Boat Battery Question

ysmoose

Light weight baby!
  • Apr 17, 2013
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    778
    Brea
    Name
    grant
    Boat Name
    Parker 1801
    This past weekend, one of my two batteries on my boat died.
    I got to the launch ramp and tried to start the boat on battery 1 and did not start.
    So I started the motor with battery 2 and it worked.
    I was a little hesitant to go out knowing I only had one working battery, but decided to go out anyways since we were only going to fish the breakwall.
    When we got to the breakwall, I did not turn off the motor because I was afraid that once I turned it off, I wouldn't be able to start it in case battery 2 was also bad or too low to start a 150HP yamaha. So I had the motor on and had the stereo, fish finder, and live bait tank running.


    So anyways, my question is, are you suppose to have the motor running in idle while running the stereo, fish finder, bait tank, etc just like a car so you won't kill your battery? Or can you shut off your engine and run the boat accessories on your battery?

    Also, if battery 1 is cranking battery and battery 2 is deep cycle, do you start your boat on battery 1 and switch to 2 while the boat is running?

    SOrry for the long winded question.

    Thanks in advance!
     
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    MYNomad

    Heading South
    Dec 12, 2007
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    On boats, the preferred set up is to have two banks of batteries, one for all of the "house" loads (like stereo, but really everything other than the engines), the other to start and run the engine(s). With twin engines, it is common to have separate starting batteries for each engine.

    With a two bank setup, you don't need to keep the engine running because the starting batteries are not being run down by the house loads.

    You should figure out why your battery was dead. There should not have been any load on either battery (ie, battery switches off) after the time that you last ran the engine, and if the battery was not fully charged then, you should have charged it promptly after getting the boat out of the water. And if the boat sits for an extended period, it should have a trickle charger on it.
     
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    Garrison

    Garrison
    May 21, 2008
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    Temecula
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    Garrison
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    Mikelson 43’
    Both batteries should be the same type and age if not using an isolator. When we had a trailerable I installed a Blue Sea set up so I could have a large house battery and separate cranking battery. If batteries of different types or age are in the same system, they will kill each other in short order. One will draw off the other.

    As far as what you can run, you need to calculate your amp draw and know your amp hour capacity of your battery. I sized mine to run my bait pump overnight and still have 50% capacity. I would of liked more reserve, but it was all I could fit.

    The Blue Sea kit will charge the starting battery to capacity first, then switch to the house bank.

    If keeping your current set up. You need to get two matching dual purpose batteries, the largest you can fit. After charging one or both while running, isolate one so you have a fresh starting battery and run down the other while the engine is off. The more times you drain a battery past 50%, the shorter its life will be.

    Garrison
     
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    JK155

    Almost A Member
  • Nov 8, 2019
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    625
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    Name
    John
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    Wellcraft 18 Fisherman
    If you want that untouched backup battery and you don't want to rewire your boat with a start and a house battery, I would consider a lithium portable jumpstarter. I leave mine in the storage area in the cc next to my towboat info so I can grab it if it catches on fire or something. 4 months untouched and it still has full charge.
    In regards to leaving motor idling all the time, other than wear and tear on the motor and impeller, I don't think it's bad in 4 strokes or newerish 2 strokes.
     
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    ysmoose

    Light weight baby!
  • Apr 17, 2013
    946
    778
    Brea
    Name
    grant
    Boat Name
    Parker 1801
    On boats, the preferred set up is to have two banks of batteries, one for all of the "house" loads (like stereo, but really everything other than the engines), the other to start and run the engine(s). With twin engines, it is common to have separate starting batteries for each engine.

    With a two bank setup, you don't need to keep the engine running because the starting batteries are not being run down by the house loads.

    You should figure out why your battery was dead. There should not have been any load on either battery (ie, battery switches off) after the time that you last ran the engine, and if the battery was not fully charged then, you should have charged it promptly after getting the boat out of the water. And if the boat sits for an extended period, it should have a trickle charger on it.
    Thank you for the response.
    I bought the boat used and I remember the previous owner saying that one battery was recently replaced but the other one was the original battery that came with the boat.
    The boat is about 4 years old, so it could be that it was about time that the original battery needed to be replaced. OR I could have damaged battery 1 by overcharging the night before, I forgot to unplug the charger and left it charging over night..

    Either way, my plan is to replace both batteries and start new.

    So to clarify,

    1. Start the boat on battery 1 (cranking)
    2. Get to the destination on battery 1 (cranking)
    3. Once I get to the fishing spot (switch to batter 2 deep cycle) where I can switch the engine off and run radio, bait tank, etc..
    4. Start the boat on battery 1 (cranking)
    5. Go back to dock on battery 1 (cranking)

    Is this right?
     
