Adding another set of batteries

Discussion in 'Electrical Stuff' started by Loyd Dinneen, Sep 12, 2017.

  1. Loyd Dinneen

    Loyd Dinneen Member

    116
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    I am thinking about adding a pair batteries in my 1977 240 SDA as a backup for cabin power. I have a battery switch and not sure on how to incorporate the batteries into the system. The batteries should also be able to also work as a emergency starting battery. I would put them in the center hatch which has access to the fuel tank which is enclosed a box. Any help in how to wire this up would be appreciated.
     
  2. Wylie_Tunes

    Wylie_Tunes Member

    427
    Oct 26, 2012
    Lake Wylie NC area
    N/A
    N/A
    Can you clarify what style of battery switch the boat has? And do I understand correct that the boat already has a house bank and a main cranking bank and you want to make the house bank larger?
     
  3. Bt Doctur

    Bt Doctur Well-Known Member

    Aug 21, 2010
    New Jersey
    Ex SRV 240 Weekender twin
    in between
    what type of switch is there now? a on-off or a 1-Both-2
    How will you be charging the house bank thru a battery switch set to "Both" or a automatic type like the ACR
     
  4. Loyd Dinneen

    Loyd Dinneen Member

    116
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    At the moment it only has a battery for each engine(twin 470s). I would like to incorporate it where the added batteries would charge off the engines and assist in starting them. The switch it has now is a perko 1/both/off/2 type that is very stiff and I will probably replace it. I also have a 50 watt solar charger that I will be using to help keep them maintained when I'm not using the boat. I will have the switch on both when running. The idea to add the batteries is to create a house battery set with a inverter for the fridge,and to boost the starting ability. I don't want to have the issue of waking up to a dead or low set of batteries and not able to start my engines. I am really not educated on how this boat is wired and really need help, diagrams would be helpful. So many wires and all hard to get to.
     
    Last edited: Sep 30, 2017
  5. NorCal Boater

    NorCal Boater Well-Known Member SILVER Sponsor

    Jan 24, 2008
    Covington, LA
    Cobalt CM23
    GM SB 383" Stroker" Alpha Gen I
    Again Loyd, check YouTube. You will find this info there.
     
  6. Bt Doctur

    Bt Doctur Well-Known Member

    Aug 21, 2010
    New Jersey
    Ex SRV 240 Weekender twin
    in between
    Those charging systems dont take kindly to a heavy charging load, your better off installing the alt conversion setup.
     
  7. Loyd Dinneen

    Loyd Dinneen Member

    116
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    The alternator add on is 500.00 to 600.00 per engine something I was only going to do if the other system goes out. I have the solar panel that can keep the center battery charged at least it will keep it maintained. I figure if the engine batteries have an issue I can jump across from the house battery with cables. I was figuring on putting a 4d battery as the house in stead of two batteries and it has more cranking amps and reserve power than the rv batteries and will last alot longer.
     
  8. Loyd Dinneen

    Loyd Dinneen Member

    116
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    Have installed a gp 29 dual deep cycle battery with 210 reserve minutes in the center hatch area and installed a on board battery 3 wire charger and an inverter for the fridge. I haven't hooked it to the engine batteries which are also grp 29 duals as they are charging fine with the new charger. I figure when I have it at the marina ( not a powered slip as such have an outlet close but can't use it at night) I will use the solar charger to maintain the fridge battery. The fridge only uses .01 amps per hour and the solar puts out 2.9 amps. I can use the marina power If I am there during the day to charge the batteries. I have the engines starting up with the first turn of the key so no problems with the starting batteries. I guess I'm rambling on because I would like to let people know that there are other ways to make thinks work with out interfearing with the engine charging system. I have about 375.00 in all the parts including the charger,inverter,battery,and solar charger. I will be carrying jumper cables incase the main batteries go dead from running the house stuff and will jump from the center battery, Just have to start one engine and it will charge both starting batteries to start the other engine. But to prevent that I am going to install three digital volt meters to see the voltage on each of the three batteries to keep an eye on it.
     
  9. Creekwood

    Creekwood Well-Known Member GOLD Sponsor

    Apr 26, 2009
    Oakville and Georgian Bay, Ontario
    '97 330 Sundancer
    2X 454 w/ vDrives
    I think your fridge consumption number is wrong. That looks far too low.
     
    SloBurn likes this.
  10. Loyd Dinneen

    Loyd Dinneen Member

    116
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    The fridge is only a 1.7 cu ft unit and I had it on a medium setting. When I started the battery reading was 12.5v and two hours later it 12.4v and I converted it over to amps so I could figure out how long the battery would last. I may be figuring and reading it wrong but it is not using much power when set on a lower setting. The real truth will come when I get out and use it over a 8 hr or longer period. I will also see how the solar charger maintains the battery with the fridge on, worst case will be it runs the center battery down and since it isn't but for that purpose will now be a big deal and I will know it's limitations.
     
  11. Creekwood

    Creekwood Well-Known Member GOLD Sponsor

    Apr 26, 2009
    Oakville and Georgian Bay, Ontario
    '97 330 Sundancer
    2X 454 w/ vDrives
    The refrigerator manufacture site will likely give you consumption information. Just checked Norcold's site and their 1.7 cu ft draws 3.6 amps on 12v. That is their latest version with the efficient Danfoss compressors. If yours is older it will draw a lot more. Maybe double. Now that is only while it is running, so you would need to know the cycle times too. But its more than what you are budgeting for.
     
