6 volt or 12 volt batteries

[Mr_D]

Doesn't bother me to have to check my wet cell batteries and add distilled water if/when necessary. I would add mineral oil to the cells anyway which cuts down on off gassing and corrosion. So replacing the 4 8D AGMS with 8 GC-2 wet cells would be no problem. For our use the extra cost isn't justified.

[ramblingdon]

So much truth presented in different ways.

When it comes to batteries for an RV, what is the best, once you throw out the cost differences even, should be based on which has the best internal construction.

That means; plate material plate size, plate connection technology, along with the internal plate mounting.

Again, the replacement costs aside, your batteries are taking a lot of punishment from; constant deep discharge and re-charge, high-G force shocks (usually more than in a car), charger internal management if charging modes, and temperature (weather) extremes, to name the main ones.

The best to use, in my opinion and after years of experience with 6 different motorhomes, should always be based on the factors listed above, and then consider cost.

RamblingDon
2006 Fleetwood 35E Bounder
2015 Kia Soul - TOAD

[Forest Grump]

I don't know if anyone makes a 195ah 12 v battery. Trojan as mentioned makes both 6 and 12 volt batteries. The Trojan 27 series are 100 ah and the J185H is 225 ah. So one 12v J185 H is equivalent to 2 6v T105's. The J185 is on a 31 footprint but 18" high and 115#'s. If you were to find a 195 ah it would be about 100#'s, size 27 and about 18" tall..

The construction of both (Trojans) is the same. So what you buy in a reputable true 20 ah rating deep cycle battery does not matter if it is two six volts or one 12v. What does matter is will they fit in your compartment. I have two 450 ah tall 6 volts 16" because they fit and is in the ah range I need.

[beenthere]

I would recheck your math for this...as 2 6v at 225amp in series gives 225 amp hours....now add another parallel set and you have 450 amp hours...now the 12 v were 195amps each x 4 in parallel is 380 amp hours.. jeff

Originally Posted by OLYLEN

I'm going to get flamed for this, OK.
The major battery companies are now building true 12 volt DEEP CYCLE batteries.
Now with 4 6 volt say 225 amp hour you get 225 amp hour usable with 4 12volt at 195 amp hour you get near 400 amp hour usable at 50% on each set.
The difference is attributed to adding amp hours for parallel and not for series.
I have used both 12 and 6 volt and don't see much different although I normally keep the charge on the upper end.
Cost seems to be with in the same ball park for quality on both setups.
Now I only run two batteries in my C and they are 12 volt.
I see what I believe is a lot of parroting of the older technology without investigating the newer 12 volt DEEP CYCLE systems available.
I would love to see side by side tests not the manufacturers numbers.

LEN

[Forest Grump]

Originally Posted by beenthere

I would recheck your math for this...as 2 6v at 225amp in series gives 225 amp hours....now add another parallel set and you have 450 amp hours...now the 12 v were 195amps each x 4 in parallel is 380 amp hours.. jeff

Beenthere you haven't.

4 x 195 = 780 Ah oops!

It's all about chemistry. Wether 2v, 6v or 12v deep cycle the same mass of lead is required to produce a given Ah at a given voltage. Trojan is an excellent manufacturer of deep cycle batteries.



So what you see is an 1110Ah 2v battery, a 360Ah 6 volt battery and a 225Ah 12v battery L16's, big around 100# + or - each.

Buy the configuration for the Ah you want for the compartment size you have and remember parallel wiring increases Ah while series wiring increases voltage.

I had 3 12v J185H's in my old MH 645Ah.
In my new Thor ACE I have 2 6v J105's 360Ah with 480 watts of solar panels.

[beenthere]

ya I meesed up and after rereading he even said at 50%.....added parallel series with both instead of just parallel for 12v..and I thought but don't know fro sure that it was surface area of lead not mass and that's why 6v are thicker plates..

[ramblingdon]

Good conversation on batteries, so i thought I would add my2-cents.

A battery, regardless of voltage considerations, with larger cell size and plate area, will have a longer discharge rate than an equivalent one with a smaller cell size and plate area.

This should be considered in your battery decisions.

Consider that Amp-Hours is defined as X-Amps of current delivered for Y-Hours.

Here is a good explanation for everyone from a reputable reference site on the web, (batterystuff.com);

"The battery’s AH rating goes down the faster you use it. This is not the same thing as saying you use up what is available faster, but you actually decrease the total overall capacity itself. To ensure that ratings are given in a realistic way, lead-acid batteries have a few parameters on how they get that ‘AH’ rating.

In order to get an AH rating, the battery that is being tested has to be drained down to 0 over the course of a specified amount of time. The amount of amperage that it took to get it down to zero, over that specified amount of time constitutes the AH rating.
Because of the Peukert effect (aka, The faster a battery is drained, the less overall amperage is available), if you discharge a battery over the course of 100 hours, the AH rating looks higher that if you discharge that same battery over the course of 1 hour. So, there has to be a standard. For deep cycle batteries the standard rating is 20 hours.
So, if a battery has a rating of 100AH @ 20 Hr rate, then that battery was discharged over 20 hours with a 5 amp load.
Starting batteries on the other hand, are typically rated at 10Hr rate, because they are used faster, so the 20Hr rate is not as important.

So, that weird 20Hr rate that you see after the AH rating on batteries, that tells you that the rating in question is the realistic, common rating; rather than an over-inflated number to make the battery look better than it really is.

- See more at: What does “20 Amp Hr rate� mean?

Knowing this, should help in your battery selections in the future.

