6 volt vs. 12 volt

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Lou Schneider

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Do what you want, just be aware that you won't find a 100 amp-hour 6 volt battery, which makes your interpretation moot.  6 volt batteries are typically 200 amp-hours each, meaning a pair wired in series will deliver 200 amp-hours at 12 volts.

Here are a couple of practical examples from the same source (Batteries Plus, a nationwide chain of battery stores).

First, a pair of 6 volt GC-2 deep cycle batteries:

Duracell GC-2 Golf Cart Battery

At $99 each, two six volt batteries will cost $198 for 12 volts, 225 amp-hours of storage.  That's 88 cents per amp-hour.

Next, a 12 volt, 105 amp-hour deep-cycle battery of the same brand, from the same source:

Duracell Group 31M 12 Volt Deep Cycle Battery

At $130 for 12 volts, 105 amp-hours of storage, it costs $1.24 per amp-hour.  While one of these batteries is three times as much storage as your present 12 volt, 35 amp-hour battery, you'll need two of these to approximately equal the capacity of a pair of 6 volt GC-2 batteries.

Your present battery is 12 volts at 35 amp-hours:

Duracell 12 volt 35 amp-hour battery

At 35 amp-hours of storage, it's considerably smaller than either of the above examples.  You'll need 6 of these to get the same performance as a pair of golf cart batteries, or 3 to equal the single 12 volt, 105 amp-hour battery.  At $90 for 35 amp-hours, it has a cost of $2.57 per amp-hour.

But note this is a maintenance free, sealed AGM battery.  The other examples are wet cell batteries, which require venting and occasionally replenishing the water levels.

The physical size and weight may also be a consideration.  The 35 amp-hour battery is 7.67"L x 5.13"H x 7.09" D and weighs 20 lbs.  Both the golf cart batteries and the 31M 12 volt batteries are considerably larger and heavier than this.

I hope this helps in your decision.
 

Gary RV_Wizard

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The least cost answer is a 12v Marine/RV battery in the Group 24 size. You can find them anywhere batteries are sold, even Walmart, for around $100. 

https://www.walmart.com/ip/EverStart-Maxx-Lead-Acid-Marine-RV-Battery-Group-24DC/139801236

The GC2 golf car batteries will supply more power and last longer (typically 6-7 years), so they are less costly over time even though you have to buy two upfront.
 

IBTripping

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Lou Schneider said:
Do what you want, just be aware that you won't find a 100 amp-hour 6 volt battery, which makes your interpretation moot.  6 volt batteries are typically 200 amp-hours each, meaning a pair wired in series will deliver 200 amp-hours at 12 volts.

Here are a couple of practical examples from the same source (Batteries Plus, a nationwide chain of battery stores).

First, a pair of 6 volt GC-2 deep cycle batteries:

Duracell GC-2 Golf Cart Battery



At $99 each, two six volt batteries will cost $198 for 12 volts, 225 amp-hours of storage.  That's 88 cents per amp-hour.

Next, a 12 volt, 105 amp-hour deep-cycle battery of the same brand, from the same source:

Duracell Group 31M 12 Volt Deep Cycle Battery

At $130 for 12 volts, 105 amp-hours of storage, it costs $1.24 per amp-hour.  While one of these batteries is three times as much storage as your present 12 volt, 35 amp-hour battery, you'll need two of these to approximately equal the capacity of a pair of 6 volt GC-2 batteries.

Your present battery is 12 volts at 35 amp-hours:

Duracell 12 volt 35 amp-hour battery

At 35 amp-hours of storage, it's considerably smaller than either of the above examples.  You'll need 6 of these to get the same performance as a pair of golf cart batteries, or 3 to equal the single 12 volt, 105 amp-hour battery.  At $90 for 35 amp-hours, it has a cost of $2.57 per amp-hour.

But note this is a maintenance free, sealed AGM battery.  The other examples are wet cell batteries, which require venting and occasionally replenishing the water levels.

The physical size and weight may also be a consideration.  The 35 amp-hour battery is 7.67"L x 5.13"H x 7.09" D and weighs 20 lbs.  Both the golf cart batteries and the 31M 12 volt batteries are considerably larger and heavier than this.

I hope this helps in your decision.

Lou, thanks for the info. Much better price than I found on Amazon. Fortunately, there is a vendor near me so I won't have to pay shipping. I'd prefer using a true deep cycle battery rather than marine. So, I'll start with a pair of 6v and add another pair if needed.

And, thanks to everyone else who commented. This discussion has been very educational and was a great help to me in making a decision on which batteries would best meet my needs.
 

kennyshark

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I put two 6V Interstates on my 26' Tracer, I bought the battery boxes from Amazon and the Batteries Local. Remember to keep distilled water on hand and check them at least once a month. I've had mine on since 2013 and They still work great.
 

