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Boat electrics - solar controller

  • 25 Sep 2012 18:04
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    Reply # 1082934 on 1075616
    Deleted user
    The warm LED strip light arrived. Very nice glow in the cabin, 1000% improvement on the white LED dome light. I think we've sorted out what to do lighting wise.
  • 25 Sep 2012 16:20
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    Reply # 1082829 on 1075616
    Anonymous member (Administrator)

                                                                        Stavanger, Tuesday

    Hi Lesley and Peter.

    You both seem to take your boat electrics more seriously than I have ever done. I guess I get away with it by having a very simple "system": One 85Ah gel battery charged from shore via an intelligent, Swedish Ctek charger. A very attractive feature with that little charger is that it starts charging by checking the battery and if necessary goes through a desulphation phase which will extend the battery’s life. With my fjord sailing and soon-to-come LED-only for lights, the battery lasts for a season. Your more serious cruising of course will call for more serious electric systems than mine.

    One thing: I bet you will have some sort of permanent shore AC input. In Practical Boat Owner I once picked up this tip: To the protective ground lead, fit a set of diodes as shown on this diagram. They will provide a voltage barrier of 1.2 -1.4V. In other words, if the Boat’s Ground (connected to engine or keel or somewhere else in the boat) has a slightly different potential (static voltage) than the Shore Ground, the diodes shown will prevent current to flow and bad corrosion caused by this. In case of a short-circuit occurs in some equipment on board, the protective ground lead will still do its job and hold the case of the faulty unit grounded (give or take 1.4V). Just remember; those diodes must be rated to at least the same current as the AC inlet fuse (I would double it).

    Arne

    PS: Lesley, I couldn't open your link as I am not a Box user.

    Last modified: 25 Sep 2012 16:21 | Anonymous member (Administrator)
  • 25 Sep 2012 10:59
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    Reply # 1082593 on 1075616
    Deleted user
    Having noted that Lesley has installed Smartguage I though it may be of interest to mention my electrical installation on Malliemac. I too am no expert on boat electrics and took a long time reading and discussing systems with various bodies of knowledge. In the end I opted for Smarguage but also added Smartbank Advanced. I also have an Adverc alternator controller and a Victron battery charger/inverter. It is too early to say how the system performs as Malliemac is not yet in the water but the system seems to be working satisfactorily. The real test will come when I am drawing serious current from the batteries.  I have installed a small ring main with 2 double sockets and one single fed from the Victron through a consumer unit. The cables run down the starboard side of the boat well away from the electronics. For lighting I have fitted recessed lights designed to take 10 w halogen bulbs but now fitted with warm white led's These give a pleasant and quite warm light. I have a strip light behind the cooker with 30 led's embedded in resin  so should be resistant to moisture and easy to keep clean. There also some reading lights presently with halogen bulbs but soon to be fitted with led's. All the lights are controlled by a number of switches so I can turn on various combinations to minimise current draw when away from shore power.
    Some might say that this is an over complicated system which plenty of potential to fail but in practice it fulfills my requirements and I am hopeful it will prove reliable. Time will tell.
    I have taken great care with the installation and all the connections have been protected with shrink sleeving.
    Last modified: 25 Sep 2012 11:05 | Deleted user
  • 25 Sep 2012 03:38
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    Reply # 1082234 on 1075616
    Deleted user
    Arne,

    Many thanks for that. I have uploaded my sketch of what I did in the end. here I've kept the engine battery totally separate. It only parallells when smartgauge senses current coming in and the house bank is charged. It then tells smartbank to do so. All currents go in to the main house bank so I can set the controllers to optimise for the (more expensive than a truck battery) AGM type. Both balmar and merin advised this. The temperature sensors are onto the house bank, and I can emergency parallel if the engine battery is down (That's the theory altho I've never tried it!)  After reading various opinions I decided to keep the lightening grounding totally separate from the electrical grounding but in practise, a lightening strike would probably leap across into the electrical circuits anyway. For the same reason I've not included the bronze seacocks into any grounding system and so far they seem ok.

    When I first realised we'd have to rewire, I was daunted  to say the leastand it took me over 6 months of reading and sounding out what friends had done on their own boats, to start to get my head around it. The proof is in the pudding. It functions well, we have batteries that are at 100% capacity virtually all the time (which funnily enough is not actually the best thing for them!!) including over two weeks at sea without the engine running.

    Regarding the smartgauge

    It is well worth the money, believe me. Aside from not having to fit shunts and the like, it tells me voltage of two banks and %capacity left in one of them (which is of more use to me in preserving them, than simply what the voltage is (it tells me that too, for both banks)  It also has alarm functions that show me if for example the batteries are getting too high a charge from the incoming sources.

    Plus, if I'm honest, I like a nice little gadget.

    Yes I have a spare one

    Yes there's a traditional 1-2-both switch that I use as the eng battery switch  and if the electronic gadget dies, I can wire the main house bank up to it pretty quickly if pressed.

    Now back to cutting out a  bulkhead so we can change an awkward exhaust elbow!

    a bientot
    Lesley
  • 20 Sep 2012 04:07
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    Reply # 1077148 on 1075616
    Deleted user
    That puts a damper on my plan to buy cheap eBay solar panels..
    Whitworths sell 20W panels for $49. I better remember to take a magnet to test the screws before buying.

