Another set of Battery questions.

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RedandSilver

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Aug 25, 2016
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I've seen some battery questions floating around here But haven't seen too much on the difference
between 6volt and 12volt house batteries.

I have 4 huge house batteries that I believe are 12volts each.
They are dated 3/08 SO I assume that I'm going to need to change them sooner then later.
When hooked to shore power OR driving down the road they (house batteries) do get charged.
I have to assume that the PO used campgrounds and didn't use the inverter very much most of the time.
I assume that's why he didn't replace them before I bought it, as the coach batteries are dated 5/15 so replaced recently.

My questions are:

Is there an advantage to using 6 volt vs. 12volt other then the weight savings you might get?
If I have 4 huge 12 volt batteries would I need 8 6volt batteries to replace the 4 I have now?
Is there a cost savings buying 6volts vs. 12volts? 
Are AGM batteries worth the cost when the wet cell batteries have worked for the 15 years this coach has been alive?
Are the CCA's the same?


IF (at this time) I don't use the inverter - because I'm hooked to shore power OR can run the generator -
Do I really need to change the batteries that I have?  They are NOT dead.  I checked the water level on the 2 that I could get to
and they were at the proper levels and didn't need any added to them.  There is a ground wire? hooked up that wouldn't
let me pull the tray out farther to check the other 2 and I didn't have tools to remove the wire, at that time so I assume
they might be OK too.

I had the vehicle hooked to shore power for about 5-6 weeks straight and just after Christmas I unplugged it to give them
a break from constantly charging.  I plan to go back out (the MH is sitting outside in my backyard) soon and plug it back it as temps
here are in the teen's for highs and single digits overnight, so I assume charging them will help keep them from freezing, right?

Also I flipped the disconnect switch for the house so no energy should be being used - but left the chassis batteries on so the step
will still work if I want to get inside it.  SO If the switch is flipped do the house batteries still get charged when on shore power?

Would any of the answers you plan on giving change if adding solar panels in the future was a possibility?
It's too early (for me) to tell if I will be doing that to this coach down the road or not. I doubt it would be before 3-5 years are up.

Thanks for any info you can send my way.  :)
 
 
Please read my article titles Choosing an RV Battery. It's in the forum Library at http://www.rvforum.net/miscfiles/Choosing_right_battery.pdf

6 vs 12 Volt has nothing to do with it, but the type of 6v battery used in golf carts is an excellent quality deep cycle type.  You can get equally good 12v deep cycles, but the golf cart batteries are usually priced much better.
 
Thanks Gary for the link - I read it and it was full of info as usual.

One thing I'm not sure of is, you say the 6volt deep cycle golf batteries are cheaper and work well.
But if I have 4 house batteries - would I need 8 - 6volts? If so, are they ? the size of most 12volts - so they could fit in the same tray?
Plus wouldn't there be extra cables required to hook up the 6volt batteries if they all have to be wired in series?
 
RedandSilver said:
Thanks Gary for the link - I read it and it was full of info as usual.

One thing I'm not sure of is, you say the 6volt deep cycle golf batteries are cheaper and work well.
But if I have 4 house batteries - would I need 8 - 6volts? If so, are they ? the size of most 12volts - so they could fit in the same tray?
Plus wouldn't there be extra cables required to hook up the 6volt batteries if they all have to be wired in series?

They're not cheaper when you consider you need two of them to make 12v, but they do store more energy. Generally, they're also larger than 12 volters.
You would need short cables to interconnect each battery, be it in series or parallel. Good, fat cables with properly affixed terminals.
 
I will take the "If I have 4 12 volt would I need 8 Six volt" question.

NO

I may have said this before but
Group 24, about 75AH
Group 27/29 just under/over 100
Group 31 130

GC-2 pairs, each pair, is 220 +/-10 so unless you have Group 31's  A pair of GC-2 has the same capacity as say a pair of Group 29's.. OR MORE

Plus they are true DEEP CYCLE instead of MARINE batteries first then (deep cycle) as an afterthought.
MY GC 2s are 230 AH.. I had to have help to install them.
 
One thing people do not understand about the 6v v 12v question is that the 6v produces roughly twice the amperage so the total wattage they produce is roughly the same.  In other words if the 6v puts out 200 amp then it is putting out 1200 watts. Then the 12 volt battery the same size will put out 100 amp and 1200 watts. No free lunch.
 
John From Detroit said:
I will take the "If I have 4 12 volt would I need 8 Six volt" question.

NO


I may have said this before but
Group 24, about 75AH
Group 27/29 just under/over 100
Group 31 130

GC-2 pairs, each pair, is 220 +/-10 so unless you have Group 31's  A pair of GC-2 has the same capacity as say a pair of Group 29's.. OR MORE

Plus they are true DEEP CYCLE instead of MARINE batteries first then (deep cycle) as an afterthought.
MY GC 2s are 230 AH.. I had to have help to install them.

