Two 6 volt vs two 12 volt run time

pnichols,

Right on! Amp hours stored in a battery is amp hours of stored current available whether it be a 6 volt battery or a 12 volt battery and that's no secret at all. Only takes one 12 volt battery to supply 12 volts but it take two 6 volt batteries to supply 12 volts. Thus approx twice the cost for just drawing 12 volt DC current from a storage battery source. Also, you can have 1, 3, 5, 7, or 9 etc batteries in a 12 volt batteries system bank. Try that with using 6 volt batteries!

How many battery DC amp hours one wants to have available at 12 volts determines how many batteries and their size of either 6 volt or 12 volt one needs to have in their system. Also no secret either. Simple as that whther the person is highly educated or not! The batteries don't care at all as they know how many amp hours they have stored whether anyone likes it or not! What is, is!

When a 6 volt battery dies in a 12 volt system, 2 batteries must be disconnected but only one battery (the failed battery) if 12 volt batteries are used. Doesn't matter if it's for the engine start battery/batteries or the 12 volt system of the RV or the inverter power supply. 12 volts systems means 12 volts are required and 6 volts is as good as nothing and won't hack it. Like in nothing requiring 12 volt DC in an RV will work at all nor will the 12V DC to 117V AC inverter nor will the engine even turn over so it obviously will not start. How hard is that to understand? Simple as that too for anyone to understand!!!

I've had both 6 volt DC GC battery banks and 12 volt DC battery banks and will not have a 6 volt one again for so many reasons. What other want, do, or have means nothing to me as it their money spent and they'll live with the results. Thankfully, learned my lesson many years ago and am smarter than to do the same thing over again and expect different results stupidly. Sounds like the definition of "stupidity"? Perhaps some commenting/posting on this thread have never even tried both ways personally but yet say they have all the answers. O'well!

Gjac wrote:
From a practical sense I think you were informed correctly if you look at life cycles per cost. s.

the statement was "I was just informed that two 6 volt batteries would run the residential refrigerator many times longer than two 12 volt batteries. I wonder if this is just hype? "

where do life cycles per cost enter into that information? run many times longer was the claim.
bumpy

rjxj wrote:
Trojan SCS225, $240/130 AH $1.84 per ah
Trojan two GC2 $250/225 AH $1.11
Lowly Sams two Gc2 $170/215 AH .79
Sams Gp 27 $80/90 AH .88

It appears that your pricing is a bit off on the SCS225's: https://www.ecodirect.com/Trojan-Battery-SCS-225-p/trojan-battery-scs-225.htm

But I get your point. It comes down to money when a true apples to apples comparison is made. It's not actually a discussion of 6V deep cycle batteries versus 12 volt deep cycle batteries.

The above is the reason for the misleading part of most "6V versus 12V" RV battery discussions. The discussions tend to make one who isn't into batteries think that, inherently, 6V golf cart batteries in series are somehow superior to all 12V batteries in parallel.

From a practical sense I think you were informed correctly if you look at life cycles per cost. I have not found a true deep cycle 12v battery that is close to the cost of a 6v GC battery. I paid $74 each for 2 Sam's Club 6V GC batteries 9 years ago which are still going strong and I dry camp 95% of the time. At the time 2 12 v deep cycle batteries were more than double that. As others have stated it is not a fair comparison to compare 2 12v starting or a 2 12v marine battery to 2 6v GC batteries for cycle life. So yes if I had to choose today to buy batteries I would choose 2 6v GC batteries over 2 12 v batteries unless someone on here can post a true 12v deep cycle battery with the same cost and cycle life of the 6's.

My 12 volt group 31 deep cycle marine batteries are 130 Ah each, not 55 Ah each. Therefore, 2 of them are 260 Ah VS 2 GC2 6 Volt to make 12 volts and only 210Ah total.

12 volt deep cycle marine batteries in group 27 and group 31 are very widely available in all areas of the country in the farm, marine, many automotive stores, lots of tire stores, big box stores like Walmart's and Sam's Clubs etc we have been in and seen with our own eyes. Prices do vary a lot around the country as about everything is a lot higher priced west of the Rockies.

