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Thread: another battery charging question

  1. #1

    another battery charging question

    i currently run a deep cycle 120 a/h for the electric motor and a 100 a/h hybrid for starting and the new sounders.

    the issue is i am now camping a bit more and only get a days use from the batteries and dont have mains power to recharge them
    i have bought a generator and want a onboard charger hardwired so im not lifting hatches and taking lids off battery boxes to attach charging cables.

    12V 8A 8-Step Automatic Marine Battery Charger with Dual Output | Jaycar Electronics

    cetek dont do anything and trying to avoid paying 500 for some other options that are out there.

    anyone been down this path and done something like this ?

  2. #2
    Ausfish Addict disorderly's Avatar
    Join Date
    Sep 2006
    Location
    In the Jungle/Mission Beach Hinterland

    Re: another battery charging question

    mate, with an 8 amp charger you will have to run your genny for 8 hours just to recharge 50% of the 120Ah battery..

    You need to find a much more powerful charger then that for your camping trips....I just use a 5amp 240v charger at home but it takes half a day to recharge...for comparison sake my Honda alternator puts out 90 amps and most outboards will be 40-50amps or above..

    You could maybe supplement the charging with a large solar panel or solar blanket..we have a 330 watt panel to charge up my 100 amp battery for fridge and oven..

    Also just remember though i dont think you can use your electric motor at the same time as charging the battery..

    BTW what genny did you buy..?

  3. #3

    Re: another battery charging question

    Also check the recommended charge voltage and current of your batterys some are as low as 20 amps. A high charge current can cause buckled plates in your battery. So you will need a charger to suit the battery

  4. #4

    Re: another battery charging question

    Quote Originally Posted by stevej View Post
    i currently run a deep cycle 120 a/h for the electric motor and a 100 a/h hybrid for starting and the new sounders.

    the issue is i am now camping a bit more and only get a days use from the batteries and dont have mains power to recharge them
    i have bought a generator and want a onboard charger hardwired so im not lifting hatches and taking lids off battery boxes to attach charging cables.

    12V 8A 8-Step Automatic Marine Battery Charger with Dual Output | Jaycar Electronics

    cetek dont do anything and trying to avoid paying 500 for some other options that are out there.

    anyone been down this path and done something like this ?
    Unfortunately - there is no real way of avoiding spending the $$$ ........ It took me several years to come up with my system & it wasn't cheap .

    A generator is the only real way of charging your battery if you fish daily - DCDC chargers only work if you do a lot of running around. Solar panels ... not enough charge & you wont be doing it when you are out in the boat.

    A 12 volt system that worked for me was going with a big battery to start with - A 200amp or 2 x 120amp (in parallel) . It's heavy though (60kgs ish in batteries) . The bigger battery capacity will allow you to use a bigger output charger without the fear of damaging your battery ....... that 's a 25 amp charger . So if you drew your batteries down to 50% you'l only need to run your genny for just over 2 hours to take you up to 160 amp . Then the charge rate will drop - (Typically 80% & it will take another 2 -3 hours to get it back to full charge . A Victron Blue smart 12/25 charger is a good choice for an on board charger ( been very happy with these - IP67 rated) .

    A better alternative is to go with a LiFePO4 battery (150amp would be sweet) Now you have a battery that you can draw down to 90-95% , charge faster - LiFePO4 can take a 50 amps (if you can find a big charger) They also charge at full rate up to 95% ..... So that means a 50% discharged 150amp battery could be recharged to 95% in less than 3 hours with a 25amp charger .

    Yes you are spending the big bucks - Around $2K for a decent LiFePO4 battery & Victron 12/25 Bluesmart charger . However , running a genny for 2-3 hours at the end of the day is much better than half the night. ..... Weight reduction is a bonus 20kgs vs 60kgs

    I hope this helps .

