Please note this thread has been inactive for 90 days. For the best results, please start a new thread.
Results 1 to 10 of 10

Thread: Silly Questions

  1. #1
    Cadet
    Join Date
    Nov 2009
    Location
    Brownstown, MI 48183
    Posts
    3

    Talking Silly Questions

    Hi Guys & Gals,
    Have a (silly) question for you experienced motorheads. I have a "86 60 HP Mariner with trim & tilt. 19' Starcraft Superfisherman boat. I fish on the Great Lakes a lot. I run a lot of extra equipment (downriggers, power planer board reels, autopilot). I have the chartplotter/fish finder and radio on a separate stand alone deep cycle battery to eliminate interference. I constantly charge both batteries (the deep cycle and the starting battery) upon returning from fishing. The 60 hp engine can't possibly keep up with the load requirements I run on the starting battery. When I put the charger on the battery it usually reads that the battery is 50% discharged. It is an Optima gel starting battery, 4 years old.

    The question is this- can I put another dual purpose (starting & deep cycle) battery in series on this battery, retain 12 volt current for the absolutely necessary fishing goodies, and expect the motor to somewhat charge the system? I am beginning to believe that no matter what, my demands for electrical power are too much for the motor and I am destined to live a life of constant recharging the batteries.

    Thanks for your input in advance,
    Chuck

  2. #2
    Chief Petty Officer
    Join Date
    Jun 2008
    Posts
    557

    Default Re: Silly Questions

    With a four year old battery, you should start fresh. If you put another battery, (in parallel not series, unless you want 24 volts to really crank your starter, at least for a moment ) the weaker battery will lower the fresh battery, to its level, and you will still not get the cranking amps you need. I would set the system up with fresh new batteries, and yes two in parallel would be better for yours I think. As for charging, I am not sure what your motor's DC chargeing output is, or if there is an optional larger one for it. Perhaps others here can tell you that information.

  3. #3
    Commander
    Join Date
    Jan 2004
    Location
    Poulsbo, WA
    Posts
    2,265

    Default Re: Silly Questions

    You're pretty much stuck with the stock charging system which is approx 10 amps max.

    If you're gonna install dual-batteries, as the poster suggested, for best results they should both be new, also the same brand, same size.

    BTW if you have a voltmeter in your system, check charging voltage while you're underway with a light electrical load, if your rectifier was marginal, voltage would be somewhat low. Or throw a digital V.O.M. on the battery terminals to see what you've got.

    It's an unregulated system, so it's possible to run batt voltage up to 18V or so, lightly-loaded. But I don't expect you'll ever have that problem, with all the electrical loads you have on at any given time!

    HTH...........ed

  4. #4
    Cadet
    Join Date
    Nov 2009
    Location
    Brownstown, MI 48183
    Posts
    3

    Talking Re: Silly Questions

    Thank you for your replies, FuzztTBay & Emckelvy! I will put a volt meter on the batt next time I am out. I have the cranking amps for the starter all the time with no problem there. So, I believe the stator and rectifier are ok. I have a dual purpose Blue Top Optima (new) D3M CCa 900,MCA 1125, AH 75. I am thinking to get another and hook them up. I will still have to charge these batteries every time I take the boat fishing, but with the size of the 2 batts, they should last quite a while as I will not be drawing them down past 30% charge. Do you think this is a good solution, or should I get that 29' Hydrasports Vector I've been drooling over?

    Thanks again,
    Chuck

  5. #5
    Lieutenant trendsetter240's Avatar
    Join Date
    Jun 2009
    Location
    Vancouver, BC Canada
    Posts
    1,457

    Default Re: Silly Questions

    Quote Originally Posted by Turning Point View Post
    Thank you for your replies, FuzztTBay & Emckelvy! I will put a volt meter on the batt next time I am out. I have the cranking amps for the starter all the time with no problem there. So, I believe the stator and rectifier are ok. I have a dual purpose Blue Top Optima (new) D3M CCa 900,MCA 1125, AH 75. I am thinking to get another and hook them up. I will still have to charge these batteries every time I take the boat fishing, but with the size of the 2 batts, they should last quite a while as I will not be drawing them down past 30% charge. Do you think this is a good solution, or should I get that 29' Hydrasports Vector I've been drooling over?

    Thanks again,
    Chuck
    Hi Turning Point,

    I think, as mentioned, you need to replace your 4 year old starting battery. Starting batteries don't last long if they get discharged down to 50% and after 4 years that one is likely on it's last legs.

    The Optima that you described sounds like a sufficient size. If you are going to be adding another battery in parallel then do it with two new batteries, don't mix old and new. Also, don't buy a battery now if you are just going to store it until spring. Batteries have a limited lifespan & warrenty so no point in wasting 6 months of both.

    The greatest benefit you will get from dual starting batteries is the longer life. The less you discharge your starting batteries each trip the longer they will both last.

