Dual 6V Batteries.....

I went dual golf cart batteries after researching my options.

The difference with a 12v x2 setup is that any 12v group 24 or 27 is not a true deep cycle battery.  The plates are thinner, so they can only take a fraction of the cycles.  Unless you use group 27s, they're lower in AH than golf cart batteries.

While it's possible you can buy a large enough 12v true deep cycle battery, they are not common and can weigh over 100 lbs, and they are expensive.  Golf cart batteries are basically an exact half of a 12v battery, so you have two halves that are easy to move and cost much less because they are so common.  Batteries plus sells them for $99 each or less, with a 10% off online pickup purchase.  No need to buy Trojans, either.  Their suble difference in quality doesnt justify their >30% cost difference.

The zamp works great, and the built in converter charges them OK.  You can increase your battery's life by using a smart charger such as a CTEK to top them off from time to time.

Can use 2 6 volt in series or 2 12 volts in parallel.  I have 2 12v in parallel and have had good luck with charging (hook up + on 1 battery and negative  on other battery)

Dual 6 volt batteries can give you more AH but at the cost of a larger size and weight.  

wizard1880 said:

I went dual golf cart batteries after researching my options.

The difference with a 12v x2 setup is that any 12v group 24 or 27 is not a true deep cycle battery.  The plates are thinner, so they can only take a fraction of the cycles.  Unless you use group 27s, they're lower in AH than golf cart batteries.

While it's possible you can buy a large enough 12v true deep cycle battery, they are not common and can weigh over 100 lbs, and they are expensive.  Golf cart batteries are basically an exact half of a 12v battery, so you have two halves that are easy to move and cost much less because they are so common.  Batteries plus sells them for $99 each or less, with a 10% off online pickup purchase.  No need to buy Trojans, either.  Their suble difference in quality doesnt justify their >30% cost difference.

From what I have read, day to day performance between Trojan and other batteries is not a huge difference, but other RV owners seem to indicate longevity on Trojans is better.

wizard1880 said:

The zamp works great, and the built in converter charges them OK.  You can increase your battery's life by using a smart charger such as a CTEK to top them off from time to time.

You aren't using the inside converter to charge if you use a solar panel, you are using the solar controller. I would recommend looking into an MPPT controller.

Always find it amazing how many threads there are on batteries - Would think the definitive answer is somewhere :-)

And opinions :-)

Hey, 2+2=3 for crying out loud. Get you facts straight :-)

JustJohn said:

JD, I went with a single AGM 12v battery. It has a 155 ah rating and weighs 95lbs. It also fit the tub of my Outback without the need for any modification. The standard charging system handles it with no issues and I have camped for 11 days straight using a 100w suitcase panel without a problem. 

Oiy!! Now that's a workout. Lifting 95 lbs up and over the Outback Tub lip!!!

Just John..........which AGM 12v battery did you go with?   And you are saying it fits in the same case as the batteries that normally come with a T@B?

SAM said:

Thanks for that info JustJohn.  That is the setup that we plan to use.  I thought I may need to add another 50 - 60 watt panel, but your 11 day results are encouraging!  What charge controller are you using?

Sam, I installed a MPPT  type controller sized so I could add another 100w panel if necessary. So far I have not needed the second panel.T@Balong said:

Just John..........which AGM 12v battery did you go with?   And you are saying it fits in the same case as the batteries that normally come with a T@B?

I had to buy a larger battery box ($15.00 at a local auto store) but it fit in the same space as the original battery and I used the same tie down as the original. The battery is a VMax https://www.vmaxtanks.com/XTR12-155-12Volts-155AH-Deep-Cycle-XTREME-AGM-Battery_p_154.html, link may not work but has the info needed to google. 

That's also the same brand of controller that was in our T@B's replacement, a 2015 Roadtrek on a short Sprinter chassis. It seems to work quite well, charging (at least to a degree) even before the sun actually rises. As soon as the sky gets light, it starts showing a "charging" status.

Stupid question alert:  How does one wire 2 6V batteries together?  Can anyone post a pic?  

gooselady - If you search on "6V" or "batteries", there's a bunch of threads with pics.

SAM said:

 we went with their 30 amp PWM Wanderer.  I knew if this set up did not work out, I can change to a MPPT. 

MPPT controllers are a Technology that is able to help capture the excess voltage at a panels Maximum Power Point.  This MPP only occurs under near perfect conditions including low temperatures, ideal alignment and crystal clear atmosphere.  Think Denver on a blue winter day at noon.  A condition that rarely exists with our small portable systems.   The technology can not and will not capture any additional energy in less than optimum conditions and is actually less efficient than a standard PWM controller under most conditions.
Spending those funds on additional panel wattage will always produce more energy.

 I just bought a 60w folding panel to supplement the 136w Unisolar panels on my roof for those times when the conditions aren't keeping up with power consumption.   The Unisolars have had me covered in all of our travels for 5 years.  The extra 60w will let me do something to help during those moments when I find myself watching the meters closely as we test our storage capacity.



Have fun!!!

For 6 volt golf cart batteries, many folks go for Trojans.  Personally, I went to batteries plus and got their Duracell branded batteries for about 60% less cost than Trojans, and they're made by East Penn, a close competitor of Trojans.  Under $200 for 230Ah of capacity.