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Reconnecting Dual Batteries


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After winter storage with my batteries out, I'm having trouble reconnecting the batteries, and am really hoping for help so that I don't do anything detrimental.  I've researched schematics, read the manuals, and searched this forum, but can't confidently identify the setup well enough to be sure I won't blow something up.

I have a 2004 215 SSI with dual batteries.  This is before yellow was negative, so the negative lines are black.  The yellow line is actually to the bilge pump I believe (?). I have the thick black (negative) line not connected to anything with ends labeled 1 and 2.  And I have my red positive lines labeled for battery 1 and 2 as well.  I believe the black negative line goes from battery 1 to battery 2.  But I am unsure how I'm completing the circuit to ground.   Where does the small black line in the pic go, and does that complete the ground, or is that actually just for a supplemental system?  Also, the yellow line I thought went with the positive (I know it was stacked with another line on the battery),  would that make sense to go to positive on battery 1 if it is the bilge line?  Or am I missing something completely and should that be on a negative anode?   From the pic of the yellow line going down into the engine compartment, do you agree that's the bilge pump?  Thanks so much for your time and any help you can provide. 

boat battery compartment1.jpg

boat battery compartment 2.jpg

boat battery compartment 3.jpg

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If you are in doubt about the 2 large red wires (with no batteries installed) put the switch in all and check it with an ohmmeter and it should 0 ohms (possibly 0.1 or 0.2 ohms) this will prove that they are the positive leads for batteries 1 and 2.

There will be a short negative jumper wire between the negatives on batteries 1 and 2. There will also be a negative cable going from one of the batteries to the engine block.

The small black cable is (probably) a ground (negative) cable to your trim pump.

The cable with the yellow maybe the cable from a battery positive to the starter.

Some of these can be checked with an ohmmeter with no batteries connected.

Hope that helps.

 

 

 

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ALWAYS   ALWAYS take too many pictures and paint the big cables with red & black paint. Also use a tape piece wrapped around each wire with a number of each battery. the batteries CAN BE DIFFERENT amperages. Starter or music job.  Pictures !!

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Yes I will absolutely take pictures once this is set correctly, print and store with my manuals.

Boatman - the yellow leads down toward the engine and was told it was the bilge pump power.  And if so, that would still go on the battery positive as you said if,  correct?

If the small black cable is what we expect, should it go directly on a negative anode of a battery as well, and would it matter if it was battery 1 or 2?

I'm not confused on the large red wires being positive leads, I have those labelled well to go to the positive anodes of the batteries.  Not confused on the short  negative cable from batt 1 to batt 2 either.  I don't seem to have a negative to engine block though.  unless it's that little wire. could a small wire function as that?

Thank you very much for responding and helping me out here.

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More pics to clarify:

where yellow leads down to the engine block, and attached to the back of it.

Showing the middle thick red wire from the dial (one pic) that leads down to the engine block (another pick).  Could that actually be what is completing the circuit to ground, even though it's red from the dial?

The black marine accessories box where the small wire leads. coming out of are two black wires that lead across the back compartment where I can't see final output, guessing it could possibly be depth finder or something.

 

dial.jpg

 

red to engine block.jpg

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Get someone experienced in marine wiring !!  That skinny black wire does not carry the starter motor current. There  was & still is a heavy CABLE to carry current to the metal of the engine. Look around the engine for a thick cable BOLTED to the engine . It is there. Might have slid out of sight.

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Unfortunately I am stuck in rural northwoods, hours from any boat mechanics, without the ability to get the prop back up without connecting the battery power, so can't tow it to a qualified professional. Hence, I'm trying my best to research and have used this forum to seek some help. 

Could the thick cable bolted to the engine block (strangely in red wrap) comjng out of the middle of the switch box be what you are talking about?

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Start posting lots of pictures...…...Do them in logical sequence. top of engine. Left to right. Down a little. Left to right again. Repeat until we can be sure all the wires are being seen in some kind of order.  You can do it.  Use a light of some kind to help with details of the wires.

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Thanks cyclops.

Sadly, this forum has a 500k size limit on pics uploaded and I blew it all already before I knew it.  I tried to delete a prior picture to hopefully be allowed to post another, but no luck.   The battery switch is on the left, while looking at the engine compartment.  There are three large red wires coming out of the bottom of it.  the left and right are positive wires that should be attached to battery 1 and 2 respectively.  the middle one leads directly to the engine block, on the left side of the engine.  It is securely attached there with a rubber housing over the connection.  There is a thick yellow coming from the back of the engine, where there is a bolt of some sort coming out the back, a series of nuts on it, with the yellow wire attached in between the nuts (and the free end comes back to be attached to a battery).  I believe it was a positive it attached to.  Let me know any questions i could answer to help or any other thoughts.  Thanks again.

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If you Google " marine dual battery install". There is a ton of info on this. Is to the small black wire I would trace it back to see what it is used for. Most likely  a ground.

