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  • #31
    I did a Google search for "battery switch wiring" and found some info on the Marinco web site. I have updated my block diagram to add a wire connection between the starter and the "feed" terminal on the back of the battery switch. I have no idea where this new wire comes from. My guess is that is comes off the positive lead of the starter. Can anyone clarify and/or verify this? What gauge wire should I use for this wire?
    2002, X30, L-18, Red Metal Flake (the possessed boat)

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    • #32
      Ok - I'm keep reading things that make me more nervous. On the Yandina web site (www.yandina.com), they state the following.

      "Often a boat will have a lead-acid starting battery but you would prefer to use a low maintenance, deep cycle marine battery for the "house" loads. The problem is, the alternator has a built-in regulator set for the lead-acid charging voltage which will damage an AGM or GEL style battery".

      This is exactly what I'm trying to do. They state there is a feature built into their combiners that makes it act as a voltage regulator for AGM/GEL style batteries. One of the cables or terminals on the top is labelled "HI VOLTS". When this control is connected to a voltage of about 14.2 volts, it disables the combiner until the voltage drops below this threshold. This added jumper connection carries no current so a 16 or 18 gauge wire is more than adequate.

      Has anyone used these Battery Combiners? Am I going to have problems if I use my isolator?
      2002, X30, L-18, Red Metal Flake (the possessed boat)

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      • #33
        You'll need to check the exact charging specs for the Optima batteries. Alternators put out about 14.4 volts. I believe that the Optima batteries will accept that voltage for charging as there are lots of people using them with no additional regulator.

        Most GEL cell and some AGM batteries are very sensitive to high voltage charging, and require this regualtor feature to prevent over charging.

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        • #34
          Originally posted by prostar205
          Ok - I'm keep reading things that make me more nervous. On the Yandina web site (www.yandina.com), they state the following.

          "Often a boat will have a lead-acid starting battery but you would prefer to use a low maintenance, deep cycle marine battery for the "house" loads. The problem is, the alternator has a built-in regulator set for the lead-acid charging voltage which will damage an AGM or GEL style battery".

          This is exactly what I'm trying to do. They state there is a feature built into their combiners that makes it act as a voltage regulator for AGM/GEL style batteries. One of the cables or terminals on the top is labelled "HI VOLTS". When this control is connected to a voltage of about 14.2 volts, it disables the combiner until the voltage drops below this threshold. This added jumper connection carries no current so a 16 or 18 gauge wire is more than adequate.

          Has anyone used these Battery Combiners? Am I going to have problems if I use my isolator?
          All BS IMHO. Here are Optima's charging specs:

          Recommended charging information:

          Alternator:
          13.3 to 15.0 volts, no amperage limit.

          Battery charger:
          13.8 to 15.0 volts, 10 amps maximum, 6-12 hours approximate.

          Rapid Recharge:
          Maximum voltage 15.6 volts (regulated).
          Maximum current: No limit as long as temperature < 125°F (51.7°C).
          Maximum recharge time: Charge until current drops below 1 amp.

          Float charge:
          13.2 to 13.8 volts, 1 amp maximum current, time indefinite (at lower voltage).



          Combiners are basically a smart relay. The connection is open between the batteries until voltage drops then the combiner directs current to the set of batteries that need it. The simple relay method creates one large battery for the alternator when the engine is running. I like to keep is simple myself, plus I am cheap.

          In regard to you isolator, I would not use it. Google isolators and you will find tons of information about how ineffiecient they are. Plus I do not think your isolator will be able to handle the upgraded alternator current.
          05 ProStar 209, Navy Flake, Slate Gray, MCX 1:1 Sold
          15 X23 7.4 FOR SALE

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          • #35
            Originally posted by BrianS
            I believe there is one drawback to using a "dumb" relay. When the key is switched to ON the batteries are immediately placed in parallel. If one of the batteries is significantly drained it will pull the other battery down and equalize at a voltage level somewhere in the middle. This could all happen between the key hitting ON and START. Potentially the voltage could drop low enough to prevent the boat from starting. I have never had this happen but I think it is theoretically possible.

            I'm not trying to knock the method above, obviously it works very well. Just throwing out another alternative. I'll draw up a diagram for the setup I'm planning and post it.
            It's funny you call it a drawback because I see it the other way. If by some chance you leave a light on in your boat overnight and it drains the starter battery as soon as the key is turned your aux battery(ies) are brought online and the boat starts right up. As much as I hate to admit it I have had this happen more than once and I was very glad the relay was "dumb".

            On the other hand, I have many, many times run my stereo so long and hard that both my aux batteries were not able to power the system any longer yet never had any problems starting the boat. I like the relay being "dumb" because I have complete control over the system under any circumstances.............call me a control freak! Plus it's much cheaper, easier to install, and can be bought just about anywhere.

            Now, I have nothing against combiners and they are by far much better than isolators but I just don't see the benefits to justify the cost.
            05 ProStar 209, Navy Flake, Slate Gray, MCX 1:1 Sold
            15 X23 7.4 FOR SALE

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            • #36
              Robert- if you have a test light or multi-meter, you can check for drain by removing one cable from the battery and connecting one lead to the cable, then one to the battery post. If it lights up or the meter shows more than about 15mA, you have a draw, somewhere. You can find it by pulling fuses, one-by-one until it goes away. If you pull all fuses and it still lights up, remove the charging lead from the alternator. If it goes out after that, your rectifier in the alternator is bad and needs to be replaced. Not expensive, but call around for prices- it may be better to do a total rebuild and you can tell them that you want it beefed up.

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              • #37
                I am going to try and summarize, to the best of my ability, the options outlined in this thread for separating and charging 2 "banks" of batteries. For this thread, the word "bank" will refer to a two batteries wired in parallel.

