6V GC batteries for 2016 FC23D

[Atsushi]

I measured the size of the battery bank of our 2016 FC23D, and it is roughly 12" x 15" x 12" (depth).

So it appears that I can put two 6V batteries, like these:

http://www.trojanbattery.com/pdf/dat...ata_Sheets.pdf

http://www.trojanbattery.com/pdf/T10...t_DS_Final.pdf

http://www.trojanbattery.com/pdf/dat...ata_Sheets.pdf

Has anyone had a success story with these batteries?

Atsushi

[Atsushi]

https://www.dropbox.com/s/opd9je0j1p...rsion.jpg?dl=0

I'm wondering if this is how to convert 2 12V battery system (parallel) to 2 6V battery system (serial).
Is my understanding correct?
Thanks!

Atsushi

[Atsushi]

I think I figured out how to post an image.
Is this a correct way to run wires for 6V set up?

[uncle_bob]

Hi

Why do this? At best you are getting a 10% boost in capacity compared to other options.

Of the bunch, the Trojan T-105's are the only ones worth bothering with. You want to be sure you have their brand name and model. A "Uncle Bob" T-105 is not the same thing ... The AGM's give you no advantage over 12V AGM's from several other outfits.

Bob

[rmkrum]

As an engineer, I find that 6-volt batteries in series are more predictable in charge and discharge behavior than paralleled 12 volt batteries.

Nasty thing happen when one cell in a set of parallel batteries fails--the other battery tries to pull up the dead cell, dumps tons of current into it, and fries both batteries...not a pretty scene. Things get hot, cells spew acid vapor, and you get a hazardous situation in a hurry...

Yes, series batteries have their issues, but the failures tend to be self-limiting--a dead cell just drops the voltage of the set, and may not draw excess current from anything but the battery charger.

I have a slightly larger battery box with two CG-2 batteries in series, and monitor the voltage at the center point of the string to see if anything untoward is going on...except for the crappy OEM battery charger (its going away soon) this works fine for my needs, and the solar keeps them charged in storage...

[dmbecke]

6 V batteries are usually too tall for the box
I put two group 31 batteries in and got similar amp hrs as the 6 v

[uncle_bob]

Originally Posted by rmkrum

As an engineer, I find that 6-volt batteries in series are more predictable in charge and discharge behavior than paralleled 12 volt batteries.

Nasty thing happen when one cell in a set of parallel batteries fails--the other battery tries to pull up the dead cell, dumps tons of current into it, and fries both batteries...not a pretty scene. Things get hot, cells spew acid vapor, and you get a hazardous situation in a hurry...

Yes, series batteries have their issues, but the failures tend to be self-limiting--a dead cell just drops the voltage of the set, and may not draw excess current from anything but the battery charger.

I have a slightly larger battery box with two CG-2 batteries in series, and monitor the voltage at the center point of the string to see if anything untoward is going on...except for the crappy OEM battery charger (its going away soon) this works fine for my needs, and the solar keeps them charged in storage...

Hi

A shorted cell will kill you if it's in a series connection or in a parallel setup. There's no magic there. In both cases the converter / charger will boil the battery with the short. If you catch it right away you *might* save the second 12V battery. You are unlikely to save the second 6V. In both cases the batteries will be replaced together so no big deal. The subtle issue is that charging is by far the most likely time to short a cell .

If you want to keep 6V in series properly equalized, you should do a balancer (just like on a lithium stack). With a 12V parallel you would do a current balance. Nobody ever does either one so again, not much of a difference.

My main point is that people seem to rush out and "go 6V" like it's some sort of magic answer. It's very much not a magic answer. It's a "maybe 10%" sort of thing at best. Battery capacity is also a "maybe 10%" sort of thing. Some will do 120% of ratings. Others struggle to get to 90% of what's on the label. There are other things that one could put the same effort (and money) into to get a 10% here or there.

No this is not the only area that people to wild pulling out batteries and re-configuring things. The guys with big boats make RV people look pretty tame in this regard. I've been through enough of those very major re-do's to have seen the results. Lots of effort for very modest gain is the normal outcome.

Bob

[TouringDan]

Originally Posted by Atsushi

I think I figured out how to post an image.
Is this a correct way to run wires for 6V set up?

Looks good to me. I say go for it. I am only one data point, but I installed 2 6v golf cart batteries 7 years ago and they are doing fine. We typically boondock and camp 3-4 days. The voltage typically never drops below 12.6 ,no load, after 3-4 days. We carry a 1,000 watt Honda but it is only an insurance policy in case something weird happens.

Dan