Two 6 volt batteries or two 12 volt batteries ??

And if you get rear ended at a stop light, you're in trouble.

I bet the latter is more likely to happen than a 6V die unexpectedly.

FrankShore wrote:
One 6v goes out and you're in trouble.

I had the single OEM battery config grp 24. Upgraded to grp 31. Added 2 GC2 golf cart batteries that had to be set on the ground with cables run to the single.

Re-engineered the entire setup.
3 true deep cycle grp 31 AGM batteries (East Penn/Dekka) with 2/0 welding cable, able to mount the extra 2 batteries in a compartment since there is no outgsssing.

Original setup....pros- inexpensive batteries, can be found anywhere.
Cons - out gassing, slow rate of charge, always needed water, high self discharge, one dies both worthless, corrosion on terminals, must be in pairs, voltage drop when using 2000 psw inverter at 1300 watts.

New setup....
Cons- more expensive, only sams club has them in stock.
Pros- no outgassing, higher rate of charge/ less gen time with decent converter, never need water, one dies just remove it, no corrosion, lower self discharge, less voltage drop when pulling high amps with inverter, vibration resistant, mount it anywhere, add them in ones.

If you can afford double the price of GC2 then all the pros outweigh the cons imho. Plus you can go odd number of batteries or whatever suits your needs, not just pairs.

Go with 4 6V GC-2's

No room..

Oh I did do the voltages here with a test..( last year) This was with the eco worthy controller. The eco read the most accurate voltage with a .1 volt off due to volt drop.

Started with about 13 volts, ended at 12.6 .

That was making a pot of coffee and a pizza in toaster oven. Both appliances were about 900-1000 watts.

Last draw voltage was showing 11.9-12 volt

( DO the 6 Volters do this?????)

It was two batts and not the added third truck camper batt. I always have the truck battery as shown as a third and truck plugged in.

I upgraded the wire to fuse box to #6 or #8 from truck battery ( Cant remember) I want to upgrade back to 7 pin too but a lot of work.

Its a bit crappy video as I mumble through it.. Its kind of Mundane...

https://www.youtube.com/watch?v=w8DE0lGCkFk&t=228s

crosscheck wrote:

ktmrfs wrote:

wowens79 wrote:
I asked this same question back in the summer. We don't boondock, but we do have a residential fridge. I got a similar reply, and I read a bunch of threads.

In the end I went with 2 6 volt GC2's from Sams Club. They were about the same price as the RV/Marine batteries. I really think for my use, it really probably doesn't make much of a difference, I went 6v just to see how well it worked, and figured with price being the same, I didn't have much to lose, but there did seem to be alot of people talking about getting longer life from the 6v.

Unless you boondock just pick one and go camping and enjoy!

even a residential fridge probably isn't an issue with GC. It's when you get above a 30-50A draw that the GC start showing the limitiations due to internal resistance. I have a dorm fridge I run in one trailer on a pair of GC. the GC handle in short inrush no problem and the actual draw is way less then the nameplate. I see 8A or so as the continous draw.

It's microwaves, toasters, coffee pots, tea kettles, that can be frustrating with GC batteries. Things that are drawing 80-100A

Go with 4 6V GC-2's and as long as you keep them charged up, high drawing appliances like micros, toasters, hair dryers are no problem(for a reasonable run time) when dry /boondock camping. It's the only way to go.

Dave

that's what I did, and yes it works, BUT first you need to have room for them, second you need to be able to handle the added tongue weight if they are on the tongue, and finally it gets spendy. Now if you boondock a lot for long periods like we do, it's a great solution.

Not sure I'd say it is the only way to go, IMHO If you don't boondock often, then a pair of good 12V will do just fine if you have high loads from an inverter.

ktmrfs wrote:

wowens79 wrote:
I asked this same question back in the summer. We don't boondock, but we do have a residential fridge. I got a similar reply, and I read a bunch of threads.

In the end I went with 2 6 volt GC2's from Sams Club. They were about the same price as the RV/Marine batteries. I really think for my use, it really probably doesn't make much of a difference, I went 6v just to see how well it worked, and figured with price being the same, I didn't have much to lose, but there did seem to be alot of people talking about getting longer life from the 6v.

