6 Volt VS 12 Volt

[dogpa]

Tried a search but no luck. 2022 Windsport 31c. House batteries dead and looking to replace. Any pros or cons of going double 6 volt or double 12 volt??

 

[ducksface]

The double 6volt thing is good for laboratory advantages you'll never see in an rv.

That's it in a nutshell.


Signed,
I have 12 six volt batteries here and did not install them due to anything and everything being a better choice.

 

[SDMiramar]

Double 6’s are only good if you do a lot of dry camping and need the Amp hours, otherwise it’s just old technology. If you stay with 12V, AGM is a good option vs lead acid but they are both heavy options. or bite the bullet and go lithium and never look back. Half the weight, can be drawn all the way down to a zero charge without damage and supply a constant 13+ V all the way to a complete discharge.

 

[dogpa]

Thanks for the advice. Good note about the dry camp issue.

 

[lwmcguire]

Comes down to maintenance issues, cost, space, need and your abilities.

There are advantages to all the three primary choices.

 

[Bob Nodine]

If I have two egg cartons, each with 6 eggs in them, then I have a dozen eggs.

If I have one egg carton with 12 eggs in it then I also have a dozen eggs.

Now if we start talking about large eggs versus regular sized eggs then things get a little fuzzy.

In the case of batteries it is about the amp hours.

If you have a 6 volt battery with 100 amp hours and you need 12 volts you must connect two in series. That gives you 12 volts but you still only have 100 amp hours.

If you have a 12 volt battery with 100 amp hours then you have the same as the two 6 volt batteries in series.

Folks often use two six volt batteries in series if they can fit a taller battery than the existing 12 volt because they can get more amp hours by using 6 volt batteries with a higher amp hour rating than a single 12 volt in the same space.

With the current cost of Lithium batteries I would not waste my time fooling with 6 volt golf cart batteries and just go Lithium.

With flooded and AGM batteries the voltage will drop to an unusable level once the batteries are drawn down to about 50 % of their amp hour rating. With Lithium batteries the voltage stays flat as you draw them down. What this boils down to is that 100 amp hours of flooded or AGM is only good for 50 amp hours but with Lithium you can use almost all of the 100 amp hours before you must charge them. So with Lithium you get twice the power for the same space as the flooded or AGM and that is also at less weight than lead batteries.

 

[RACarvalho-FRF]

Tried a search but no luck. 2022 Windsport 31c. House batteries dead and looking to replace. Any pros or cons of going double 6 volt or double 12 volt??

Technical arguments are good but nothing beat reality and real use data.

There are 100s of thousands of golf carts in this country that use 6V FLA batteries and most of them see hard use and abuse and yet, 6V FLA is what they use....


Early this year I installed 2 x Duracell Ultra SLIGC145UT 6V batteries in place of 3 x VMAXtank XTR27 that got worthless after 2 years....

So far the 6V batteries are holding good.

The reason I did that is:
1 - The way Thor have the system designed favors FLA
2 - GC 6V batteries are build for abuse, with additional space above and below the lead plates for additional liquid, sulfation residue, etc.
3 - As my expensive experience with AGMs demonstrated, AGMs can't handle abuse very well...
4 - I can't use lithium w/o an open heart surgery in my MH electrical system for we do use the MH in freezing temps so I would have to relocate the batteries and all cabling connected to them (jacks, inverter, etc) to inside the MH so I decided I will only use lithium when I buy a MH which system was properly designed for it.

 

[Machinetools1]

I am in the same boat as you were with the lithium batteries. We do a lot of boondocking. I currently have 400 watts of solar on top of the motorhome with 3 27 series deep cycle led batteries. I would put more batteries but made just enough room for the 3rd battery.

In the summer months it seems to work o.k. but in the winter months with less sun it struggles to keep electrical power to run the heating fan at night. Even after we run the generator a few hours to recharge the batteries.

Could I run 3 6 volt batteries and be better then the 3 12 volt 27 series.

Not sure what direction to go.

 

[16ACE27]

I am in the same boat as you were with the lithium batteries. We do a lot of boondocking. I currently have 400 watts of solar on top of the motorhome with 3 27 series deep cycle led batteries. I would put more batteries but made just enough room for the 3rd battery.

