What batteries would make sense to power 12v devices (e.g. blankets, lights) for camping?

Question

I have looked into a number of solutions to power 12v devices:

• Goal Zero battery packs (too expensive? $300+)
• 12v sealed lead acid battery with adapter (too dangerous? impractical to recharge? ≈$50)
• Anker Astro Pro2 20000mAh (would this even work? ≈$80)

I have a Goal Zero solar panel which ideally I could use to cycle the charging of my power source(s) during the daylight hours. One of my use cases might be heating a large family tent and I don't really want to use propane as an energy source. Are there alternative (low power draw) heating solutions that might work for this use case?

Assumptions:

• I'm already bringing at least one fully charged Sherpa 50 power pack as I use it for several other things as well. So, I'm kind of trying to maximize its utility during the trip.
• In fact assume any battery I bring will be fully (solar) charged prior to the trip and will (hopefully) only need a partial trickle charge during the sunlit hours.
• An electric blanket adds insulation on its own even without supplying power.
• An electric blanket has an automatic shut off after 30 min, and moreover will only be used intermittently during the night. I don't intend to draw 8 solid hours of power for this blanket each night.

Additional devices I'm considering running on these batteries:

• Tablets
• Phones
• Speakers
• Lights
• Frying Pan
• Electric blankets
• Air mattress pump
• Anything else?

Extra credit implied question:

• If one were to go all in with solar powered camping; what would the ideal core of that system look like?... and why?

Answer 1

Some back-of-the-envelope calculations:

12 volts * 4 amps = 48 watts * 8 hours = 384 watt-hours. That's the minimum battery capacity you'll need to power this for a night.

The Goal Zero Sherpa 50 you propose to use will power it for about an hour, give or take efficiency losses. To power the blanket for the night, you're looking for something more along the lines of the Yeti 400. Solar charging is also a problem: you can only expect 4-6 hours of good sunlight unless you're constantly moving or re-aiming your panel, so you'll want at least a 100-watt panel.

You should never fully discharge a lead-acid battery: doing so will destroy the battery in only a few charge-discharge cycles. For reasonable life, you'll want to work with the top half of capacity (deep-cycle battery) or the top 10% (automotive battery). To power an electric blanket for the night, you'll want a 64+ amp-hour battery (deep cycle) or 320+ amp-hour (automotive).

25 pounds of lithium batteries, 100+ pounds of lead-acid batteries, or just get a warmer sleeping bag? I know which I'd pick.

Edit: In response to your list of additional gear, a Sherpa 50 cannot run the frying pan: it's got a current draw of 13 amps, while the Sherpa 50 has a maximum output of 8 amps. The rest of your list is fairly reasonable, assuming the lights are LED and not incandescent.

Answer 2

My friend has made a camping power box that uses (two?) car batteries to store the power. Instructions for making something similar can be found here and probably many other places. This more than supplies our needs including phones, lights, radio and electric 'fridge'.

The major issue is getting enough solar power to recharge it particularly when it is not sunny the entire day. IIRC his setup currently has 2 ~40W panels which just about do the job provided the weather is decent and you don't use too much power.

Obviously this setup is not appropriate for backpacking as it weights 5-10kg and lies in a tool box plus two large solar panels.