RamblingDon
2006 Fleetwood, 35E Bounder
2015 Kia Soul - TOAD

[gemini5362]

WARNING ! WARNING! WARNING ! DANGER WILL ROBINSON

If after reading this highly informative thread you decide to replace your 6 volt golf batteries with 12v deep cycle batteries DO NOT wire the 12 batteries in the same manner as the 6 volt batteries you are replacing. 6 volt batteries are wired in Series- Parralel which means you add the voltage of 2 (6) volt batteries together to produce 12 volts.

12 volt batteries would always be wired in parallel which means if you try to just take out the 6 volt batteries and put the 12 volts in their place wiring two of them in series you will have 24 volts which will not be good for anything that runs off of DC. I. E. Most of your Motor Home.

If you are changing over to all 12volt batteries only ALL the Plus terminals will be wired together and all of the negative terminals will be wired together. This is only if you are using ALL 12 volt batteries

I realze that most people already know this but this post has been offered as a public service announcement for those that do not know the difference.

[Forest Grump]

Ramblingdon - great summary! Great explanation!

[Forest Grump]

Originally Posted by gemini5362

WARNING ! WARNING! WARNING ! DANGER WILL ROBINSON

If after reading this highly informative thread you decide to replace your 6 volt golf batteries with 12v deep cycle batteries DO NOT wire the 12 batteries in the same manner as the 6 volt batteries you are replacing. 6 volt batteries are wired in Series- Parralel which means you add the voltage of 2 (6) volt batteries together to produce 12 volts.

12 volt batteries would always be wired in parallel which means if you try to just take out the 6 volt batteries and put the 12 volts in their place wiring two of them in series you will have 24 volts which will not be good for anything that runs off of DC. I. E. Most of your Motor Home.

If you are changing over to all 12volt batteries only ALL the Plus terminals will be wired together and all of the negative terminals will be wired together. This is only if you are using ALL 12 volt batteries

I realze that most people already know this but this post has been offered as a public service announcement for those that do not know the difference.

Whoa! Series-parallel???? Series battery wiring voltage is additive. Parallel battery wiring is amp additive.

2 6's in series = 12v
3 6's in series = 18v

Depends upon the voltage you need. RV's typically are 12v, hopefully, unless you have a really old 6v VW conversion. Ah the 6 volt VW, park it on a hill.

[Ray,IN]

Originally Posted by Forest Grump

I don't know if anyone makes a 195ah 12 v battery. Trojan as mentioned makes both 6 and 12 volt batteries. The Trojan 27 series are 100 ah and the J185H is 225 ah. So one 12v J185 H is equivalent to 2 6v T105's. The J185 is on a 31 footprint but 18" high and 115#'s. If you were to find a 195 ah it would be about 100#'s, size 27 and about 18" tall..

The construction of both (Trojans) is the same. So what you buy in a reputable true 20 ah rating deep cycle battery does not matter if it is two six volts or one 12v. What does matter is will they fit in your compartment. I have two 450 ah tall 6 volts 16" because they fit and is in the ah range I need.

I have 3 Exide deep-cycle house batteries in my MH, each has a 200AH rating. I think the model # for them is 31MDC. My chassis batteries are Interstate 195AH rated, also gp 31. All are sealed lead-acid, no way to add water.

[Forest Grump]

Originally Posted by Ray,IN

I have 3 Exide deep-cycle house batteries in my MH, each has a 200AH rating. I think the model # for them is 31MDC. My chassis batteries are Interstate 195AH rated, also gp 31. All are sealed lead-acid, no way to add water.

Chemistry is chemistry you do not have 200Ah batteries at the 20 hr. Rating. They are 115Ah so the three of these are about equal to my two 6v. They are a marine deep cycle hybrid which I choose not to buy. Also the 115 Ah rating seems high but I don't know how much the battery weighs. A 200 Ah 12v battery is going to weigh 100+ pounds because that much lead is required.

Sealed lead acid batteries also pose a problem for hot dry arid regions since you can't replace the fluid that does and will evaporate. I'm talking about 100+ degrees with single digit humidity.

31DC
Manufacturers Part Number31MDC
Battery TypeDeep Cycle Lead Acid
Terminal TypeM1 Post w/Stud (3/8P 5/16N)
Core Unit Value1.5
Power Rating
Voltage12
Cold Cranking Amps (CCA) @ 0°F725
Marine Cranking Amps (MCA) @ 32°F900
Reserve Capacity Minutes @ 25A205
Amp Hours (20 Hr Rate)115
Manufacturer Warranty
Free Replacement Period12 Months

[Ray,IN]

Originally Posted by Forest Grump

Chemistry is chemistry you do not have 200Ah batteries at the 20 hr. Rating. They are 115Ah so the three of these are about equal to my two 6v. They are a marine deep cycle hybrid which I choose not to buy. Also the 115 Ah rating seems high but I don't know how much the battery weighs. A 200 Ah 12v battery is going to weigh 100+ pounds because that much lead is required.

Sealed lead acid batteries also pose a problem for hot dry arid regions since you can't replace the fluid that does and will evaporate. I'm talking about 100+ degrees with single digit humidity.

31DC
Manufacturers Part Number31MDC
Battery TypeDeep Cycle Lead Acid
Terminal TypeM1 Post w/Stud (3/8P 5/16N)
Core Unit Value1.5
Power Rating
Voltage12
Cold Cranking Amps (CCA) @ 0°F725
Marine Cranking Amps (MCA) @ 32°F900
Reserve Capacity Minutes @ 25A205
Amp Hours (20 Hr Rate)115
Manufacturer Warranty
Free Replacement Period12 Months

I'm glad you caught my goof. That was my old batteries, which were replace with 31 XPD's last Monday. I'll take a picture of their labeling Monday if I can remember. DW is having a garage sale this weekend and I don't have time tomorrow.