6v or 12v?

[Freep]

All else being equal, which is preferable and why?

2 220 AH 6v batteries
or
2 110 AH 12v batteries

[Freep]

Freep wrote:

pnichols wrote:

I reviewed the brochure for that propane fuel cell and it looks like it might have great potential for use in an RV.

According to it's specs, it'll even run about 4 hours on one of those little green 1 lb. disposable propane bottles!!

Note that it runs at only a 40 db sound level. That's 13 db less than an idling Honda EU2000i portable inverter generator ... hence for all practical purposes it is "silent".

I wrote them to see if I could get a price and also mentioned that the RV market is starved for a product like this. Depending on the price points and manufacturing costs, they could sell these things like hotcakes.... if there are no major issues. Apparently they were DARPA funded and the portable model is intended to be used by soldiers to cut down on the battery weight they currently have to carry.

I got a response from my email inquiry. 16K for the fuel cell.

Yikes!

Hopefully over time we will see prices go down to a more affordable level.

[Chris_Bryant]

I worked on a rig with 6 2 volt batteries-



I forget the ah rating of those- I'm thinking it is in the 5-600 range.

[brholt]

Freep wrote:

adamis wrote:
Additionally though, I would really like to see a fuel cell system to replace the nearly unused generator. A propane powered fuel cell would dramatically increase efficiency

I'd pay a pretty penny for a fuel cell to replace the generator.

I wonder what they charge for this fuel cell.

Ethanol based but at least one forum member uses it and is very happy with it.

Ethanol Fuel cell for rv's/ marine

One truck camper installation:

Efoy Fuel Cell in Truck camper

[Freep]

pnichols wrote:

I reviewed the brochure for that propane fuel cell and it looks like it might have great potential for use in an RV.

According to it's specs, it'll even run about 4 hours on one of those little green 1 lb. disposable propane bottles!!

Note that it runs at only a 40 db sound level. That's 13 db less than an idling Honda EU2000i portable inverter generator ... hence for all practical purposes it is "silent".

I wrote them to see if I could get a price and also mentioned that the RV market is starved for a product like this. Depending on the price points and manufacturing costs, they could sell these things like hotcakes.... if there are no major issues. Apparently they were DARPA funded and the portable model is intended to be used by soldiers to cut down on the battery weight they currently have to carry.

[pnichols]

Freep wrote:
I'd pay a pretty penny for a fuel cell to replace the generator.

I wonder what they charge for this fuel cell.

I reviewed the brochure for that propane fuel cell and it looks like it might have great potential for use in an RV.

According to it's specs, it'll even run about 4 hours on one of those little green 1 lb. disposable propane bottles!!

Note that it runs at only a 40 db sound level. That's 13 db less than an idling Honda EU2000i portable inverter generator ... hence for all practical purposes it is "silent".

[pianotuna]

Give where you live that is a great decision.

It boils down to what suits your camping style. My general advice is use what ever voltage will allow for the greatest amp-hour capacity.

Photomike wrote:
I went with 4 - 6V on my current RV and so far not an issue but also most of the time lately I have been plugged in so cannot say it is a fair test. I did so for those cold winter nights that I want to run the furnace and not worry about the power as what I have should do a night with lots left over.

Reason for 4 is so I have a redundant battery or two.

[Photomike]

I went with 4 - 6V on my current RV and so far not an issue but also most of the time lately I have been plugged in so cannot say it is a fair test. I did so for those cold winter nights that I want to run the furnace and not worry about the power as what I have should do a night with lots left over.

Reason for 4 is so I have a redundant battery or two.

[Freep]

adamis wrote:
Additionally though, I would really like to see a fuel cell system to replace the nearly unused generator. A propane powered fuel cell would dramatically increase efficiency

I'd pay a pretty penny for a fuel cell to replace the generator.

I wonder what they charge for this fuel cell.

[Freep]

time2roll wrote:

Freep wrote:
I don't how the battery is charged now when the gen is running or when I'm plugged in. I do remember seeing some device in the basement wired between the gen and something. I'll have to check that out.

Post the converter model number for best suggestions.

OK the box in the basement connected to the Onan gen is a Progressive Dynamics 5100 series Automatic transfer relay.