    Chris
    Give a man a fish & he will eat for a day !
    Teach him how to fish
    & he will sit in a boat - & drink beer all day!
    TEAM MOJIKO

  5. #5

    Re: another battery charging question

    This link is always worth a read for anyone interested.
    https://www.powerstream.com/SLA-fast-charge.htm

  6. #6

    Re: another battery charging question

    Thanks for the replies
    The linked charger was just an example of a dual output charger is all

    a days fishing id used 60 amps out of each battery the Sounders draw a lot it seems
    i Can’t use solar as you said while fishing and not enough hours of sun at the end of the day.
    The only way solar would work would be to have two batteries back at camp charging to swap over and that seems like a lot of work lol

    im limited for space as it’s only a 4.2m boat and quintrex won’t warranty the hull with more then one battery up the front and I have the biggest battery I can fit in the rear

    disorderly it’s just a cheap kings unit to see if it works then will get a Honda or yamaha one when it dies

    tbh I need a bigger boat to carry everything but it all just escalates from there

  7. #7
    Ausfish Platinum Member
    Join Date
    Mar 2015
    Location
    Kalbarri, WA

    Re: another battery charging question

    Everything Nagg said is correct. I've been looking into this hard for a long time now, and have just committed to a new LiFePo4 setupo for my camper. With your size of boat, onboard solar is out of the question. The maths are basic--use something drawing 5 amps for 8 hours, that's 40 amp hours. Now to charge that battery back up to where you started, for lithium, you'll just need to put 40 amp hours back in. So, 20 amps charge for 2 hours. For AGM/lead acid, you need to put around 1.1 to 1.2 amp hours back in to get it back. And running them down to 50% capacity really shortens their life-lithium doesn't mind that at all. Lithium is really getting to be a no-brainer nowadays. Just stay away from the really cheap cells--they might look OK outside, and even show up OK on a discharge test, intially, but their internals are where the cost savings are, and they fail prematurely. Or they have less cells than advertised, and give you about 68% of claimed capacity, straight from new. Some actually use decent cells, prismatics, but are let down by a cheap BMS and light guage internal cabling. Or use circular cells, which have about a million possible points of failure built in by design. OK for stationary, wouldn't use them on something which bounces and bangs. I'm looking at you, Voltax.

    If you want to understand how this all works, and I now find it really interesting, but maybe that's just me , go to Youtube and find a young bloke by the name of Will Prowse. He has his own channel, as well as a DIY solar forum on the net. He tests stuff, actually cuts stuff up--some real horror stories there--builds complete systems, including from raw cells, explains how it all works. I'd be confident to take raw cells and build my own system after spending a couple of days watching his channel.

    As for a possible source of backup power on a boat, have you seen the Baintech batteries with the built-in DC DC chargers? Baintech are a Brisbane company, using batteries built by Lithium Battery Systems in Brisbane. You have probably heard you can't connect lthium direct to an alternator on a boat or car, you'll quite possibly destroy your alternator due to overheating. So You need to insert a DC Dc charger into the system between your alternator and the lithium battery. This should be as close to the load, not the alternator, as possible. I'm doing this for my camper, mounted in the camper. But I want something for the ute, to run the fridge in the rear of the Xtra cab. Baintech batteries are all in an aluminium case, and some have Andersen plugs built in--either dual straight connections to the terminals, or one is connected to an internal 20a DC DC, differentiated by a blue plug. So you can just plug it straight into an alternator fed andersen. They do a 110 ah flat case job, 50mm thick, 635mm long, and 300 high. So you can fit it in just about anywhere--behind a ute seat, for example. And it will be completely portable. I'm going to use it in the ute, and take it on the boat when we are camping, to run stuff like the travel buddy for dinner, and the fridge overnight, as I am currently using a start rated lead acid as a house battery, fed by 120 w of solar, and sometimes it struggles to do the job. So, I get the portable one, use it as decsribed, then plug it into any one of the numerous andersens I have on board, run off the house battery, to recharge while I am underway next day. Hell, I'll even just chuck it in the car to run the big engel when taking fish and crays on the long trip down to the big smoke to friends and rellies. Don't be put off by the price quoted, they are available elsewhere for $1500 https://baintech.com.au/product/12v-...thium-battery/
    So, lots of options out there, but not a cheap exercise. It doesn't have to be as expensive as it is for some people, for sure, but there is realistically a lower limit you can spend and get reliable performance, I'd be thinking.

