Debating 2 6V vs 1 12V battery

[eamarquardt]

At 50 cycles a year, that is 60 years.

I'll need 20 years tops. Can I return em when I no longer need em? Enquiring minds want to know.

Thanks,

Gus

[Bogo]

At 50 cycles a year, that is 60 years.

I'll need 20 years tops. Can I return em when I no longer need em? Enquiring minds want to know.

You likely could sell them to some EV home builder. I know of 4 home built EVs that use them.

[Esteban]

Iflyfish, you mention wanting to use an electric powered cooler.

An AC/DC cooler by TruckFridge might be a good one for you (or other teardrop campers). Its a portable top opening refrigerator/freezer that is relatively low power and low priced. Expedition Portal folks have a lot of interest in them. A lengthy favorable discussion begins at http://www.expeditionportal.com/forum/threads/81797-Truck-Fridge-sale-Prices-only-visible-in-checkout They're a 4 wheel drive group so they would probably be much harder users of the coolers than teardrop campers would.

Post #27 in the Expedition Portal discussion:

by 77volvo
Consumption

The Truckfridge/Indel B 50l consumes .7w when the compressor is not running, when the compressor is running on ECO my amp meter says 3.5a/44w and on MAX 5.7a/71w. Although I did not record the totals consumed, my 50l performed well, connected to 40w (labelled), actual 25w peak output measured, of solar panels and 2 - 12v 100 amp deep cycle batteries over 9 days. I set up the fridge and panels the afternoon of 8/11, and disconnected them on the morning of 8/19. Temperatures during the day were up into the 90's, but down to the lower 60's at night, and I had the thermostat set at 34. The lowest the battery voltage I observed was 12.05v, and the milk was still cold when I loaded up to head home.

TruckFridge.com sells three sizes at http://www.truckfridge.com/store/page6.html.
Both the TF31 and the TF41 would probably fit easily in a teardrop galley.

TF31 SALE PRICE $399.00
Great for traveling, camping and all outdoor activities.
Portable, top opening fridge/freezer
13 ¾"W x 14 ½"H x 23"L
1.0 cu. ft.
DC 12-24 Volt / AC 115-230 Volt / 50-60 Hz

TF41 SALE PRICE $499.00
Great for traveling, camping and all outdoor activities.
Portable, top opening fridge/freezer
13 ¾"W x 17"H x 23"L
1.5 cu. ft.
DC 12-24 Volt / AC 115-230 Volt / 50-60 Hz

The taller TF51 might be a tighter fit.

TF51 SALE PRICEn$529.00
Great for traveling, camping and all outdoor activities.
Portable, top opening fridge/freezer
13 ¾"W x 20 ½"H x 23"L
2.0 cu. ft.
DC 12-24 Volt / AC 115-230 Volt / 50-60 Hz

[Shadow Catcher]

Our Lifeline AGM 150 AH is only a couple of years old and has worked well and hopefully will last a good number of years before it needs replacement. BUT I am starting to look at alternate battery technology's for the future. One of the problems is that while the battery is 150 AH only 75 AH are usable to keep it above the magic 50% state. One alternative currently available is Lithium ion http://www.lithionicsbattery.com which can be discharged much further and is inherently less weight which means a smaller battery will supply needs. As an example a Li3 100AH is 32 lbs where as my 150AH AGM is 100 lbs and the 32# battery has more usable current. There is a bit of a price difference!

[Bogo]

A Lithium Ion battery of any type requires a quality charger to charge properly. They are sensitive to over voltage when charging. It causes a different reaction to occur that is irreversible. Capacity is then permanently lost. They also don't like excessive heat so you should have a temperature probe on the battery bank that the charger monitors as it charges the batteries. Don't skimp there. I know one company is using Li-Iron batteries for powering a DC air conditioner for semi truck cab use, but the battery bank is expensive.

Looking quickly I see a 12V 55AH Lithium Iron @ $1109.00 each. $1319.00 with charger and management system. http://www.powerstream.com/LLLF-12v55ah.htm

A place selling on Amazon has a 12V 100Ah Lithum Iron at $1,299.00 each. You'll then need a special charger, etc..

It is interesting to note, these prices are about half of what they were when I first looked at them a few years ago. They'll need to halve again before I'll look at them seriously, but I can see that happening as the LiFePO4 process is quite robust in comparison to most other Lithium type batteries. Where weight is a major issue, they have their uses.

[bdosborn]

Good old fashioned golf cart batteries still have the lowest $/amp-hr. Yeah, you gotta water them and they make a mess but you can't beat them on price.

Bruce

[bdosborn]

On depth of discharge vs. cycle life: From that Trojan battery spec. Note 80% DOD is well over 500 cycles. 50 weekend trips a year times 10 years is only 500 cycles. Chances are the battery will be killed by winter neglect, or simply die of old age before it cycle lives out for the average TD user. Note: the chart is for that Trojan battery. A typical AGM deep cycle/starting will only have 250 to 400 cycle life at 80% DOD. Still a long time for an occasional use RV.

That graph only applies to golf cart batteries and I probably shouldn't have posted it as it would seem to show it's okay to cycle the batteries down to 80%. However, none of the battery manufacturers recommend going below 50%, including Trojan. Cycle your Wal-mart marine battery to 80% more than a handful of times and you'll be buying a new one.

Bruce