Low voltage disconnect

Discussion in 'Sport Boats' started by Arminius, Feb 3, 2020.

  1. Arminius

    Arminius Member

    61
    Oct 30, 2019
    Seattle
    Bowrider 200 Select, 2003
    5.0L MPI, 260 hp w/Alpha 1 Drive
    Does anyone have any experience with a low voltage disconnect switch such as the Blue Sea Systems-m-LVD? Another is the Victron BatteryProtect.
    I want to preserve sufficient charge in the battery to start the boat while running the amplifier equipped sound system. The amplifier would be automatically disconnected by the switch when the battery voltage fell below a given voltage. Eg: 12.1 volts. This would be an alternative to a second battery. Another alternative might be to carry one of these small, lithium battery based car starters sold at the auto parts stores. I like the switch idea though. My likely use of the amplifier would be incidental and occasional as it was already on the boat when I bought it.
     
  2. Hillzy_Aus

    Hillzy_Aus New Member

    3
    Feb 4, 2020
    2007 175 Sport Bowrider
    Mercruiser 3.0 TKS
    I was looking at the Victron LVD with Bluetooth which looks the business but decided on adding a proper dual battery setup as I run 2 amps - using blue sea add a battery kit

    Everything I read about the Victron one was positive tho hell I may even add one down the track to the AUX battery
     
  3. Lazy Daze

    Lazy Daze Well-Known Member TECHNICAL Contributor GOLD Sponsor

    Apr 21, 2009
    PA
    Various
    Various
    I've never used Victron stuff, although I hear it is excellent. I've used Blue Seas stuff a lot... A LOT. Excellent stuff and while I haven't used the exact piece you are referencing, I wouldn't hesitate.

    But, if you're looking for the most reliable method to do what you want (and give you the longest lasting music time)... adding a second battery is the way to go. Inexpensive and very easy. You've got plenty of room under the port side, flip-up jump seat for it. Use a Group 27 DC and you'll be set.
     
    OllieC likes this.
  4. Arminius

    Arminius Member

    61
    Oct 30, 2019
    Seattle
    Bowrider 200 Select, 2003
    5.0L MPI, 260 hp w/Alpha 1 Drive
    I've put a 2nd battery in a couple prior boats but was hoping to do something simpler this time. Another battery does double related maintenance chores and costs. I appreciate the info regarding Blue Seas as it seems better adapted to marine use.
     
  5. Lazy Daze

    Lazy Daze Well-Known Member TECHNICAL Contributor GOLD Sponsor

    Apr 21, 2009
    PA
    Various
    Various
    Maintenance... true, but it's (typically) only every 5-ish years on a bowrider (usually more on a cruiser since they are usually being charged constantly). In the game of boating, $140 battery is awful cheap once every 5 years.

    My concern with the disconnect is that you're relying on a single piece of equipment for an important event (starting the engine). You'd also be limiting the amount of time you can listen to the music. Having a second battery is 'redundancy' and redundancy is a very good thing in the marine world. Plus, personally, I prefer to rely on physical switches whenever possible, rather than electronics as it's more reliable in the long run.
     
    OllieC and Kwik like this.
  6. yobub

    yobub Active Member PLATINUM Sponsor

    407
    Jul 29, 2016
    Chicago
    1998 400 Sundancer
    Cat 3116's
    Inhave always used a 2nd battery.in my runabout. I typically use it when something was accidentally left on when the boat was out away (I have an absent minded boat partner). I installed a blue sea systems switch last fall, haven't really used it yet.

    I also keep a jump start pack on the boat. Small investment to protect a day on the lake.
     
  7. Stee6043

    Stee6043 Well-Known Member

    Jun 1, 2015
    West Michigan
    1997 Sundancer 400
    7.4L Gassers
    Blue Seas gear is not cheap. How much more would you invest in the battery/switch vs the Blue Seas setup?

    Another thought - perhaps confirm that your amplifier and/or head-unit doesn't already have a low voltage cutoff. Some brands will have low voltage cutoffs built-in, no further tech required.

    And on the "jump starters" - I have one onboard. They are not only great for your own use but when someone else asks "hey, can I have a jump" they're great for lending. Far easier (and safer?) than hooking up jumper cables. I also use mine each year to run my oil change pump. Easier than connecting to the boats batteries. A great (and very small) investment.
     
