Battery power questions???

[tsquared1965]

Happy holidays all
I have a 1988 300da with three batteries and one battery switch the issue I am having is the battery switch is hooked up to one engine and house battery, one engine will start with battery switch in the off position I assume there are isolators located somewhere just cant seem to find them. I believe they are just wired wrong My boat dosn't have a gennerator
any help would be appreciated

 

[GrandMaster]

You sure you dont have a second battery switch somewhere?

With twin engines and 3 batteries, I believe your boat should have one switch thats "off/on" and one switch thats "off/1/2/both"

 

[tsquared1965]

Just the one its a 1988

 

[tsquared1965]

Once i get it straightened out i will install a second switch

 

[2texoma]

With 3 batteries and 2 engines I find it reasonable to have #1 battery dedicated to #1 engine with no means of drawing power from #1 battery other than starting #1 engine. #s 2&3 batteries could power house or start #2 or #1 engine depending on switch position. Finding complete scamatics for larger boats can be a problem due to both factory and dealer options availble at delivery. If that were not enough,there has been plenty of opertunity in 24 years for other options that might effect wireing. Somtimes going at it with a vom is only way to know how it is arranged.

 

[tsquared1965]

Thanks Ed, 2texoma and Grandmaster Looks like I am trying to fix something that isn't broken I will add a second switch this spring
Sometime being a auto tech makes me look at things different than a marine tech would look at it