That was one confusing response. Given what the poster is asking, YES, a 12v system will require twice the number of 6v batteries.
But seeing that a 6v battery will store more energy, he can probably equal his present battery bank with the same number (4) of 6v batteries.
 
RedandSilver said:
I've seen some battery questions floating around here But haven't seen too much on the difference
between 6volt and 12volt house batteries.

I have 4 huge house batteries that I believe are 12volts each.
They are dated 3/08 SO I assume that I'm going to need to change them sooner then later.
When hooked to shore power OR driving down the road they (house batteries) do get charged.
I have to assume that the PO used campgrounds and didn't use the inverter very much most of the time.
I assume that's why he didn't replace them before I bought it, as the coach batteries are dated 5/15 so replaced recently.

My questions are:
Note: A lot of your questions don't have simple yes or no answers.
Is there an advantage to using 6 volt vs. 12volt other then the weight savings you might get?
You probably have 4D or 8D batteries which usually are deep cycle batteries and usually are 12V.  So probably the answer is no. 
If I have 4 huge 12 volt batteries would I need 8 6volt batteries to replace the 4 I have now?
You probably have 4D or 8D batteries. for the battery sizes go to https://www.batterystuff.com/kb/tools/bci-battery-group-sizes.html for battery sizes and then measure your batteries to see what you have. To replace your larger batteries with golf cart batteries (GC-2 in the battery size link above) you will need to measure you space and see what fits.  You will also need extensive wiring changes.
Is there a cost savings buying 6volts vs. 12volts? 
Are AGM batteries worth the cost when the wet cell batteries have worked for the 15 years this coach has been alive?
Are the CCA's the same?
True deep cycle batteries don't have CCA (Cold Cranking Amps).  The batteries are not used to start engines.  You only want to compare Amp Hours (AH)


IF (at this time) I don't use the inverter - because I'm hooked to shore power OR can run the generator -
Do I really need to change the batteries that I have?  They are NOT dead.  I checked the water level on the 2 that I could get to
and they were at the proper levels and didn't need any added to them.  There is a ground wire? hooked up that wouldn't
let me pull the tray out farther to check the other 2 and I didn't have tools to remove the wire, at that time so I assume
they might be OK too.  They MIGHT be but you don't know unless you check.

I had the vehicle hooked to shore power for about 5-6 weeks straight and just after Christmas I unplugged it to give them
a break from constantly charging.  I plan to go back out (the MH is sitting outside in my backyard) soon and plug it back it as temps
here are in the teen's for highs and single digits overnight, so I assume charging them will help keep them from freezing, right?
Batteries fully charge will handle freezing temps.  Batteries with a low charge can be damaged.  Can't answer your question because I don't know for sure if the batteries are fully charged.

Also I flipped the disconnect switch for the house so no energy should be being used - but left the chassis batteries on so the step
will still work if I want to get inside it.  SO If the switch is flipped do the house batteries still get charged when on shore power?
Probably not.  Best to check with a meter.  Meters are available at Walmart for around $20

Would any of the answers you plan on giving change if adding solar panels in the future was a possibility?
Going to solar does not have a simple answer.
It's too early (for me) to tell if I will be doing that to this coach down the road or not. I doubt it would be before 3-5 years are up.

I suggest you find out the condition of the existing batteries.  Much more to this than I have time to detail.  You could start a new topic about how to determine condition of your batteries.

Time for a question of my own:  Will you be doing any dry camping?  That is staying in the RV without connecting to shore power?  Especially for more than overnight.  If not then you don't need batteries which are in really good condition.  So the batteries you have my work just fine for several more years.


Thanks for any info you can send my way.  :)
You asked a number of questions.  I'll try to answer at least some of them.  I put my answers in red in the quote above.
 
But if I have 4 house batteries - would I need 8 - 6volts?
Short answer: NO

A pair of 6v golf cart (GC2) batteries will provide about the same  power (voltage and amp-hours) than a pair of 12v Group 27 batteries, about 230 AH @ 12v, so four of either one will be roughly equivalent.

The GC2 size is a bit taller than a typical 2v, but not as long.
 
Gary [ RVer Emeritus] said:
Short answer: NO

A pair of 6v golf cart (GC2) batteries will provide about the same  power (voltage and amp-hours) than a pair of 12v Group 27 batteries, about 230 AH @ 12v, so four of either one will be roughly equivalent.

The GC2 size is a bit taller than a typical 2v, but not as long.
Since the OP says he has 4 huge batteries, I am pretty sure he has either 4D or 8D batteries.  So to replace that capacity will require more than just 4 golf cart batteries. 

The space the batteries are located in will need to be measured and then figure out how to arrange the smaller sized golf cart batteries to fit in the space. 
 
Just went out and looked and the batteries have C8 on them.

They are Werker Pro Series  They measure about 10" x 7" (w x d)

Part No. GC11
Mins. @ 75 Amps to 5.25V  110
RC Mins. @ 25 amps  390

I don't believe that there would be room, height wise, for 6 volt golf cart batteries because
the ones I saw were much taller then the batteries I have now.

