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  1. #1

    Default both batteries we charged, used battery 1, but then battery 2 dead also....

    I recently had to call seatow and get a short tow to the dock:

    boat = 2015 superair nautique G23 with PCM 409 engine
    batteries = 2 x 800 CCA marine batteries, approx 2.5 years old

    A. i had battery selector switch set to battery #1, i cut the engine, and used the high power stereo/10in sub for an hour or so, expecting the battery to run down....no worries since i had a 2nd battery.
    B. but then boat would not restart with battery #2, which was dead also (i turned switch from #1, to #2, not 1+2)
    C. seatow was able to jump and start the boat, but with difficultly
    D, the boat idled for about 2 minutes then died again - i watched the voltage meter on my consol go from 12v rapidly to 7v, then the engine died.
    normally once i get an engine jumped and running, it runs fine after that. first time ive ever seen this happen


    back at home:
    1. trickle charged batteries over night - boat cranks strong and starts and runs fine, like new, on either battery #1 or #2
    2. alternator is putting out 14volts, as tested on a volt meter
    3. i took both batteries in to autozone, both batteries tested good. 800+ CCA on the tester


    only possible solution now was that there was still current drain from the battery#2 even when the the battery selector was set to #1.
    1. noticed that with the boat consol off and everything else off, completely, the battery terminals still sparked lightly when i connected the them back to the battery - this means that there is current drain going on
    2. i tested with a DC amp setting on my meter - Even with the battery selector switch set to off, their is still current being used from the batteries. about 1/2 amp

    so apparently, the normal drain on the battery, even with boat off and nothing in use, is .5 to 1 amp, which will drain a battery after a while.
    i leave the batteries on the trickle charger when not in use, although the previous owner didnt do this, so the exact condition of the batteries is unknown.
    i have had autozone test batteries to be good, even when they were bad. so my best guess is that the batteries are probably at some fraction of their original new capacity, and the residual current drain that occurs even with the boat off and battery selector switch in off, drained both batteries.


    1. is this normal for the battery selector switch to not actually turn off a battery completely?
    2. what should do about it? i have always just left my engine idling when at anchor or sandbar, etc, just in case. but it would be nice to be able to turn the boat off occasionally
    3. currently i have bought a 3rd battery and jumper cables as a backup measure. the battery is keep in storage locker and not connected at all unless needed. i will put it on the trickle charger to keep topped off and healthy every 2 weeks or so.

    only thing i didnt test yet is if the sound system amp is wired to bypass the battery selector switch, and is connected directly to both batteries, as is common with amp setups. that might be the most plausible explanation here.


    thanks
    -Phil
    Last edited by makesumwake; 02-10-2018 at 07:37 PM.

  2. #2
    Join Date
    Apr 2016
    Location
    barnegat NJ
    Posts
    2,908

    Default Re: both batteries we charged, used battery 1, but then battery 2 dead also....

    with battery switch in the off position, see if amp stays warm,Also check bilge pump for current draw

  3. #3
    Join Date
    Sep 2008
    Location
    Maryland - USA
    Posts
    7,095

    Default Re: both batteries we charged, used battery 1, but then battery 2 dead also....

    Quote Originally Posted by makesumwake View Post


    1. is this normal for the battery selector switch to not actually turn off a battery completely?
    2. what should do about it? i have always just left my engine idling when at anchor or sandbar, etc, just in case. but it would be nice to be able to turn the boat off occasionally
    3. currently i have bought a 3rd battery and jumper cables as a backup measure. the battery is keep in storage locker and not connected at all unless needed. i will put it on the trickle charger to keep topped off and healthy every 2 weeks or so.
    1) if they are installed properly, battery switch should isolate the battery from any load.
    2) I'd be inclined to figure out what you have, determine the deficiencies and resolve them.
    3) that's a bandaid....though it may prove satisfactory for the interim.

    I'd suggest a full-up load test for assessing the batteries....the 'new' testers don't always identify issues. You may also want to inspect your battery cables to make sure the connections are clean and tight. Finally, be careful with trickle chargers. They are not all in the same catagory and frequent use of a simple one may cause more harm than good.

  4. #4

    Default Re: both batteries we charged, used battery 1, but then battery 2 dead also....

    ok, problem is solved. the battery selector switch was broken from jolts the boat took riding in chop.

  5. #5
    Join Date
    May 2010
    Location
    DC Burbs/Maryland Eastern Shore
    Posts
    1,238

    Default Re: both batteries we charged, used battery 1, but then battery 2 dead also....

    Delete it...get an isolator and a VSR
    Practicing the ancient art of ren-ching

  6. #6
    Join Date
    Jun 2008
    Location
    Island Heights, NJ,
    Posts
    2,744

    Default Re: both batteries we charged, used battery 1, but then battery 2 dead also....

    Quote Originally Posted by makesumwake View Post
    ok, problem is solved. the battery selector switch was broken from jolts the boat took riding in chop.
    No properly mounted switch should fail this way. I did have one battery switch fail on one of my boats when the thin plastic front face (which retained the moveable part of the switch) cracked. My boat came that way so I had no idea how that happened, but highly unlikely riding in a rough chop would do it. A battery that is NOT strapped down ( a safety violation) could cause stress on the cables (especially if short with no slack!) to break the terminal's mechanical connection to the case of the switch.
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280
    1972 22ft Bristol
    Honda 7.5HP 4 stroke Long shaft

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