                As I see it, there for four (4) different methods to get the engine's alternator to charge (or re-charge) two separate banks of batteries. They are 1) isolator, 2) battery combiner, 3) perko switch, 4) "dumb" relay. I will try to list the pros and cons of each.

                1) Isolator
                Pros: provides diode isolation between the two banks of batteries so there is no cross feed of voltage
                Cons: generates heat, some say not very reliable - however, I would argue that a solid state device (such as an isolator) is more reliable than a mechanical relay.

                2) Battery Combiner - basically a "smart" relay
                Pros: provides isolation when power is taken away. Also, acts as a voltage regulator for different type of batteries in Bank 1 verses Bank 2.
                Cons: links both banks of batteries together when voltage is applied which "could" lead to the low bank of batteries draining the high bank of batteries.

                3) Perko Switch - basically a manual relay
                Pros: easy to wire, simple, cheap
                Cons: operator must remember to manually turn switch from Off, Both, 1, 2 in order to operate correctly. Also, links both banks of batteries together when voltage is applied which "could" lead to the low bank of batteries draining the high bank of batteries.

                4) "Dumb" Relay
                Pros: easy to wire, cheap, simple, compact, able to take high currents
                Cons: links both banks of batteries together when voltage is applied which "could" lead to the low bank of batteries draining the high bank of batteries.

                I am not an expert in this field. However, I want to wire my stereo batteries correctly and am finding alot of conflicting information.

                I would really appreciate anyones comments. Please feel free to modify any of my finds.

                Thanks,

                PS205
                2002, X30, L-18, Red Metal Flake (the possessed boat)

                Comment


                • #38
                  One important thing to remember, the alternator still needs to be up to the task. A 55A unit is not enough to supply the needed voltage or current to a boat full of accessories + a 1000 W stereo with 2 batteries. The OEM alternator will overheat and at minimum, the bridge rectifier will go and worst case, the bearings and field go at the point that Murphy talked about, possibly leading to smoke and then some. I worked with 12V for a long time and have seen a lot of bad things happen to systems that didn't have adequate power supply upgrades. Regardless of what is done to the system, P(power) still equals I(current) x E(voltage) and that can't be changed.

                  One other negative to battery isolators- most are basically diodes and cause a voltage drop which can keep the battery (or batteries) from fully charging.

                  Comment


                  • #39
                    JimN -

                    Thanks for the reply. This is the type of info I am looking for.

                    Regarding my alternator, the OEM alternator is a Leece-Neville that only puts out 51A. It seems alittle small for the L-18. Anyway, my local electric shop is going to pump it up to 120A and it will be all marine certified. I also plan on upgrading the wiring from the alternator to the starter to at least 4 AWG maybe even 0 AWG because I'll have some left over from the stereo install.

                    Am I leaving anything out? Or missing anything? I only want to do this once and do it right the first time.

                    Do you have a perference between battery combiners, "dumb" relays or just use the Perko switch when charging two banks of batteries???
                    2002, X30, L-18, Red Metal Flake (the possessed boat)

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                    • #40
                      The lead from the alternator goes to the battery, not the starter. The starter already has the proper size of cable. What you want to change, if anything, is the charging lead. The best way to do this is by abandoning the original (disconnect it from both ends and tape the terminals so they can be uncovered later when restoring it to factory condition) and running a heavier one along the harness to the battery, then wrap it with split loom and tape it the same as the original. Any terminals should be crimped (properly) and soldered. IIRC, the OEM charging lead is 10 ga. 6 ga should be fine for your purpose.

                      If a Perko will handle the current, those work fine. I don't really have a preference, other than just making sure it will handle the load and placing it on something that will handle any heat the switch throws off.

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                      • #41
                        Thanks Jim.

                        When using two battery banks, the wire that needs to be upgraded from the alternator should run to the Engine battery bank or the AUX battery bank? My guess would be the Engine battery bank, I'll call it Bank 1.

                        Upon your recommendations, I think I'll remove the alternator and just run either a Borg Warner "dumb" relay like Diesel has done or just go for the Perko switch.

                        Also, what does IIRC stand for?
                        2002, X30, L-18, Red Metal Flake (the possessed boat)

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                        • #42
                          Great job Diesel! Definitely FAQ!

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                          • #43
                            IIRC is 'If I Remember Correctly' Just one of the snazzy internet abbreviations.

                            Are the second batteries going to be close to the primary battery? With the switch or re;ay in the 'Both' position, all batteries will receive charging voltage, but if the switch is in either the 1 or 2 position, only the primary battery will get that.

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                            • #44
                              My starting or engine battery will be in the compartment on the driver's side of the engine and the stereo or AUX battery bank (2 Optimas) will be on the passenger side of the engine. So, I would say they are relatively close together.
                              2002, X30, L-18, Red Metal Flake (the possessed boat)

                              Comment


                              • #45
                                Jim -

                                I took the boat apart this weekend and learned alot of stuff. First, I have an orange wire, probably 8-10 AWG, going from the POS lead of the alternator direct to the starter. Then, there is a 2 AWG battery lead going from the starter to my Perko Battery Switch COMMON terminal. I did not find any wire going directly from the alternator to either battery. This is how my dealer wired in my isolator and battery switch and it worked fine. Now, I am getting rid of the isolator and running only the Perko switch (for now, I may add a Borg Warner Relay down the road or a battery combiner). So, what am I missing. I know a few threads back you said there should be a wired going from the alternator direct to the battery - which battery, Engine or Stereo???

                                Thanks for the help. I will post another block diagram later this evening of how I am planning on wiring my batteries and Perko Switch.
                                2002, X30, L-18, Red Metal Flake (the possessed boat)

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