In the summer months it seems to work o.k. but in the winter months with less sun it struggles to keep electrical power to run the heating fan at night. Even after we run the generator a few hours to recharge the batteries.

Could I run 3 6 volt batteries and be better then the 3 12 volt 27 series.

Not sure what direction to go.

How would you get 12 VDC out of three 6 volt batteries?

If you do a lot of boondocking and already have a lithium compatible solar charger, then at this point is time (actually, Thanksgiving through Christmas) you would be unwise to throw money at more lead acid batteries instead of LiFePO4 (LFP) batteries.

Prices have been as low as $100 for a 100 AH LFP battery.

There are plenty of other threads on this Forum that discuss LFP conversions. You could probably fit 400 or more usable AHs of LFP batteries in the same space as you would only get 150 usable AHs with lead-acid batteries.

 

[Machinetools1]

Thanks for the reply....I figured it would not work but I did not know if it could have been done somehow.

My solar charger is lithium compatible I believe. I have too check to make sure.

Would I have to change the BMI or any wiring or inverter?

 

[16ACE27]

Thanks for the reply....I figured it would not work but I did not know if it could have been done somehow.

My solar charger is lithium compatible I believe. I have too check to make sure.

Would I have to change the BMI or any wiring or inverter?

Inverter? No

Or did you mean converter? Again, no you don't HAVE to change it.

By BMI I assume you mean BIM? Replacing a standard BIM with a Li-BIM is a good idea, but not required. You may want to install a switch to disable the standard BIM to help prevent alternator overheating if the LFP batteries are low.

 

[Machinetools1]

Thanks for the reply...yes I meant BIM. This i am going to look into. It might be a viable option

 

[PS89]

I am in the same boat as you were with the lithium batteries. We do a lot of boondocking. I currently have 400 watts of solar on top of the motorhome with 3 27 series deep cycle led batteries. I would put more batteries but made just enough room for the 3rd battery.

In the summer months it seems to work o.k. but in the winter months with less sun it struggles to keep electrical power to run the heating fan at night. Even after we run the generator a few hours to recharge the batteries.

Could I run 3 6 volt batteries and be better then the 3 12 volt 27 series.

Not sure what direction to go.

If you want to explore a journey into lithium in a 29M, you can follow what I did at https://www.thorforums.com/forums/f27/large-case-lifepo4-into-29m-38172.html


Just ignore all the side detours from the peanut gallery...

 

[Mark54]

It's not about amps. It's WATTS your looking for. Volts x Amps = Watts. Convert everything to watts, and it is a lot easier to understand what you can get away with.

You can get a few more amps/watts out of two 6V batteries, but not enough to justify the space and weight they use, imo.
I used GC6 batteries once, and decided that 12V were easier to get and weighed less than the GC6 ones. You also need an even number of 6V batteries to make 12V.

12V for me, and lithium at that. less weight, more watts.

Good article here- except I argue against the size and weight aspect. I found GC6's about same weight, if not heavier, than a G27 Lead-acid, and taller, not smaller.

https://thecampingnerd.com/6-volt-vs-12-volt-rv-batteries/

 

[ducksface]

There is a reason almost all old golf carts and some dinosaur new golf carts use six volt batteries.
The reason does not interpret well into rv language.

I'd suggest looking into modern alternatives instead of adapting old techniques.
If an of you can find a reason to use six volt other than they did power cars pre-1958...please Post the researched reason here.

Typewriters will still write a letter.
Six volt batteries will still power an rv.
Lead acid will still power an rv.
Horses can still pull a Conestoga wagon.

 

[Chateau_Nomad]

There is a reason almost all old golf carts and some dinosaur new golf carts use six volt batteries.
The reason does not interpret well into rv language.

I'd suggest looking into modern alternatives instead of adapting old techniques.
If an of you can find a reason to use six volt other than they did power cars pre-1958...please Post the researched reason here.

Typewriters will still write a letter.
Six volt batteries will still power an rv.
Lead acid will still power an rv.
Horses can still pull a Conestoga wagon.

New technologies usually begin as very expensive conveniences. The DVD player replaced the VCR. Along came MP4 to (sort of) replace all that hardware. Then there's the LED TV revolution. Add lead-acid batteries to that analogy... LiPO4 started as an expensive curiosity, but have now become mainstream with prices dropping just like the previous mentioned tech.

