Starter battery Back up

[Moodymike]

Ideas please on wiring and switch units to provide power source from house battery to starter battery short of using jump laeds.

[Symphony]

I have a BEP Marine switch cluster which has an isolator for each bank and a parallel switch. Can also have a VSR to replace the split diode. available from www.power-store.com

[Lazy Pelican]

I have a key operated switch which connect the engine starter to the domestic batteries in an emergency. Not sure of the wiring as it was on the boat when we bought it, but widely available i think.

John

[tiger79]

If you have standard quarter-turn on/off switches with removable red handles, add another on/off switch, like your existing starter battery switch.  Wire it between the domestic positive and the engine side of the existing starter battery switch.  Remove the red handle from the switch.  If your starter battery is flat, remove the red handle from the starter battery switch and put it in the emergency switch and switch on.  The starter battery will remain isolated so it can't drag down the voltage of the domestics.  Your engine will then start from the domestic batteries.  The starter battery will recharge as normal from the alternator.  Remember to replace the red handle in the normal starter battery switch later.

[Moodymike]

Should I be cautious of Bavaria's system of switching the negative side of the batteries?

[tiger79]

Should I be cautious of Bavaria's system of switching the negative side of the batteries?

If the negative is switched, then my comment about connecting the domestic positive to an emergency switch would obviously not apply.  How old is your boat? 

[Moodymike]

Boat is a B32 2003.  My understanding is that all Bavaria's are  negative switched.

[tiger79]

Really?  Be worth checking.

[Ripster]

Boat is a B32 2003.  My understanding is that all Bavaria's are  negative switched.

My 2011 36 is positively isolated (red 90 deg key switch) on the engine batt. 

[Symphony]

Older boats have the isolator in the negative, usually a switch under the chart table. I left mine in when I fitted the BEP cluster and have it in the on position so the isolation is now via the positives.

[Moodymike]

Thanks Symphony that seems to clear up the negative disscussion.   Could you please describe how you wired up your BEP cluster to give me the the result I am after.

[Symphony]

The cluster comes with a wiring diagram. You can find details on www.marinco.com/en/products/distribution-clusters/single-engine