Kennethh

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For those who are confused about choosing between 6 volt and 12 volt RV batteries for motorcycles and touring trailers, we offer these tips: Many 12-volt batteries on the market have an amperage of 50 Ah to 100 Ah. The average 6-volt battery on the market provides 225 amp hours, typically ranging from 160 Ah to 260 Ah. 6-volt battery systems have thicker and heavier plates that allow them to withstand the chemical changes inside the battery, so 6-volt batteries can be said to have a longer lifespan. But in terms of cost, 12-volt battery systems are inexpensive and available at most auto supply and battery stores.
 

IBTripping

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For those who are confused about choosing between 6 volt and 12 volt RV batteries for motorcycles and touring trailers, we offer these tips: Many 12-volt batteries on the market have an amperage of 50 Ah to 100 Ah. The average 6-volt battery on the market provides 225 amp hours, typically ranging from 160 Ah to 260 Ah. 6-volt battery systems have thicker and heavier plates that allow them to withstand the chemical changes inside the battery, so 6-volt batteries can be said to have a longer lifespan. But in terms of cost, 12-volt battery systems are inexpensive and available at most auto supply and battery stores.
This is an ancient thread which includes a naïve question by me when I first bought my TT. At any rate, I ruined one of my expensive 6 volts. Decided to change to one 12 volt. Got big 12 volt from Walmart with 122 amps for about $80. Works great even when the shore power goes out for several hours.
 

John From Detroit

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For those who are confused about choosing between 6 volt and 12 volt RV batteries for motorcycles and touring trailers, we offer these tips: Many 12-volt batteries on the market have an amperage of 50 Ah to 100 Ah. The average 6-volt battery on the market provides 225 amp hours, typically ranging from 160 Ah to 260 Ah. 6-volt battery systems have thicker and heavier plates that allow them to withstand the chemical changes inside the battery, so 6-volt batteries can be said to have a longer lifespan. But in terms of cost, 12-volt battery systems are inexpensive and available at most auto supply and battery stores.
I had no problem finding GC-2 Golf Car (6 volt Deep cycle) batterries. Sam's carries 'em Costco can order ''em most any golf course gets 'em by the truck load (Why they are low cost)
They are actually CHEAPER than 12 volt for the same capacity

What's more because they are DEEP CYCLE they can take an "OH C**P! level discharge and come back for more better than most 12 volt types.

That said you can get genuine 12 volt DEEP CYCLE batteries.. but they tend to be pricy because they are rare. Not as rare as they used to be (Check the GC-12) but pricey.

Another difference... Pound per watt hour (Amp hours times volts) most all lead acid batteries are within 10% or less of each other.. So 220 amp hours divided between TWO six volt jars is.. Something I can wrangle into/out of my motor home (And did) 220 amp hour 12 volt battery (4D) Forget about it.
 

Gary RV_Wizard

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I will once again offer the article I've written on this subject. It explains the choices (trade-offs) of the various battery options for RV house batteries. I've tried to keep it simple - most owners just want the lights to work and not require them to fuss with batteries all the time. The tech types already know batteries, so I didn't see the need to write for them.
RVForum - Choosing a battery
 

Ex-Calif

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It is simpler to understand when you use the math. Watts is the measurement of power

Volts X Amps = Power in watts

6V X 80 amps = 480W
12 X 80 amps = 960W

In a series circuit voltage is cumulative and amps are constant

6V + 6V = 12V X 80 = 960W

In a parallel circuit volts are constant and amps are cumulative.

(12 V X 80 = 960W) + (12 V X 80 = 960W) = 1920W

1920 / 12V = 160 amps

Deep cycling is important if you boondock a lot. Golf carts use 6V batteries because they are basically run flat each day.

I use 12V marine batteries because I don't deep discharge a lot ad I get more usable amps in the battery space available.
 

creativepart

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@IBTripping, you keep mentioning getting "2-6v batteries and wiring them in "Parallel" to get 12v."

That's not correct. you wire the 2-6v batteries in "Series" to get 12v.

Wiring in Parallel the voltage stays the same but the amp hours (wattage) double.

Wiring in Series the voltage doubles but the amp hours (wattage) stays the same.

Also, you won't find standard size 6v batteries configured as 100 amp hour batteries. They will be 200+ amp hours. So, two 6v 220aH batteries wired in Series will yield one 12v-220ah Battery Bank. (Series doubles the voltage, doesn't change the amps.)

Group 31-sized 12v batteries are typically 100ah. Two of them wired in Parallel will yield one 12v-200aH battery bank. (Parallel doubles the amps, doesn't change the voltage.)

With Series wiring the positive terminal of one battery is connected to the negative terminal of the other battery.

With Parallel wiring the positive terminal of one battery is connected to the positive of the other battery (and negative to negative, too).
Par-Series.png
 
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IBTripping

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creativepart I may have said that in 2018. But, I'm not going to go through this old thread to see what a I posted 3 years ago when I got my first TT.​

 

creativepart

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Sorry about that. I went through this thread from the beginning and saw you and others posting this past week. I should have noticed that the thread was old.

Bold text... nice touch.
 
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