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If you bought the boat used ?  All bets are off about wire colors & where they went to. You might want a GOOD electrical marine mechanic to rewire the wires. That way he screwed up something.  Your wiring is very simple to us. If he will not do it in less than 1 hour... Minimum billing.  He is not good enough to be allowed on your boat.

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Thanks for the thoughts. I did buy the boat used and have been googling for a week looking for a definitive answer but haven't found the equivalent setup with that that yellow wire. Like you said, all bets are off, not knowing what the previous owner was thinking/did.  I will take give it a couple more days of searching and then try my best from memory of the setup with my fingers crossed and protective gear.

I've seen conflicting info on the order of connection for the dual battery system.  Could any of way in on whether you concur that I should attach both positives to the batteries 1 and 2, then connect the black ground wire from battery 1 to battery 2? (making sure the dial is switched to Off of course). Positives first, then negatives, yes?

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That skinny black wire...………. WILL NOT carry the starter motor current.  My best guess is it SHOULD ???? be the negative lead from the bilge pump motor. 

Find that BIG wire that goes from the metal of the engine or 1 of the starter motor bolts holding the starter in place.

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It looks to me that the red cable that you say runs to the block actually runs to the positive post on the starter. With an ohmmeter and the switch in all see if you have continuity from the red cable near the block to both red battery cable ends. If so it is mounted to the starter and is a positive cable. The yellow cable...with an ohmmeter go from the end of the yellow cable and check for continuity to the engine block. If it shows continuity it is a negative cable that should go to the negative on one of the batteries (they are connected by the short yellow cable) and is the main engine ground.

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I hear you that there 'should' be a big negative wire from the engine.  I have looked and looked and looked.  The only large wires coming from the the engine are the red positive from the left side of the engine (looks like it's where the starter is) back to the center of the switch, and the big yellow wire from the back of the engine which I'm not completely sure of.   (But black is negative on this wiring setup throughout, and I seem to remember the yellow being stacked on a positive battery terminal and being told it was the bilge pump power.)

Could it be that that big red wire from the starter area of the engine back to the switch completes the ground?

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19 minutes ago, Boatman609 said:

It looks to me that the red cable that you say runs to the block actually runs to the positive post on the starter. With an ohmmeter and the switch in all see if you have continuity from the red cable near the block to both red battery cable ends. If so it is mounted to the starter and is a positive cable. The yellow cable...with an ohmmeter go from the end of the yellow cable and check for continuity to the engine block. If it shows continuity it is a negative cable that should go to the negative on one of the batteries (they are connected by the short yellow cable) and is the main engine ground.

Thank you... I'm a novice with an ohmmeter, so just to be clear, the continuity you are referring to means that while I have the switch set to "ALL" I hold one lead on the wire coming out of the starter area of the engine block, and try the other lead on each of the positive wires coming out of the switch check the ohmeter shows continuity and not "OL" for open loop on both?  And does it matter if I use either the red or the black lead on either end?  Any tips on how to touch the wire coming from the block to the switch (since the attachment to the block is within a rubberized housing and I don't see any easy access, would it be easiest to unscrew the switch cover and test the wire there?).

For getting an ohmmeter reading on the yellow cable... when you say the end of the yellow cable , do you mean the free end that I would attach to a battery?  And when you say continuity to the engine block, where would I touch the engine block to check for continuity? Does it matter what the switch it set to to test this?  Does it matter on which one I use the red vs. the black test lead?

Thank you so much!   I'm just really not "wired" for the electrical stuff and genuinely appreciate you walking me through it.  I'm googling what I can to help understand.

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Update: Red cable from starter block tested and is as suspected - closed circuit to both positive cables when in "All" (and to 1 only when in 1, and to 2 only when in 2).

Yellow cable questions still outstanding - can not get a closed circuit continuity to the engine block, but not sure if I know where to touch the engine block for proper test (I tried the starter where the red cable connects, as well as other places).

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When testing the yellow cable put one lead of the ohmmeter on the loose end of the yellow wire to some clean metal on the engine the alternator housing is usually a good contact for engine ground.

When you test the ohmmeter by putting its two leads together you will get a reading of zero or very close to it. When you are testing the cables you should get approximately the same reading.

 

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You did it Boatman.  I was able to get continuity on the yellow cable touching to a nut on the back of the exhaust manifold drain (couldn't get anything on the alternator housing).  I got the continuity whether the switch was in All or Off.  FYI, I did of course also get continuity when touching the free end of the yellow line to the place where it attaches to back of the engine with a nut. Unless you tell me anything about any of this sounds weird or any other considerations otherwise, I now feel confident enough that the yellow is actually the negative ground to give it a shot at reconnecting everything.  

I'll sleep on it and tomorrow configure as follows:

Red Positive line 1 from switch to battery one positive

Red Positive line 2 from switch to Battery 2 positive

Two foot long Thick Black line from Battery 1 Negative, (with small skinny black line on same battery 1 negative) to Battery 2 Negative.

Yellow cable to battery 2 negative.

Tighten everything down then attempt switch power to 1 or All.

 

FINAL QUESTION - Does this order of connection seem correct and safe??

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