Problem with 12V system

[Sacriverfolks]

Hello. I have a 1986 300DA and I have a BIG problem. On shore power everything on all boards works fine. However when I unplug and try to switch things on, nothing will start off battery but the engines. I have checked over the fuses and all are intact. Also I have had issues with getting the charger (brand new Pro Mariner 1230) to kick on and charge the batteries. Batteries are brand new (two group 24 starters and an 8D house) and have been fully charged with a portable charger. My biggest concern with this (because we just launched and I am still dealing with little micro leaks and other picky details) is that the blowers and bilge pumps only seem to go on shore power and WILL NOT activate when I am on 12V.

Any thoughts would be helpful at this point.:grin:

 

[jpk33]

If you have a multi-meter start following the 12v current, with shore power on. I am guessing that you are powering your 12v off the converter wired to 120v AC. When you go to boat power (12v) you loose power to all 12v, check your house ground off the batteries. You probally have a common 12v ground bus that a lot of your 12v connects to and this wire is loose, broken or corroded. You might have a negative wire that did not get reconnected to the 8D battery - but the large engine cables are connected allowing you to start/run engine. Good Luck! - Jeff

 

[Sacriverfolks]

Thanks Jeff! That is just the kind of direction I was thinking since I obviously would not get a start if my combiner was shot. I am heading out to the boat in about 1/2 an hour to fix this. I'll let you know what I come up with.