CampMacD
Rough & Ready, CA
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Joined: 10/31/2007
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Thanks for the great information. While I would love to get two 6v AGM batteries, my budget is more in line with the acid wash. And that is the path I will go.
Ahab, we pretty much have operated like you do relying on the Mr. Heater Buddy to take the chill off first thing in the AM, and unsing down comforters overnight. Water is used at the bare minimum (use Campground showers, toilets, etc). We do still have the 8w incandensents in our TT, but we seldom will have over 1 fixture on at a time, and use portable lights in the trailer. That's kind of our frustration point - our trailer has all these 'comforts' but they can't be used for fear of killing the battery bank.
I honestly don't know the brand and exact specs of the batteries that were delivered with our TT. There is no labeling or logo on it at all. I've found some sort of stock number embedded on the battery and a Google search seems to indicate that these are Chinese knock-offs of a Interstate battery. The water levels of the two batteries are slightly different, and one has cloudy water. I am again guessing that these are not two batteries of the same stock or age - but I can't tell for sure.
Thanks again for the insight - any other thoughts would be gladly welcomed!
Dennis, Marni (DW), Son (2)
Rough & Ready, CA
2002 GMC Sierra Ext. Cab 4WD
2008 Trail-Cruiser TC26RKS
Prodigy Brake Control
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Bumpyroad
Virginia
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Joined: 12/01/2005
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could go to the 31 batts also.
bumpy
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smkettner
Southern California
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Costco has a good value on group 24 (85 amp hr) group 27 (115 amp hr) and golf batteries (232 amp hr per pair).
2001 F150 SuperCrew 5.4 Lariat Offroad 4x4 Tow Package 4.10 Truetrac
2006 Keystone Springdale 249FWBHLS
12K SuperGlide, KGE3000Ti 2.3kw rated 2.6kw max
Frank's voltage booster, Prosine 1800 powered by 4 GC2 batteries
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Bumpyroad
Virginia
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smkettner wrote:Costco has a good value on group 24 (85 amp hr) group 27 (115 amp hr) and golf batteries (232 amp hr per pair).
what's the price difference between two 27s at 230 ah and 2 golf batteries 232 ah?
bumpy
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smkettner
Southern California
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Less than $10 last I was in.
Today was 75.99 per 6v and 68.54 for the 12v group 27.
* This post was
edited 10/08/08 01:36pm by smkettner *
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greenrvgreen
open road
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Joined: 09/05/2007
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Quoting Profdant139:
"I installed two Costco group 27s on my tongue (actually on the trailer's tongue)."
Thank you for clarifying this, Prof, and just in the nick of time: I had my tongue stretched out with C-clamps and I was ready to start drilling pilot holes.
Actually, I should be thankful the topic wasn't "tail lights".
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profdant139
Southern California
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Joined: 11/14/2005
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Someone asked about hooking them up in parallel, versus just bringing two and using one as a spare. I have thought about parallel, but here is my concern -- sometimes, a battery fails unexpectedly, or someone leaves a light on, or whatever. If the batteries are in parallel, the strong one will cover for the weak one and you will not know that there is a problem until both are dead.
By contrast, using just one at a time lets me monitor how much power I have used on that battery. When it gets low (to 12.1), I switch them.
Maybe I am wrong -- I would sure like to hear from those who know more than I do. I am not an expert, by any means!
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smkettner
Southern California
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profdant139, one at a time has the advantages you stated. Running in parallel cuts the amp load in half at any given time and that gives more total energy. You may get 10% extra power from running both in parallel. It is called the Peukert effect. Wikipedia has a detailed explanation.
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Bumpyroad
Virginia
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profdant139 wrote:Someone asked about hooking them up in parallel, versus just bringing two and using one as a spare. I have thought about parallel, but here is my concern -- sometimes, a battery fails unexpectedly, or someone leaves a light on, or whatever. If the batteries are in parallel, the strong one will cover for the weak one and you will not know that there is a problem until both are dead.
By contrast, using just one at a time lets me monitor how much power I have used on that battery. When it gets low (to 12.1), I switch them.
Maybe I am wrong -- I would sure like to hear from those who know more than I do. I am not an expert, by any means!
and if you use an A/B/AB switch, it makes that job easy.
bumpy
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bryanl
Reno, NV
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Joined: 12/25/2003
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Your usable battery capacity will be about 10 watt hours per pound. It don't matter the voltage of the components of the bank! 12v as good as 6v. The battery trade-offs are cost, durability, and capacity and the differences in a line, say between a Trojan T105 vs T145 or SCS200 vs SCS220, really won't be significant due to all the other things that influence your battery.
AGM batteries are very nice, especially for high current needs, but don't provide a life expectancy matching the price premium.
There is good reason to run your batteries together in a bank rather than isolated one at a time. See the smartgauge web site for some good explanation of why.
See Basic battery guidelines for some rules of thumb and links to where they came from.
Bryan
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