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    ysmoose

    Light weight baby!
  • Apr 17, 2013
    946
    778
    Brea
    Name
    grant
    Boat Name
    Parker 1801
    If you want that untouched backup battery and you don't want to rewire your boat with a start and a house battery, I would consider a lithium portable jumpstarter. I leave mine in the storage area in the cc next to my towboat info so I can grab it if it catches on fire or something. 4 months untouched and it still has full charge.
    In regards to leaving motor idling all the time, other than wear and tear on the motor and impeller, I don't think it's bad in 4 strokes or newerish 2 strokes.
    If possible, I'd rather turn motor off while fishing. I have a trolling motor with separate batteries.
     
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    Garrison

    Garrison
    May 21, 2008
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    Garrison
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    Mikelson 43’

    If you are going to spend money on batteries. This is one of the best things I spent money on in boating. Doesn’t require a whole lot of effort to install. It allows for a smaller starting battery with the cold cranking amps to turn over an engine, and a larger house battery or batteries with larger amp hour capacity to run your gear, without worrying if you can make it home. It will also keep them from scavenging off of each other if you forget to flip a switch, and if being honest we alway do.

    Garrison
     
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    ysmoose

    Light weight baby!
  • Apr 17, 2013
    946
    778
    Brea
    Name
    grant
    Boat Name
    Parker 1801
    Both batteries should be the same type and age if not using an isolator. When we had a trailerable I installed a Blue Sea set up so I could have a large house battery and separate cranking battery. If batteries of different types or age are in the same system, they will kill each other in short order. One will draw off the other.

    As far as what you can run, you need to calculate your amp draw and know your amp hour capacity of your battery. I sized mine to run my bait pump overnight and still have 50% capacity. I would of liked more reserve, but it was all I could fit.

    The Blue Sea kit will charge the starting battery to capacity first, then switch to the house bank.

    If keeping your current set up. You need to get two matching dual purpose batteries, the largest you can fit. After charging one or both while running, isolate one so you have a fresh starting battery and run down the other while the engine is off. The more times you drain a battery past 50%, the shorter its life will be.

    Garrison


    If you are going to spend money on batteries. This is one of the best things I spent money on in boating. Doesn’t require a whole lot of effort to install. It allows for a smaller starting battery with the cold cranking amps to turn over an engine, and a larger house battery or batteries with larger amp hour capacity to run your gear, without worrying if you can make it home. It will also keep them from scavenging off of each other if you forget to flip a switch, and if being honest we alway do.

    Garrison
    Appreciate that Garrison, will look into it!
     
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    watersdeep

    I CATCH IT. I KILL IT. I CLEAN IT. I DON'T DELIVER
  • Jan 19, 2016
    2,635
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    Name
    Jed Venture
    Boat Name
    the twisted ducker
    On my boat,with a 40 hp Honda outboard four stroke. I am not capable of flipping from one battery to the other (perko switch) with the engine running. Made the mistake of trying that one time and blew a fuse under the cowling. So in order to go from house battery to starting battery I need to turn the engine off prior.
     
    sickcat
    sickcat
    Either you have a very old Perko switch or you passed through "off" when switching between batteries. Most all the common switches including Perkos have been "make before break" for a couple decades now. When switching between 1/2/both contact is made with the next pole before the previous pole is released.
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    watersdeep
    watersdeep
    Thanks sickcat, going to take a look at that. the boat and switch are 2005. It was my first time running the boat and it is possible I flipped it to the off position without knowing it.
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    MYNomad

    Heading South
    Dec 12, 2007
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    Rick
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    Yes
    Thank you for the response.
    I bought the boat used and I remember the previous owner saying that one battery was recently replaced but the other one was the original battery that came with the boat.
    The boat is about 4 years old, so it could be that it was about time that the original battery needed to be replaced. OR I could have damaged battery 1 by overcharging the night before, I forgot to unplug the charger and left it charging over night..

    Either way, my plan is to replace both batteries and start new.

    So to clarify,

    1. Start the boat on battery 1 (cranking)
    2. Get to the destination on battery 1 (cranking)
    3. Once I get to the fishing spot (switch to batter 2 deep cycle) where I can switch the engine off and run radio, bait tank, etc..
    4. Start the boat on battery 1 (cranking)
    5. Go back to dock on battery 1 (cranking)

    Is this right?
    That is one way to do it, but lots of people use their starting batteries only for starting. That starting battery should be left to charge immediately after starting, but it doesn't take long. You can get an isolator that will let electrons (from charging) in but not out, so the better practice, if you want to always know that your starting batteries are fully charged, is to use them only for starting. Probably not worth the effort, but you could rewire so that you have separate on-off switches for each bank, with the start batteries wired only to the starter, and the house batteries wired only to the house. That way, you don't have to be flipping switches, except at the beginning of the day (to turn both banks on) and at the end of the day (to turn both banks off). That way, you know that if you forget at leave something on, your batteries won't be run down (and ruined). Lastly, it is nice to be able to use your house batteries, in a pinch, to start the engine. This is often accomplished through a momentary combiner switch.

