Best Battery/switch set up? starting from scratch........

[rogerb]

Hey guys,

New to the forum and to bigger boats so this may be an elementary question to most. Please bare with me. Purchasing an older SRV255 and I am pondering the battery set up. I have the luxury of setting up the batteries/ battery switches any way I would like to and was looking for input. Two old batteries and no switches installed at this point. I am considering two starting batteries, one for each motor, and two 6 V batteries for house power. No generator and I will be running lights, stereo and fridge on house power. I have been trying to think through the layout and cannot seem to work it out in my mind how I should connect the batteries or the switches. My brain tells me one starting battery and one house battery per switch, but that leaves me no way to tandem the 6V batteries and I am mixing battery types. If I use three switches, one for each starting battery and one for the two house batteries, can I still wire it to charge all three banks via the engines? Is there a simple way to have two independent starting batteries and two tandem 6V's that I am missing? Very slim chance of overnighting, mostly day trips, so this idea may be overkill. Any advice on batteries and layout would be greatly appreciated!

 

[dpmulvey]

Here is a start. Some would consider this overkill.



http://www.diy-boats.com/wp-content/uploads/2010/09/2sw2eng.jpg



Here is another approach with explanation.

	[FONT=Times New Roman, adobe-times, Times]ONE BATTERY SELECTOR SWITCH, ONE ON / OFF SELECTOR SWITCH, ONE ISOLATOR - TWO ALTERNATORS - THREE BATTERIES [/FONT] [FONT=Times New Roman, adobe-times, Times]Installation of isolator separates both alternators so both alternators will charge simultaneously, automatically charges lower charged battery first. All batteries can be used for start, third battery, ship's source.[/FONT]​

If you are running day trips, I would consider 4 golf cart batteries. The fridge and stereo will drain a bank a lot faster than one would think. BTDT!

 

[rogerb]

Perfect! Exactly what I needed. Also, any thoughts on a multi-bank charger to keep the batteries up while on the trailer at home? How would it wire in if you did go with two switches and an isolator? Many thanks!

 

[kaz911]

Perfect! Exactly what I needed. Also, any thoughts on a multi-bank charger to keep the batteries up while on the trailer at home? How would it wire in if you did go with two switches and an isolator? Many thanks!

if you look at BEP marine products they have some "combo" switches that are really nice for multi bank setups. That simplifies wiring quite a lot.

 

[390x]

I have a single off/1/both/2 switch, and I put 3 batteries on the #1 side of the switch, and 1 battery on the number 2 side. The genny battery is by itself and hooked to nothing other than the genny. I want to know that I'm drawing off only the batteries I choose. I'm always switched to number 1, and if I run low on the number 1 side of the switch, I can switch to #2 to start the engines, and then switch to both once running to charge everything. I can also fire the genny to get the charger going. I want things simple, and I don't want automatic switching devices, etc. to do my thinking for me.

 

[Danny Troy]

Assuming you have good batteries, I only use one switch and only two batteries. I use one while at anchor, and keep the frig on the low setting, and switch to the other to start. I did this on my last boat also, and never had a problem. Of course, it all depends on how long you are drawing from that one battery, and the devices you use. Air conditioner is definitely out. Not without adding two additional batteries. The microwave use is kept to a minimum, and never more than about 5 minutes at a time, but I'll run the audio system and a flat panel TV all day. Just keep an eye on the voltage as the day goes on. As extra protection, I carry a booster pack, which also comes in handy if a fellow boater needs a jump. Of course I have an inverter to power the 110v devices.