Smaller Solar Panels

[Pete7]

No reason why you shouldn't take the laptop, just don't use it for navigation but instead communication. An 80 watt panel will give what? 25 amps a day? to run the GPS and LED lights. When in port use the local wifi cafe and plug the laptop in. No reason why the solar shouldn't be used to top up the laptop from time to time.

Pete

[hellosailor]

" 80 watt solar panel, I bought an outboard with a 12 Amp alternator, and I have a 150 ah battery bank. Should that do the trick? "

Let's see if I can screw up my numbers again today. (G)

80 watt nominal solar panel, that's about 4.7 amps at 17 volts. A guesstimate since panels may be rated differently. A full sunny day provides the equal to about 4 hours at full power, so 4.7amps x 4 hours = 18.8 amp hours from that solar panel to your battery, each sunny day. With an MPPT controller you might squeeze another 10% out of that, but that's also another expense.

Taking Sandy's numbers for the Garmin, it seems to consume about 1/2 amp when "cruising". If that's so, times eight hours, it would consume about four amp hours over the course of a day, leaving about 14 amp hours from the solar panel production to feed your nav lights and other needs. With LED nav lights, you might make it through each day without any losses, or with minimal losses, all depending on whatever else you are running and how long you run it for. The cost of LED lighting can become very cheap--when you weigh it against the cost of extra batteries and charging them with regular use, sure.
So you'll have to look at the whole picture, but it sure looks better with the larger panel. If you're only going out for a few days, two or three sets of good rechargable AA cells can make a good way to run a GPS, just swap 'em out and recharge at home. But if the GPS can run on AA cells--the odds are it will sip way less than 1/2 amp from ship's power, so part of the choice is "gps" versus "chartplotter".
The laptop can be a deal breaker if you are using it constantly, odds are it will draw 45 watts minimum, up to 100 watts these days. If you just plan to use it intermittently, or you can get a couple of spare batteries for it without spending a forunte, it might be more practical. And, again, using a direct dc-to-dc power supply (sale prices under $50) cuts about 10% off the power consumption versus using an inverter and AC power brick.

Heck, what fun would sailing be without seeing all the electronics go belly-up when the power goes out? 'cause it always will go out, sooner or later. (G)

[unbusted67]

Originally Posted by hellosailor

"
Heck, what fun would sailing be without seeing all the electronics go belly-up when the power goes out? 'cause it always will go out, sooner or later. (G)

Thank you that was very helpful.

I think I am probably looking at 30 AH/day for total consumption. So if I can get 18 ah from solar and then run the motor for an hour a day I could probably get away with still using the laptop, right?

A big part of this is that we are thinking of heading down the Mississippi this summer and have ENCs already loaded on the cpu. If I buy Chartplotter then I will have to buy the card with all of the river charts on it so there's another $230 on top of the $350 for the plotter. All of this gets to go away when I sell the boat. It just seems wasteful. I just feel like having solar will improve my resale more than having a chartplotter that will probably be out of date by the time I sell anyway. When I sell, my computer and all of the free charts comes with me off of the boat and whoever buys the boat will have a lot more options on what they want to do with the boat gizmo-wise than if I just had a bought a gps. That's my thinking anyway.

[hellosailor]

The math seems about right. Good point about the computer coming with you, although of course you could also remove a chartplotter and sell the boat without it. Odds are that if you keep the boat for even a year--the next owner may want something newer with whatever next year's features are going to be.

No doubt a miniprojector that puts a 6' x 8' image of the chart up on the mainsail or genoa at night, so you can see it clearly. And has it's own solar power source built in. And gets automatic updates via some wireless network. OK, so maybe two years.
:-)

[unbusted67]

Patent that!

[sandy daugherty]

Unbusted, I think you are missing an important point. In Coastal waters, you need your navigation information at the helm. Its dangerous to keep popping back and forth to the cabin to see your laptop, but you have to because its just not useable in daylight, much less direct sunlight. Yes, even toughbooks are just too hard to read. You have to take time to get yourself 'positioned' and your eyes adjusted, and that's just too much 'inside' time. Your eyes need to be 'outside' the boat, paying close attention to whats happening on the water around you.

Offshore is a different matter; someone can be watching the computer and just passing headings to the helmsperson, because its a big ocean and there are no bends to look around.