    And I agree with the suggestions that you carry a jump start battery -- I have one for my dinghy (which otherwise has only one battery, used for both starting and house).
     
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    tbev

    Member
    Dec 21, 2017
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    tom
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    Skipjack 24 Fly
    It's important that you figure out, or have someone figure out if your not sure, exactly how your setup is wired. Lots of people think the 1,2,both switch is just how you explained it but it's not necessarily like that and that's not necessarily isolating or prioritizing your starter batter; (this is that the isolator or ad a battery kit or whatever is supposed to do. Ideality you charge the starter battery first and only start with it but you have to confirm that. Lot's of systems with those "perko" switches are not isolating or separating the batteries.


    Also, jump boxes are fantastic, but like any high cap batteries they shouldn't be left in a vehicle. High temperatures are very bad for them but also they blow up. Spend ten bucks on a fireproof bag and keep the jump box in that and don't leave it in a vehicle all the time.
     
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    sickcat
    sickcat
    Excellent point about understanding how your system actually is setup. Over the years I've seen plenty of crazy stuff people have done. :Exploding_Smiley:
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    sickcat

    Silverback
  • Aug 5, 2003
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    Kerry
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    Yellow spot
    +1 on the add a battery kit and separating the engine from the house load as mentioned. The add a battery kit isolates the two batteries until the cranking battery is well charged then the house battery charges. No switching needed to keep both charged.

    I would respectfully disagree with Garrisons' point about mixing battery types. Nowadays AGM batteries are engineered to play nicely with flooded lead acid.. Having an AGM house battery and a FLA cranking battery with the add a battery kit is fine.

    In your situation with a known bad battery leaving the engine running was the right call. Unless I'm fishing boiler rocks in tight I'm a shut the engine off type.

    I'm in Long Beach if you can use a hand with installing the kit but odds are it is an easy install with your boat.
     
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    Garrison

    Garrison
    May 21, 2008
    574
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    Garrison
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    Mikelson 43’
    +1 on the add a battery kit and separating the engine from the house load as mentioned. The add a battery kit isolates the two batteries until the cranking battery is well charged then the house battery charges. No switching needed to keep both charged.

    I would respectfully disagree with Garrisons' point about mixing battery types. Nowadays AGM batteries are engineered to play nicely with flooded lead acid.. Having an AGM house battery and a FLA cranking battery with the add a battery kit is fine.

    In your situation with a known bad battery leaving the engine running was the right call. Unless I'm fishing boiler rocks in tight I'm a shut the engine off type.

    I'm in Long Beach if you can use a hand with installing the kit but odds are it is an easy install with your boat.
    Sickcat,
    I think we may actually be in agreement. I was referring to two dissimilar batteries in the same bank. All the literature I have read from the various manufactures says AGM and Flooded batteries should not be mixed in a bank. They go as far as to say they should be the same age size and even have different chargers due to their charging profiles. When the PERKO switch is set to “both”, that is essentially what the two batteries become, a connected bank. If you forget to use the PERKO switch to isolate them it can lead to premature failure, ✋🏼 guilty. If extremely diligent, then yes they will be isolated and all will be well. I was not and got tired of the battery switch ballet and the worry when anchored overnight with limited capacity, hence the Blue Sea kit. Which costs much less than a replacement battery or a tow home BTW. In our ski boat, I have the PERKO set up and two group 27 AGM dual purpose that have been pretty much trouble free.

    On a previous boat, I did exactly what you described. I had a flooded starting battery for the engine (high CCA) and I think a Group 31 AGM for the house (deeper discharge and higher amp hours). I also installed an onboard charger that could be set for the individual battery types so when we got home or were at the dock, all we had to do is plug in an extension cord to a handy little waterproof disconnect. Wahla, no mas problemas.

    Heck of a nice offer to lend a hand! 👍🏻

    Garrison

    E994E6AB-5CEE-4637-ADD0-0618AAF464BE.jpeg
     
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    sickcat

    Silverback
  • Aug 5, 2003
    4,364
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    Kerry
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    Yellow spot
    Sickcat,
    I think we may actually be in agreement. I was referring to two dissimilar batteries in the same bank. All the literature I have read from the various manufactures says AGM and Flooded batteries should not be mixed in a bank. They go as far as to say they should be the same age size and even have different chargers due to their charging profiles. When the PERKO switch is set to “both”, that is essentially what the two batteries become, a connected bank. If you forget to use the PERKO switch to isolate them it can lead to premature failure, ✋🏼 guilty. If extremely diligent, then yes they will be isolated and all will be well. I was not and got tired of the battery switch ballet and the worry when anchored overnight with limited capacity, hence the Blue Sea kit. Which costs much less than a replacement battery or a tow home BTW. In our ski boat, I have the PERKO set up and two group 27 AGM dual purpose that have been pretty much trouble free.

