House Battery, Installation - Maxum Boat Owners Club

Milt P. · 06-25-2010, 02:08 AM

Planning to install a 27 series battery. I have two starting batteries (twin 4.3s) and plan on disconnecting the 2nd battery from the first (port) quest switch and make the house battery position two. I will keep jumper cables should I every need to help the starboard battery start the engine. If I have the port switch on both will it charge the house battery when running? Should I hook the house battery up in a different way?

ss3964spd · 06-25-2010, 03:06 PM

Lots of ways to wire that set up Milt, depends on how complex you want to get.

If the switch is on Both (1+2) it will likely charge both batteries but check the specifications of the switch. You also want to make sure the switch is of a "make before break" design so you don't blow the alt's output stage when changing the switch position.

Assuming both engines have an alternator. In that case I would use a 1/2/1+2 switch and wire the two starting batteries to it and take the alt feed from one engine to feed the starting bank. That way you can isolate the two starting batteries from each other, and from the house battery. Use a 2nd on/off switch for the house battery and use the alt feed from the 2nd alt to feed it.

If only one alt you can wire similar but you'd probably need to use a combiner so that the atl output can be switched from one bank to another. Or you could use just one 1/2/1+2 switch, wire both starting batts together so they appear as one batt to the switch, and wire the house batt to it. This isolates starts from the house, but not the starts from themselves.

If it were my boat I'd use one 1/2/1+2 switch, use only one start battery for both engines, and have two house batteries.

Dan

Milt P. · 06-25-2010, 09:28 PM

OK - Not good with electrical schemes but u think I understand this.

My two switches (1 port and 1 starboard) allow are configured as 1/2/1+2 - therefore the port battery can be isolated or connected to the starboard battery and vice-verse. Both engines have alternators that are connected to each battery (port engine charges port battery and starboard engine charges starboard battery). If I remove the starboard battery connect to port switch and connect the house battery instead will that work. My shore power battery charger also connects directly to the batteries. Will the battery charger charge both port batteries thru the switch (1 + 2). Can you diagram your recommendation - that would be a great help.

Also - I purchased a 12 ft jumper cable and plan on replacing the clamps with post connectors. Couldn't see paying $5.75/ft for 6 gauge wire at marine store.

Milt P. · 06-26-2010, 03:57 AM

So all lines going into the switch is red/positive. So where should the negative cable attach? I will take the jumper going from position 2 to the starboard battery and connect to the house battery..right.

I'm not good with electricity...Thanks for your help!

ss3964spd · 06-28-2010, 02:54 PM

Oh. I missed the word "first" (signifying the frist of TWO switches). What you suggest will also work.

Ground cables are not connected to the battery switches, they only connect to the batteries. I could cobble a diagram together but it would be ugly. Either the Guest site, or the Blue Sea Systems site, has some wiring diagrams. There's also a marine wiring book available.

If I am reading correctly it appears you plan to use the jumper cable wire for your permanent installation? I'm afraid that's not going to work out for you Sir. 1st, you need 4 AWG wiring to/from batteries as a minimum - and that depends on how long the cable runs are. Engine starter motors draw a LOT of current and undersized wiring will get hot, possibly too hot, creating a potential fire hazzard. 2nd, marine grade cabling is tinned to help prevent corrosion.

All the battery cables on my boat are 2 AWG. When I added a second battery I made my own cables using 2 AWG marine grade battery cable. I have a post about the project in the "Projects" forum on this site.

Dan

Milt P. · 06-28-2010, 11:08 PM

Got it....regarding the cables I figured this wasn't the best decision but I get so feed up with the prices we are sometimes charged in the name of boating. Upon further review I only need about a 6ft run. Can I connect to the negative post of the starboard (closer battery) to ground the house battery. Will the house battery get charged by the engine alternator when set to both? The starboard battery will no longer be connected to the port for emergency starting. I plan on storing ja umper cable to solve this problem. Finally...what size wire do I need?

Thanks for all your help...

Milt P. · 06-28-2010, 11:13 PM

battery scheme.pdf

See the attach scheme...

seapuppy · 06-28-2010, 11:22 PM

Milt...can you rotate it 180 degs??..it's upsidedown..

SP

Milt P. · 06-28-2010, 11:47 PM

Its a PDF...If you right click it should allow you to rotate it...The port switch will kill house power when set to off the starboard switch does not.

Milt P. · 06-28-2010, 11:49 PM

I'm full questions...how does the trailer switch for the outdrives work.

ed & inge · 06-29-2010, 09:01 AM

Quote:

Originally Posted by Milt P.

I'm full questions...how does the trailer switch for the outdrives work.

press on the button on the gas handle (throtle..?) then it starts trimming after the trim position is at its end, you press the same button deeper/stronger....than the tail will be in trailer position. (thats how it works with my 5.0 260 hp engine)