LiPO4 chemistry batteries have finally superceded lead-acid, both in function and price. I have a feeling we haven't seen the end of battery chemistry evolution.

In the 1960s the transistor started the micro-electronics revolution. In a very short timespan, other than nostalgia, there's was no logical reason to use tubes in power supplies... and now there's no logical reason to use lead-acid for storage batteries.

 

[Machinetools1]

Thanks for all the information it's very much appreciated.

When I purchased the motorhome it came with 2 group 27 batteries. They did not last long at all. I made provisions for 3 group 31 batteries and that has worked well but are bad now and in need of 3 more.

One of my issues I seem to have is not being able to manage the depth of a charge. Meaning....the touch panel indicates the batteries are charged 13.5 volts also with a volt meter measuring off the batteries.

How can you visually see how charged the batteries are (full capacity) . I understand a fully charged battery is 12.65 volts but how can you determine it is at full capacity. I hope I am making sense to someone?

Also a battery should not be discharged below 50% of capacity. If 12 65 volts is fully charged how many volts would be at 50%?

I was always instructed to never run a battery lower than 11 volts. How do you measure the 50% left in a battery.

 

[Chateau_Nomad]

Thanks for all the information it's very much appreciated.

When I purchased the motorhome it came with 2 group 27 batteries. They did not last long at all. I made provisions for 3 group 31 batteries and that has worked well but are bad now and in need of 3 more.

One of my issues I seem to have is not being able to manage the depth of a charge. Meaning....the touch panel indicates the batteries are charged 13.5 volts also with a volt meter measuring off the batteries.

How can you visually see how charged the batteries are (full capacity) . I understand a fully charged battery is 12.65 volts but how can you determine it is at full capacity. I hope I am making sense to someone?

Also a battery should not be discharged below 50% of capacity. If 12 65 volts is fully charged how many volts would be at 50%?

I was always instructed to never run a battery lower than 11 volts. How do you measure the 50% left in a battery.

There's many charts on the Internet. Also install a $40 shunt with remote display. You "tell" the shunt when the battery is full. Then you tell it what 50% is... which is your safe empty point. The display will then show state of charge as a percent.

 

[16ACE27]

Thanks for all the information it's very much appreciated.

When I purchased the motorhome it came with 2 group 27 batteries. They did not last long at all. I made provisions for 3 group 31 batteries and that has worked well but are bad now and in need of 3 more.

One of my issues I seem to have is not being able to manage the depth of a charge. Meaning....the touch panel indicates the batteries are charged 13.5 volts also with a volt meter measuring off the batteries.

How can you visually see how charged the batteries are (full capacity) . I understand a fully charged battery is 12.65 volts but how can you determine it is at full capacity. I hope I am making sense to someone?

Also a battery should not be discharged below 50% of capacity. If 12 65 volts is fully charged how many volts would be at 50%?

I was always instructed to never run a battery lower than 11 volts. How do you measure the 50% left in a battery.

I second CN's advice above.

13.5 volts is a CHARGING voltage, not a resting CHARGED TO voltage. 12.65 volts is a fully charged Lead-Acid battery at rest with no left over surfac charge.

The shunt-based battery capacity meter is the only way to truly see what's in the tank at any time.

 

[Beau388]

Technical arguments are good but nothing beat reality and real use data.

There are 100s of thousands of golf carts in this country that use 6V FLA batteries and most of them see hard use and abuse and yet, 6V FLA is what they use.... [snip]
.

Well the used to be -- now days the golf carts are 48 volt or 51 volt If a cart of the 48 volt variety, they use 6 GC-8 FLA or AGM batteries. If they are 51 volt variety, they use a 100 A-h modular LFP battery. The bigger carts come with two modular batteries. The GC-2 6 volt batteries are used in the cheaper 36 volt golf carts manufactured before 2012 As the CG-8 cost only 10% more than the GC-6, you will not find the GC-6 in a modern golf cart. GC-2 and GC-8 weight the same - 61 lbs for the cheep ones and 78 lbs for the expensive ones (Trojan).

All GC batteries are deep cycle which means the can be rapidly discharged to 12.06 volts repeatedly without damage. A 2004 EZ-GO TXT (1996-2006) has a 350 amp controller.