Moving batteries forward on a Mako 20

[chuckmcb]

I recently installed a Mercury 4 Stroke 150 on my 1988 Mako 20 replacing the original Black Max (served me well!)

I chose the Mec in part because of it's lighter weight compared to the Yamaha, Honda and others (about 40 lbs lighter than Yamaha...and $4000 less!). Even so, the added weight of the 4 Stroke compared to the old 2 stroke Black Max brings the water line up to the bottom edge of the scupper drains in the transom.

To shift some weight forward I want to move the two batteries (total weight about 100 lbs) from their present location in the stern, up, and under the center console. The distance from the old to new location will mean a battery cable run of 18 ft. There appears to be plenty of room under the console and space in the port wiring chase to do the job.

My questions:

1) Will 4 gauge cable work for this distance...(4 is much less costly than 2 gauge but I want to do it right, not cheap)

2) Has anyone done this mod and what issues did you encounter?

Thanks Much for your advice!! Chuck McB

[Triplecrownnc]

quote:

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Originally posted by chuckmcb


I recently installed a Mercury 4 Stroke 150 on my 1988 Mako 20 replacing the original Black Max (served me well!)

I chose the Mec in part because of it's lighter weight compared to the Yamaha, Honda and others (about 40 lbs lighter than Yamaha...and $4000 less!). Even so, the added weight of the 4 Stroke compared to the old 2 stroke Black Max brings the water line up to the bottom edge of the scupper drains in the transom.

To shift some weight forward I want to move the two batteries (total weight about 100 lbs) from their present location in the stern, up, and under the center console. The distance from the old to new location will mean a battery cable run of 18 ft. There appears to be plenty of room under the console and space in the port wiring chase to do the job.

My questions:

1) Will 4 gauge cable work for this distance...(4 is much less costly than 2 gauge but I want to do it right, not cheap)

2) Has anyone done this mod and what issues did you encounter?

Thanks Much for your advice!! Chuck McB

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4 gauge is not big enough, dont skimp there. Many people on CM have done the same thing, use power posts to extend your cables.

[keyman]

As TC commented 4 gauge cable is not the proper wire gauge. Suggest you refer to Ancor tables for calculating the proper size (suggested minimum size #1/0 or larger). Determine the total lenght for both the plus and negative conductors and estimated current requirements. I have provided Excel spreadsheets for required electrical components. Consider using BEP cluster for battery management. Estimated cost between $600-800 for cable, power posts, BEP cluster, battery boxes, and terminal lugs. Hope this helps. Contact at DMK one one six at comcast dot net if you want a spreadsheet.

[chuckmcb]

Thanks for the recommendations. Chuck McB

[cgmiller]

If you undersize the wire you risk melting one when trying to start the engine. Although the new engines usually start pretty easy, they are sensitive to voltage and the cpu will not let the engine start if the voltage it too low..the engine might crank but it wont start. Over cranking the engine could melt the insulation on a wire and possibly start a fire...worst case but does happen from time to time. I have had close calls with dirty connection causing lots of resistance and heating up cables.

[chuckmcb]

quote:

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Originally posted by cgmiller


If you undersize the wire you risk melting one when trying to start the engine. Although the new engines usually start pretty easy, they are sensitive to voltage and the cpu will not let the engine start if the voltage it too low..the engine might crank but it wont start. Over cranking the engine could melt the insulation on a wire and possibly start a fire...worst case but does happen from time to time. I have had close calls with dirty connection causing lots of resistance and heating up cables.

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Thanks for that info. Chuck

[chuckmcb]

quote:

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Originally posted by keyman


As TC commented 4 gauge cable is not the proper wire gauge. Suggest you refer to Ancor tables for calculating the proper size (suggested minimum size #1/0 or larger). Determine the total lenght for both the plus and negative conductors and estimated current requirements. I have provided Excel spreadsheets for required electrical components. Consider using BEP cluster for battery management. Estimated cost between $600-800 for cable, power posts, BEP cluster, battery boxes, and terminal lugs. Hope this helps. Contact at DMK one one six at comcast dot net if you want a spreadsheet.

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I appreciate your advice and help. Chuck

[cooter98]

Did the same when I repowered years ago. Not sure what gauge wire but 1/0 sounds about right. Also installed the rotary battery switch in the console next to the door. Easy to reach down when at the helm and switch from one to the other or both. I'm paranoid so when ever I drift or anchor it's only on 1 battery.