320DA Starting Quirk

[MNCra]

I've developed a quirk when starting my starboard engine on my 2006 320 DA - 350 MPI Horizon V-Drives. The port engine sounds the alarm and starts when the rocker switch is depressed just like normal - no problem. When I depress the rocker switch for the starboard engine the alarm goes off twice and all of the panel switches ie; blower, radio, lights etc go off. The engine starts fine and than I have to turn back on all of the rocker switched that went off. No circuit breakers or fuses are tripping or blowing. I'm thinking maybe low battery on starboard engine that is causing high amp draw and dash panel shuts down ?

Any help or things to check wou be appreciated

Thanks

 

[MNCra]

I used the parallel switch on the starboard start up and it started normally. Great suggestion and I thank you !
Not surprising the batteries need replaced, they are the originals from 2006. The marina load tested before they splashed the boat but didn't identify an issue.
I agree with your suggestion for Optima. I run them in all of my custom bikes and they are the only batteries that stand up to the vibration and they have a much higher cranking amp then the listed CCA

Thanks Again !