6 volt vs. 12 volt

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John From Detroit

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The same reason a 10 gallon bucket costs more than a 5 gallon bucket: the 6V is only half the capacity, storing 6v x 230 AH = 1380 watt-hours of electrical energy. The 12v battery is 12v x 230 AH = 2760 watt-hours of energy. The 6v is also half the physical size of a 12v with the same AH capacity - see Ex-Calif explanation of the lead plates. A 6v battery requires only 3 cells, while a 12v requires 6. Lead is actually quite expensive, so doubling the amount of lead plates (6 cells vs 3 cells) nearly doubles the production cost of the battery.
You missed "A Pair" A pair ofr 6 Volt 230 AH batteries. in series **IS** a 230 amp hour 12 volt battery.. So why are they so much cheaper than say a 4D?
 

Ex-Calif

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Well a few of us got sucked into this one, I guess.

I only look at the last couple of postings most of the time so that's my story and I am sticking to it...
 

Gary RV_Wizard

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For a decent house battery, a trick that usually works is to make sure there is NO CCA (Cold Cranking Amps) or MCA (Marine Cranking Amps) rating at all.

That us because a decent house battery is NOT designed to start an engine--but usually still can do such if needed in an emergency. If they do have a Cranking amp rating, a decent one will have a poor rating, so they normally don't mention it.
That is "traditional wisdom" among RVers but is somewhat belied by the fact that battery companies like Trojan and Rolls, famous for their industrial and motive batteries, do indeed give a CCA rating for their batteries. But, they don't feature it in big numerals on the battery case like some other brands. Generally, a prominently displayed CCA or MCA rating indicates the battery is very likely the hybrid type, whether it says deep cycle or not.

** It's easy to get re-involved in these old threads, especially on popular debates like this one.
 

DonTom

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That is "traditional wisdom" among RVers but is somewhat belied by the fact that battery companies like Trojan and Rolls
They may give such in the specs, but it is NOT on any of the six volt Trojans batteries I have owned. Are they now putting a CGA rating on the Trojan true deep cycle batteries?

I would rather NOT see such on the battery itself. I don't care if it is listed on a spec sheet somewhere. I figure a spec sheet should have every spec possible regardless of its main purpose. But on the true deep cycle battery itself, just have what it is mainly designed for and that is NOT for starting engines.

-Don- Reno, NV
 

Rob&Deryl

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Here's what I've found doing some research in the library and other places. I'd have to use a pair of 6v batteries hooked in parallel to make it 12v for my TT. But, a pair of 6v with 100AH each, hooked in parallel would only produce 100AH; not 200AH. However, one 12v at 100AH would would cost less than a pair of 6v.

But, if 6v gets more cycles than a 12v, the long term cost would be less. (So glad I didn't choose to be an accountant.)

I did a search for golf cart batteries on Amazon and found there are 12v batteries that claim to be true deep cycle batteries. Here's an example of a 12v 35AH: Mighty Max Battery 12V 35AH SLA Internal Thread Battery Kangaroo TG-31 Golf Cart Brand Product - Amazon.com: 12V 35AH SLA Internal Thread Battery for Kangaroo TG-31 Golf Cart : Health & Household

I also found 12v 100AH batteries which are used for solar and TT applications. Example: Mighty Max Battery 12V 100AH Battery Solar Wind DEEP Cycle VRLA 12V - https://www.amazon.com/dp/B00S2MDZFK/ref=psdc_389574011_t3_B00S1RT58C

With the growth of solar applications, I'm wondering if more manufacturers are producing 12v true deep cycle batteries at a lower price than Trojan.
Not in parallel, but 2 6v in series is 12v
 

Rob&Deryl

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When I did this, I just bought a pair at the local Batteries plus Bulbs store. 220ah. I decided to spend a bit more for AGM so I did not have to check water levels and no worries about venting.
They even carried them out to the truck. Super heavy .
 

DonTom

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Technically every lead battery has either a CCA or MCA or both... Just with true DEEP CYCLES they tend not to waste label ink. But the battery has 'em.
Of course.

But I do NOT care to see it on the battery itself. Those who will bother to look at the spec sheet will probably know enough to realize a poor CGA rating for the size of battery is what they want to see for a decent house battery. At least until they invent a new type of 12V battery where an AH is an AH at every current draw.