    On a previous boat, I did exactly what you described. I had a flooded starting battery for the engine (high CCA) and I think a Group 31 AGM for the house (deeper discharge and higher amp hours). I also installed an onboard charger that could be set for the individual battery types so when we got home or were at the dock, all we had to do is plug in an extension cord to a handy little water proof disconnect. Wahla, no mas problemas.

    Heck of a nice offer to lend a hand! 👍🏻

    Garrison

    View attachment 1383643

    Certainly IMO the add a battery kit (or setup that accomplishes the same thing) is the way to go for most setups. The aptly named "battery ballet" is SO old. Too many better things to concern yourself with when out fishing than if the battery switch is on 1 or 2.

    I agree that AGM and FLA do have different charge profiles but I think AGMS may be more tolerant of sharing the charge with FLAs than you think. Other than reduced outgassing and better tolerance of deeper discharge cycles one of the advantages of AGMs is that they can be charged at a higher rate than FLAs. Especially useful if you have a big house or inverter bank and want to minimize the recharge time. If you charge the AGM at the rate a FLA likes your just not taking advantage of the faster potential charge rate of the AGM.

    Around the time Optima batteries came out I used to do a lot more work than I do now but I used Yandina combiners (their name for an ACR) for AGM/FLA setups because they have an option to limit the voltage across it so the AGM only would see just over 14 volts max. More voltage and the AGM would take a beating. Limiting voltage via the combiner was about the only easy option for O/Bs. Inboards you have the $$$ option of a programable regulator like the Balmar stuff. I know Optima had some issues initially partially because people would use them in systems setup for FLA - like putting them in cars where you have no control over the charging profile. Fast forward a few years with plenty of unhappy AGM buyers and AGM manufactures getting tired of dealing with the situation they made some changes and seems the AGMs were notably more tolerant of a FLA charging profile. I got to the point where I stopped bothering to use the Yandina voltage limiting feature.

    Keeping batteries the same size/age/type in banks is certainly the best way to go. Just saying, at least in my experience, that AGM and FLAs sharing a charge is not nearly as problematic as it once was.

    Nice work BTW - clean!! I have the same charger and it has been great.
     
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    Garrison
    Garrison
    We had 4 8D Lifeline AGM’s installed this past year, for all the properties you mentioned. We got lucky, there was a many month nationwide backorder at the time, I called everywhere.

    I am normally a DIY kind of guy, but with a herniated disc, 180lbs X 4 in an engine room and under the salon didn’t sound all that great. 😁
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    ShadowX

    I Post A Lot But I Can't Edit This
    Oct 10, 2010
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    The first thing you need to do is get a load meter for your battery. It will check the battery condition with a terminating load. You can get a cheap version from Harbor Freight that uses a resistor to generate heat as the load or a digital load load meter. It will help to determine the battery condition.

    If the batteries were bought at the same time, its possible that the charger is not connected properly or has corrosion on the wire. I have seen it before where the terminals were broken or had a bad connection. As a result, the battery was not getting charged properly. What happens is that most people connect the charger terminal directly to the battery terminal. However, with vibration, the terminals can break right at the crimp location and break the wire. Water can also wick inside and cause the wires to corrode which results in high resistance. Typically, the factory terminals are not heat shrink connectors, so any water would wick inside and cause a break. I often use tie wraps to strap the charger wires to the main battery cables. This way, the vibration doesn't cause the terminals to vibrate and break off. Its a good practice with any wires that are in high vibration areas. You can also put a volt meter across each battery terminal while its charging. It should be around 13.8V to 14.5V depending on the charger.

    The last thing is to check your battery fluids at least 6 months to a year. It would give you a good indication of the battery condition. If one of the batteries has low fluid, it gives you an idea of something is not going right. We have a 36V troll motor and one of the batteries had the bad charger cable due to corrosion. As a result, the other batteries cause the bad battery to work harder since its in series. The fluids boiled away and there was an obvious problem as soon as we check the battery fluids.

    In my personal opinion, people with less than three batteries should only run the two batteries as house batteries . In today's boat, there is a lot of power drain from electronics to pumps. A single battery would tax the entire system by the end of the day. If you have two batteries and only use one for house while the other is a starter, only one battery gets deep cycled constantly. As a result, that one battery would die first. The other battery would hardly get used since its only used for starting. If you worry about not being able to start, its best to get a portable starter as a backup since its cheap. However, if you feel like you absolutely need need a separate starter battery, you should add in a third battery with the same or lower rating and have that as your starter battery.
     
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