Will a 100 Watt Solar Panel Cover the Following?

[Sumner]

With 180 watts (now 200) we broke about even with a compressor style portable 63 quart fridge and running a computer a lot and a CPAP machine at night. I made the computer and it draws a lot less than our laptops, more versatile also, at about 2 amps without the long distance WiFi and about 3 with it and the router running. The CPAP draws about 1 1/2 amps for about 6 hours of the night. The portable fridge about 30-40 amp-hrs/day in 80+ deg. weather.

I'd try and put on 200 if you could and two 6 volt golf cart type batteries and there is more info here.....

Macgregor 26S Outside Mods page 33

...excess never hurts ,

Sum

[LBW399]

Hey some excellent replies here thanks.

She is a small boat, and I'm solo and have accepted I am not going to take my shore based life with me...... but some of you think I may need a bit more Solar than I thought, even for the small amount items.

The small cooler idea was just an extravagance as I am fully prepared to live without refridgeration if it is too much bother - but nevertheless I will look into the waeco ones. I have no idea what Peltier means.

I have some work and research to do don't I, because, yes, I do want to be "off the grid".

Also a small matter of aesthetics and perhaps seamanship is I don't like the idea of having solars mounted off davits off the stern both because it looks ugly to me, and is vulnerable to the following seas.

There also seems to be a view that rigid panels will last longer than the floppy portable ones.

[Sumner]

Originally Posted by Kiwi399

.. I have no idea what Peltier means....

This is the cooling method used....

Thermoelectric cooling - Wikipedia, the free encyclopedia

...by the cheaper (usually under $200) 12 volt coolers, ones without a compressor/condenser/evaporator. I had one in our teardrop and it would drain the battery in about 8 hours and also only lower the temps by 20 degrees over ambient.

I'm sure our solar arrays are ugly to some, but for us they are a thing of beauty. Once one starts cruising and living on the boat full time or even just weeks at a time perspectives can seem to change ,

Sum

[LBW399]

Heh heh true - there is what you would "like" and the "reality". But if can get away with not having the panels hanging off the stern then I will try. The boat is only 26 feet with 7.5 feet beam, so might be a mission, but we will give it a go hey.

Cheers

[Pblais]

But if can get away with not having the panels hanging off the stern then I will try. The boat is only 26 feet with 7.5 feet beam, so might be a mission, but we will give it a go hey.

Nothing ugly about solar panels. If they make all the power you need they start to look a lot better Consider adding all that can fit. The whole boat is vulnerable so getting picky seems a bit misplaced. The numbers above should guide you in what you can realistically expect. Given you have no other charging source more solar is a good option. Bang for the buck they are your best value. Adding batteries just delays the problem of not being able to charge them properly. You'll need battery capacity to get you through the night and then some to last during bad weather.

[Sumner]

Originally Posted by Kiwi399

..The boat is only 26 feet with 7.5 feet beam, so might be a mission, but we will give it a go hey. Cheers

Ours Mac with 200 watts...



.....is also 26 feet long....



...and just a bit wider at 8 feet so it can be done,

Sum

[LBW399]

Ok guys, what do you think of this set up?

This guys boat is a 28 foot Triton, so only a couple feet bigger than mine, and even though these are mounted off the stern, they actually do not look too bad aesthetically I must admit!

[Sumner]

Originally Posted by Kiwi399

Ok guys, what do you think of this set up?



This guys boat is a 28 foot Triton, so only a couple feet bigger than mine, and even though these are mounted off the stern, they actually do not look too bad aesthetically I must admit!

Hey it is whatever works for you and the panels you pick. Similar wattage panels can vary in width and length, but I just looked at the 100 watt panels we bought...

Solar Cell, Solar Panel, Solar PV, Solar Products, Charge Controllers, Solar Trackers

....and they are about 4' X 2 1/2 feet ( 122 X 76 cm). That might be a bit big to mount like that. Don't forget you are going to have big wind at times. How big are those panels in the picture?

Sum

[Nicholson58]

Originally Posted by Don Lucas

Shop around for panels more. For the price of a 100W unit you can get a much larger one for not much more money, especially if you can pick it up instead of shipping it.

