Lifepo4s are indeed superior, far superior
BUt they too have needs or they can be destroyed by a single overcharge or undercharge.
Their voltage remains very flat throughout their charge and discharge, except for the very ends, so one really has very little idea where the battery is in its percentage by looking at voltage.
So say one decides to forgo automatic low voltage disconnect systems and says I'll just be there and stop discharging before they get to low. Well without being there the whole time, eye on a voltmeter, that too low would happen too quickly.
Recharging them, same thing, once they get near the top end, they can begin the damaging process of overcharging all too quickly, and thus a high voltage disconnect is needed too.
Each lifepo4 cell is 3.2 volts nominal and thus 4 are needed in series to make a 12 volt battery, and each battery needs to be top or bottom balanced, meaning it needs to be the same exact voltage when wired in series with the other cells, or bad things can happen. They will likely also drift apart with more accumulated cycles, so a rebalancing is likely required every so often. This requires charging each cell individually, basically babysitting the whole time during this process.
So Lifepo4 is not just a drop in replacement for lead acid batteries that simply costs more initially.
http://www.pbase.com/mainecruising/lifepo4_on_boats
Blars a member here is using them, and I hope I did not screw up too badly in the above paragraphs.
I've basically bought my last lead acid deep cycle battery. next will be Lifepo4, simply because I need to get a good grasp on it. Though I can make any lead acid battery work hard and last its manufacturer claimed cycle life through proper recharging, the challenge is now gone.
But a battery newb whose grasp of electrics is still in its infancy, dipping their toe in the Lifepo4 world, is why you have gotten the response you have regarding this superior technology.
Lead acid batteries are quite forgiving, when one considers their overcharging or undercharging. One event is not going to kill them.
Kill a lifepo4 bank by one single overcharge, and it is not a matter of driving to walmart and having one of their employees remove the old battery and slap in a new one, and ringing the 'just fine' bell over and over.
As far as a drop in 12v Lifepo4, I saw this the other day:
http://www.batteryspace.com/LiFePO4...V-100Ah-1.28-KWh-10C-Rate-With-Balancing.aspx
They are claiming 1000+ cycles. Does this mean 1001? IDK, I hope not.
1100$+ for 100AH, and that does not include a proper charging source which can be configured to the lifepo4 needs/desires
Regarding electrical consumption.
1250 watts at 12.2v is ~103 amp load. Add in inverter inefficiency and this will be about 120 amps. Unless the battery bank is quite large expecting the battery to maintain 12.2v under such a load is unrealistic. As the wattage remains the same and volts x amps=watts, a lower voltage means higher amperage to power the load, so that 103 amp load at 12.2v is now a 113 amp load at 11.1 volts, and the inverter efficiency at lower input voltages gets worse, so the total load would likely be nearing 140 amps, which of course drags the battery voltage even lower, making the amp draw even higher. Vicious cycle.
Add to this Peukert's law, which says the larger the load, the less capacity the battery has to give. A healthy fully charged 400Ah battery bank under a 140 amp load is not going to be able to provide 400AH total, but more like 220AH total, and only 110 of that before reaching that 50% mark one should never really take a lead acid battery to.
So, transferring your stick and brick mr coffee to battery power can certainly be done, but designing such a huge battery bank and all its accoutrements in order to properly recharge it and keep it happy for an acceptable number of cycles, is a huge investment and will still be a hard workout on the batteries.
When one considers that one can make coffee overpropane, and consume Zero electricity the 'I have to have my Mr. coffee' gurgling away before i get out of bed!" seems quite obviously ridiculous.
Living on battery power is not simply a choice to carry around enough battery capacity and transfer stick and brick luxuries to it, but consideration of how much juice those wall outlets actually need to provide to power them, and how little energy that huge heavy expensive battery can actually store and supply, and all the very significant inefficiencies along the path from battery to heating element.
If it were easy to power such things, there would not be an energy crisis in the world, and we would not be burning all the fossil fuels we can find and extract, and toxifying the planet in the process of extraction or burning them.
Easier to use less electricity in the first place, and a Mr Coffee machine is a slutty selfish Ampwhore.
