Pontoon Boat & Deck Boat Forum

Long time lurker, first post.
I have a 2004 Sylvan 820 Mirage with a 75 HP Mercury 2 stroke. I have two fishing/ captains chairs in the front and a wrap around couch from the middle back. I also have a 22 gal gas tank and two batteries mounted in front of the motor.
My winter project is to rewire EVERYTHING as diagrammed by BobG (viewtopic.php?t=13546&p=105893#p105893). My question is; can I/ is it worth it to move my batteries to the front corners (inside custom speaker boxes in each corner) for the benefit of getting that 100 lbs on the front to help with weight distribution? My main concern with doing this would be my next question: will #2 battery cables be sufficient to carry the cranking amps for the motor from 18 ft away?

Thank you all in advance for your comments and suggestions.

I would leave the batteries where they are.

When one person moves from the stern to the the bow make a difference while you are running? Likely not that much right?

If you are going to use that diagram, I have one suggestion if you plan on using an onboard battery charger. Connect the ACR to the output of the switch. That way, the ACR won't combine with the switch off and the battery charger on.

I leave off the fuses from the ACR to postives of the battery. If you don't feel happy about doing that, you really only need a fuse on one of the legs. I do use the fuse on the negative lead.

babock wrote:If you are going to use that diagram, I have one suggestion if you plan on using an onboard battery charger. Connect the ACR to the output of the switch. That way, the ACR won't combine with the switch off and the battery charger on.

I leave off the fuses from the ACR to postives of the battery. If you don't feel happy about doing that, you really only need a fuse on one of the legs. I do use the fuse on the negative lead.

I'm guessing that Blue Sea Systems actually know a bit more about this than you - that's their diagram. Do it differently if you want. Oh, and I have relocated my batteries into my console. I couldn't get any #2 AWG, so I ran three each of #4 AWG to the motor.

BobG wrote:I'm guessing that Blue Sea Systems actually know a bit more about this than you - that's their diagram.

I know that and I actually talked to their engineers and they had no problem with only having a fuse on one side.

I can understand the fuse issue. Better safe than sorry.

They did like my idea of putting the ACR connections to the output of the switch if you are using a battery charger, especially a dual bank. Said they may incorporate that into a future drawing.

If you want custom battery cables, go here:

http://www.genuinedealz.com/marine-wire ... tery-cable

You can get very large gauge sizes there. No need to double up cables.

They do high quality work and put on any size connector you want. Very clean.

Personally, I would always make sure there is shrink sleeve on the cable connector. http://www.genuinedealz.com/custom-cables

As far as running cables to a console you need to use a voltage drop calculator or a gauge chart. If for example you are using 4 gauge cable and you currently have a 6 foot one way run but you need to now have an 15 foot run, to get the same voltage drop, you will need to go at least up to 1/0 cable. a 1/0 cable is 2.5 times the area of a 4 AWG cable. Basically, figure out the ratio of your cable length to the new one and increase the area of the cable to the same ratio.

custom cables
are only as hard as you make it. I used some of my old welding lead