12 volt coach batteries.

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29er

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Sep 5, 2006
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Location
2845 Sorrel Street, Las Vegas, NV 89146
We do not boondock very often. While at Quartsite last month we stayed for a week.  Our MH is an 08 Tour, wonderful vehicle.
The MH has three (3) 12v coach batteries. Sorry to say we had to run the generator much more than previous MHs with four (4) 6 volt deep cycle batteries.
Operating the generator four hours, it never went off bulk charge. With only the TV (and inverter) on, the indicator went from 12.9 to 11.9 and the inverter kicked off in only four hours. My question is: can the batteries be converted to four 6v deep cycle as currently factory configured?  I'm referring to the charging, etc., systems.The 12v's are NAPA type batteries. Thanks.

Kerry.
 
Likely your 12V batteries from Napa are not really deep cycle batteries.  Yes you can install 6V batteries in a series parrall  configuration.  I recommend AGM batteries or if you want the flooded cell type Trojan or Interstate DEEP CYCLE.
 
I am a wet cell fan myself, but yes, the 6 volt swap is a great idea. Your only limiting factor that you will need to check first is the size of your battery tray.  If there is room you are good to go.

Sarge
 
Kerry

Don't forget, 3 12v batteries only supply 300-330 amp hours. 4 6v provide about 440 ah. As long as you are using that setup you have to make sure that your charger is set to that level.
 
Our Horizon came with three deep-cycle group 31 batteries and one of my first upgrades was to replace them with Lifeline AGM batteries.  I'm a big fan of AGM batteries for various reasons - here is an excellent treatise about AGM as implemented by Lifeline.

There are premium flooded cell batteries (Surette, Rolls) that are also excellent choices but they are not maintenance free like AGM.

Are you experienced boondockers?  I assume you know what to shut down on your Tour to conserve energy?

In our usual 'boondock mode', I found we would need about three to four hours of generator running to keep the batteries topped off and allow for some Internet time (with our Datastorm satellite Internet) and a couple of hours of TV time.  When we are not watching TV or surfing, the inverter is turned off.

It would also be a good idea to have a service shop do a load test on the batteries - don't assume they are okay simply because they are fairly new.
 
We removed the 3 12 volt batteries and installed 4 6 volt agm batteries . The batteries need to be repositioned and the tie downs need to be reconfigured a little bit, this is assuming your battery tray is similar to the tray in our 07 Vectra.

Jim
 
BernieD said:
Kerry

Don't forget, 3 12v batteries only supply 300-330 amp hours. 4 6v provide about 440 ah. As long as you are using that setup you have to make sure that your charger is set to that level.

I love how folks keep assuming that all 12 volt batteries are about 100 amp hours

I've used 12 volt batteries that were closer to 1,000 amp hours

(Though those are not practical for RV use)
 
I've used 12 volt batteries that were closer to 1,000 amp hours

(Though those are not practical for RV use)

Right, so what's the point? There are also 1.8 amp-hour 12v batteries, but those aren't practical either.

12v batteries in typical case sizes for automotive, marine & RV use (Groups 24, 27, 65, etc) all yield about 80-105 amp-hours, depending on specific size and quality.
 
John In Detroit said:
I've used 12 volt batteries that were closer to 1,000 amp hours

(Though those are not practical for RV use)

Why not - how about an electric Class A - 25,000 pounds of batteries with a CCC of 150 pounds  8)
 
John In Detroit said:
I love how folks keep assuming that all 12 volt batteries are about 100 amp hours

I've used 12 volt batteries that were closer to 1,000 amp hours

(Though those are not practical for RV use)

John

So how does your response relate to 12v coach batteries ??? ???  If we weren't talking about coach batteries we wouldn't be assuming that 12v batteries are about 100 hours.
 
Methinks John was just making a point and got carried away with his example. 8D batteries, which are 12V, have a capacity of 200AH (or more), and I know several folks who have them (or had them) in their coach, although they're less popular than they used to be.
 
Me thinks John was just being "John". ;)  It's in his DNA. ;D ;D  He must enlighten the world at least once a day. ::)
 
The point is that batteries come in assorted sizes.. 8D, which many coaches use, is over 200 amp hours

Group 31 around 120-130

Group 24 as low as 80

So assuming a 12 volt battery is 100 amp hours.. Not accurate at all

On and multiply by 3/4 if it's an OPTIMA
 
AGM'as are great batteries but unless you have need to place them in an enclosed area or absolutely have no intention of preforming any maintenance on them I have a hard time finding the value in AGM's.

When I replaced our five year old wet cells last fall the price of  220AH Trojan T-105's were $131.50 each available locally and the price of 220AH Lifeline GPL-4CT AGM's were $261.50 each plus freight. I do not believe the AGMs will come even close to lasting twice as long as the Trojans.
 
JEFF....As a guy in the battery bizz, I couldn't agree more with your opinion! 

Sure, AGM's are neat, sealed, maintenance free, etc., etc....but I don't believe they will last any longer in RV use than properly maintained Flooded Cell type batteries...and at TWICE the price, I also don't believe it's best use of one's battery budget dollars...

There are certain installations where you're forced to go to AGM's, but for all the others, save some money and use Flooded Cell type, Deep Cycle batteries...keep the connections tight and clean, perhaps with some anti-corrosion grease smeared on the terminals, and keep em' charged up when not in use to prolong their life.




 
AGMs have a lower internal resistance so they charge faster and self-discharge slower.  Worth every penny to me to install them and forget them.  I used gels on the boat and I would never go back to flooded cell after years of good experiences with non-wet batteries.
 
For us, the decision to go to AGM batteries was based on the simplicity of zero maintenance as well as the better charging performance that John stated.
 
The longevity arithmetic is certainly correct - an AGM costs 2x as much as top quality flooded cell battery and probably doesn't last a day longer.  In my opinion you are paying solely for the zero maintenance advantage.  And some battery banks are hard to get at for routine check/maintenance, which adds to the value of a zero maintenance solution.

Many people, however, fail to get anywhere near the  full life from their wet cells because they fail to maintain them. For those folks, an AGM may actually be cheaper.

We have  Trojan Group 31 AGMs, so you know where I came out on the cost/benefit equation.
 
I'm on the side of AGMs for no maintenance. The batteries in the rear of our battery tray are almost impossible to maintain on a good, regular basis so the extra cost of the AGMs was a no-brainer deciscion. Haven't looked at them in the 6 years since installation.
 

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