Crossfeed stbd bank with outback

[MikeP]

http://www.samsmarine.com/forums/sho...-power-voltage

As I clearly pointed out in that post, The problem occurred because of low shore power, which I failed to recognize.

Of course, if the banks had been separate, only the house bank would have been depleted and the start bank would have been unaffected. And, as I have pointed out innumerable times re this subject over the past 10 years, combining banks has good points and bad points.

FOR OUR USE, which was almost always on the hook, the combined banks worked better, providing a lot more flexibility and basically worry-free use of the batteries for fairly lengthy periods without needing to run the Genny and the batteries never dropped below 70% running everything that needed to be run But, as I have said over and over re this issue, IF your generator start battery is NOT separate from the mains, it's a bad idea.

In any case, all that is required is some cable and a battery on/off switch to be able to decombine or combine the banks in the length of time it takes to turn a switch.

Speaking of batteries...it's battery replacement day so I have to get to work; the new ones are being dropped off at the dock this afternoon so I need to get the old ones out/new ones in today. I didn't find it too difficult the last time...but I was 6 years younger.

[Pascal]

The original set up of one bank sharing start and house duty is a bad compromise to start with. It's ok on a small boat but ridiculous on a 50 footer at least by modern standards. Adding an inverter on that house bank makes it only worst. Can it work? Yes but It it doesn't make it a good setup

There is plenty of room in these boats to add a dedicated inverter or house/inverter bank which unless you rarely use the boat is th best option.

[MikeP]

Old batts out/new batts in! Took me a bit less than 5 hours of work. Of course, I can hardly move at the moment; it's why God made rum!

So Batts are ready for another 5-6 years...to be changed on the next owner's watch!

I wouldn't argue with a totally separate battery bank for the inverter but, for us, the combined bank worked great without the expense/complication of a third battery bank.

[SKYCHENEY]

I see absolutely no problem with using the house bank as an inverter bank. Adding a separate inverter bank adds more cost, more weight, and more expense.

There are two ways to deal with the Outback on the house bank:
1) Add another charger for the start bank.
2) Add a switch to charge either the house or the start bank. Do not combine them. Just switch the 1-off-2 switch to the other bank to charge it. This is feasible as you rarely need to charge the start bank. It charges while running and there should be minimal if any other load on that bank with not running.

[Chasemmc]

What size cable?
Anybody use automatic voltage relay instead of a switch?

[gbharrington]

I have used a Blue Sea automatic relay for 12 years with no problems. On my Hatt I use 2 of them; one to split off the gen battery and another for the start battery. Up until recently I had one inverter charger for all batteries. I recently added another I/C that is parallel with the original on the DC side but is strictly for powering the aft cabin air conditioner on the AC side.

[Scarlett]

Don't know if the charge relays are available in 32 volts. Have used them a lot in 12 volt applications and they work great. John

[Chasemmc]

Haven't found them in 32v yet.
Any one have an opinion on cable size.?

[Boatsb]

4/0 is most common.

Bigger is better for inverters and start batteries.

[Chasemmc]

8 new batteries showing up on tuesday.

Will need to buy a case of ben gay