Over nighting, offshore power ?

Discussion in 'Downeast Boat General Discussion' started by Captinlon, Jan 14, 2020 at 8:21 PM.

  1. Captinlon

    Captinlon Senior Member

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    I often over night offshore fishing on my boat. I do not have a genset, have to start up main engine about 4 or 5 hours in and charge battery up. I would like to know what you guys have set up in your rig, if you don't have a generator. I would like to add more power storage. Like to run basic lights, livewell pump and sounder. I did pick up a suitcase generator this winter and might take that out and try that route. What are other guys doing and how is it set up? Thanks.
     
  2. djmarchand

    djmarchand Captain

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    The simplest way is to add another battery to your setup. I suspect that you probably have two batteries, one is for "house" use such as the livewell and the other is for starting the engine. You usually switch the 1,2,all switch to the house battery while the engine is off to save it for starting later.

    Tell us what kind of batteries you have: size or group number and type: AGM or flooded lead acid and we can recommend the right battery to wire in parallel to extend your fishing time.

    David
     
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  3. MC35

    MC35 New Member

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    Solar panel`s and spare batteries, you can run LED lights and a live well all night.
     
    MC35,
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  4. Diesel Jerry

    Diesel Jerry Captain

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    Solar panel+nighttime=0
     
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  5. Captinlon

    Captinlon Senior Member

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    Thanks guys. I have 2 8d batteries, one house and one start. I believe that are flooded but honestly don't remember of top of my head.
     
  6. Diesel Jerry

    Diesel Jerry Captain

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    Please don’t use your engine as a generator. Prolonged idling is not good for any engine, especially diesel.
     
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  7. djmarchand

    djmarchand Captain

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    OK, two 8D's probably flooded cell type. An 8D typically has 220 amp hours of capacity. You shouldn't run a battery below 50% for best life so that gives you 110 amp hours available at night time. So I am surprised that you run it down by the middle of the night and have to start your engine to recharge it. It is probably going bad.

    Why? Because there are very few 8Ds that are true deep cycle batteries and if they aren't deep cycle they don't last very long in that service.

    So get your batteries tested and throw away the worst one. Replace that battery with 2 or preferably 4 6V golf cart batteries wired in series/parallel. Two will fit in the space of your 8D, have the same capacity and may cover you throughout the night. But better yet add two more GC batteries to increase your usable capacity to 22o AHs. I am sure that will cover you overnight and will last much longer than the non deep cycle 8D.

    And when you do change out those batteries, manage your battery switch to draw from your new GC house bank at night to save the starting battery and switch back to start in the morning but after it starts switch back to recharge the GCs.

    David
     
  8. Tunatown

    Tunatown Captain

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    It can be hard depending on the way you fish I kind of run into the same problem I have 1 8D starting battery and 2 8D deep cycle for everything else this is the hard part I run out to the fishing grounds 1.5-2 hour run then sit on the hook for 6-10 hrs the run home if your on a mooring like me I don’t feel it’s a long enough ride to recharge I may be wrong but probably mostly a surface charge if I was on a dock with shore power to properly charge and top off the batteries it would be best so solar panels will help bring them up during the week if your not doing this every day just the way I look at it I’m going to replace both my house batteries this year they are getting tired things that really beat them down quick is toilet flushing a lot and friends that turn on the big wash down pump by accident to wash there hands ask me how I know haha
     
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  9. leaky

    leaky Captain

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    Pretty much anything other than a generator (even a real small one) is a waste of time & money. You have a generator now - problem solved.

    The killer is the fishing part, with livewell, open water so you probably run flood lights for awhile. Sure enough big batteries in parallel will do it but it's a lot more weight and space than generator & fuel.

    Assume you got an 1800 watt sort of unit? If so spend your $$ on a good charger like a xantrex in the 30 to 50 amp range and you will never have dead batteries (or bait).
     
  10. Diesel Jerry

    Diesel Jerry Captain

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    You have many options. All depends on what you want to spend. Assuming your boat is diesel a 12VDC generator with an auto start feature may be the way to go. It would work like an air compressor. When your voltage drops to a point the generator starts automatically.

    On one of our boats this spring we will be installing a series of 3volt (3.2) lithium ion battery’s all wired in a series/parallel configuration to give the customer an enormous 12 volt batter bank. We are also going to be installing a very big Balmar alternator and regulator to support the bank, along with a battery management system.

    These...12V 300 AH Lithium Ion Battery | Deep Cycle Lithium Ion Battery | Smart Battery would be cheaper than a generator and do not require a management system, but you will still need a bigger alternator to charger them on your cruise back in.
     