  12. Loyd Dinneen

    Loyd Dinneen Member

    116
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    I believe that this isn't the original fridge since it is a straight 110v model and looks fairly new. I can't remember the model at the moment but it is a retail brand not marine. Your most likely correct about the usage but if I can get 5 or 6 hours out of it during an outing then I will be happy since I will be only cooling water or sodas perhaps bait at a lower temp setting. I did look for the manuf. imformation for this unit but could not find the amperage output imfo. One thing I also have to figure in is what the inverter uses also. From what I can see I used .4 volts with the fridge off and charger unpluged in a 24 hr period. I hooked up the 50 watt solar charger and in about three minutes it had already put .1v back into the battery. It is suppose to put out 2.9 amps at 14.5 volts. Summer time will not be a problem here in Las Vegas as the sun shines almost all the time. I am going to put a cutoff switch on neg cable going to the inverter so when I am not using it I can save battery power and prolong its life. I have one on my RV and it keeps the battery from getting low as there is something running somewhere that runs it down over a period of time. Anyway if it works great it is better than what I had before which was nothing.
     
  13. Loyd Dinneen

    Loyd Dinneen Member

    116
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    I did some more checking and finally found some amp specs and you were really close in your estimate it uses 14 amps. So with a 210ah battery and a 2.9 amp solar charger running it can get 14 plus hours of running before losing power but that is also at full power reduce the setting and I will use less power. Again I will see how it all pans out when I try it out on the water. The brand is Haier 1.7 cu ft.
     
  14. gdavis67

    gdavis67 New Member

    28
    Mar 1, 2017
    Saugatuck, MI
    1990 390ec
    Twin 454 Mercruiser T 340 with Hurth drives
    On our previous boat, Carver 332 Voyager, it came equipped like yours, one battery per engine. In order to add a house bank and ensure that that bank charged properly, I added a Blue Sea "add a battery" system. It worked fantastically and gave me many options for use/charging. The best part was I had a back-up bank for starting if needed. Check out the link below. Their website also gives many different wiring scenarios.

    https://www.bluesea.com/resources/170/Battery_Management_Wiring_Schematics_for_Typical_Applications
     
  15. Loyd Dinneen

    Loyd Dinneen Member

    116
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    I checked out the imfo you sent and it has a great diagram for what I would need to do to set it up so it charges thru the engine. I'm not much of an electrican but the diagram is pretty simple, but at the moment I will see how my system works and if I have to throw some more cash at this boat I will. The charging system on these 470's don't like a heavy load and a conversion is like 600.00 per engine. Right now I'm battling two outdrive issues just as I was going to take her to the lake. The typical B.O.A.T issue. Thanks for the imformation.
     
  16. NorCal Boater

    NorCal Boater Well-Known Member SILVER Sponsor

    Jan 24, 2008
    Covington, LA
    Cobalt CM23
    GM SB 383" Stroker" Alpha Gen I
    What's wrong with the outdrives, Loyd?
     
  17. Loyd Dinneen

    Loyd Dinneen Member

    116
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    The starboard one won't shift out of forward and won't shift into reverse. When you shift into reverse there is no shift resistance on the control. If you put it in forward gear you can't stop the prop when put in neutral. On the port side there was water in the oil in the lower end. I took it to my merc guy and we installed a complete waterpump kit including the base and put in a new shift shaft seal. We then pressure tested it and everything held. All I have to do now is get the starboard side to shift properly' One thing I did notice is when I started the engine the rpm's were higher than what they should be (1250 instead of 959-1000). That could of kept it from kicking out of gear but doesn't explain the lack of reverse. It's cooled down here in Vegas with wind blowing so I'm not going to work on it anymore today and will wait for a warmer day. I may have to get my merc guy to come over and play with it he will most likely only take a few minutes to fix it.
     
  18. NorCal Boater

    NorCal Boater Well-Known Member SILVER Sponsor

    Jan 24, 2008
    Covington, LA
    Cobalt CM23
    GM SB 383" Stroker" Alpha Gen I
    You know about the Shift Interrupter Switch, right? If that is out of adjustment the drives will not shift correctly. The high RPMs are a problem. I was always taught that the idle should be set with the engine in forward gear, under load and set the idle to 650-750 RPMs.
     
  19. Loyd Dinneen

    Loyd Dinneen Member

    116
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    I suspect the interrupter switch could be causing an issue as it doesn't look like it is centered in the grove. I will have to see how to adjust that to get it centered. Normally the adjustments are made with the boat in the water whether it be the rpm or shift adjustments. It's like in a car where you adjust the idle in drive.
    I need to check the carb adjustment or check for perhaps a vaccume leak which would cause the rpms to go up. I will tighten up the base bolts and give the linkage a little lubrication. I will also check the choke flap to make sure the choke is operating on warmup as the engine runs a little rough unless I increase the rpms and clear it a bit. She may need a carb rebuild, I did that to the port engine and it sweetened it right up where it starts right up now.
    Anyway I need to get the shift issue fixed that worries me the most right now. I also have to get the port lower end installed, the new fluid put in and ran.
    I see your from northern cal. I'm originally from Central Cal Merced County area.
     
    Last edited: Feb 20, 2018 at 12:29 AM
  20. NorCal Boater

    NorCal Boater Well-Known Member SILVER Sponsor

    Jan 24, 2008
    Covington, LA
    Cobalt CM23
    GM SB 383" Stroker" Alpha Gen I
    Check on YouTube for video instructions on the interrupt switch adjustment. You can adjust it out of the water but to really test it the prop should be under load. If you are having these shift on the trailer you may have bigger issues....or it's a cable adjustment issue. Check YouTube. Lots of good instructional videos.

    I lived in California from 1979-2016. I started in Sacramento, then Long Beach for 16 years, Orange County for 2, Las Vegas for 2, Fresno for 2 and then Elk Grove (Sacramento) for 10. In June of 2016 I retired and my wife and I relocated to the New Orleans area. She has family here and my retirement $$$ go much farther,
    Shawn.
     

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