I opened up the step to the bed to see if there is a charger in there and I see a Blue Sea systems battery link automatic charging relay with aux battery priority #7611.

[Kayteg1]

pnichols wrote:
It's espeically a shame that motorized RV manufacturers don't install their expensive built-in generators such that they are more quiet and vibration-free to use ... which does not take rocket science engineering or money to do.

Don't blame manufacturers.
My 2001 Fleetwood has Generac inverter generator. Very quiet and way more fuel-efficient than high-rpm models of the same size.
From what I could read it was $4500 option at the time, so not too many sales.
Now even better options are available, but I don't see TC owners standing in lines at service office with 5 grands in their hand.

[pianotuna]

Hi Freep,

If the inverter is large enough the lifelines will do short runs--just don't try to cook a roast.

Freep wrote:
PianoTuna, thanks for the detailed explanation. This makes me wonder if I would even be able to run a microwave for a few minutes with 2 fully charged Lifeline gpl-31xt 12v batteries.

I really wish the LiFePo batteries were more mature(and cheaper). The reason I settled on AGM is that by the time the AGMs need to be replaced, the LiFePo batteries should be a lot cheaper and easier and also have some built in protection from trying to charge when they are too cold.

[pnichols]

adamis wrote:
Additionally though, I would really like to see a fuel cell system to replace the nearly unused generator. A propane powered fuel cell would dramatically increase efficiency

Right on -> about an automatic-top-up propane powered fuel cell system being the ultimate battery bank maintainer ... rain or shine, day or night. This is even a great solution with current liquid or AGM lead acid battery technology.

However inefficient, or otherwise undesirable, generator power may be ... it's power is priceless in curtain situations. Beyond the obvious air conditioning for pets and overall comfort, a generator can also fill in to suppy emergency electrical heat if other propane heating systems should ever fail in cold weather.

Some of us refuse to own an RV that is limited to mostly sunny days, cool-enough air temperatures at low altitudes, or high-enough altitudes. It's especially a shame that motorized RV manufacturers don't install their expensive built-in generators such that they are more quiet and vibration-free to use ... which does not take rocket science engineering or money to do.

[Freep]

PianoTuna, thanks for the detailed explanation. This makes me wonder if I would even be able to run a microwave for a few minutes with 2 fully charged Lifeline gpl-31xt 12v batteries.

I really wish the LiFePo batteries were more mature(and cheaper). The reason I settled on AGM is that by the time the AGMs need to be replaced, the LiFePo batteries should be a lot cheaper and easier and also have some built in protection from trying to charge when they are too cold.

[adamis]

It would appear that 12v versus 6v could be as contentious as Diesel versus Gas or Ford versus Chevy (or that other brand...).

I'm also looking at the LiFePo batteries but with the new Giga-factories coming online in the next couple of years I think it's too early to buy unless money just isn't a problem.

Additionally though, I would really like to see a fuel cell system to replace the nearly unused generator. A propane powered fuel cell would dramatically increase efficiency and coupled with a decent sized LiFePo battery with inverter will cover most of your needs quite nicely. I hope that the industry will shift there though I expect it will be another 5 to 10 years before it becomes common enough. The only thing this setup likely could not handle is the AC but honestly it's not very efficient to run the AC on the generator anyway.

[pnichols]

pianotuna wrote:
Since the current for twin six volts is going to be double that of twelve volt jars in parallel, there is MORE chance of plates warping from high loads.

Related to that ... I've often read the "6 volt golf cart (i.e. deep cycle) batteries have thicker plates so they last longer than 12 volt batteries" argument thrown up countless times in the forums. The implication is that this is true even if the 12 volt batteries being compared are of true deep cycle design.

Well, 6 volt GC/deep cycle batteries better have thicker plates than 12 volt deep cycle battery plates because the plates in each 6 volt battery in a series bank are carrying twice the current as the plates in each 12 volt battery in an equivalent capacity parallel bank.

Hence, I expect that equal quality and equally maintained 6 volt deep cycle versus 12 volt deep cycle batteries would have about the same lifespan - so much as lifespan depends upon the thickness of the battery plates.