400 Sedan Bridge battery issues

[Runnin on Empty]

While anchored this weekend we used the house batteries to run lights and fridge. When I tried to start the starboard engine in the am the battery was dead. I used the cross over switch and it started with no problem. Question, can the engine start battery be affected by a drain on the house battery?

 

[tobnpr]

Um, the quick answer is no- if you're truly talking about an isolated house battery bank.
Only two possibilities:
There is something you're using that's drawing power from the stbd. starting battery that you're not aware of, or
Perhaps your stbd. starting battery went bad, and won't hold a charge. You can rule that easily by getting it up to full charge, let her sit at least overnight, then try to start it.

 

[boatmailster]

While anchored this weekend we used the house batteries to run lights and fridge. When I tried to start the starboard engine in the am the battery was dead. I used the cross over switch and it started with no problem. Question, can the engine start battery be affected by a drain on the house battery?

it will depend on batt. switches configuration
do you have 2 or 3 battery switches?

 

[Runnin on Empty]

Two

 

[SR400DB]

My boat does not have an isolated house bank. I have four group 31's, two for stbd and two for port, with a switch for each side. Most of the house load is tied into the stbd bank and will draw the batteries down while on anchor. My solution (for other reasons) was to install an inverter with an isolated battery bank, now I can be on the hook for several days with only minimal generator use for hot water and battery charging. If I did not go with the inverter, I would have changed the battery set up and created an isolated house bank.

 

[dgrumm]

I had the owners manual out last weekend trying to understand the wiring due to bad batteries. Mine has 2 batteries on the stbd side and one on the port. I am fairly certain that the stbd bank runs the house and the port is starting only (I hope). If this is true, then you should never be left in a no start situation. As you described, if you run down your bank on the hook, the stbd will not start but the port has a full charge. I was in a pinch for time last weekend so I just bought 3 new 31's and replaced both banks. My plan is to understand the wiring this weekend, and if the house load is in fact all on the stbd side, I am going to add another 31 in parallel to my stbd side (ie. 3 on stbd, 1 on port). After reading all of the threads on batteries here, it seems that if your house bank is undersized (and you drain it completely) your batteries will never be the same. My goal is to prevent this!

 

[boatmailster]

Two

looks like stb side batteries are used as cranking and house batteries
you could modify system adding additional 3rd switch (or change existing switch with dual position one) and dedicated house battery (your converter is probably already 3 banks charger) or live with this and remember to start generator to recharge batteries