EPenney
Galt, Ca
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Joined: 03/03/2003
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I currently have (2) 12-volt batteries, and am considering adding 2 more.
The current batteries are (2) Group 24 12-volt Marine/RV that came with the 5er. There is plenty of space for adding 2 more batteries. What I need to decide is, do I stay with 12-volt, or switch to 6-volt batteries. I already have 2 barely used 2-year old Trojan T105 6-volt batteries that came out of a TT I traded in 1-year ago. Whatever I decide to do, I will have to purchase 2 more batteries.
My last 2 TT's had dual 6-volt batteries that gave me years of reliable service. When I purchased the 5er last year, the dealer talked me into going with dual 12-volt batteries. The 5er is a power hog, and I can only go about 1-1/2 dry camping days before I need to hook the genset up to charge. We have about 26 dry camping days scheduled for this summer.
What is your opinion....(4) 6-volt or (4) 12-volt batteries?
'07 Chevy 2500HD Silverado "Classic" CC D/A 4x4
'07 Komfort Trailblazer T252FS fifth wheel
Reese Signature 18K Slider and other stuff.....some useful.....some not
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Matthew_B
The boonies near Dallas, Oregon
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Joined: 08/18/2005
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If you already own 4 partially used batteries, why not just put them all in?
Yeah, it's not the perfect setup to have two 12V batteries in parallel with a 6V string. But they are all paid for right now, so whatever service you do get out of them is "free" compared to going out and buying 4 new batteries.
Once they die, put in 4 6V batteries.
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smkettner
Southern CA
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I would get a single box to hold all four of what you have and use them as is. http://www.alliedbattery.com/boxes.htm Connect the two T105s in series and then parallel with the two existing group 24 batteries. They might seem mismatched but they are paid for, you may as well use them. While in use they will all stay balanced as far as charging and discharging. If you store it without a foat charge you may want to disconnect the parallel connection after fully charging.
That should do fine for a few seasons at least. When you spend money on batteries get four of the golf batteries. The single box will save some space compared to three or four battery boxes.
I assume you have a multistage converter with 45 to 60+ amps for charging.
2001 F150 SuperCrew 5.4 Lariat Offroad 4x4 Tow Package 4.10 Truetrac
2006 Keystone Springdale 249FWBHLS
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RJsfishin
Winston Or.
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I agree, use what you have.
If you think you will get a whole bunch more AH capacity out of 4 6'ers, rather than 4 12'ers (grp 27) you're thinking wrong. They all are near the same capacity. But the 6'ers are consistently reported to have better longivity in yrs of service.
Rich
'98 Flair, 454, Onan Microlite 4k, Intel PD 9155 w/ wizard, Sta-power 1500 watt Inv, 2 6v batts, ammeters, KingDome/sat, Oly Catalytic Heat, hauling 2 Bent Bikes and sometimes towing a Tracker F&S boat.
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EPenney
Galt, Ca
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Regarding adding the (2) 6-volt batts to the (2) 12-volt batts:
I have been told it's not a recommended practice to mix battery types, since the combination is only as good as the weakest battery. Or that when charging, it is possible to overcharge a lower rated amp battery.
Purchasing 2 additional batteries to have a matching set of 4 is not a $ issue for me.
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bryanl
Reno, NV
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Joined: 12/25/2003
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the energy capacity will depend upon the weight of the batteries, not the voltage. (it is really the surface area that counts but modern batteries are optimized for this in terms of lead content)
how long they last will depend upon how you use and maintain them, not the voltage or brand or whatever.
Matthew had good advice - put what you have into service and don't worry about replacements until you really need to. Put your money first into a good charging and maintaining system for your batteries.
It is best to have all batteries in a bank as similar as possible but as long as they are the same chemistry and reasonably healthy you'll be OK.
It is a myth that 6v batteries have any edge over other voltages. All wet cell lead acid batteries can last maybe 5 years depending upon use and management (re Az Wind Sun FAQ et al).
The 'combination only good as weakest' idea is also a myth if paralleled. There is some sense to this if series, though, because a series weakness shows as a decrease in voltage which can be a problem in RV systems.
See Basic battery guidelines for links and additional information.
Bryan
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smkettner
Southern CA
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EPenney wrote:Regarding adding the (2) 6-volt batts to the (2) 12-volt batts:
I have been told it's not a recommended practice to mix battery types, since the combination is only as good as the weakest battery. Or that when charging, it is possible to overcharge a lower rated amp battery.
Purchasing 2 additional batteries to have a matching set of 4 is not a $ issue for me.
These are the same battery types as they are deep cycle wet cell batteries. Don't mix them with maintenance free, gell, AGM, starting batteries etc. They will all charge and provide power in proportion to their individual capacity.
If they have slightly different resting voltages one might drag the other to the lowest common voltage while in storage with no float charge. That is why I said disconnect the parallel connections in storage.
Many will also say don't mix old and new batteries. So technically if you want to do it right you will need four new batteries. In practicality they will do fine together assuming they are in good shape.
If money is easy get four of the T125s if you want all matched and a little more power.
Either way I would go with the four golf batteries as four 12 volt in parallel is harder to keep balanced. Here is an article on keeping parallel batteries balanced: How to correctly interconnect multiple batteries to form one larger bank Mostly geared toward higher amp loads like an inverter but the issue still applies.
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wa8yxm
Wherever I happen to park
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Joined: 07/04/2006
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The thing I look at is the watts per dollar (Or if you like Amp Hours per Dollar)
And so far I've found 6volt pairs give the best return on investment
Which is better technically...12 of one,dozen of the other
But ona dollars per usable watt... Six volt pairs
One thing to think about
-{batt}+={Batt}+ (A six volt pair)
Equales
-{BATTERY}+ (A BIG! 12 volt battery) 232 amp hours
This holds true for most everything with the following exceptions
Cleaning posts (Clean all 4)
Hefting in and out of rig
Lift 232 amp hours of six volt battery in twice,hook it up properly and you get 232 amp hours of 12vdc
Heft 232 amp hours of 12volt.. You get... Hernia?
Nothin adds excitment like something that is none of your business
John is Near Kenwood TS-2000 housed in a 2005 Damon Intruder 377
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pnichols
Santa Cruz Mountains
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Joined: 04/26/2005
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"Heft 232 amp hours of 12volt.. You get... Hernia?"
Huh??????
How is it that two true deep cycle 12V batteries in parallel to provide 232 AH (116 AH each, so two needed for 232AH total) weigh more than two true deep cycle 6V batteries in series to provide 12 V (232 AH each and total, but two needed for 12V)?
John, I don't think you meant exactly what it came out sounding like!
Phil, 2005 E450 Itasca 324V Spirit
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mike4947
N. Syracuse, NY
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Joined: 08/26/2002
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Since you've got them I'll go along with use them.
BUT, here's a couple of things to do:
Charge the batteries and then check their specific gravity. If they are all within a point or two you are good to go. Any battery with a significantly lower SG will draw down the others in the bank as they try and charge it.
Also for the first few charges keep an eye on the batteries for "boiling". If one does more than the rest you've found a weak link that needs replacing.
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