solar panels and refrgeration

Discussion in 'OnBoard Electronics & Controls' started by urisvan, Jun 6, 2010.

  1. troy2000
    Joined: Nov 2009
    Posts: 1,743
    Likes: 170, Points: 63, Legacy Rep: 2078
    Location: California

    troy2000 Senior Member

    Thanks, Bill. I'm at a regional union conference and just got back into my hotel room; I'm not even going to try to look at that tonight. I sat in on meetings all morning on a 'continental breakfast' (coffee and rolls), and all afternoon and evening on a sandwich for lunch. Then we went to dinner, and I tossed down a couple of quick drinks on top of stuffing myself. I'm about three-quarters asleep on my feet....

    But I do thank you, and I'll sit down and look it over thoroughly before the weekend is over.
     
  2. troy2000
    Joined: Nov 2009
    Posts: 1,743
    Likes: 170, Points: 63, Legacy Rep: 2078
    Location: California

    troy2000 Senior Member

    I'm home and rested up, and finally sat down to look at the file. Again, thanks for doing it. The system you laid out sounds reasonable in cost, weight and space, and installation is well within my capabilities.

    A question about the batteries, though. If those Trojan T-125 batteries are unsealed lead-acid batteries, how much ventilation do I need for them? I was planning to have the battery compartment under the bridge deck, and accessible from inside the cabin. Do I need to have a tight access door and provide ventilation to open air, instead of allowing them to out-gas into the cabin?
     
  3. Bglad
    Joined: May 2010
    Posts: 175
    Likes: 5, Points: 18, Legacy Rep: 67
    Location: Jacksonville, Florida

    Bglad Senior Member

    I don't think gassing in the cabin is a problem but what is important is the batteries have small spaces on all sides and a well ventilated box so they don't build up heat when charging. Hydrogen gas is very volatile and dissipates so quickly it doesn't pose a risk in the cabin but inside the battery box it can reach explosive concentrations. Condensing caps would be a good idea on wet cells but you need to leave room in the box for them (http://www.contaxusa.com/pdf/catalog/batt_enc_access.pdf).

    On the other hand if you don't mind spending a bit more a pair of 8D gel types would also do the job. They can be had with a 240 ah rating and have certain advantages over lead acid types. Especially if your boat will have extended lay-ups without power since their rate of self discharge is substantially less. Plus I think they would stay cleaner over time. They still need good ventilation to avoid overheating.

    If you plan to construct your own battery box out of wood make sure it is completely fiberglassed and is structurally up to supporting the weight of the batteries. I have seen many resin coated or lightly glassed wood boxes crack and spill electrolyte onto wood hulls and cause serious damage.

    Let me know if you have any other questions or thoughts!
     
  4. capt littlelegs
    Joined: Apr 2010
    Posts: 237
    Likes: 8, Points: 0, Legacy Rep: -67
    Location: England

    capt littlelegs New Member

    The normal marine practice for open lead acid is to have a fully enclosed battery box ventilated to outside. Gel batteries are less forgiving to fast, overcharging and overheating, you can't top them up so they require a lower charge voltage, not a problem if you've plenty of charging time at a lower overnight rate as you should have.

    Your outboard may have a lighting coil and possibly a rectifer so that this small output can contribute to charging while motoring and as a back up.
     
  5. girvin
    Joined: Dec 2009
    Posts: 73
    Likes: 3, Points: 0, Legacy Rep: 37
    Location: Vancouver Island

    girvin Junior Member


    I have 3 75wt panels and run the same gear but with a radar gps and sounder. I also have a wind generator. The radar eats the juice up horribly. But my fridge and lights are fine with the panels. I did however buy a honda 2000i and it has been the best little genny. I use it when we have parties or to run power tools or if there has been no sun/wind for a few days. With this set up we lived off the hook for six months only running the genny once every 2 weeks or so.
     
  6. Fanie
    Joined: Oct 2007
    Posts: 4,603
    Likes: 170, Points: 63, Legacy Rep: 2484
    Location: Colonial "Sick Africa"

    Fanie Fanie

  7. Bglad
    Joined: May 2010
    Posts: 175
    Likes: 5, Points: 18, Legacy Rep: 67
    Location: Jacksonville, Florida

    Bglad Senior Member

    What amp hour capacity is your battery bank and what type of batteries?
     
