Two 6 volt batteries or two 12 volt batteries ??

lawrosa wrote:
Good read

http://yarchive.net/car/rv/golf_cart_batteries.html

http://yarchive.net/car/rv/battery_resistance.html

My comments are exactly the same as I posted in your own concurrent thread on this same topic, as follows.



More than a "good read", rather both are great articles from someone who understands much more than the masses here on this forum about the intricacies of deep cycle battery use for RVs, and which is summarized nicely in this statement which I've copied because most won't want to read through either of these links in their entirety. It sums up what a few of us have been trying to explain anytime this subject comes up - why 12 volt jugs in parallel are often the better choice than 6 volt jugs in series for RV use.

"Brian, if you have any large 12 volt loads such as an inverter I predict you will be disappointed with the golf cart batteries. I'll explain.

Two years ago I accepted the advice here in this group without thinking too much about it and replaced my two paralleled group 27 batteries with a pair of golf cart batteries. I immediately noticed several differences. One, anytime I operated a heavy load the voltage sagged MUCH more than it did with the old batteries. My inverter would trip off long before the batteries were discharged because of this. I'm speaking of terminal voltage and not at the other end of a length of wire. I could no longer fast charge them. The internal impedance was so high that they simply would not accept a fast charge without heating. My cordless battery charger could charge the old pair in an hour. It took several hours with the new one. Cranking the genny would drop the voltage so much that the inverter would trip. I got in the habit of hitting the interconnect switch before cranking so that the start battery could do the job.

I did some research like I should have done in the beginning. I learned that golf cart batteries are optimized for long, moderate rate discharges and are NOT designed for heavy loads. This is a mis application. In RVs that don't have heavy loads and don't need to fast charge it is not a problem."

And this has been just my point anytime this discussion comes up - adapting deep cycle 6 volt batteries that were originally designed for moderate, intermittent long term draw in golf carts is not the best choice when one of the main tasks of those batteries in an RV application is to supply power for short duration, heavy load inverter draws. These 2 articles you've linked to are the best I've seen that explains this in terms that are easy to understand, even for the "6 volt or go home crowd". :R

Good read

http://yarchive.net/car/rv/golf_cart_batteries.html


http://yarchive.net/car/rv/battery_resistance.html

lawrosa wrote:
Are there any single 12 volters that are true deep cycle that will fit in the space of two 24's?

SoundGuy wrote:
If you've got the height a Trojan J185H-AC which is just 15" long would easily fit where a pair of T-105s would fit.

lawrosa wrote:
123lbs...lol... Who is lifting that??? Im old and weak...Ha ha

Hey, you asked. :W Whether one big battery or two smaller ones it takes this kind of weight in total if you want a 220 AH rating at your disposal. ;)

SoundGuy wrote:

lawrosa wrote:
Are there any single 12 volters that are true deep cycle that will fit in the space of two 24's?

I wouldn't get too hung up on what forum pundits define as "true" deep cycle - even Trojan Battery refers to their RV/Marine series as "deep cycle", including their infamous T-105. As to size, sure there are 12 volts with a foot print no bigger than a pair of GC-2s like the T-105 which is 10.3" long or ~ 21" for a pair. If you've got the height a Trojan J185H-AC which is just 15" long would easily fit where a pair of T-105s would fit. Other possibilities may exist in AGM and with other brands - just make sure though you have a means of properly recharging the battery (or batteries) you intend to buy, especially Trojans. ;)

123lbs...lol... Who is lifting that??? Im old and weak...Ha ha

http://www.trojanbattery.com/product/j185h-ac/

lawrosa wrote:
Are there any single 12 volters that are true deep cycle that will fit in the space of two 24's?

I wouldn't get too hung up on what forum pundits define as "true" deep cycle - even Trojan Battery refers to their RV/Marine series as "deep cycle", including their infamous T-105. As to size, sure there are 12 volts with a foot print no bigger than a pair of GC-2s like the T-105 which is 10.3" long or ~ 21" for a pair. If you've got the height a Trojan J185H-AC which is just 15" long would easily fit where a pair of T-105s would fit. Other possibilities may exist in AGM and with other brands - just make sure though you have a means of properly recharging the battery (or batteries) you intend to buy, especially Trojans. ;)

But those are not true deep cycle batteries. They are the marine deep cycle hybrid type battery. True deep cycle 12V batteries are much more expensive for the same Amp Hr rating.