I suggest that a chartplotter is even better than a paper chart at the helm, because it stays oriented and the picture moves with the boat. With more sophisticated systems that include radar and weather data, the advantages of a single place to glance at for an integrated update of your situational awareness are meaningful. Thats why heads-up-displays are so important in modern fighter aircraft, and are showing up in race cars too.

Before you go much further, take your laptop outside and see how easy it is to use. Then imagine your self approaching a bend in the river, with traffic, and shallow water on either side, while you have to decide where you want to be, and still keep the mast pointing up!

A good little chartplotter, with the charts preloaded, can sure take a lot of pressure off, and you can take it to your next boat too!

[hellosailor]

Sandy, if you've got a 24'er and your "coast" has good depths and marks...I'd say a chartplotter is gilding the lily, a useless excess for many folks in many places.

A copy of Eldridge and maybe a compass is enough to bring someone from the Chessy up through Cape Code. It isn't all gunkholing and rockhopping when you are "coastal".

[Chipg]

Originally Posted by unbusted67

Patent that!

It's called the LG projector phone and has a 1ghz computer, there are some videos of it projecting a 8 foot image on youtube. You can only use something like that at night.

http://www.youtube.com/watch?v=RJDRcqCMpW0

[chala]

Originally Posted by unbusted67

I really hate the idea of plowing through aa batteries with a battery powered GPS. I don't think that is exactly the most socially responsible option.

Use rechargeable AA.

[hellosailor]

Chip-
Nah, the LG "phone and projector" (they say it isn't a projector phone, apparently there are two separate devices that just piggyback together) doesn't work off solar power. Yet.

[Pete7]

Originally Posted by hellosailor

Sandy, if you've got a 24'er and your "coast" has good depths and marks...I'd say a chartplotter is gilding the lily, a useless excess for many folks in many places

Sorry but I am with Sandy on this one, chart plotter much more valuable coast hopping especially if its mounted near the helm.

Agree with your maths though and if he fitted another 80w solar the problems disappear, even enough to charge up the lappy.

Interestingly my basic Dell Vosto laptop which is aimed at low end business users runs happily on a 90w 12>240 DC coke can converter, however the kids laptop which are higher spec for games and stuff really heat it up.

Pete

[Chipg]

Originally Posted by hellosailor

Chip-
Nah, the LG "phone and projector" (they say it isn't a projector phone, apparently there are two separate devices that just piggyback together) doesn't work off solar power. Yet.

Yes, you have to buy the optional projector module for it that snaps on the back but get this, it's a PC, a GPS, a projector (with the module) and a world phone! They make solar powered phone chargers for $99, no need to wait 2+ years, you can have it now.

[unbusted67]

Originally Posted by sandy daugherty

Yes, even toughbooks are just too hard to read. You have to take time to get yourself 'positioned' and your eyes adjusted, and that's just too much 'inside' time. Your eyes need to be 'outside' the boat, paying close attention to whats happening on the water around you.

I would beg to differ on that point. Toughbooks are built specifically for outdoor use. Their screens are back lit. Here is an excerpt from one of the reviews that I can relate to fully having had my Toughbook in the cockpit on many sunny days in San Diego.

"Both versions utilize a 10.4" 1024 x 768 transmissive, indoor/outdoor LCD. Tested outdoors under the bright Arizona sun, the screen remained readable with good contrast....We found the viewing angle to be comparable to most Tablet PC models."

A small chart plotter has a teenie screen which is usually mounted to a bulkhead 3 feet away. If anything that makes me want to go with a laptop more.

[Solitude]

I have used laptops in the cockpit. I understand what you want to achieve. But... I'm still for doing it a simple and foolproof as possible. Paper for coastal.... Handheld GPS for backup. Lapptop for kids movies at anchor and a BB for email.

I tossed out the car stereo suchking back my batteries onboard and bought a rechargable Ipod dock with radio.

Everything is rechargable so when I motor I plug em in. I like the idea of distributed independant systems. There is no single point of failure for them all at once and they don't put a strain on the important boat systems. I even like solar lights and fans (individual batteries). The garden ones are just too small.

Keep updating this so we can find out how it goes.

[unbusted67]

I relent. I will give up my laptop idea. Although I think it stinks. Are there any handhelds that will receive river charts?

If I were to give up my laptop idea does everyone think I could get away with just using the 12 amp alternator on the outboard to charge the batteries; I guess it would be down to VHF and Nav lights doing all the draining, maybe I will get a 12v aa recharger to cut down on the waste.

Also should I go back to a smaller battery bank. Maybe a couple of 6 volts with 90AH?