  8. Kwik

    Kwik Active Member GOLD Sponsor

    120
    Jun 14, 2019
    Indianapolis
    2004 Sea Ray 240 Sundancer
    2017 F150 Ecoboost 4x4
    Raymarine Axiom 9
    Raymarine Sirius 200 reciever
    5.0 Mercruiser w/Bravo III drives
    A second battery with selector switch was one if my first upgrades on my bowrider. Also kept a wallet sized jumper pack in the dash. But, mine was an outboard. I could have pull started it if all else failed.
     
  9. Arminius

    Arminius Member

    61
    Oct 30, 2019
    Seattle
    Bowrider 200 Select, 2003
    5.0L MPI, 260 hp w/Alpha 1 Drive
    How long will the charge on a jumper pack reliably last? Which is the best as some are priced as toys? I downloaded the amp's manual but found no built in cut-off although it was an awfully good suggestion. I have used a Koolatron cooler in the car for years and come to rely upon its low voltage cut-off. Evergreen RV's warning on the cut-off was that I would wear out my battery prematurely but I thought repeated drain down was the super talent of deep cycle batteries. I'm going to try the Blue Seas switch for $65 from Amazon as I am replacing the battery and the install will be easy. Just one short, heavy jumper with cable lugs. My primary concern is that sessions with the amp equipped radio will be relatively brief although starting the 2003 5L-MPI and idling will be my plan for 2020.
     
    Last edited: Feb 5, 2020
  10. Lazy Daze

    Lazy Daze Well-Known Member TECHNICAL Contributor GOLD Sponsor

    Apr 21, 2009
    PA
    Various
    Various
    Have you used any type of jump pack before? Maybe a wet-cell type? I have an older style jump pack and it seems like that lasts AT LEAST a couple months. I personally have never used a lithium pack, but that should last longer. Charge it once a month, as a precaution, and you should be good.
     
  11. Stee6043

    Stee6043 Well-Known Member

    Jun 1, 2015
    West Michigan
    1997 Sundancer 400
    7.4L Gassers
    I've had the rig linked below for 5 years now. Still works like a charm. If/when it sits idle I will charge it 2 or 3 times per year even though it still shows full charge...

    https://www.amazon.com/gp/product/B002X6VXL4/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
     
  12. Arminius

    Arminius Member

    61
    Oct 30, 2019
    Seattle
    Bowrider 200 Select, 2003
    5.0L MPI, 260 hp w/Alpha 1 Drive
    I installed the disconnect but did not include the remote which adjusts the disconnect voltage from the default of 12.1. Maybe I will add it while I have easy access. My prior experience is with a Koolatron electric cooler in my 3.2 liter V-6 SUV. That was set at 11 volts and I definitely would not have wanted to go any lower but it always started.
     
  13. Hillzy_Aus

    Hillzy_Aus New Member

    3
    Feb 4, 2020
    2007 175 Sport Bowrider
    Mercruiser 3.0 TKS
    Be careful here.... depending on the battery type you are using, 11v is dangerously low.

    a AGM battery has under 50% charge remaining at 12-12.1v and you wouldn’t want to be deeply discharging past this point regularly unless you didn’t care about the battery life/longevity. Hence why the default is 12.1v I would think mate
     
  14. Arminius

    Arminius Member

    61
    Oct 30, 2019
    Seattle
    Bowrider 200 Select, 2003
    5.0L MPI, 260 hp w/Alpha 1 Drive
    DSCN0158[1].JPG Mine is a new First Interstate, Deep Cycle battery. It is not an AGM. I thought these batteries were intended for severe discharge as with a trolling motor. Am I wrong?
    I found a place for the remote switch and thought I would start out at 11.5 volts.
    I remain suspicious of retailers who advise that their products need an extended warranty or are not really suitable for the manufacturer's advertised uses. They want more money and fewer legitimate warranty returns.
    A battery authority says: "Deep cycle batteries are designed to be discharged down as much as 80% time after time and have much thicker plates. The major difference between a true deep cycle battery and others is that the plates are SOLID Lead plates - not sponge. This gives less surface area, thus less "instant" power like starting batteries need. Although these can be cycled down to 20% charge, the best lifespan vs cost method is to keep the average cycle at about 50% discharge." His chart shows an 80% discharge at 11.5 volts while it is only 50% at 12.1 volts. https://www.solar-electric.com/learning-center/deep-cycle-battery-faq.html/ I'll call 1st Interstate to confirm the plates are solid.
    My Searay came with a battery switch mounted on a partition/bulkhead in the battery compartment. I hogged out a rectangular hole for the remote switch and routed the wires behind the bulkhead. Included an alarm I found in my junk.
    First Interstate says their deep cycle battery has perforated plates but you can take it down to 20% if you must. These seems to be controversial. Astro Instruments says: "Anyone with a battery that appears to be cutting off too early may be damaged through too deep discharge (even once), damaged from poor electrolyte maintenance or is old and no longer serviceable. A battery that is discharged to 10.8 volts regularly and then recharged can expect to get 354 charging cycles out of the battery. A battery that is discharged to 11.6 volts regularly and then recharged can expect to get 900 to 1000 charges out of the battery. A properly maintained battery will last many years."
    So I put in the remote and the alarm. Actually, just the low voltage alarm would be sufficient for most situations as I got lucky with a very noticeable Radio Shack buzzer:
    87dB Piezo Pulse Buzzer
    [​IMG]