Yes but I myself barely fit those in my tiny space. There is no option for a bigger battery for most.

I have 6 volt boxes and would have to remove all what I got to see if they even fit.

Because of the design of the lids with the part that lets the wires come out under the lid I had to stagger the batts. one, one way, and one they other.

Are there any single 12 volters that are true deep cycle that will fit in the space of two 24's?

But those are not true deep cycle batteries. They are the marine deep cycle hybrid type battery. True deep cycle 12V batteries are much more expensive for the same Amp Hr rating.

lawrosa wrote:

Westcoasting wrote:

SoundGuy wrote:

Atlee wrote:
At the same time, the idea of an unexpected GC2 battery failure is also blown out proportion.

2oldman wrote:
By that logic, a single 12v battery camper should always carry a spare battery.

One always has the tow vehicle's 12 volt battery as temporary back up AND tow vehicle electrical system for temporary load support if necessary. I carry just one 12 volt and have no concerns at all I'll ever be stranded as I also have a lithium ion jump starter to cover the truck so I know I can always get it started, regardless. And yes, I've been doing both for several years now and for my purposes both methods work just fine. One's preference for 6 volt or 12 volt jugs should be based on one's own situation and personal preference, not on biased views from either camp on the internet. ;)

What's a good 12 volt battery(s) to buy for a rv?

I got the 89.99 batts here. I got mine at sams but Batts and bulbs has them. Find one near you.

Plus 10% off..

Abot $175 for two with 10% and core...

https://www.batteriesplus.com/battery/marine-and-boat/deep-cycle/bci-group-24m

Westcoasting wrote:

SoundGuy wrote:

Atlee wrote:
At the same time, the idea of an unexpected GC2 battery failure is also blown out proportion.

2oldman wrote:
By that logic, a single 12v battery camper should always carry a spare battery.

One always has the tow vehicle's 12 volt battery as temporary back up AND tow vehicle electrical system for temporary load support if necessary. I carry just one 12 volt and have no concerns at all I'll ever be stranded as I also have a lithium ion jump starter to cover the truck so I know I can always get it started, regardless. And yes, I've been doing both for several years now and for my purposes both methods work just fine. One's preference for 6 volt or 12 volt jugs should be based on one's own situation and personal preference, not on biased views from either camp on the internet. ;)

What's a good 12 volt battery(s) to buy for a rv?

I got the 89.99 batts here. I got mine at sams but Batts and bulbs has them. Find one near you.

Plus 10% off..

Abot $175 for two with 10% and core...

https://www.batteriesplus.com/battery/marine-and-boat/deep-cycle/bci-group-24m

SoundGuy wrote:

Atlee wrote:
At the same time, the idea of an unexpected GC2 battery failure is also blown out proportion.

2oldman wrote:
By that logic, a single 12v battery camper should always carry a spare battery.

One always has the tow vehicle's 12 volt battery as temporary back up AND tow vehicle electrical system for temporary load support if necessary. I carry just one 12 volt and have no concerns at all I'll ever be stranded as I also have a lithium ion jump starter to cover the truck so I know I can always get it started, regardless. And yes, I've been doing both for several years now and for my purposes both methods work just fine. One's preference for 6 volt or 12 volt jugs should be based on one's own situation and personal preference, not on biased views from either camp on the internet. ;)

What's a good 12 volt battery(s) to buy for a rv?

BurbMan wrote:
Amp hrs are about the same but the 6v's are true deep cycle whereas the 12v's are "combo" deep cycle and marine. You'll get better performance from the 6v's. If you are going to boondock a lot and recharge from a generator, search over in tech issues about upgrading your charger/converter and the wiring to the batteries.

Perfect answer! I have also found that in the limited battery space available on our 20 foot trailer, 6V batteries wired to make 12v provides more amp hours.