    We made the decision to not install a fridge/freezer, opting for an icebox, so the load on this electric system is not going to be much.  But things change, now China is producing cheap polyurethane insulated fridge freezers for half the price they used to be. (WAECO copies, same Danfoss compressors - $500 instead of $1100). Tempting.
    Last modified: 20 Sep 2012 04:09 | Deleted user
  • 20 Sep 2012 01:52
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    Reply # 1077023 on 1075616
    Anonymous member
    Gary K,
    Whatever you do, steer clear of the low cost 15W amorphous solar panels. I bought four in America, and they've all failed now. They're held together with mild steel screws, and salt water gets in and corrodes the cells. Worse, once they'd failed, they seemed to be providing a discharge path, so that my better crystalline panels weren't doing as well as they should, being linked to the same regulator.

    On a brighter note, I bought some Turnstrip LED lights from Whitworths chandlery, and they have turned out well. The 30 LED model draws under 2W, is quite bright enough to read by but not so bright as to glare, and emits a pleasant yellow-white light that doesn't change colour with voltage.
    Last modified: 20 Sep 2012 01:55 | Anonymous member
  • 19 Sep 2012 11:53
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    Reply # 1076376 on 1075616
    Deleted user
    Lesley, the Smartgauge site you posted has a magical black box called, Smart bank.

    Arne's solution ^ looks much cheaper..
     

    Though the smartgauge thing seems a little pricey for moi. 
    Cheap voltmeter will have to do.
    Last modified: 19 Sep 2012 12:30 | Deleted user
  • 19 Sep 2012 11:52
    Quote
    Reply # 1076375 on 1075616
    Anonymous member (Administrator)

                                                                         Stavanger, Wednesday

    Lesley

    You seem to have a quite good grasp of boat electrics.

    The fault in your friends generator was probably a failure in its built-in rectifier bridge (a block of 6 diodes making DC out of the AC generator’s output). That could happen to a separate blocking diode as well.

    Here I made a sketch for you, showing how two batteries are being fed via diodes. With this setup you can drain a (domistic) battery flat without killing the other (starting) battery. As you start the engine/Generator, more current will go to the flat battery than to the other. Charging batteries this way is a compromise. What is not so good is to combine batteries of different type. I guess I would not mix gel batteries with normal batteries in such a bank. In my sketch I show two separate diodes, but in reality you often buy them as one integrated unit.

    Cheers, Arne

    Last modified: 19 Sep 2012 11:53 | Anonymous member (Administrator)
  • 19 Sep 2012 10:10
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    Reply # 1076332 on 1075616
    Deleted user
    You're right, the amp rating of the controller is for the maximum input. Just out of interest I put the meter on our 20A controller - 18v coming in, 14.7 going to batteries as requested and a whacking great 15.8 at the dc load out.  I've a feeling that that would be enough to fry a few things. Happily, we only use the cockpit light at night when there's no input!

    Blocking diodes. mmm. now we're into the realms of what I turned my back on! Crib was so full of heat sinks and diodes that I vowed that once removed, they'd stay removed. I also threw out the tome on zener diodes so i wouldn't be tempted to read it again and try to understand what language it was written in. The space the heat sinks took up was in part, replaced by heavy duty fuses which I thought more important for safety.  I understand their need and use, within a 1-2-both switch system, to stop one bank drawing from another but I went for a solenoid split charging system that parallels the separate banks only when the circuitry calculates it's right to. For the solar panel system, the diode in our controller prevents the panels discharging the batteries at night. (Although Nigel Calder reckons that the voltage drop through a diode can be greater than the nighttime drain back to the panel dep on size of panel!) I took to heart the message that diodes cause significant voltage drop and left them out. A friend did have his alternator develop a fault and it drained his battery, so maybe I should reconsider my stand?

    My understanding is, that if you put another battery onboard at a later date, isolated from the original then what you'll have is two separate battery banks and not two batteries in parallel forming a single battery bank.  I dont understand how I would use blocking diodes within a bank of parallelled batteries. I would love to see the schematics for this as no doubt it's easy really and I am probably completely missing something! As usual.

    Lesley

    Your brother in law would love a shop I found in Hong Kong that sold EVERYTHING electronic including tiny little widgets to reduce 12v to 3v or 6v or 9v! also picked up a transformer that runs off the 12v supply and charges the laptop at 19v more efficiently than running the laptop's own transformer from the inverter.

    Anyway, back to more mundane matters like fixing the leak on the fuel tank...
  • 19 Sep 2012 09:00
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    Reply # 1076293 on 1076287
    Deleted user
    David Robinson wrote:Hi Gary - article on the Mollymawk blogsite about various led lights and the light quality of same might be of interest. David R

    Thanks for the link, I had a read. He notes the chinese LEDs certainly dont last long, but maybe because they are unregulated, while the Bebi LEDs are.
       " ...there is nothing - absolutely nothing - half so much worth doing as simply messing about in junk-rigged boats" 
                                                               - the Chinese Water Rat

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