The 4 batteries there now say "Shipped Mar 08"  so they are approaching 9 years old and there appears to be some slight
bulging of the cases - not real bad but not perfectly straight and square.

So I don't know if any of the above info will help you give me any advice on what I should replace them with or not.
But sooner or later (Summertime?) they will need to be replaced.
 
RedandSilver said:
Just went out and looked and the batteries have C8 on them.

They are Werker Pro Series  They measure about 10" x 7" (w x d)

Part No. GC11
Mins. @ 75 Amps to 5.25V  110
RC Mins. @ 25 amps  390

I don't believe that there would be room, height wise, for 6 volt golf cart batteries because
the ones I saw were much taller then the batteries I have now.

The 4 batteries there now say "Shipped Mar 08"  so they are approaching 9 years old and there appears to be some slight
bulging of the cases - not real bad but not perfectly straight and square.

So I don't know if any of the above info will help you give me any advice on what I should replace them with or not.
But sooner or later (Summertime?) they will need to be replaced.
Thank you for coming back with specific details on your batteries. 

First, it is not unusual to see some minor bulging of the sides of the batteries.  The bouncing and jostling of the batteries while traveling will spread the sides a bit. 

I was incorrect in thinking you had "4D" or "8D" batteries.  They are much larger than the 10"x6" batteries you have.

I believe you have 12 volt, 75AH (Amp Hour) battery.  I "think" it is an AGM battery since most of what I have seen online for Werker batteries are AGM batteries.  Doing several different web searches I finally came up with this web page http://www.upsbatterycenter.com/werker-wkdc12-80p-battery which seems to be about what you have.  It is an 80AH battery and the dimensions are about 10" by 6".

Going by this link for Trojan batteries:  http://www.trojanbattery.com/products/deep-cycle-flooded/signature-line-flooded-2/ it looks like you have "Group Code 24" batteries which are in the 70-80AH range. 

Golf cart batteries are about 10.3" x 7.2" and about 11.5" high.  Here is a link to a Trojan golf cart (GC2) battery spec sheet:  www.trojanbattery.com/pdf/datasheets/T105_Trojan_Data_Sheets.pdf  You can get the exact dimensions from the spec sheet.

Bottom line, if the 4 batteries you have just fit in the space with little or no room to spare you won't be able to replace them with 4 golf cart batteries. 

However, the total AH capacity of your current batteries is between 280AH and 320AH.  You could replace them with a pair of 6V golf cart batteries, wired in series, which would give you about 220-250AH capacity at 12V.  While this is not as much as you have now, unless you are going to be doing quite a bit of dry camping or have a residential refrigerator, you don't need the extra capacity. 

Note:  If your battery compartment is not well ventilated, you will need to replace your batteries with AGM batteries and not with the inexpensive flooded cell batteries I have referenced. 

Hope this helps.
 
Assuming a flooded cell type, 6 volt or 12 volt is generally pretty easy to tell: A 6V will have 3 battery caps and a 12V will have six caps.
 
The specs you provided are typical of a 6v battery, as is the GCII model (GC2 is the standard size for a 6v gold cart (GC) battery). Note the 75A discharge spec is to 5.75v, which is the "dead battery" level for a 6v battery.

The GC2 standard case size is 10-3/8"L x 7-3/16"W x 10-5/8H

If those batteries have 3 cells, they are definitely 6v. The other way to tell is the wiring, which would be positive terminal on one to the negative terminal on the next, with all batteries paired (to provide 12v from two 6's).
 
I just went out and looked again.

It seems strange that nowhere on the batteries can I find a voltage number.

There are 3 cells on each battery so I assume that they are indeed 6volts each.
I added about 2 oz. (of distilled water) to each cell in the front 2 batteries as they were reachable with out disconnecting cables.

Now it looks like there is some corrosion on the positive posts - but in most cases corrosion is on the negative posts - Right?

I attached (I think because it doesn't show in the preview) a picture of the batteries.

 

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Yup. Definitely six volt. Three cells each and the proper wiring for 6V. If you added that much water to some batteries, then you need to get to the others and fill them, too.
 
Well it was 60? here on Saturday (very unusual for this time of year) so I got a chance to work on my 6volt batteries.
I used baking soda and water to clean the connections.
Then removed the negative cables and then the positive cables then cleaned the crud off the tops
of the batteries and then I was finally ready to add some distilled water to them.

The batteries in the rear that I had never gotten to - took about 4-6oz of water in each compartment.
The plates were NOT dry and were well under water but are now topped off as were that front batteries
that took 1-2 oz to top off.

I then measured the voltage at each battery and the ALL read 6.6 volts ?.01.
So I was happy with that.  I know that may not tell how "good" the batteries are so I will get
this https://www.amazon.com/gp/product/B019VDATLG/ref=ox_sc_sfl_title_13?ie=UTF8&psc=1&smid=A1R6UJOVLZW60Q
the next time I place an Amazon order.  Then I should be set and hopefully get another year or 2 out of these 9 year old batteries.  ;D
 
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