Replacing two 6 volt house batteries with one 12 volt

I got the 12 volt deep cycle battery and it was a challenge getting the cables to reach the terminals. Had to install it on an angle but it worked.

BFL13 wrote:
Honest question--I don't know---can a single 12 house as the Aux, start the Diesel engine, which now has two 12s for it, if those two 12s are dead?

It is all in the switching. Via battery switches you can use or combine any battery bank for any purpose.

I have a boat that had 6 grp 31 gel cell batterys arranged in 3 battery banks. I could use any of those 3 banks for starting, house or all together. The drill was to put all together when running & take one bank out of line when anchored leaving the amperage of 4 grp 31s available for the house. Something like having 6 6V GC batterys.

If you like to dry camp battery power & water capacity are king.

Yes this is why i feel the 12 volt battery might be a better choice for me.
Thankyou to all for the feedback.

If you are keeping the starting battery topped up, you should never need to break out the generator but yes it will work. Note: the typical generator 12v system is only 8-10amp and it's unregulated. OK in a pinch but it will be slow.

It's not so much 6v vs 12v for CCA...it's deep cycle vs starting battery. CCA correlates closely to the surface area of the plates in the battery.
- The 6v golf cart batteries are designed for deep cycle use in golf carts. They have a smaller number of lead plates but the plates are thicker. There is no harm in using them for starting but they won't generate as many CCA.
- The 12v starting batteries are designed to put out a huge boost of power to start an engine and then the engines alternator is providing the ongoing power. They have more but thinner plates. The extra plates provide ore CCA.

Googled the cold cranking amps of 6 volt batteries and it seems that a 12 volt marine style battery will have double the cranking amps in the event it is needed to boost the engine. So half the working amps but double the cranking capacity. Is this correct?

Im parked seasonally currently but i was thinking that if and when the engine batteries need a boost, i would start the genny and put the external charger in to play. I do keep the engine batteries topped up with a solar panel while camping.

Monaramblee wrote:
The 12 volt battery i have my eye on has 800 cold cranking power and 80 amp hours.
I dont know the cold cranking power of the 6 volt batteries.

Borderline for a diesel. If the main truck batteries are just down and you hook the battery up with thick jumper cables, probably will be enough.

If the truck batteries are completely dead, good chance it won't be able to do it.

The difference between gas and diesel: Diesel starters have to overcome much higher compression and they have to spin fast enough to self ignite the fuel/air mixture before the walls of the cylinder absorbs the heat generated by compression. Gas engines have lower compression to overcome and the spark is what sets off the fuel.

pianotuna wrote:
BFL13,

Gas maybe, diesel very iffy.

Why not diesel? Cranking power?
I was thinking that a 12 volt battery might have more cranking power then a 6 volt if needed to assist in starting the diesel engine but im not sure.

BFL13,

Gas maybe, diesel very iffy.

The 12 volt battery i have my eye on has 800 cold cranking power and 80 amp hours.
I dont know the cold cranking power of the 6 volt batteries.