24v200ah lifepo4 with no solar. Thinking about solar panels & diy heating for safe charging

nyoffgrid

Hey all,

I have an off grid cabin in Sullivan county NY. Very shaded land with tall 50ft trees. I have a single 24v200ah lifepo4 battery that runs my cabin (fridge,rv water pump, ductless ac, and so on) using a victron multiplus II. Been going great. When I am in the cabin my SOC goes from 100% to about 65% at the end of the day. I then charge with my generator - 2200w honda for about two hours and it goes back to 100%. This works well to me. But.. I came across some good quality used panels near me. 260w each for $50. So assuming they are good.. 

Since I don't have any power draw while I am away from the cabin, so let's assume - in summer - that I stay there for two days ( weekend) battery will go down to 30% soc and then I leave for one or two weeks.. If I use two of those panels plus a victron 100/30 mppt then it might be able to fully charge my battery while I am away, or close to it, right?

Also, if I set up a solar system like this then I might charge a little while I am there so when I leave it won't even be at 30% soc and be higher? 

Really rookie question but is there any issue with using cabin, so inverter will draw from battery, during the day but the mppt will also charge the batteries at the same time? is that an issue? 

In winter... I cannot charge using panels when cold. While I am there the cabin is hot from woodstove and pellet stove but when I am away.. it will be frozen. I am thinking of using a thermostat controller module (like the Dwyer TS-88T) to then feed a relay (like the Bosch 0986AH0081) that then connect to those stick on heating pads (maybe 4 of them 30w each for a total of 120w) - will need buck converter i know) and then set it up so when battery is cold - the dwyer will send power to the heating pads only - only drawing from solar panels, and then once reaches a safe temp - it will switch off heating pads and send power to mppt to charge.. Sounds possible? 

Wheelman55

OP. You’ll need a space for the array (solar panels) that is sunny, with zero shade, for a couple of hours each side of solar noon. 

Even a leaf or single branch will severely limit solar production. 

The Honda is a good solution if you don't have the sunny space. 

BB.

Do you have access to a 'sunny' spot within a few hundred feet of the cabin?

Using a high voltage array and MPPT charge controller (MPPT upwards of 400 VDC), you can send the power pretty efficiently over smaller AWG copper wire.

-Bill