Adding second battery to a MC

rvs9 · Newbie Joined: 29 Jan 2003 Posts: 28 City: Chattanooga, TN

I want to add a second battery with a setup similar to the Malibu's (switch to control which battery supplies juice, both batteries get charged, etc.). Anybody know a website where I can find the hardware?

skobi1 · Addict Joined: 15 Jan 2003 Posts: 639 City: eugene, or

I got my batt switch from overtons.com It has a pos. for batt 1, batt 2, both, and off.

kschroeder · Newbie Joined: 13 Jan 2003 Posts: 39 City: Raleigh, NC

I went with a isolator over a switch. You never have to worry about leaving it in the wrong posisition and killing your starting battery. An isolator only allows the path to your starting battery and alternator to be open when your engine is running, therefore you always have a good starting battery. Just run all your accessories off the 2nd battery.
This is what I got:
http://www.darvex.com/miva/merchant.mv?Screen=PROD&Store_Code=D&Product_Code=SR80&Category_Code=CB

jdr · Newbie Joined: 16 Feb 2003 Posts: 2 City: Burleson, TX

Yes, get an isolator instead of the switch. Nothing to think about.

C-Stone · Posted: Feb 16, 2003 9:50 am Post subject:

PERKO MAKES THE MOST SUITABLE DUAL BATTERY SWITCH FOR BOATS... US DISTRIBUTION KEEPS THEM IN STOCK... E-MAIL IF YOU NEED MORE INFO...

rvs9 · Newbie Joined: 29 Jan 2003 Posts: 28 City: Chattanooga, TN

Couple of questions -

1. Will both batteries be charged while the engine is running?
2. What size isolator should I buy?

C-Stone · Posted: Feb 16, 2003 2:32 pm Post subject:

YOU DONT NEED AN ISOLATOR AND IF YOU HAVE SWITCH ON BOTH IT WILL CHARGE BOTH...

kschroeder · Newbie Joined: 13 Jan 2003 Posts: 39 City: Raleigh, NC

Both batteries will charge while the engine is running only. If the engine is not running with a switch and you leave the switch on both you have the potential to drain your starting battery.. You never have to worry about that with an isolator. The one I posted in the link above is probably sufficient for most installs unless you have an upgraded alternator. That will handle 80Amps I believe. Most newer boats have a stock alternator from 50-70 from what I've seen.

rvs9 · Newbie Joined: 29 Jan 2003 Posts: 28 City: Chattanooga, TN

kshroeder (or anyone else) -

a few more questions,

did you only install an isolator or do you have a switch as well?

my boat will automatically shut off everything (radio, lights, etc.) when the battery drains to low and engine is off. think that this will cause problems?

kschroeder · Newbie Joined: 13 Jan 2003 Posts: 39 City: Raleigh, NC

There is no switch the isolator does all the work. When your engine is running it bridges the positive channel to allow charging of both batteries. When it's off it unbridges the positive channel so that no drain can occur to your primary battery as long as all your accessories are running of the 2nd. Your boat shutting everything off when the primary drains to low will not cause a problem.

glsurf · Outlaw Joined: 19 Feb 2003 Posts: 117 City: Tampa, FL

So is the second battery basically a backup?