In search of best battery for house bank.

Discussion in 'OnBoard Electronics & Controls' started by MrPopper, Feb 15, 2016.

  1. MrPopper
    Joined: Feb 2016
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    Location: Maryville, TN

    MrPopper New Member

    Hey everyone, I have a Cal 2-25 sailboat (25 ft) and I'm working on the planning phase of redoing the whole electrical system. I'm trying to find the batteries. My potential load is about 150-200 amp hours. I need a 12v system.

    The question is what battery/batteries have worked for you or what's your opinion of the best battery bank?

    Thanks MrPopper

    (First post)
  2. Chuck Losness
    Joined: Apr 2008
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    Location: Central CA

    Chuck Losness Senior Member

    On my Gulfstar 37 I have 4 six volt golf cart batteries for the house bank and a group 31 12 volt battery to start the engine. I use a battery combiner to keep the engine battery charged and solar panels to charge the house bank. The batteries are lead acid wet cell batteries. My batteries last on average 5 to 6 years with proper maintenance. My first set was from Costco. The second set are LTH batteries purchased while cruising in Mexico. Six volt golf cart batteries take the least amount of space and have the most amp hours for their size. Group 31 12 volt batteries are next. Whether you chose 6 volt or 12 volt batteries you will need 2 batteries to get 150 to 200 amp hours. It seems like everybody uses more electricity then they planned for. I don't know what your intended use is but having more battery capacity then you think you will need is always better. There are numerous ways to arrange your batteries. IMHO the West Marine article on marine grounding systems written by Stan Honey (sp??) is about as good as it gets for figuring out how to wire your electrical system.
    Good luck with your project

    Attached Files:

  3. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    Lithium Ion have the best efficiency and longest life. They can be discharged about three times what a lead/acid can. Also, they can receive a faster charge; between 20-50 times faster without degradation, depending on their chemistry. However, they need a more expensive and complicated charge and load management.
  4. Barry
    Joined: Mar 2002
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    Barry Senior Member

    Look at the Northstar Battery site
    We use SMS agm 400 or SMS AGM 480
    The reserve capacity is high and will give you up to 480 minutes at a 25 amp draw
    As an AGM battery you can discharge these 80% up to 400 times without issues
    And made in the US
    Not cheap,
    The last set that we had lasted 8 years, so while expensive at the start they certainly gave us good performance
    They can be installed in any orientation except upside down. They should still be installed in a vented battery locker to meet ABYC specs
  5. SaugatuckWB
    Joined: Jan 2014
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    SaugatuckWB Junior Member

    I have 4 Universal Power Group AGM batteries Group 30 (?) 110ah . I've had them for 6 years and still going strong with lots of use (daily all summer). They are Chinese made and pretty cheap ($230 I think). I'd stick with AGM and avoid flooded batteries because of the out gassing, and needed maintenance. Also, winter or long term storage problems that you don't face with agm. Lithium would be the most compact, powerful, and durable, but the cost is prohibitive. When AGM was the new thing it was expensive too. I always buy the next to the latest technology and let others by the expensive "new thing".

    Also, while AYBC still requires vented compartments for AGM, its widely accepted that its not necessary, My boat is a charter and inspected by MI-DNR and they don't require venting.
  6. gonzo
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    gonzo Senior Member

    AGM batteries may vent gas at high temperatures. It is uncommon compared to flooded acid types though. I wouldn't say 80% discharge is reasonable unless you have equipment that can run at 8 volts. Maybe it means at 80% of charged voltage, which is different. AGM also take a higher charge rate than flooded acid.
  7. Barry
    Joined: Mar 2002
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    Barry Senior Member

    Depth of Discharge

    The end-of-discharge voltage for lead acid is 1.75V/cell; At this level, roughly 95 percent of the energy is spent and the voltage would drop rapidly if the discharge were to continue. To protect the battery from over-discharging, most devices prevent operation beyond the specified end-of-discharge voltage.

