I think I would rather follow the leads from some of the boaters who have bought individual Lifepo4 cells and crafted their own battery banks, rather than buying a Drop in lifepo4 battery.
Lots of good reading in this thread( started in 2011) and one can quickly determine who knows their stuff, and who just needs to feel like they do.
http://www.cruisersforum.com/forums/f14/lifepo4-batteries-discussion-thread-for-those-using-them-as-house-banks-65069.htmlOne thing that strikes me, again, is it really is all about voltage, and achieving the right voltage. If one can simply reduce voltage to 13.6v and basically stop charging, well an adjustable voltage power supply, perhaps on a timer, can also be utilized, and keep the lithium battery out of the 'knees'.
It is when the human needs everything to be fool proof and completely automatic and tries to find produts wich can do everytthing and fellate the owner afterwards, that issues arise.
I think many could get away with a low voltage disconnect and perhaps a 3 decimal voltmeter on each cell in the battery, and if one or more cells is significantly different from the others, be able to apply voltage to that particular cell outside the others to balance them again.
I'd have to do a lot more reding before I'd feel comfortable buying 4 Lifepo4 cells and making my own battery.
But the electric car conversion guys and their websites are a great place to shop.
http://www.evwest.com/catalog/index.php?cPath=4&osCsid=vmfh9uo96gvpt5u7cp2bu8jv34One think I wonder about is the OP's Kill a watt readings.
80 watts for a laptop is fairly high. My laptop is an older dell that requires a 90 watt adapter, but if the battery is already full, it uses about 30 watts to type this.
I find my DC to DC car adapter uses about 10 to 20% less electricity than using my inverter to power the orignial power brick the laptop came with. the actual number depends on teh laptop's task a the time.
Also we do not know how much the Op will be driving. Alternator contribution when the batteries are depeted, can be significant, but highly variable from vehicle to vehicle due to the voltage regulation imposed on the alternator and premature efloatuation.
While I am still sitting on the fence, there is a Lead acid AGM battery claiming to be resistant to sulfation from partial state of charge cycling, which is the nemesis of lead acid batteries. Lead acid needs to be fully charged every so many deep cycles, or the battery loses capacity like a gas tank which shrinks whenever it is kept less than full.
No Personal experience with these expensive batteries, this is not an endorsement or recommendation, but many are opting for these instead of going lithium.
https://www.bruceschwab.com/advanced-energy-storage-systems/firefly-energys-oasis-group-31/Regarding the amount of slr one can fit on a van, it is of course limited to total roof space, but also the shape of that roof space, and the conversion van roofs can be convoluted. Also flex panels should not be allowed to flex in the slip stream at highway speeds. there have been many reports of early failure of flex panels.
Also flex panels are not immune to temperature, and if adhering right to a roof tey will heat up more than a framed panel with ventilation underneath.
It was touched upon, but 9 hours of laptop use during the day, means that most of the solar harvest is not going to recharging the batteries, but powering the loads.
I see difficlties meeting the OP's electrical demands as stated, without a generator.
As far as a portable battery, well Unhooking the battery each time to take inside to recharge will have to follow a sequence of events, like disconnecting the solar panels from charge controller before disconnecting solar controller from batteries.
A small honda inverter generator on a toe hitch mount might be the cheapest easiest most effective solution to the OP's desires.
Then Size the battery and solar to make it through the night, and to do some bulk charging in the morning before turning on the loads.