  8. Bglad
    Joined: May 2010
    Posts: 175
    Likes: 5, Points: 18, Legacy Rep: 67
    Location: Jacksonville, Florida

    Bglad Senior Member

    Fully enclosed box to the extent the batteries and terminals are protected, vented to outside can be anywhere aboard that has good ventilation. I don't think you mean to say sealed box ducted overboard like a gas/petrol or LPG tank. A configuration like that would allow a lot of heat to build up in the box without some way to flow air through and dissipate it. Any standard production battery box will do the job if it is located somewhere in the vessel that has good natural ventilation.
     
  9. girvin
    Joined: Dec 2009
    Posts: 73
    Likes: 3, Points: 0, Legacy Rep: 37
    Location: Vancouver Island

    girvin Junior Member

    I have 4 trojan T 105's Good for the money but next time I think I will go with rolls bc of the individual cells.
     
  10. capt littlelegs
    Joined: Apr 2010
    Posts: 237
    Likes: 8, Points: 0, Legacy Rep: -67
    Location: England

    capt littlelegs New Member

  11. capt littlelegs
    Joined: Apr 2010
    Posts: 237
    Likes: 8, Points: 0, Legacy Rep: -67
    Location: England

    capt littlelegs New Member

    No I mean the box is required to be reasonably airtight and explosive gasses are vented to the outside air, just like gas/LPG. If your batteries are getting that hot then they are seriously overcharged and overheating is the least of your worries, don't believe all you read about fast charging, you can't attempt it without a penalty in the form of plate damage and constant topping up etc!

    One installation I saw recently has the battery switches incorporated in the battery box, controlled from outside, one little spark from those switches is nicely placed to make a big pop!
     
  12. Bglad
    Joined: May 2010
    Posts: 175
    Likes: 5, Points: 18, Legacy Rep: 67
    Location: Jacksonville, Florida

    Bglad Senior Member

    I agree completely with your remarks regarding switches, fusible links or anything else in the box with the batteries but I have never encountered a sealed box vented overboard in the same manner as a fuel or LPG tank in a powerboat or long range cruising sailboat. There is still time though:D

     
  13. capt littlelegs
    Joined: Apr 2010
    Posts: 237
    Likes: 8, Points: 0, Legacy Rep: -67
    Location: England

    capt littlelegs New Member

    The sealed box isn't always done or needed I know but it is very common over this side. The thinking is if a regulator fails then you can get overcharging and a very large amount of hydrogen gas and acid mist build up in the confined space of an enclosed boat or engine room which although the gas is lighter than air this is still not a good thing. If the boat is open then there's no problem like LPG or gas laying in the bilge. My boat is built to a Lloyds spec and has the ventilated box as most others I've worked on.

    I have had a couple of batteries explode on me in the past due to sparks at the terminals when just under normal charging, it makes a mess of the battery, not to mention the acid sprayed everywhere so like you say, at least have the terminals protected and work with protective clothing and face/eye shields just in case. The SLA or gel battery is safer in this respect but can still be overcharged! Personally I'd always fit the batteries outside if possible.
     
  14. CDK
    Joined: Aug 2007
    Posts: 3,324
    Likes: 146, Points: 63, Legacy Rep: 1819
    Location: Adriatic sea

    CDK retired engineer

    Bglad, you are discussing with a real pro here, look at his rep. points.

    Hydrogen is the first element in the periodic system, which makes it the lightest substance on this planet, so if it escapes from a battery it goes straight up and vanishes immediately.

    If your battery is placed in a "marine battery box" with a red plastic lid, trow that away to make sure it collects no gases. Then smoke and spark all you want, nothing will ever happen.
     

  15. Bglad
    Joined: May 2010
    Posts: 175
    Likes: 5, Points: 18, Legacy Rep: 67
    Location: Jacksonville, Florida

    Bglad Senior Member

    Right on!
     
Loading...
Similar Threads
  1. brian eiland
    Replies:
    1
    Views:
    1,312
  2. HKG1997
    Replies:
    3
    Views:
    1,132
  3. Bahama
    Replies:
    23
    Views:
    3,888
  4. ProBoat
    Replies:
    1
    Views:
    481
  5. Vulkyn
    Replies:
    14
    Views:
    569
  6. Jonny3777
    Replies:
    3
    Views:
    759
  7. Vronsky
    Replies:
    22
    Views:
    1,923
  8. BertKu
    Replies:
    11
    Views:
    6,479
  9. Vulkyn
    Replies:
    54
    Views:
    4,237
  10. L'eau.Life
    Replies:
    45
    Views:
    4,888
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.