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Thread: Surprise!

  1. #261
    Join Date
    Sep 2008
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    Saratoga
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    So Bob, . . .

    I'm curious to know if you spread those cardboard mock ups around, and if there was any deck left to walk on, after you did? Wouldn't you rather stack sails with all that deck space?

    For $1300, I'd be tempted to put a nine foot (above deck) spar in your mizzen hole, with a modest wind generator on top, and have a similar wattage but, night and day, overcast, or not.

  2. #262
    Join Date
    Sep 2007
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    I did and there's enough available real estate, but at least one panel would be partially shaded at any given time. I wouldn't use the old 42 watt panel, since one of the big ones would fit across the dodger in its place. Another panel could lay across the seahood, one could lay flat on the afterdeck and there's enough space elsewhere to move one or two around to avoid shading from the sails.

    But you know, the spar is a great idea. Maybe I could find a taller one and have a mizzen - I always wanted a yawl!
    .
    Last edited by BobJ; 03-24-2020 at 10:36 AM.

  3. #263
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    Sep 2008
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    Saratoga
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    Don't you park under it?
    The Sea is my Church; the Boat is my Pew.

  4. #264
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    Sep 2007
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    Name:  Mizzen.JPG
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  5. #265
    Join Date
    Dec 2007
    Location
    Sausalito
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    Hey Bob, I was going over Surprise's updated energy budget. It looks like you've got about 48 hours before you NEED to charge. I think if you were willing to put up with running the engine every day until you got into the sun, you could probably go with two of the solar panels and one regulator, plus Jackie's. Once you're in the sun, two of those panels should almost keep up with you.

  6. #266
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    Sep 2007
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    Hi Rob,

    I tweaked it a bit more, getting rid of the small panel and cutting down the alternator output to what I think I'll actually see. I'd rather use the space on the dodger for one of the new, big panels. And unless the batteries are really flat the alternator output drops rapidly, so 40A seems more realistic as an average. This latest budget shows charging every 24 hours and is more in line with what you originally predicted.

    Greg N suggested SunPower's 110W panels that are rated at 18.8 volts* (and 5.9A each). My understanding is that the MPPT controllers convert excess voltage into additional current, so the 110W panels could be more efficient. So maybe three 110W panels that are less likely to be shaded, instead of four 160W monsters, and charge every day instead of every other day. What do you think?

    * Edit: I just checked, and the 160W Renogy panels you suggested are rated even higher @ 19.1 volts. Hmm, now I'm confused...
    Attached Images Attached Images
    Last edited by BobJ; 03-26-2020 at 11:10 PM.

  7. #267
    Join Date
    Nov 2013
    Location
    Humboldt Bay
    Posts
    132

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    I have to replace my batteries this year and I was thinking of going with the carbon foam. I've read that you don't want to charge them at more than 14.4 volts. is this true. I have found that with the MPPT controller I have it will charge my lead acid at more than that. Do you set up the controller differently with the carbon foam?

  8. #268
    Join Date
    Dec 2007
    Location
    Sausalito
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    74

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    Hey Bob, I'm chuckling at your confusion because it's a confusing subject. Here is a little online calculator that may help: http://www.ohmslawcalculator.com/ohms-law-calculator For solar panels, there really is no rating convention. For example, 100-watt panels are popular. Manufacturers can easily "rate" a panel as 100W by adjusting the voltage it's rated at. If all panels were rated correctly (in my mind that would be 14.1V) then you could easily tell the output. So if you have a 100W panel that's rated at 17V and one rated at 22V, then the 17V would be more powerful.

    I think the Sunpower panels are really good ones. I chose the Renogy panels for Amazon Prime shipping, quality of mfg and price point.

  9. #269
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    Sep 2007
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    Quote Originally Posted by Steevee View Post
    I have to replace my batteries this year and I was thinking of going with the carbon foam. I've read that you don't want to charge them at more than 14.4 volts. is this true. I have found that with the MPPT controller I have it will charge my lead acid at more than that. Do you set up the controller differently with the carbon foam?
    Yes. 14.4 volts is what they want. The Victron controllers should allow me to change the settings. The "Smart" version includes Bluetooth so you can do that from your phone. Jackie's version can accept a Bluetooth dongle so you can at least see what the controller is doing. I haven't bought anything yet and will investigate all this before I do.

  10. #270
    Join Date
    Sep 2007
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    Quote Originally Posted by robtryon View Post
    Hey Bob, I'm chuckling at your confusion because it's a confusing subject. Here is a little online calculator that may help: http://www.ohmslawcalculator.com/ohms-law-calculator For solar panels, there really is no rating convention. For example, 100-watt panels are popular. Manufacturers can easily "rate" a panel as 100W by adjusting the voltage it's rated at. If all panels were rated correctly (in my mind that would be 14.1V) then you could easily tell the output. So if you have a 100W panel that's rated at 17V and one rated at 22V, then the 17V would be more powerful.

    I think the Sunpower panels are really good ones. I chose the Renogy panels for Amazon Prime shipping, quality of mfg and price point.
    This reminded me of my post about the sizes of toilet paper rolls.

    Since the SunPower panels are a foot shorter, they open up more options on deck. But yes, they're more money per watt.

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