Lazy Daze Owners' Group

Why two 6 volt house batteries?

August 01, 2010, 06:00:35 pm

Yahoo Message Number: 114951

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I know at one time I read why the house batteries are two 6 volt instead of one 12 volt.  But I can't find the answer now.  Can someone enlighten me?  Thanks.

John 1994 22' TK Chug
 PS-Optima claims you gain nothing by 2 6-volt instead of one 12 volt.  M

Re: Why two 6 volt house batteries?

Reply #2 – August 02, 2010, 01:14:13 am

Yahoo Message Number: 114954

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From: Andy Baird
 Sent: Sunday, August 01, 2010 3:14 PM
 To: lifewithalazydazerv@yahoogroups.com
 Subject: [LD] Re: Why two 6 volt house batteries?

"Optima claims you gain nothing by 2 6-volt instead of one 12 volt."
 However, as a purely practical matter, would you rather deal with the two 65-pound 6V batteries you have now... or a single 130-pound 12V battery of the same Ah capacity?

Andy Baird

Andy,
 Maybe not the whole story. There can be advantages in scale with fewer and larger cells that come with using two 6 volt batteries in series (6 cells total) vs. two 12 volt batteries in parallel (12 cells total) given the same amp hour capacity of the two battery banks. The 6 volt batteries gain an internal space savings in having half the number of cell wall dividers, half the cell plate insulator mats, and half the cell interconnects. This allows the golf cart style battery to have more robust, heavy duty plates, all else being equal (though it's likely not).
 If you are going to use flooded batteries, a maybe slight advantage goes to two 6 volts for RV applications. I'm not surprised Optima would pooh-pooh that idea - - they make sealed batteries.
 I have no problem with AGM's, I use them in plane, glider and in my FJ Cruiser. When the flooded 6 volts wear out in Yonder, they'll be replaced in kind. I think flooded cells represent a better value if you don't mind adding water and can have the battery bank vented.

bumper
Yonder
Minden, NV

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Re: Why two 6 volt house batteries?

Reply #4 – August 02, 2010, 03:35:49 pm

Yahoo Message Number: 114966

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"The deep cycle 6 volt battery has more mass to it then a deep cycle 12 volt."
 I gotta say, I'm disappointed with the vagueness of Optima's replies. Since they never specify what battery model they're talking about, or what the amp-hour capacities are that they're comparing, their advice as given is meaningless.
 Nevertheless, I agree with what Bumper said: *in a Lazy Daze*, the typical factory-standard setup--two flooded-cell 225 Ah 6V batteries--is the most cost-effective. It beats AGMs by a large margin if your criterion is dollars per amp-hour of storage.
 Zero-maintenance AGMs are definitely more convenient, though, which is probably why the factory has switched to AGMs for 2010.

Andy Baird http://www.andybaird.com/travels/