We do get a kick out of seeing the very inflated prices and costs for land, homes, goods, fuel, and even most foods on the west coast so we avoid buying much when out there and take from home or wait till we get back east of the Rockies. the inflated cost of living in some areas of the nation can be very discouraging to be at and we are not cheap or poor but not stupid either. Being ripped off (in our opinion) on the same exact items doesn't sit well at all with us and why should it?

Just another reason multiple 12 volt batteries make more sense as it's so quick and easy to just disconnect the one battery if it should fail and hardly notice the difference and wait till we can get a replacement at a cost that suits us. We do use inverters in all our RV's from 1500 watt to 2500 watt and all also have a generator with some being built in or even a min of a Honda EU 2000 secured on a cage rack on the rear of the RV. We want, like, and enjoy being ready for any foreseeable or reasonable un-foreseeable situation that arises and/or still being very comfortable with all the conveniences we want wherever and we have it that way! Just us very happy well pampered retired Midwesterners and we will have it no other way!

Unfortunately it's very hard to find affordable true 12v deep cycle batteries. True deep cycle 6v batteries are a dime a dozen so cost relatively little.

As I understand it, more golf carts today are using single 12V deep cycle batteries. In due course, the 12V battery will become as numerous as the 6v's are today. Then it will not make as much sense to go to 6v batteries.

As things stand today, I will change over to a pair of 6v batteries, just because they can be found everywhere and they are relatively inexpensive.

I'd rather have a single 12V battery, but that is not in the cards, currently.

toedtoes wrote:

Old-Biscuit wrote:
Two 6V batteries in series.......12V with SAME amp hour

Two 12V batteries in parallel----12V with double amp hour


So depends on WHICH 6V/12V and their amp hour ratings

Such a simple and clear response in a sea of fog. :)

If your 6v batteries are 210Ah, then two will give you 12v @ 210Ah total.

If your 12v batteries are 55Ah, then two will give you 12v @ 110Ah total.

Many people (and manufacturers\dealers) will install cheap basic 12v batteries. Even with 2, you are not getting a lot of amp hours out of them. So upgrading to 2 6v batteries will often give you more bang for your buck.

However, if your 12v batteries are of better quality, that significant benefit can become minimal.

but it makes those who have drunk the 6 volt kool ade feel better when they compare using size 24 puny 12 volt, non-deep cycle ,car batteries.
bumpy

Old-Biscuit wrote:
Two 6V batteries in series.......12V with SAME amp hour

Two 12V batteries in parallel----12V with double amp hour


So depends on WHICH 6V/12V and their amp hour ratings

Such a simple and clear response in a sea of fog. :)

If your 6v batteries are 210Ah, then two will give you 12v @ 210Ah total.

If your 12v batteries are 55Ah, then two will give you 12v @ 110Ah total.

Many people (and manufacturers\dealers) will install cheap basic 12v batteries. Even with 2, you are not getting a lot of amp hours out of them. So upgrading to 2 6v batteries will often give you more bang for your buck.

However, if your 12v batteries are of better quality, that significant benefit can become minimal.

.

A deep cycle battery will also start and engine as ours have 810 cold starting amps each as listed on the manufacturer's label right on the top of each of our 12 volt group 31 deep cycle marine batteries. Our diesel truck has 2 large batteries for starting the diesel engine and their 2 battery cold starting amps are just a fraction of what the 5 deep cycle batteries will deliver thru the #2 gauge cables from the RV.

Standard vehicle starting batteries make very poor long draw from batteries as they are designed to give a high amperage shot duration amps unlike deep cycle batteries which have much thicker plates but fewer inside the lead/acid batteries. See one of each broken apart and it's obvious! Having Less plates means less plate surface but thicker plates gives a much longer useful working life but also less cold starting amps but still plenty to start an engine normally. Just will not give that instant short high RPM spin that some older worn engines may want to have to start them in the very cold temps.

My system design on each pf my trucks also includes the ability to jumper the RV batteries to the engine starter circuit + junction block in the case of the truck batteries failed or get run down somehow or even get shorted out inside. Just disconnect the cable to the shorted out battery and jumper the RV batteries cable connection under the truck hood at the alternator + junction block, start the engine, and be on your way!

Give it some thought!