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  11. djmarchand

    djmarchand Captain

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    Replacing an 8D with four GC batteries will be a whole lot cheaper and will probably do the job. About $400 for the batteries and maybe $50 for jumpers to install them.

    But it is possible that the 1-1/2 hours each way is not enough to recharge them fully. There are two possible solutions for this: solar panels to recharge them fully during the day or an external regulated high output charger to fully charge them on the round trip. You can add about 300 watts of panels for about $500. A high output externally regulated alternator will cost about $1000.

    A combination of the two might be best. The high output alternator will put a lot of juice in quickly and a single 100 watt panel will top up the batteries fully during the day.

    David
     
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  12. Fishinengineer

    Fishinengineer Senior Member

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    2000 watt Honda coupled to a 3 or 5 gallon outboard gas tank. This keeps a 400w metal halide light on all night, makes coffee, and powers the microwave. Keeps batteries topped up through battery charger so no issue running sounder, radar, and livewell pumps all night. Early in the season I can get by with the one gallon tank on the generator, but as the nights get longer it won't make it. An aluminum cap goes on the tank fill that couples to a outboard fuel tank for a long run time. Whole setup goes on cabin top.
     
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  13. kcassells

    kcassells Captain

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    Got some pics?
     
  14. leaky

    leaky Captain

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    The problem with trying to do it with lots of batteries is two fold, first you need enough power stored but secondly eventually you need to charge them. The more batteries the harder it is to charge them on the water.

    For sure, something you didn't mention, you need a good onboard charger so that at least when you leave the dock the batteries are fully charged.

    As far as placement of one of those small portable generators, some put them on the roof, some put them up on the bow/trunk, some on the deck, sometimes even a swim platform. My preference is put it on the deck in the cockpit and if you really can't stand the sound (which is louder the more you are drawing, at low speeds most of these are fairly quiet) then look for other options. Whatever you do - make sure the thing can't tip over.

    Jon
     
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  15. PatriciaLynn

    PatriciaLynn Senior Member

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    A portable generator is just one more thing to have to remember and then you have to bring it down to the boat, especially a pain when you are on a mooring.

    Upgrade you battery bank to stay on through the night and add a solar panel for slowly topping the battery up while you are away. I know what DJ is saying about idling the engine forever, but n hour here, an hour there won't hurt anything if you get in a bind.
     
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  16. Captinlon

    Captinlon Senior Member

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    Thanks for all the advice guys, I plan to replace both batteries this winter and add a charger to hook to my honda. My boat is moored so will look into a solar panel as well and I understand the steam is not long enough to charge now, was thinking that last season but wasn't sure.
     
  17. CCtuna

    CCtuna Captain

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    Two 6 volt golf cart batteries wired together for your house. Ton of amp hours. I run two 5k lumen leds, nav lights, sounder, and livewell pump. Accidentally slept all night on the hook once (6+/- hours) and still had 12.0 volts when I woke up. I also run my electradyne with this setup and it doesn’t put a dent in it even hauling 100 traps
     
  18. djmarchand

    djmarchand Captain

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    Here is what you can do to analyze your electrical system:

    Buy a clamp on DC ammeter like this one for $45.00: https://www.amazon.com/Multimeter-R...jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

    With everything on that you normally use while night fishing, measure the current from the house battery. Say it is 10 amps which is high IMO. Then for a ten hour overnight fishing gig you will use 1oo amp hours. That is ok to draw from two GC batteries. But if you draw like 15 amps then you probably need four GCs to keep it below 50% of nominal capacity.

    Let us know how much you draw overnight. Then in the morning when you start up your engine to go home, after you get up to cruising speed, measure the DC amperage of your alternator at the battery. Then measure it again 1-1/2 hours later as you approach your dock but still at cruising speed.

    With that data we can figure out how much current you use overnight and how much you replace cruising home. That will determine the best way to replace the difference.

    David
     
  19. Genius

    Genius Captain

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    Isn't 12.0 VDC basically dead for a lead acid battery? I've always heard you want to limit the draw downs to 12.2VDC. It doesn't sound like much but I believe it drastically reduces life of the battery. AGMs kinda shine in this type of service. I usually don't promote them because they have some negatives with alternator loading, but with careful planing I think you can set up a good system.
     
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  20. CCtuna

    CCtuna Captain

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    I believe yes technically but 12.0 will still start my engine with a bump of the key. (Only an outboard). My point was that this was for house service, I’d definitely have a separate cranking battery if I had a “real” boat. As far as battery life is concerned I’ve had this set up for two years so far and haven’t had any issues
     
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