    A battery is said to be discharged when the voltage hits 1.75 volts per cell. 10.5 volts overall. (1.75 x 6 for a 12 volt battery) I should have been more clear. I did not mean that the voltage in the battery would be 20% of 13.4 volts.
    AGM's can be used as a deep cycle battery or a start battery
  8. philSweet
    Joined: May 2008
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    Location: Beaufort, SC and H'ville, NC

    philSweet Senior Member

    1. Decide on every component that draws power and get their specs.
    2. Locate them in your boat.
    3. Figure out how to run the wires to them.
    4. Now that you can count the wires at the control panel, figure that out.
    5. Figure out the load profiles when day-sailing or cruising, or just hanging out.
    6. Figure out the charging system performance. Still got the old Universal 11?. Solar, genset, shore charger?
    7. Match the charging power to the load business so that you can script when and for how long the charging happens.
    8. Buy some batteries that will span you over between charging secessions and accept the current that your engine charger can deliver.
  9. MrPopper
    Joined: Feb 2016
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    MrPopper New Member

    I've done all that. I'm interested in which batteries to look at. I know what systems I want but I want to install the battery side first. ( e.g. battery, batt switch, buses, breaker panel and so on) Then I'll start adding accessories and what not.
  10. waeshael
    Joined: Mar 2013
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    Location: charleston

    waeshael Junior Member

    Electrical Power engineer advice on batteries

    Travelled 12,000 miles on the oceans over six years and Live aboard some ten years. I have always used 6V Golf Cart batteries which are less than $100 each at Batteries Plus and can be replaced anywhere in the world.
    The size of bank depends only on the amount of charge you can put in daily.
    I have 400 watt solar setup which can put out 24 Amps in the peak of the day, which means about 120 A-H per day into the battery which creates about 100 A-H of stored capacity. This means I can use 100 A-H a day in the summer or in the tropics. It is important not to discharge the battery below 50% in order to increase the lifetime (measured in charge/discharge cycles.) So I could get by with 200A-H battery capacity. Batteries lose their capacity over their 5 year lifetime which is calculated as the Capacity dropping to 50%. So if I start with 400A-H capacity, there will still be 200 A-H left at the end of life cycle. Four 6V golf cart batteries have 440 A-H of initial capacity. So, I needed room for four batteries.
    Another factor. The maximum capacity of the battery is only possible if the battery is brought up to 14.2V every day at which point it will bubble and gas out and some water will be lost, so the batteries should be checked weekly and water added. If you prefer to keep the batteries below this level, say 13.8V, they won't gas, but the capacity will deteriorate faster. When I am off the boat I leave the charger set to 13.8V max charge and 13V float voltage.

    I have designed several battery systems to 480 Volts DC at 100A load, and many boat systems. I wouldn't get glass mat, and especially avoid Gel-cels, as it is easy to dry them out through overcharging, and they are hard to replace outside civilization.

    I have a small motorcycle sized 12V battery charged from its own solar panel, and with the negative floating, and it does not connect to the house system. This is used to power all electronics used for navigation and communications. The reason for this is to avoid damaging the electronics in a near lightning strike. More on this on my website where there is a lot of information on how to set up ground systems (this is my private site and non-commercial.)
    STart here:
  11. Packeteer
    Joined: May 2005
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    Packeteer Junior Member

    being land bound, I do a lot of camping. but we still like some comfort. so I have a 100Ah Powersonic AGM battery. it powers our fridge and camp lights. I charge it using a Redarc multistage dc-dc charger running off the primary battery (charged by alternator). this setup has served us well for 4 years now
  12. missinginaction
    Joined: Aug 2007
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    missinginaction Senior Member

    When I restored my 25 foot Silverton cruiser I faced the same issue. Golf cart batteries are certainly an option. I wanted my battery bank low in the bilge (but dry of course) for stability and near the center of the boat in the main cabin. So I wanted sealed batteries and settled on AGM's.

    I installed Duracell Brand AGM's and purchased them at Sam's Club. Duracell is just a brand name. The batteries are actually manufactured by East Penn Manufacturing in Topton, Pennsylvania. East Penn makes the Deka brand which you might be familiar with for cars.

    These batteries have been in my boat for three years (2 - 105 amp hr house batteries and a separate starting battery) and I've had no problems with them. They're attached to a Xantrax True Charge 40 at the dock and I use a low rpm high output alternator (rated 100 AMPS) from ARCO Marine when the boats out.

    You might want to look at your power consumption. If you draw 200 AH between charges, conventional wisdom says you'd need at least 4 of the AGM's I use and they're heavy, about 70 lbs. each. You could also consider 6 volt golf cart batteries and series them to get to the 12 volts you need, you can get them as a sealed AGM as well.

    Good luck with your project,


  13. Barry
    Joined: Mar 2002
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    Barry Senior Member

    A quick comment on a wet cell that is vented to atmosphere like a golf cart battery
    You must have these in a sealed to the inside of the boat compartment but vented outside
    Of the boat to be safe
    Some will say not a problem
    ABYC specifies this so you do not have the hydrogen that is produced when charging explode
    AGM are better, though ABYC still requires a vent and do not take a lot of care
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