Offgrid autostart propane generator, battery chargers, & distances?

[lutefisk]

I am happily enjoying Christmas Eve dinner leftovers, and starting to think of the New Year, and future offgrid solar power plans. (Merry Christmas everyone! I am just starting to do some research, and thought that if anyone had some good URLs to read, or specific products to recommend, that would be awesome.

Specifically, I am thinking of getting a large propane tank (installed/serviced/filled by the local propane company) installed at the top of the driveway down to my offgrid cabin, and then building a small snug shed very close to it in which to place a propane-fired power generator (3-4kws or so?) that would have the capability to be started automagically when my existing battery bank is drained beyond some pre-set level.

Problem, or no? ...The distance... between existing cabin/solar panels/battery bank/inverter & this propane generator setup would be about 70 yards or so...a distance I was thinking I could bridge via an AC 120v power line from generator back to battery bank. Then, I would acquire some form of combined 12v charger/electronic device that would monitor the battery charge, and have the ability to send the 'start/stop generator' signal back to the propane generator to start up and begin charging when my power load drained the batts below a certain level.

My current inverter is a Xantrex Prowatt SW 2000, which is just slightly inadequate now that I have installed a chest freezer-modified-to-run-as-refrigerator (with a separate temperature/power controller to keep it at 36 degrees or so) but it seems like one option would be to acquire a new invertor/charger unit to replace that prowatt.

Does this seem like a decent plan?

If you were thinking of doing something similar, how would you approach it...and what products/devices would you consider...and/or what links would you recommend me to research these ideas?

Thanks!!!
Lutefisk



add'tl info, in case it matters:

- money is not necessarily an object...I want to buy top quality stuff, sized to be able to support a little more capacity in future if needed.
- propane tank is likely not able to be placed right next to cabin, due to the muddy nature of the access road to cabin. (single lane gravel road ~ 70yards above my property is known to be adequate for the local propane delivery trucks)
- existing battery bank is 4 x Dyno 8Dd deep cycles, wired 12v & ~240AH capacity when new)
- existing solar is only 2 x Kyocera 140watt panels, soon to be augmented by 2 x 300w panels of some kind
- existing charge controller is small Morningstar PWM 30a model, soon to be superceded by (likely) a MidNite Solar Classic MPPT charge controller.
- heat & hot water currently provided by propane on-demand appliances...no plans for any electric heat of any kind.
- cooking currently provided by propane oven/burners
- actual AC power load is very small, mostly a laptop, a 2nd 27" LED computer monitor, some LED AC lights, the aforementioned freezer/fridge conversion, and a little microwave oven action, and a few teensy devices like a temp/wind/humidity guage. Not planning on adding much more electrical loads...

[Sunking]

Problem, or no? ...The distance... between existing cabin/solar panels/battery bank/inverter & this propane generator setup would be about 70 yards or so...a distance I was thinking I could bridge via an AC 120v power line from generator back to battery bank. Then, I would acquire some form of combined 12v charger/electronic device that would monitor the battery charge, and have the ability to send the 'start/stop generator' signal back to the propane generator to start up and begin charging when my power load drained the batts below a certain level.

First problem is 12 volts. Where did you come up with using 12 volt battery?

[lutefisk]

First problem is 12 volts. Where did you come up with using 12 volt battery?

Well, the use of 12v for the batteries is just a legacy of how I first set it up - originally I only had the one charge controller + panels and a couple batteries so it seemed logical to use 12v, since my original loads (a car stereo and a couple light bulbs) were also 12v.

Since I don't use the 12v lights/stereo anymore, I could certainly rewire the batteries to be 24v or whatever makes sense. I know the MPPT doesn't mind whatever battery voltage I use, not sure what else would be made easier w/different battery voltages...except of course being able to use much longer battery cables at higher voltages.

[Mike90250]

When you get to the 24 & 48v systems, both the inverter and charge controllers often have signals or controls for generator modules. The starter module is an additional purchase, and then you need to have a generator that has inputs for auto-start signal.

In your area, what's the coldest cold you get ? in really cold places, propane wont vaporize from the tank fast enough to fuel an engine.

[lutefisk]

When you get to the 24 & 48v systems, both the inverter and charge controllers often have signals or controls for generator modules. The starter module is an additional purchase, and then you need to have a generator that has inputs for auto-start signal.

In your area, what's the coldest cold you get ? in really cold places, propane wont vaporize from the tank fast enough to fuel an engine.

I think the historical record low for the area is -2 f, but an average cold for the winter probably hovers around the mid-twenties. In the 10 years I have been there, I think the coldest I have experienced is just about 20 degrees f. Then again, it isn't *quite* a year-round cabin for me, I visit occasionally in Jan/Feb but (since it is at 1500 foot level of a mountain with single-lane gravel road that isn't plowed)

I tend not to linger for long in Jan/early Feb due to the risk of a random snowstorm snowing me in for a few days at a time. My neighbors up the road live there year-round and a few years ago there was a dump of snow that kept them in for a couple weeks until it was safe enough to drive back down the mountain for supplies...

On the other hand, I am able to 'work from home', and have reliable internet access from a cell tower so I am contemplating someday becoming a permanent resident. The rents in the Puget Sound area are crazy high, and I would much rather save that $$ or spend it on hardware for the cabin, and maybe a small yurt too...