-Don- Auburn, CA
 

Ray-IN

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I need to get one or more deep cycle batteries for my TT. I've learned a lot researching this forum about battery use & care for dry camping. While I do most of my own maintenance/repair, I don't know much about DC. My question: Does a 6v 100AH deliver the same amount of service as a 12v 100AH battery for operating RV electrical devices? I'm finding a 6v costs less than a 12v.
I wonder about the decision?
 
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John From Detroit

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Ok a single 6 volt is basiclly useless. you need two so -{6V}+-{6v}+ = 12 volt
And if those are 100 amp hour battereies then the resulting 12 volt will be 100 amp hour as well. Roughly a Group 27 or 29.
The Difference however is between MARINE/deep cycle or RV/deep cycle starting batteries and Golf Car (GC) DEEP CYCLE batteries.. not the use of case in this sentence.
The MARINE/deep cycle or MARINE/rv or RV/deep cycle the deep cycle is an after thought. they are primary starting batteries.. You should not run 'em down much more than 25%.
DEEP CYCLE you can run down to 50%
And some newer chemisteries (Like LiFePO4) 95%
 

Ex-Calif

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Technically every lead battery has either a CCA or MCA or both... Just with true DEEP CYCLES they tend not to waste label ink. But the battery has 'em.

Well... Not to be that guy but all batteries have both. CCA and MCA are just discharge tests done at different temperatures. It's whether they were tested at each temperature and/or whether they were labelled with one or the other result.

I find the "outside" difference between auto/marine batteries and "deep cycle" batteries is that it is often hard to find the a/h rating on car batteries. It's almost never on the battery and frequently not in the spec sheets. Especially lower end batteries.
 

Lou Schneider

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One advantage of using two 6 volt batteries vs a single 12 volt battery of similar amp-hour capacity is the 6 volt batteries divide the 12 volts into two packages instead of one. At least for heavy lead acid batteries this makes them much easier to handle. I can lift and maneuver into place a pair of 60 lb GC-2 golf cart batteries (215 amp-hours at 6 volts each), I can't say the same for a 120 lb 8D size battery (200 amp-hours at 12 volts).
 

John From Detroit

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That is misleading IMO. LA batteries may be discharged by 80%, the only ramification is reduced lifetime duty cycles.
Exactly But with starting batteries that "Rapid aging" starts around 20% discharge
Marine/deep cycle 70-75
DEEP CYCLE 50
Also I've run Starting batteries down way too low due to failed alternator. They got replaced.
I've also run DEEP CYCLE even lower and they.... Recovered.
 

Gary RV_Wizard

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I can lift and maneuver into place a pair of 60 lb GC-2 golf cart batteries (215 amp-hours at 6 volts each), I can't say the same for a 120 lb 8D size battery (200 amp-hours at 12 volts).
Sure, but you could easily handle two 12v batteries of 105AH each, which also yield 210 AH when wired in parallel. For example, two Group 27 12v deep cycles at around 55 lbs each.
 

Mooree

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I will refer to deep cycle batteries when talking about 6V or 12V batteries for RVs. The good news is that you can connect two such batteries in parallel to increase the amps to 100 Ah or 200 Ah. Connecting two 6-volt batteries in a series will meet the 12-volt electrical requirements of modern touring trailers, campers, motorcycles, and RVs. However, the amperage rating remains the same.
Deciding between 6 volts vs 12 volt RV batteries is a breeze if you know what you want. Most RV owners will pick a 12-volt battery because of its affordability and availability. You will likely never worry about connecting more than one 12V battery to your system to run your motorhome’s electric devices.
 

Larry N.

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Deciding between 6 volts vs 12 volt RV batteries is a breeze if you know what you want. Most RV owners will pick a 12-volt battery because of its affordability and availability. You will likely never worry about connecting more than one 12V battery to your system to run your motorhome’s electric devices.
Hmmm... that's odd- only ONE 12V battery? I'd run out of juice in a hurry. I have eight 6V batteries for the house and two 12V batteries for the engine/chassis, and this came from the factory. So note that what is needed depends a LOT on the RV - not all are the same. What kind of motorhome are you referring to?

Note, too, that a pair of 6V deep cycle batteries tend to be cheaper than a single 12V of the same size. So I'd disagree with "most RV owners."
 

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