6v or 12v?

[Freep]

All else being equal, which is preferable and why?

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

[SidecarFlip]

12 volt for me because the original battery was 12 volt and I added another, the original was fine. When they poop out, a set of Battle Born Lithium's is in order (saving my allowance now for then.....)

[srschang]

I ordered the batteries from https://batteryguys.com/, price was comparable & free shipping. The inverter came from Amazon. I think I may have overdone the cable size between the batteries & inverter, I used 4/0 for the three foot run, probably could have used 2/0, but I know I'm good with the larger cables. Figuring out where to put the circuit breakers & how to run the cables was the tough part. Cables that big aren't real flexible.

Oh, and most importantly, my wife's hairdryer uses about 6ah at 50 amps to dry her hair in the morning. So to make 3 cups of coffee, some toast, and her drying her hair, we use 20-25ah each morning. The solar panels put out 10-15 amps during peak daylight, so they charge the batteries back up quickly. And since the batteries are a total of 250ah, using 20-25ah each day is no problem.

[Freep]

srschang wrote:

Wow, what a coincidence. I just installed 2 gpl-31xt 12v batteries in may camper a week ago. I also installed 4 100w solar panels & a Xantrex 2000w inverter. I just went out to the camper & ran the microwave for 3 minutes on the inverter. It used 4.6ah of juice at 85 amps in the 3 minutes. To put it in perspective, my single cup Keurig uses 125 amps for 45 seconds, then 70 amps for one minute to make one cup of coffee on the inverter.

Scott

Where did you get your batteries and inverter? Is there anything you would have done differently?

[srschang]

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.

Wow, what a coincidence. I just installed 2 gpl-31xt 12v batteries in may camper a week ago. I also installed 4 100w solar panels & a Xantrex 2000w inverter. I just went out to the camper & ran the microwave for 3 minutes on the inverter. It used 4.6ah of juice at 85 amps in the 3 minutes. To put it in perspective, my single cup Keurig uses 125 amps for 45 seconds, then 70 amps for one minute to make one cup of coffee on the inverter.

Scott

[pnichols]

Freep wrote:
....but I also have a gen and I hate using it because it's incredibly loud.

Right there is the problem - for those of us RV'ers with those (expensive) built-in generators that we won't use because they're too loud (and/or vibrate the coach too much): Manufacturers should not install them improperly so the generators wind up being so intrusive, and us buyers should not buy those RVs with unusable (and expensive) generators in them - speaking with our wallets at shopping time would change things fast.

We were blessed by a good Winnebago built-in install ... so it's generator is actually very useful. We wouldn't have bought our RV without it and knowing now what I know about what's possible .... would never buy another RV with a too-loud or too-shaky generator installation.

[Freep]

pianotuna wrote:
Freep,

For about 10% of the cost of the fuel cell you can have a solar charging platform and batteries that will give you more power.

One of the problems with fuel cells is that they require ultra pure fuel. That's fine if you are NASA and nothing else will work.

I have solar and I'm planning on expanding it, but I also have a gen and I hate using it because it's incredibly loud.

[GordonThree]

pnichols wrote:
Don,

Concerning ultra pure fuel for fuel cells ... is that true for propane fuel cells? If so, where are us RV'ers going to get ultra pure propane? (I suspect that part of the high price for propane fuel cells is a super filter/dryer for the incoming propane.)

P.S. Of course solar by itself is not as close to the ultimate solution for anywhere anytime power replenishment that a propane fuel cell is. I guess the ultimate solution would be solar plus a propane fuel cell keeping an AGM or lithium battery bank automatically charged 24/7. 😉

study the bloom energy fuel cell. they run off regular commercial natural gas, and I believe there are some running off reclaimed landfill methane. there isn't a propane version because propane has to be delivered OTR and that defeats the purpose

[GordonThree]

lithium iron phosphate batteries aren't really that exciting - some early adopters are marketing them at folks with big wallets, but they're not flying off the shelves.

the industry is not building cars, trucks or trains with them



I'm looking forward to mass produced, affordable NMC packs... 48v nominal is fine, trying to fit these high energy batteries into low energy pigeon holes is counter productive, jmho

[pnichols]

Don,

Concerning ultra pure fuel for fuel cells ... is that true for propane fuel cells? If so, where are us RV'ers going to get ultra pure propane? (I suspect that part of the high price for propane fuel cells is a super filter/dryer for the incoming propane.)

P.S. Of course solar by itself is not as close to the ultimate solution for anywhere anytime power replenishment that a propane fuel cell is. I guess the ultimate solution would be solar plus a propane fuel cell keeping an AGM or lithium battery bank automatically charged 24/7. 😉

[pianotuna]

Freep,

For about 10% of the cost of the fuel cell you can have a solar charging platform and batteries that will give you more power.

One of the problems with fuel cells is that they require ultra pure fuel. That's fine if you are NASA and nothing else will work.

[Freep]

GordonThree wrote:

Yes they use rare Earth catalysts that are basically manufactured in a lab in small batches. There's also very expensive intellectual property involved, the folks that patent the technology don't want it mass produced.

Bloom Energy mass produces a hydrocarbon fuel cell. Fuel from propane, methane, etc. The fuel cells are huge though.

Patents only last 7 years. Hopefully by the time my AGMs need to be replaced I can replace with LiFePo and also replace the Onan with a fuel cell.

[GordonThree]

pnichols wrote:
Yikes is right!!!!!!!!!!

Other than the disadvantages of small volume producton, I wonder why fuel cells are so expensive .... each one hand assembled by engineers .... or the materials are found only on Venus? :h and :E

Yes they use rare Earth catalysts that are basically manufactured in a lab in small batches. There's also very expensive intellectual property involved, the folks that patent the technology don't want it mass produced.

Bloom Energy mass produces a hydrocarbon fuel cell. Fuel from propane, methane, etc. The fuel cells are huge though.

[mi_drew]

I would stay with 12 volt for the simple reasons. If you have a problem with the truck battery you have a spare. You could also swap one out to your trolling motor if the fishing was good and your trolling motor battery got low ( no charging system on my small boat).And you could charge it with the truck if you have to. I have run a deep cycle battery in my work truck for 4 years with no problems.

[pnichols]

Yikes is right!!!!!!!!!!

Other than the disadvantages of small volume producton, I wonder why fuel cells are so expensive .... each one hand assembled by engineers .... or the materials are found only on Venus? :h and :E