    Cheers!

  6. #6
    Cadet
    Join Date
    Nov 2009
    Location
    Brownstown, MI 48183
    Posts
    3

    Talking Re: Silly Questions

    Thank you, Trendsetter 240! I will do as suggested.
    Chuck

  7. #7
    Fleet Admiral Faztbullet's Avatar
    Join Date
    Mar 2008
    Location
    Tennessee
    Posts
    8,277

    Default Re: Silly Questions

    Great information so far but the major problem is your charging system. That charging system puts out 10 amps at WOT and at trolling speeds only 2-3-amps so your using more power than you can replace. Before I replaced any batterys I would have them tested to see if they are still within 90% of rating and if ok they dont need replacing yet. Do not hook the batterys together as both will discharge at same rate and then the engine will not have enough amps to recharge them.
    Quote from Mercury marine:
    "Using an outboard to charge two batteries is only effective if the outboard charging system is capable of delivering more than 15 to 20 amps. One point to remember: most systems are rated at wide-open throttle and charge substantially lower amounts at slower engine speeds"
    (http://www.mercurymarine.com/service...electrical.php)
    One option is the Procharge "Charge on the run system" or the Stay n Charge. Both systems keeps batterys "stand alone" and charges them when ever motor is running and only charging battery that is the lowest 1st. This way when starting battery reaches 100% engine will only charge your "extras" battery! The Stayncharge does the same but allows you to recharge from your towing vehicle to and from lake!
    When in doubt,Trim it out!!!
    Business Owner & Certifed Technician
    Boats I own & use
    20ft Javlin w/250 Junkrude
    17ft Bullet w/200 Merc (SOLD!!)
    13ft Allison w/150 I-6
    17ft Hydra-Sport 175GT
    15ft Allison w/75 Stinger(project)
    14 x 48 Drifter with 1100SS Merc

  8. #8
    Admiral j_martin's Avatar
    Join Date
    Sep 2006
    Location
    Isanti, MN
    Posts
    7,477

    Default Re: Silly Questions

    I think your best bet would be 2 batteries for the engine, with a switch. That way if you kill the main one fishing, you'll have the backup with a flick of the wrist to get you back home.

    You can alternate the battery in use to even out the wear.

    hope it helps
    John

  9. #9
    Rear Admiral
    Join Date
    Nov 2008
    Posts
    4,528

    Default Re: Silly Questions

    I run two Group 27 deep cycles for my accessories and a group 24 starting battery. I have an onboard ProMariner 20 amp charger and it takes it a good 8 hours to charge all three batteries after a day on the lake. Now, I'll mention this as a possibility but you'll need to work through the details. I have a V-6 and I don't know if you have enough room under your cowling to do this or not but I got a hold of a 50 amp alternator off a 98 Optimax DFI engine and used the pulley and mounts with a little fabrication to bolt it on my engine. The DFI engine uses a V pulley belt rather than a serpentine belt so it's really easy to set it up and it fits nicely under my 98 DFI cowling on my 91 engine.

    I'm not quite finished with the install yet but my intentions are to run a battery isolator and charge the two Group 27's that are setup for 24v at 12v each. Alternatively, I'll hook up an inveter to it and run the onboard charger (110v) but that is my last resort because that's not very efficient.

    Just for info, the two group 27's are setup to provide both 24 and 12 volt power and I can run my 60lb Minkota trolling motor all day and not go below 60%. That's the magic number for deep cycles by the way.

  10. #10
    Lieutenant Junior Grade
    Join Date
    Sep 2002
    Location
    welland ontario
    Posts
    1,068

    Default Re: Silly Questions

    If you are going to replace the batteries anyway why not buy one large one instead of two smaller ones and putting them in parallel?

Similar Threads

  1. Silly but important questions.. first time boat owner sorry
    By Big Pete in forum Non-Repair Outboard Discussions
    Replies: 26
    Last Post: November 1st, 2009, 05:50 PM
  2. Merc. 9.9 OB 1976 Silly questions
    By Bagboater in forum Mercury & Mariner Outboards
    Replies: 1
    Last Post: July 21st, 2008, 12:16 PM
  3. Silly Volvo Penta DuoProp Questions...
    By WillyBWright in forum Volvo Penta I/O & Inboard Gas Engines & Outdrives
    Replies: 3
    Last Post: September 27th, 2006, 04:28 PM
  4. Couple of silly questions on alpha one out drives.
    By boaterntexas in forum Mercruiser I/O & Inboard Engines & Outdrives
    Replies: 6
    Last Post: August 10th, 2003, 05:20 PM
  5. Trolling, Fishfinder, and other silly questions.
    By tokanel in forum Boat Topics and Questions (not engine topics)
    Replies: 3
    Last Post: August 27th, 2001, 07:05 PM
  1. iboats Forum Directory - Over 100,000 forum posts organized by topic