Unless you boondock just pick one and go camping and enjoy!

even a residential fridge probably isn't an issue with GC. It's when you get above a 30-50A draw that the GC start showing the limitiations due to internal resistance. I have a dorm fridge I run in one trailer on a pair of GC. the GC handle in short inrush no problem and the actual draw is way less then the nameplate. I see 8A or so as the continous draw.

It's microwaves, toasters, coffee pots, tea kettles, that can be frustrating with GC batteries. Things that are drawing 80-100A

Go with 4 6V GC-2's and as long as you keep them charged up, high drawing appliances like micros, toasters, hair dryers are no problem(for a reasonable run time) when dry /boondock camping. It's the only way to go.

Dave

ktmrfs wrote:
.. microwaves, toasters, coffee pots, tea kettles, that can be frustrating with GC batteries. Things that are drawing 80-100A

and that can heat things up like cranking a car for 30 seconds.

wowens79 wrote:
I asked this same question back in the summer. We don't boondock, but we do have a residential fridge. I got a similar reply, and I read a bunch of threads.

In the end I went with 2 6 volt GC2's from Sams Club. They were about the same price as the RV/Marine batteries. I really think for my use, it really probably doesn't make much of a difference, I went 6v just to see how well it worked, and figured with price being the same, I didn't have much to lose, but there did seem to be alot of people talking about getting longer life from the 6v.

Unless you boondock just pick one and go camping and enjoy!

even a residential fridge probably isn't an issue with GC. It's when you get above a 30-50A draw that the GC start showing the limitiations due to internal resistance. I have a dorm fridge I run in one trailer on a pair of GC. the GC handle in short inrush no problem and the actual draw is way less then the nameplate. I see 8A or so as the continous draw.

It's microwaves, toasters, coffee pots, tea kettles, that can be frustrating with GC batteries. Things that are drawing 80-100A

lawrosa wrote:
Well I hope this all helps the OP anyway...

I mean I knew about internal resistance but I didnt think 6 volts would take a huge volt drop @ 75- 80% SOC.

I looked for info on the web regarding this and cannot find much , if any, real world data..

Ill have to test this and document the drop of my 12's @ different SOC this summer.

I cant really source anything bigger then awg 2 gauge without spending a small fortune..

It isn't that GC take huge drop at 80% SOC, it's that internal resistance is high to start with so you are always going to get more voltage drop than a single 12V with thin plates. so if the battery is fully charged, 13.2v and you get 1.5V drop, your ok, get down to 12.8V with a 1.5V drop and your below the inverter limit.

and with a 12V setup it's common to have two 12V in parallel. So first each battery sees 1/2 the current draw and lower internal resistance. both decrease the voltage drop.

lawrosa wrote:
I cant really source anything bigger then awg 2 gauge without spending a small fortune..

Yeah, cost is always an issue. With my current setup I have 6' of 4 gauge running from the inverter to the battery location on the tongue (12' in total for positive & negative) so my plan is to replace my aging G27 flooded with a G31 AGM, place it in the front pass through storage compartment near the inverter, and use pre-terminated 18" 1 gauge starter cables to connect to the inverter. That, combined with the fact the AGM has even less internal resistance than a similar flooded, should noticeably reduce voltage drop under heavy inverter load. Should SOC at any given time result in voltage drop that causes the inverter to alarm I can still always load support the G31 with my truck (running) as I've done before. Obviously 2 G31s would be better but the cost for the limited use I would put this to can't really be justified. I could also use even heavier gauge welding cable but in my case, for my intended use, I think the 1 gauge will suffice without breaking the bank. ;)

Well I hope this all helps the OP anyway...

I mean I knew about internal resistance but I didnt think 6 volts would take a huge volt drop @ 75- 80% SOC.

I looked for info on the web regarding this and cannot find much , if any, real world data..

Ill have to test this and document the drop of my 12's @ different SOC this summer.

I cant really source anything bigger then awg 2 gauge without spending a small fortune..