    Catalog №: 2730080
    $4.00
     
    Last edited: Feb 15, 2020
  15. Arminius

    Arminius Member

    61
    Oct 30, 2019
    Seattle
    Bowrider 200 Select, 2003
    5.0L MPI, 260 hp w/Alpha 1 Drive
    Tested it and everything works. With the 12.1 volt default cut-off, it took 9 hours of radio/amp time at reasonable volume to sufficiently reduce the voltage. The amp, with subwoofer, can produce unreasonable volume. I watched my multitester as I cranked up the volume and you could see the charge diminish. Anyway, 12.1 volts seems fine for my needs. This switch includes an alarm which sounds for 5 minutes before the controlled circuit is disconnected. The alarm sounds in response to system voltage so it would go off if you left the lights on for too long while moored.
     
  16. Bt Doctur

    Bt Doctur Well-Known Member

    Aug 21, 2010
    New Jersey
    Ex SRV 240 Weekender twin
    in between
    Add a dedicated house battery for the noise makers and leave the engine battery by itself
     
  17. Arminius

    Arminius Member

    61
    Oct 30, 2019
    Seattle
    Bowrider 200 Select, 2003
    5.0L MPI, 260 hp w/Alpha 1 Drive
    Two batteries may not be the best:
    1. You'll need to have custom cables made and do creative routing to locate one battery up front where it's 60 lbs does not slow planing time in a stern heavy I/O.
    2. Deep cycles need electrolyte level maintenance and now you have to peer down into 12 cells.
    3. My research disclosed that battery longevity is inversely proportional to discharge levels once you get below 50% and nobody keeps track of that, alternating batteries at best.
    4. After a while, you figure you can get by with just replacing the bad one but which one is that and "I thought I just bought it last year."
    5. Batteries are a hassle to replace but you really can't trust anyone else to work on your boat despite the possibility of hernia.
    6. Cost.
    7. Deep controversy regarding managing two: http://www.clubsearay.com/index.php?threads/how-to-properly-use-2-batteries-2016-sundeck.94924/
    8. I think I have just described a better way unless you are a heavier consumer of electrons.
     
  18. Lazy Daze

    Lazy Daze Well-Known Member TECHNICAL Contributor GOLD Sponsor

    Apr 21, 2009
    PA
    Various
    Various
    Most of this is all opinion based, which is fine. However, adding a second battery is pretty much a day-in, day-out thing - extremely common and VERY reliable. While there are different ways to manage the use of them, none of it is rocket science and generally, the batteries will last about 5 years on a bow rider.

    If adding fluid once in a while is looked at as a hard thing to do, or a reason NOT to add second battery... well, maybe maintenance isn't for you - you can pay someone to do it. Adding distilled water is a 5-minute job. A simple maintenance log for knowing when you replaced the batteries is all you need... or just look at the date stamp on the battery!

    Adding a second battery to your boat is quite easy - the access is very good. And, you DO NOT have to put the battery forward. Put them both right there under the port-side jump seat - planing ability will be the same. The only way you would notice a difference is in a lab.

    There's certainly nothing wrong with what you have done, but honestly, I think you should rely less on researching theories on this topic and listen to those that have "been there done it" for decades and decades of real life experience.

    If you're out on the water and your "one" battery takes a crap, that fancy battery voltage disconnect is not going to get you home... but a second battery will. Redundancy is a good thing in the boating world.
     
    techmitch likes this.

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