Adding dual 6v 235 batteries with switch to go to stock dual 12v’s

[Josserman]

Been running off stock batteries, with a 0g power and ground run to helm and 2 amps going to them. Adding a fuse panel up there and will connect that in, with the amps for accessories. I’m planning to buy 2 6v 235’s to provide additional power while anchored with engines off. My thought was to have the amps and fuse panel run to a switch in the battery compartment where I can manually switch between the new set of 6v’s or the house 12v’s. The 6v’s would be charger solely from and inverter at the dock and be used when engine is off. When running I would have the switch set to the house batteries and the system would run as it does now. I would connect the ground from my 6v series setup to the ground of my 12v so there was a common ground.

As far as inverters I would use a 20-30amp inverter for the 6v series and a 10amp inverter for the 12v pair.

Any concerns with this, in my hear it seemed straight forward, but more I think about it I wonder if I’m jut better off with 2 new 12v larger batteries, but why throw out perfectly good working batteries that I currently have. One thing I’m realizing is that I’m ending up spending a lot more on extra inverters with the above setup, perhaps the other options is just add a 3rd 12v.

 

[Gym]

I would simplify your install by adding just one additional 12v battery. Why complicate your install with 6v batteries? You don't need to replace your existing 12v battery unless it's giving you trouble. That way if your existing battery needs to be replaced at some point you only have to replace that one.

With all the money I just saved you go out and purchase a jump box. That way you have a backup to your dual battery install, can help other boaters in need and have a backup for your cars/trucks during the non boating season. Win, win, win, win.

 

[Josserman]

Yea I totally came to the same conclusion after writing this lol, only concern was mixing the batteries since current house isnt agm.

 

[zipper]

I lived off the grid for 10 years...Why do you want inverters? They invert 12vdc to 120vac for accessories like a blender from home, which I understand can be useful on a boat, but they make 12v blenders now. I think you want a 2 or 3 bank battery charger, depending on how many batteries you have.

Our Beneteau came with 1 12v start and 2 6v house batteries that I did not know they were 6v until I went to hook up the 3 bank charger we bought. I bought 2 12v deep cycles to replace the 6v batteries and did some minor rewiring. I understand that the 6v have a higher Ahr rating than the 12 of similar size. I had 6 4v electric forklift batteries that stored power from PV and Wind system wired 3 in series and 2 banks parellel. I would agree with @Gym. Stick with 12v, its easier.

 

[Josserman]

I lived off the grid for 10 years...Why do you want inverters? They invert 12vdc to 120vac for accessories like a blender from home. I think you want a 2 or 3 bank battery charger, depending on how many batteries you have.

Our Beneteau came with 1 12v start and 2 6v house batteries that I did not know they were 6v until I went to hook up the 3 bank charger we bought. I bought 2 12v deep cycles to replace the 6v batteries and did some minor rewiring. I understand that the 6v have a higher Ahr rating than the 12 of similar size. I had 6 4v electric forklift batteries that stored power from PV and Wind system wired 3 in series and 2 banks parellel. I would agree with @Gym. Stick with 12v, its easier.

Sorry was typing at 3am when I should have been sleeping lol. No inverters, meant chargers. Thanks for feedback, calling my awesome battery/wiring spot in 8 mins when they open to get a 3rd battery ready for me .