FWC stock AGM's vs. 2 6 volt batteries

[Durango1]

So Sioux and are almost done with our 4200 mile 40th anniversary odyssey. And our 2012 slide-in Hawk/ Ram 2500 combo has done GREAT! But even so we're close to pulling the trigger on a new Hawk flatbed. (More room, more amenities.) And I am FAR from being an electrician so some advice please...

We have the dual factory AGM's on our current 2012 Hawk (without solar) and since we move camp almost every day we've never had an issue with the batteries recharging from the Ram's altenator. But since the battery compartment on the Hawk Flatbed vents to the outside should we just have FWC install the separator and wiring and put two six volt batteries?

Option #1: My understanding is these "ventable" batteries would be slower to recharge but also be a little cheaper, last much longer and have more capacity.

Option #2: Order the factory AGM's- I gotta say my FWC batteries are 3 years old and going strong. I'm just looking for "no drama" and a simple solution.

So any suggestions? Thanks in advance!

 

[Old Crow]

Durango-

I don't have experience with this but thought you might want to read through the 'Selecting Batteries' section here....

http://www.marxrv.com/12volt/12volt.htm

.... then start reading through the thread at http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/28003607/srt/pa/pging/1/page/2.cfm

Lots of opinions to help you make your own!

-OC

 

[dcsparky]

I have 8 year old 6 volt batteries and still holding on. If you have the room and vented cabinet can't beat the golf cart batteries. They take a beating.

 

[PaulT]

Trojan makes AGM golf cart batteries. Best of both worlds? I haven't used them but might be worth checking out.

http://www.trojanbattery.com/pdf/datasheets/6VAGM_Trojan_Data_Sheets.pdf

Paul

 

[DesertDave]

I am using two Lifeline 6 volt batteries in my Grandby.

 

[frosty_1]

I too am using the Lifeline 6v batteries in my 2015 Side Dinette Hawk. They fit perfect and work great as well! Spendy though... =)

 

[M1010 Mike]

So I have read/seen the topic of 2 6v batteries versus 1 12v battery and it seems that many say the 2 6v work better but my question is why?

 

[PaulT]

Look at total stored energy.

Factory
size 24 12v AGM at 75aH each => wired in parallel gives 12 v at 150 aH total

Golf Cart
size GC2 6v (AGM or liquid cell) 220aH => wired in series gives 12 v at 220 aH total


Another consideration is battery design,

Factory batteries are dual purpose starting/deep cycle. The golf cart batteries are not used for starting and are single purpose deep cycle.

As we very seldom start the engine in our campers. deep cycle should be more appropriate for camper use.

Paul

 

[M1010 Mike]

Okay that makes sense but are we talking an apple to apple comparision on total space needed to house a single 12v versus 2 6v? If the combined space needed for 2 6v batteries takes more room, it would make sense they would have more capacity. What I learned from reading that link is I need to move to a dedicated deep cycle versus a dual purpose. Looking at a LifeLine GPL-31XT.

 

[PaulT]

There are other things to consider other than whether it is one battery or two.

Measure the space carefully. Check the dimensions of the batteries you are considering. Keep in mind that you have to manually maneuver the battery(s) into the space while you are in a tight space and strap them down to prevent movement.

On mine, there are some wooden strips screwed down to contain the bottom of the battery to control movement. If your batteries have them, you may need to reposition these regardless of which choice you make.

Paul

 

[DesertDave]

PaulT covered the salient points.

Here's an example. The factory battery box in my front dinette model is in the left rear corner of the camper, and it has the floor space to tightly fit two group 24 12 v batteries in there. However, there is about twice the height available there than the height of the factory batteries. I played around with various options, such as standing a pair of group 27's on end, and then realized that the Lifeline GPL-6CT was a similar footprint to a group 24, but about 2X as high at 13.02". Eventually I decided to spring for two of those.

They cost a lot so one would want to calculate their electrical usage and charging abilities in their own personal usage scenarios to see if that amount of AH capacity is really needed.

Remember that the AH capacity of 6V batteries does not increase when you use them in series, as if they were a single 12V battery. The series wiring doubles the voltage 6V ===>12V leaving the AH the same, while two 12V batteries wired in parallel doubles the AH capacity while leaving voltage at 12V.

I used a heavy gauge cable (like 1 Gauge I think) to connect the two 6V batteries together 'to make them into a 12V battery", and needed to extend the factory straps considerably to hold them down. Since I have an F350 the weight is not a factor to me, but for most it would be, since these two batteries weigh as much as an average male (180lbs a pair)