House Batteries

[sgt77]

Wise ones,

I am looking at the advantages or disadvantages of replacing my two 12v house batteries with 6v. I have seen several posts which mention the change over, but not really have seen a good explanation of why. Our coach is an 02 Winnebago Adventurer 35U.

[wa8yxm]

There is no inherent advantage of six volt pairs over 12 volt provided both are apples or oranges.

The difference comes in when you have six volt apples and 12 volt lemons.

Here is what I mean

Though you can find 12 volt DEEP CYCLE batteries, the tend to be either smaller (Like 5 or 20 amp hours) or much bigger (Group 31 to some truly giant jobs used in Fork Lifts).. They also tend to be EXPENSIVE!!!!!

The most common six volt battery is a True Deep Cycle, (Designed for use in Golf Cars) and due to the popularity of golf cars one of the least expensive, if not THE LEAST expensive, lead acid battery made.

Thus. I recommend them. Most bang for your buck and it is that simple.

Still. Lots of folks here are in love with very high priced AGM's and such and sing their praises.. I tried 'em. Never again.,

[DryCamper11]

sgt77 wrote:
I often read that 6v is better than 12v, but like most things it seems to be very subjective.

I wouldn't say it's "subjective." A battery is a battery and a 12 volt battery is nothing more than two 6 volts in a single case. However, weight and design do vary, and the market for 6 volts is different than the market for 12 volt, so far more 6 volt batteries are suitable for RV battery banks than 12 volts. That doesn't mean anything. It's only necessary that you choose a battery to meet your needs. I believe that weight and cost considerations make 6 volts more suitable for my use, but others have different needs.

[down_home]

I'm too lazy to do the math or look it up but 6 volt deep cycle like the Trojan T105s are built with heavier plates etc and higher capacities generally.

[mena661]

BFL13 wrote:
J You could use that DC DC converter to make 12v from three 8s, but no idea how to recharge the three 8s.

On the cheap? Use a 24V converter. IOTA and Powermax make some. Powermax also has a 48V converter.

[sgt77]

smkettner wrote:
The debate has been long and often.
Are there specific concerns you have with the change?

Not really specific concerns. I often read that 6v is better than 12v, but like most things it seems to be very subjective.

[RJsfishin]

I ran 12v for many years, back when we never had smart converters, and never seen over 13.8 volts, back when we never knew what the importance was of fully charging the batteries, and back when the batteries got boiled dry every summer.
They lasted 3 yrs if we were really lucky.

Then I run 6v for many yrs, on a smart converter w/ equalization etc etc.Batteries lasted much longer, like 9 yrs,
Now I am back to 12v batts in my current RV, w/ charge wizard etc etc.
I'd bet these 12v will last much longer than the ones in yesteryears, we'll see.
But performance wise, AHs are AHs, I never noticed any difference in performance tween 6v or 12v. For me, its AHs per $s !

[MEXICOWANDERER]

They would go with 600 volt batteries if they thought they could get away with it. 16 gauge wiring throughout the car. A motor that uses a quarter of the copper at a quarter of the weight.

Factor this in...

Eight volt batteries are far less likely to be "borrowed" or "misappropriated". Take a gigantic golf course with several dozens of cars. Employees know golf car batteries enjoy a large market. Good batteries are likely to grow legs and walk off. Golf pros told me stories years ago about customers who came huffing and puffing into the clubhouse complaining that their cart would not go. By the time someone went out with a rope to get it, they found the seat tipped up and the batteries gone.

In sub zero F weather, I coupled a monster 8 volt battery to 3 7-D six volt jumper batteries. 2/0 jumper cables. When I hit the solenoid button (Diesel) those 855 cummins, and 3406 24-volt engines used to quiver and shimmy as they cranked. Can't do that now with onboard electronics.

[jauguston]

13,

48v is what they were forced to go to. The 3-T1275 idea was a supposedly cheap way to lower cost because they could use the same speed controlled. Didn't work. At least now they only have to put in 4 batteries not 6.

[2oldman]

BFL13 wrote:
but no idea how to recharge the three 8s.

I also have a 24v charger.

[BFL13]

Jim, these came from 48v golf cars--four T-1275s each. I got two used ones of a set of four where the new buyer of the used golf car requested all new batts.

They also have ones that are 48v but use six 8v batts. ISTR they were trending to the 8v batt way of doing it so not as many used T-1275s at that place as before, but still some.

Can't see how we could use 8v batts except as a 24 or 48 as discussed in the other thread on that. You could use that DC DC converter to make 12v from three 8s, but no idea how to recharge the three 8s. When doing it with four 6s or two 12s you can recharge half at a time with a 12v charger.

[jauguston]

13,

Trojan built those T1275's for the golf cart market that wanted a cheaper way to power the typical 36v golf cart. They are built similar to the T105 but smaller cells. They ended up to be a disaster for the golf cart market. The majority of the golf cart sales are to golf courses and the 3-T1275's would not make a full day of cart rental if they were busy and their course was hilly. They are good batteries just not enough capacity for that application. Golf course management was not happy having to tow carts in with unhappy golfers(-:

I'm using 6-6v Full River AGM's for house batteries and so far I like them.

Jim

[DryCamper11]

BFL13 wrote:
where you can get 6s for under $100, then 6s win on cost by a bunch.

Yes, but it's so hard to compare battery life between Sam's Club etc. 6 volts, vs. Trojan sixes. You won't go wrong with Trojans. It's harder to be sure with other brands. I've noticed that people who buy Trojans, usually know what they are doing, which means they treat the batteries right. That's the critical requirement for long battery life.

I eventually went with SC, which were roughly half the price of Trojans, figuring that if I screwed up, the cost of that failure was less, and if I didn't, they only had to last a bit over half the life to make the cost the same.

[BFL13]

I have been trying out a pair of 12v deep cycle batts , treating them like a pair of 6s in application. I like them (T-1275) very much, but they do weigh 82 lbs each instead of 67 lbs for a 6.

Cost per AH of the T-1275s is about the same as 6s where the 6s cost $150 each, but where you can get 6s for under $100, then 6s win on cost by a bunch.

[Sandia_Man]

Noticeable advantages of 6 volt golfcart batteries come in to play mostly when camping off the grid as they tend to take being drained down farther without reducing their overall longevity as much as their 12 volt counterparts. Not much advantage when camping with hook-ups, amphours are amphours and gaining the highest amount for the space available is more critical overall. It isn't just the brand or type of battery one chooses to use, of more importance is how well they will be maintained and recharged. The best battery can be killed just as quickly as a cheap battery when wiring, watering, and charging are not performed properly. We currently have a set of 4 year old Interstate 6 volt GC2 batteries from Samsclub that are holding up very well, along with monthly maintenance our onboard Iota IQ4 converter keeps them happily charged.