100% charge. Wouldn't a massive solar array and low consumption for a day or two almost meet that, please?

Here we sometimes run the engine 15 hours in a row, due to headwind, we got bored of tacking perhaps and get kind of close to the 100% charge. Will replace the original 50 A alternator with a 100 A and bring the 50 A as spare, vacuum seal it first.

Cheers

[Opie91]

Originally Posted by leftbrainstuff

This is the reason most boat arches, aircraft or race cars are not built from non ferrous materials like aluminum.

You should probably not include aircraft in that statement. With some exceptions they are mostly aluminum.

[tkeithlu]

I'll give you one argument for a separate battery. All my house (big bank) and starter (engine and genset, can be crossed) batteries are very low in the boat. I realized that if I flooded, the first thing I would lose would be my batteries, ergo all electronics, including VHF, SSB, and Spot Hug emergency communications. So, I installed a small car battery behind the panel in the wheel house and an isolation switch. Normally, it's part of the house bank, but isolated, it runs the wheel house and all the electronics. What good is an SOS on a radio with no power?

[Badsanta]

I noticed in your figures that you use more power when the engine is running? My diesel doesn't use any power after it starts. ? I guess I missed something.

[Snowpetrel]

Originally Posted by Bob666

Hi!

Do you think I should replace only the controller unit and thermostat of my cooling system or change also the compressor and fan from 1994? They still work ok, but the controller and thermostat have gone havoc.

The fridge in the house, I put "5.0 degrees" and it becomes 5.0 degrees. Perhaps to much to wish for. Anyway, a rotatable knob as a thermostat, what a big step forward for me.

Regarding Ah of house bank. I cannot afford to replace the battery bank before ARC in 2018, unless it breaks. Need to buy life raft etc etc. A week after Las Palmas, what's the use of having the fridge running. Unless you catch a giant fish, but you can also hang slices of fish to dry on the rigging.

iPhones, iPads etc - might as well turn them off.

We'll bring some Kindle tablets to read with, not so power hungry I've heard. And normal books. 0 Ah.

I think we'll bring a 100 W foldable solar cell. Perfect in marinas, at anchor or when sailing in calm weather. I will also mount 2 x 50 W on the sprayhood, velcro mounted, easy to detach. I heard the MK4 connectors are not perfect for marine use?

We also have foldable 10 W for charging iPhone so if a crew member wants to listen to music from iPhone with headphones on, feel free, but charge it yourself...could buy more such devices. The one we got charges a battery pack as well. Works pretty good.

Not sure yet how many Watts of solar panels on the aft arch, we'll see soon enough.

We are currently mounting a Windpilot Pacific. So the Raymarine autopilot will be idling during passage, for sure.

But 300 Ah as it stands today. Does that effectively limit the max Watt of solar panels that would be useful for me? And should I wary what regulators to buy and how to connect them? I heard they can compete with each other and one might turn of charging for its array of solar panels because of the high voltage, when i would be better if it contributed to the charging. Is this an exact science? Can one not just buy the same brand and model for all regulators?

We got two regulators already, would be un-economical to scrap those of course. Hmm.

We could turn off VHF and AIS during calm day passages, but in the night the helmsman needs VHF, AIS and AIS receiving device (iPad or laptop) running. No need to have the plotter running during passage. Paper charts of the Atlantic will do.

We won't mount radar as it's expensive, power hungry and not necessary as prio 1 on this passage. ("Good to have" = not absolutely necessary).

Would anybody know the average consumption of a 2-3 years old laptop if running in energy saving mode? Working on a new energy budget, two in fact, one for passage, one for anchor.

Getting 100% charge. Wouldn't a massive solar array and low consumption for a day or two almost meet that, please?

Here we sometimes run the engine 15 hours in a row, due to headwind, we got bored of tacking perhaps and get kind of close to the 100% charge. Will replace the original 50 A alternator with a 100 A and bring the 50 A as spare, vacuum seal it first.

Cheers

I like your thinking.

A Laptop can be pretty thirsty, mines somewhere around 1-2 amps, more at times. Makes it around 50 a/h per day. Much more efficient to use an Ipad or a small plotter for Ais.
My 4.5 inch lowerance plotter/depth/ais display draws something like 0.3 amps. There are some very energy efficent laptops and mini computers out there, just got to find them.

