Battery question

CnC

Since we've only had our 2001 Rinker 340 FV a short while we finally had an opportunity to do an overnighter for the first time "off" shore power. I replaced the starting batteries before storing it for the winter this past season but not the house. Within 4 hours
(at 1am to be exact) both fridges along with everything else was stone dead. Couldn't even flush the toilet. We were with another couple in their boat but couldn't get back to sleep worrying whether or not the engines would fire up so we could get home. Morning rolled around and as soon as we heard them stir we decided to give them a shot. Both fired right up with zero hesitation? I'm still learning all the systems so my question(s) is/are all batteries (house and cranking) receiving a charge while the engines are running and are these two groups totally separated by an isolator of some sort through the battery panel located in the cockpit area? Also, as soon as we land to our overnight destination and shut down our engines should we immediately turn the starting battery switch off while leaving the house on to ensure that these will be 100% for engine starts if another issue arises? Although this doesn't explain our overnight stay just past? Advice I have received a few times already has been to simply leave all batteries on that panel "on" at season start and then off for winter storage. I did replace the house batteries yesterday and have a new appreciation for why almost anything in these engine bays costs a fortune to have repairs made by marinas. Absolutely no room. Anyhow as has been the case already I appreciate any feedback and would gladly welcome an explanation regarding the battery function system. Thanks again in advance.

YYZRC

House and starter batteries are separate for this exact reason. You should check that your charger and isolator is working properly. 

Do you have a generator?

LaRea

The fridges, toilet etc. all run off the house batteries.  The only loads on the starter batteries are the engines, bilge pumps, blowers and MerCathode system (assuming the wiring wasn't changed by a previous owner).  

There's no need to turn off the battery switches during normal use.  There is a battery isolator that isolates the starters from the house bank.  You can drain the house bank with no fear of draining the starters -- as you saw on your overnighter.  

It sounds like your house batteries were shot.  Now that you have replaced them, everything should work normally.  

CnC

@YYZRC yep there's a generator.  @LaRea thanks for that, now I can give a definitive answer the next time my wife asks. So not to be a pain then but do the house batteries receive charging alongside the crankers while the engines run? I'm picking up a booster pack (as added insurance) as well as a solar panel blanket that rolls up easily to lay out on the top for the house batteries if we decide to stay longer. Thanks again guys! 

YYZRC

The house will charge when engines running as long as your isolator is working properly. You could also run the generator to charge the batteries of course. 

Grahamu

How many batteries make up your house bank.? When at anchor I run the genset for an hour at breakfast and an hour at dinnertime. I did replace my battery charger over the winter to a Pronautic 1240 P and made sure that terminal one was connected to my house bank through the isolator. Check your charger's charging amperage. Also have you switched to LED cabin and cockpit lighting to drop your discharge amperage.