  8. #8

    Re: another battery charging question

    thanks ranmar
    all seems a bit much for to avoid having to lift a hatch and clip a battery charger on each battery in turn
    just dont like the idea of sending 240v via a extension lead to a boat pulled up on the bank

    lead acids are $180 so even if i treat them like crap ill still get 2-3 years compared to 8-900 for a brand name marine deep cycle

    Ill look for a decent waterproof single bank charger and just disconnect it from the generator before hoping in the boat .

  9. #9

    Re: another battery charging question

    You certainly don't want to be dragging batteries in & out of your boat ......( I didn't realise that you had a small boat) . the whole LiFePO4 now even makes more sense .
    I've run power leads to a boat in certain situations ..... like camping at Lake Somerset , or Kinchant (powered site) & a couple of other places ..... not nice but doable.

    The genny needs to be run in the boat ..... with a short lead to the charger .


    it really boils down to how long you are off grid for ? ........ I've done overnighters to Broughton Island (Port Stephens) & put the honda genny under the front hatch ...... at the end of the day - back at Esmeralda cove (Broughton Island) I fire up the genny to charge the leccy batteries. Not great when on the boat & the fumes come back in your face ..... but it works - That's one example of why you want to lower your genny time as much as possible .

    Chris

    Give a man a fish & he will eat for a day !
    Teach him how to fish
    & he will sit in a boat - & drink beer all day!
    TEAM MOJIKO

  10. #10

    Re: another battery charging question

    When I fish I go Friday to Sunday so will have to charge them twice each trip
    the new Sounders use as much as the electric motor over a days fishing

    If I go lithium I’ll then need three batteries and there just isn’t room with live wells and the like it’s a big little 420 renegade
    electric outboard
    Sounders
    starter

    I found a dual output 15 amp charger that can do lithium’s as well and just try the generator for now

    Trying to avoid buying a proper bass boat where you can mount what ever you want

  11. #11

    Re: another battery charging question

    Quote Originally Posted by stevej View Post
    When I fish I go Friday to Sunday so will have to charge them twice each trip
    the new Sounders use as much as the electric motor over a days fishing

    If I go lithium I’ll then need three batteries and there just isn’t room with live wells and the like it’s a big little 420 renegade
    electric outboard
    Sounders
    starter

    I found a dual output 15 amp charger that can do lithium’s as well and just try the generator for now

    Trying to avoid buying a proper bass boat where you can mount what ever you want
    Can you fit 2 batteries? one lead acid for crank, a dc2dc charger to charge the lithium. One lithium house will easily handle the electric motor and sounders (look at a 200aH lithium)... if $$ are of concern then build your own lithium battery bank using individual cells...

  12. #12

    Re: another battery charging question

    Well have two fitted now
    one in the rear battery tray and one under the front deck

    always been told not to run Sounders and an electric off the same battery
    havnt even priced a lithium that size after spending 9k on Sounders late late year the boat slush funds a little low

    an edit

    just checked pricing a yumcha non marine 200 ah is around 800 a brand name marine 2300 plus charger
    But they won’t physically fit anywhere in the boat all you can get in with all the hatches live wells is 2x100 ah sized batteries

    maybe it is time for a bigger boat

  13. #13

    Re: another battery charging question


  14. #14

    Re: another battery charging question

    Quote Originally Posted by stevej View Post
    The revolution battery is so expensive they can't afford to stock them.

    Baitable, if msking your own where lithium batteries which BMS would you use as this is probably the most important part of the battery and not supplied with individual cells.

  15. #15

    Re: another battery charging question

    Quote Originally Posted by Dignity View Post
    The revolution battery is so expensive they can't afford to stock them.

    Baitable, if msking your own where lithium batteries which BMS would you use as this is probably the most important part of the battery and not supplied with individual cells.
    Plenty of information on this group on FB

    Lithium batteries on a boat

    check it out.... heaps of info.

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