If you are going to switch off the fridge and the autopilot for most of the crossing, and are smart with your electronic use, and use LED lights I think a 300 ah battery pack should be plenty.

I've got by on half that, with only minimal solar as well. You have limited fuel, dollar's and solar so all you can do is reduce your usage.

But luckily have enough fuel to run the engine for charging if needed, say during multiday cloudy stuff when the solar might be struggling.

When you get to the other side you can top up on fuel easily, so running the engine in the morning to top up the batteries is probably far cheaper short term than trying to fit loads of solar.

How about making the conservation of energy, water and fuel a science, maths and social experiment for your kids schoolwork! Get them to watch "The Martian" and they can simulate being trapped on mars if that helps...

[Snowpetrel]

http://www.cruisersforum.com/forums/...ml#post1565313

Here is a link to an old thread that might be of use.

Sent from my SM-G930F using Cruisers Sailing Forum mobile app

[Snowpetrel]

I am not sure if its this thread, but you asked about solar panel mounting for a narrow stern.

Here is a well proven system on a 34 footer. Ugly, and lots of shading from the satcom and windgen but it survived non stop around the world, and if done right it would provide some shade.

I like them to tilt, but its probably not needed in the tropics.

[Snowpetrel]

Simple solar system I used. Adjustable and cheap. Minimal windage and weight. 2x40 watt panels and 2x 90 a/h batteries was all we used.

I did carry a spare unused fully charged battery I found near the skip, and a borrowed towgen tucked below that I didnt need.

[Bob666]

Hi!

I read up a bit about marine 12 V DC and checked with a specialized company working with marine alternators, regulators etc.

If I replace the current 50 A alternator with a 100 A alternator with same dimensions. Easy replacement. It has an internal regulator and sensory cable to put on the batteries to compensate for voltage drop on the way. And I'm talking house bank now, not start battery, that's not so important.

The 100 A alternator is still a dumb alternator, read more:
Alternators & Voltage Sensing - Why? Photo Gallery by Compass Marine How To at pbase.com
(Excellent site!)

I also read a bit on Morgan's Cloud, also good site.

The guy at www.startmotor.se recommends to buy the dumb alternator and fit a:
Sterling Power Products
Model # 888 13073
Documentation:
https://drive.google.com/file/d/0Byb...ew?usp=sharing
https://drive.google.com/file/d/0Byb...ew?usp=sharing

That device will fool the dumb alternator to not cut off, but to charge at 80% capacity a long time.

Sounds just like what I would get if I buy a custom marine super expensive alternator with external regulator? But saves me the trouble of constructing custom mounts for the custom alternator. I am no good with that kind of work also. Will most likely take tons of time, frustration etc.

It'll be quite expensive though. The Sterling is at USD 600 or so. The 100 A alternator is at around USD 350.

Person at startmotor.se also said I can put my solar regulators into the Sterling. Sounds great. I heard that regulators can battle each other. Totally not what I want.

Question remains, how should one configure the solar part of the electrical system?

I will mount a bunch of solar panels. If they were all parallel, would it be best to put them all into one high quality MPPT regulator properly dimensioned (say 40 Amps e.g.) for the task. I think so?

If you have two different regulators, different brands and models, they could regulate differently and one might stop charging the batteries when they still need juice.

However I am considering the following arrangement of solar panels, to simplify cabling, cost etc:

3 x 100 W on arch on boat's stern. Connected in serial. They will not be in shade much.

2 x 50 W flexible on sprayhood in parallel, they might get shaded more often.

2 x 50 W on sides of arch (good idea? Will be at a poor angle, however perfect angle for Swedish sunsets and sunrises which last a long time) in parallel as they will shaded or receive little input often.

1 x 100 W foldable flexible. Used at anchor or in calm sailing conditions. Connected to a cigarette outlet.

Shouldn't I have one regulator for the panels in parallel (3 x 100 W) and another regulator for the other ones including the cigarette outlet? Or will a high quality MPPT regulator (Victron or similar) handle the higher voltage from the three panels in serial and deal with it?

Thanks for a great forum!

Cheers