I'm definitely going to need more capacity right away in my Cougar 28SGS. I'd rather not buy TWO batteries as I'd have to if I go to a pair of in-series 6V batteries, and since the 12V one is almost new I can just get one now and go with parallel. (Of course this is once I figure out where to mount the second one -- I think there's room for a shelf and a second battery in the compartment.)Any recommendations? I have yet to see if there's going to be any problem with the existing inverter/charger system with the addition -- any tips from anyone who's done it already would be appreciated, too.....

Tell us about your usage. Why do you need more capacity?

I'm about to embark on a power-hog project (involving powering 12v electric motors) that will be used in non-hook-up places where I'll be limited in access to other power (eg, a generator). It could easily drain a single battery within a fairly short period, but two should leave me plenty enough afterward to get by for a while until I can recharge.I know that regardless of this immediate need, I know I'll eventually be looking for longer battery use time anyway, so I'm ready to move forward on it now. I just need to convince myself that I won't have problems with the charging system or other side-effects that I need to know about.

Almost everyone on here has installed more batteries. You won't have any charging problems.

My toy hauler came with one 12v. Not nearly enough. It was in one of the plastic battery boxes. I took them out and installed 2 6v in the same spot. I use a ratchet strap to secure them. Lots of room for the batteries as long as they are not in boxes.

do the switch now 2 6v GC batteries, If you have no way to charge you will run into problems quickly no matter if you have two batteries or not you need charging capabilities.

Adding second battery in new 5th wheel | Good Sam Community

GREENReactor
Explorer
Apr 12, 2017
Anyone who's followed this discussion (that you're reading now) but has missed this other one (that I'm about to suggest), you'll find a lot of good info over on this topic:

http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/29240242/srt/pa/pging/1/page/1
Boon_Docker
Explorer III
Apr 11, 2017
GREENReactor wrote:
Anybody use these Duracells? Looks like a good price....
https://www.batteriesplus.com/battery/rv/deep-cycle/6/sligc115

Good battery at a good price.
Veebyes
Explorer II
Apr 11, 2017
Read up on the specs of various batterys. Look at case sizes & performance. you probably have room for a single 4D, maybe even an 8D battery. The big single battery eliminates the potential problems created by having to link a pair of 6V batteries.
Dusty_R
Explorer
Apr 11, 2017
Boon Docker wrote:
Dusty R wrote:

Most guys on here want to go to 2-6v batteries. I prefer to go with 2-12v ones. If one dies when you are in the middle of nowhere, with 2-12s you can unhook the one died and still have power.

Dusty

If one of the parallel 12's goes down it will discharge the other one fairly quickly leaving it useless also.

Only until it is recharged after the bad one is unhooked.

Dusty
Boon_Docker
Explorer III
Apr 10, 2017
Dusty R wrote:

Most guys on here want to go to 2-6v batteries. I prefer to go with 2-12v ones. If one dies when you are in the middle of nowhere, with 2-12s you can unhook the one died and still have power.

Dusty

If one of the parallel 12's goes down it will discharge the other one fairly quickly leaving it useless also.
Dusty_R
Explorer
Apr 10, 2017
We bought a new mh in August 2015, it also came with 1 12 volt battery. It was from NAPA, so I did what you are thinking of doing.
Because both batteries should be about the same age and make, I went to my local NAPA dealer right away and bought the same size and model as what came in our new mh.

Most guys on here want to go to 2-6v batteries. I prefer to go with 2-12v ones. If one dies when you are in the middle of nowhere, with 2-12s you can unhook the one died and still have power.

Dusty
time2roll
Nomad
Apr 10, 2017
Keystone installs mostly WFCO converters. These are listed a 3 stage charging but are notorious for never switching to boost mode no matter how low the battery is. I recommend Progressive Dynamics or IOTA converters that actually perform as expected.

If you do go with a inverter/charger they are always good at charging and you can just cut power to the existing converter.
DrewE
Explorer II
Apr 10, 2017
riven1950 wrote:
I don't want to steal a thread but I think my question is related. If not, let know and I'll start a new thread.

First I am not familiar with golf cart batteries. I have a single 12v also. Someone said 2 GC batteries will fit in same space as a 12v. Will they fit in the 12v 24group box or do you have to get a larger box. I ask because the space on our TT is limited. 2017 Coachmen Apex 249rbs. Can they be mounted without a box?

GC2 (standard 6V golf cart) batteries are each a similar footprint to a typical 12V battery, but somewhat taller. You definitely can't fit two GC2's in the same space as one 12V battery. You often can fit the pair in the same space as two 12V batteries, though it's wise to check the height first as it's sometimes insufficient.

Batteries do need to be protected somehow against accidental contact, either in a box or a compartment of some description. You really, really don't want to have your lug wrench or whatever fall on top of your batteries. Their space does also need to be ventilated somewhat so that fumes (especially hydrogen gas) can dissipate safely.
GREENReactor
Explorer
Apr 09, 2017
Anybody use these Duracells? Looks like a good price....
https://www.batteriesplus.com/battery/rv/deep-cycle/6/sligc115
GREENReactor
Explorer
Apr 09, 2017
time2roll wrote:
GREENReactor wrote:
I have yet to see if there's going to be any problem with the existing inverter/charger system with the addition -- any tips from anyone who's done it already would be appreciated, too.....
You have an inverter/charger with a single battery? More likely just a fixed voltage converter that will take three days to charge the battery. Please post the model number for best replies. Probably need an upgrade if charging with a generator.

I had assumed that there was an inverter involved because I thought that we'd had the TV on while not connected (and possibly something run from an AC outlet also) but I guess I was misremembering. I'll have to dive deeper into the electrical system on this Cougar 28SGS.

I take it the converter is going to be slow to recharge a pair of deeply discharged 6V batteries when I get connected? I'm going to have to add charging system upgrades (and inverter) to the To-Do list....