For boats, it is not the cost per watt that is most important. Space is the premium. Pay extra for the best watts per square foot. We bought 3 Sanyo 220 watt panels 30 x 60 inches last year. I think you may do even better now. I think 100 is small and you will find yourself running the engine or generator. Expect only about 1/2 of the rated output too as the panel(s) will likely not be positioned optimally. Take some time to look up Handy Bob's site and read abut solar charging, shadows, wire size, living off of the grid. Bob has good advice BUT he shops panels by cost per watt (no space premium). https://handybobsolar.wordpress.com/

[Randyonr3]

We mounted our over the bimini on a custom made rack to fit the solar.. If you are not looking for them, you dont notice them there.

[westwinds]

I checked the prices one Atwood LED navigation lights. It,s 2.4 watts for port and starboard and 1.5 watts for stern for 6.3 watts. That times 12 hours at 17 volts before solar panel regulated output gives the need for 107 watt panel for navigation lights. That is divide 6.3 watts by 12 volts to get amps and multiply 12 hours to get 6.3 amp-hours. Now figure you get 4 hours full output out of 24 hours because of night time and sun angle and you have to get 17 volts from a panel for voltage regulation and you need a 107 watt panel to take care navigation lights. Also, on a cloudy day, the panel size should be twice as large for the same output, so 200 watts should do it.

[Sumner]

Originally Posted by westwinds

I checked the prices one Atwood LED navigation lights. It,s 2.4 watts for port and starboard and 1.5 watts for stern for 6.3 watts. That times 12 hours at 17 volts before solar panel regulated output gives the need for 107 watt panel for navigation lights. That is divide 6.3 watts by 12 volts to get amps and multiply 12 hours to get 6.3 amp-hours. Now figure you get 4 hours full output out of 24 hours because of night time and sun angle and you have to get 17 volts from a panel for voltage regulation and you need a 107 watt panel to take care navigation lights. Also, on a cloudy day, the panel size should be twice as large for the same output, so 200 watts should do it.

The nav lights you mentioned would use 6.3 amp hours in 12 hours ((watts/volts) X 12 hr.). A 100 watt panel should give him 25 to 30 amp-hrs/day so the lights would at the most be 1/4 of that.

I agree that 200 watts would be a nice figure for him to shoot for as it would give him some 'wiggle room' now and down the road,

Sum

[Ex-Calif]

On my 26 footer I currently have two tiny panels on the standard bimini. I have measured that 2 X 80s would fit there. If I were serious I would convert the bimini frame to a more substantial arch and mount them on top "out of sight" I am also not a fan of posts, davit mounts etc. and find most of these mountings quite ugly albeit probably efficient.

I judge by your screen name you are a kiwi - If you stay that far south I wouldn't expect super performance from solar. If you plan to get north, better.

For me at this size system I would shoot for 3 days storage capacity and the ability to meet 1.5 X my usage needs per day.

80 amps usage X 1.5 = 120amps/day charging = 240W (120a / 6 hours of sun = 20amp X 12v)

Battery capacity = 80 X 3 = 240AH X .50 (available) = 480ah

I think you should get some real world data on your usage as well. I doubt anyone uses their computer or iPad for only 1 hour a day - especially if the iPad is going to do Nav duties. The iPad 3 is a power hog.

[SunDevil]

I've been to New Zealand, and they say it is the island of the long white cloud for a reason. In the 5 days I was there, it was sunny for 1.

But, what laptop do you have? And can you cheat and recharge it on land at a fast food restaurant or someplace on land? I would also recommend recharging it when the Sun is out, but using the internal battery at night. And having enough solar panel power to recharge your batteiries during a sunny day is important, as is having enough battery power to not run out half-way through the night.

I bought one of these batteries for my small solar power system:
Amazon.com: NEW BALLISTIC PERFORMANCE LITHIUM EVO2 12V 16 CELL MOTORCYCLE BATTERY,RED,500 AMPS: Automotive
It is expensive, and at ~28 Ah, and 22 usable amp hours it might be something to look at. If you need more Amp/hours, then 4 of this type would be the better deal: Sky Energy 100 AH LiFePO4 cell

It has held up better than the small lead acid one in terms of discharging and recharging for me. It is supposed to handle 3,000, 70% discharges.

[westwinds]

Originally Posted by Sumner

The nav lights you mentioned would use 6.3 amp hours in 12 hours ((watts/volts) X 12 hr.). A 100 watt panel should give him 25 to 30 amp-hrs/day so the lights would at the most be 1/4 of that.

I agree that 200 watts would be a nice figure for him to shoot for as it would give him some 'wiggle room' now and down the road,

Sum

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You are correct. I forgot to multiply the panel output by four hours. I had the panel trying to charge in one hour.