Dual Battery Help - Mercruiser 3.0 135Hp

[Hutch]

Hey guys,

Running a Quintrex 560 Freedom Cruiser with Mercruiser 135hp alpha stern drive.

Want to put in a dual battery system as the kids are always bugging me to run the stereo when anchored.

Need advice as to the best size battery, have a besco NS70m in at the moment, should I just put another the same size in or run a larger battery as the second (or first). The current battery in my opinion "just" does the job.

With a 4 way switch, (1,2,1&2 Off) is this a simple job for us to do ourselves, have been quoted $650 for mechanic to do it which seems excesive.

Any advice would be aprreciated.

Thanks

Hutch

Edited August 8, 2010 by Hutch

[Yarraone]

The 4 way switch is a good option and is not to hard to do if you have commonsence..The other option maybe just to run the second battery for your extra items such as a radio, but this would mean a little more wirring..i do all my own electrics and it can be a hassel at times

[Bleeding Green]

Hi Hutch,

When I asked a boat mechanic about installing a dual battery setup he said the most important thing was to install a VSR, which I think is a Voltage sensor/sensitive relay?. It has something to do with which bettery gets recharged by the alternator when the motor it running.

The Magazine, TBF, has had articles over the last couple of issues which runs through the process. It is very helpful and I will be referencing back to them when I take it on. The author even threw in his email address and said he'd be happy to answer any questions which I took advantage of.

The cost of the parts to do it properly will ad up. I'd suggest you work out exactly what your quote includes as it doesn't seem over the top to me. A decent 4 way switch I think is around $200, then you need decent cables which need to be made up, crimps etc etc.

Hope this helps.

[cameldownunder]

Hi

I got it installed by Hewitt Marine, the 4 way switch, (1,2,1&2 Off), and have absolutely no problem.

Didn't want to take down the panels, getting the wiring maybe mixed up, and other complications.

It might be better pay a bit more and be sure you wont have any problems once on the water :-)

[framedtrash]

$650 to install a battery switch

you can get a basic 4way battery switch for around $30

or if your after some thing a little more tec that will manage 2 batterys the Blue Sea ADD A BATTERY Dual Circuit System will set you back around $250

very install to install yourself just read the manual

[Hutch]

Thanks for all your comments guys, I've convinced myself to do the mods myself.

A question on the batteries, I have a besco Marine battery now, should I get the 2nd one exactly the same or should I get a deep cycle battery to run my sounder/ radio etc on when I am anchored and motor is off?

[BWV]

Thanks for all your comments guys, I've convinced myself to do the mods myself.

A question on the batteries, I have a besco Marine battery now, should I get the 2nd one exactly the same or should I get a deep cycle battery to run my sounder/ radio etc on when I am anchored and motor is off?

Two of the same batteries will be fine. Alot of 4x4 mags have a lot of info on dual battery systems. I think the best set up for money is to get one with a smart solniod it will regulate the charge between both batteries and keep them evenly charged. I would run everything eg. sounder sterio and any other electrical eqiupment off the first battery that is already in the boat and have the second battery there soley to jump start the main battery if it goes flat because of the electrical equipment. This way you should never have a flat battery.

The only down side to it is that if the main battery was gone you wouldnt be able to tell because the solniod would switch over when you went to start it so you would have to get it load tested occasionally eg. every 12 months or so.

Or you could jump by a portable jump pack and connect the battery if it went flat, then you would have it for your cars etc.

hope this helps

Edited August 11, 2010 by Whaler 255

[rickb]

Hi Hutch.

Like framedtrash said you can buy a switcharound 30bucks.

Mine is off-1-2and both,I have two marine batteries wired together,No 1 battery is the one charged

by motor,I run everything else off other battery,which is a lot as I fish at night,plus I run a bait attractent for 2hrs after dark,never had a flat battery,when I put boat away just plug in lead and batteries are re charged,

a manual comes with switch.

Cheers Rick.