House batteries

[magicofmassage@gmail.com]

Can I use a 12v battery instead of two 6v batteries

[TurnerFam]

yes, but why would you - two 6v deep charge are much better for camping

[Bob Denman]

As long as you end up with 12 volts worth of output:
Having a single q2 volt battery would simplify your wiring...
But having a pair of them would be even better!
Question: would a 12 volt marine battery that has been designed for use with trolling motors be considered as "deep cycle"?

[DavidEM]

As noted above, two series wired golf cart batteries give you the most bang for the buck and are true deep cycle batteries. Most 12V batteries are not, but if you want to use them you can. Just wire two in parallel (+ to +, - to -) instead of series wired for the 6V golf carts.

David

[magicofmassage@gmail.com]

Thank you

[lwmcguir]

Upgrade your battery situation based upon need

Lots of options

[coachray]

Originally Posted by Bob Denman

As long as you end up with 12 volts worth of output:
Having a single q2 volt battery would simplify your wiring...
But having a pair of them would be even better!
Question: would a 12 volt marine battery that has been designed for use with trolling motors be considered as "deep cycle"?

When I still owned my bass boat I was always told that the trolling motor battery was deep cycle.

[Bob Denman]

I always heard that; just looking for some confirmation as regards it-s accuracy.

[lwmcguir]

I tried two new 12v Marine batteries in my Landmark twice

Neither sets performance was even close to true deep cycle batteries

Really comes down to what you're requirements are as Marines could work well for many

If you're looking at heat overnight plus fridge you're going to be disappointed in most cases

[DavidEM]

True deep cycle flooded lead acid batteries have three characteristics that set them apart from wannabe batteries: filler caps, more room above and below the plates for electrolyte, and heavier plates. Unfortunately it is hard to know about the latter two by looking and many manufacturers of 12V batteries slap a label on a starting battery and call it deep cycle. One sure fire indication is no amp hour rating on the label.

With few exceptions the only true deep cycle battery is golf cart 6V batteries. These are designed for a specific deep cycle application and any batteries that don't hold up in that service are quickly run out of that market.

The only exceptions in 12V types are very expensive like Lifeline batteries.

AGMs are different. As best I can tell there is no difference between starting and deep cycle batteries. Their design characteristics make the three criterion above meaningless.

David

[Bob Denman]

David,
Thanks for the explanation!

Can you give us an idea about how close to (or far from...) a golf cart battery's performance; is a 12 volt AGM design?

[IDguy]

Originally Posted by Bob Denman

David,
Thanks for the explanation!

Can you give us an idea about how close to (or far from...) a golf cart battery's performance; is a 12 volt AGM design?

I’ve read you are only supposed go discharge AGMs to 50%, so they would be much less useful in RV. Golf Cart batteries are the way to go.

[DavidEM]

There is a lot of hard data on depth discharge vs cycle life for GC batteries from Trojan and others, but nothing from AGM manufacturers.

My gut is that a true deep cycle battery like the Trojan golf cart battery has about the same cycle life vs depth of charge capability as an AGM. AGMs shouldn't have the same sulfation problems which is the bane of FLA batteries.

And to the PPs comment above, both AGMs and golf cart batteries lose life if routinely discharged below 50%.

Firefly carbon foam batteries are supposed to tolerate 80% depth of discharge well but I don't know why. And of course lithiums can go to 90% routinely.

David

[Beau388]

Originally Posted by DavidEM

There is a lot of hard data on depth discharge vs cycle life for GC batteries from Trojan and others, but nothing from AGM manufacturers.

My gut is that a true deep cycle battery like the Trojan golf cart battery has about the same cycle life vs depth of charge capability as an AGM. AGMs shouldn't have the same sulfation problems which is the bane of FLA batteries.

And to the PPs comment above, both AGMs and golf cart batteries lose life if routinely discharged below 50%.

Firefly carbon foam batteries are supposed to tolerate 80% depth of discharge well but I don't know why. And of course lithiums can go to 90% routinely.

David

If you look at the flooded life cycle charts you will see that the depth of the discharge and the time the battery is left in the discharged state effects the number of useful cycles. For some reason 400 cycles was chosen as the optimum. To have 400 cycles and still have 75% of the useful battery amperage available when fully charged, the battery can not be discharged below 50% capacity. The less the battery is discharged the greater the number of cycles possible.



For me the problem I find with flooded batteries, as they reach near the end of their useful life, they require a lot of water. My original Harris batteries only need about a cup of water every month during the summer for the first two years. During the third year, I was using about a pint of water every two weeks. I changed to a couple of Walmart's flooded batteries the 4th year and have only add a table spoon of water every other month.

[Pete'sMH]

Originally Posted by Beau388

If you look at the flooded life cycle charts you will see that the depth of the discharge and the time the battery is left in the discharged state effects the number of useful cycles. For some reason 400 cycles was chosen as the optimum. To have 400 cycles and still have 75% of the useful battery amperage available when fully charged, the battery can not be discharged below 50% capacity. The less the battery is discharged the greater the number of cycles possible.



For me the problem I find with flooded batteries, as they reach near the end of their useful life, they require a lot of water. My original Harris batteries only need about a cup of water every month during the summer for the first two years. During the third year, I was using about a pint of water every two weeks. I changed to a couple of Walmart's flooded batteries the 4th year and have only add a table spoon of water every other month.

One of the things I like about flooded batteries is that they seem to give plenty of warning that they are about done, AGM batterie seem to work fine until all of a sudden they don’t. I like to have shopping time.

[taylorbob1]

Originally Posted by Pete'sMH

One of the things I like about flooded batteries is that they seem to give plenty of warning that they are about done, AGM batterie seem to work fine until all of a sudden they don’t. I like to have shopping time.

I like FLA’s also
And there are three places to purchase Deep Cycle group 27 at the lowest cost, under $90:
- Walmart: Everstart ($82)
- SAMs Club: Duracell ($82)
- Costco: Interstate ($88)

So there’s no shopping time necessary

[Bob Denman]

I have Duracell type 27s right now.
They're not bad, and have used very little water; but I find myself leaning toward a pair of AGM 31s when the time comes...

[atreis]

I've gone with AGMs in my last two TTs and really prefer them. They hold up really well and it's nice to not have to worry about adding water.

[Bob Denman]

That is my biggest concern...

[EA37TS]

My current rig came with 4 6 volt AGM batteries for the house and 2 12 Volt AGM batteries for the chassis. It is definitely nice not having to add water. Check the cables periodically to make sure everything is tight and I'm good to go.