Remote Solar system Questions (1 Viewer)

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jynx

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I think I am in the right spot, and I am hoping that among the ranks someone will be able to answer my question.

So we are about to take delivery of a pole barn package for our farm. Currently I do not have grid power back onto the property and my intention is to go ahead and wire the building for electricity and install a generator plug and transfer switch to power some basic lights and outlets.

We are also planning on installing a small off-grid solar system which will power a security system with a cellular dialer. The system is relatively low draw and sizing for that isn't an issue but it does bring around my actual question.

I am looking at probably a 200W or 400W solar system with one, possibly 2 deep cycle batteries for storage. I am looking at a Xantrex true sine wave inverter for the system since I am assuming that the electronics will need that over a modified sine wave. So I am looking at either a inverter OR or charger/ inverter. In my research the price difference between the two for a true sine inverter are fairly sizable.

The reason I am looking at a Inverter/charger is I would like the ability to have the batteries charged via the generator if we happen to be out working and can run it for a few hours. So the cost difference is enough that I am trying to decide if I could install a true "off-grid" system with only an inverter coming from the batteries to power the security panel AND also connect a AC charger to the battery bank that could be powered by the generator to also charge the batteries?

If the sun was out, I would suspect that technically it could be receiving charge from both the solar charge controller as well as the AC charger, would that be a problem? Most charge controllers seem to read the batteries and charge accordingly. I realize that I would need to make sure the AC charger was properly connected and capable of powering more than one battery (should I decide to go that route) which may bring the pricing up to a more even number, but the Xantrex SW2000 can be had for under $400.00 and is an Inverter only, the Xantrex ProSine 2.0 2000W inverter/charger comes in at a shade over $1,000.00. If I use two batteries I am pretty sure I could use a single AC charger and charge both batteries in parallel using the Generator and I could buy a good AC charger for 2 bills, so I would end up $400 in the black which would probably pay for a couple of good deep cycle marine batteries or at least get me dang close.

So what am I missing, when I get grid power back to the buildings then I may bump up to a hard wired charger inverter, but with grid power I would likely not need the back-up anymore so I don't want to go all in on a high dollar inverter/charger that will not be needed in a year or so.

Also, I am looking at the Grape Solar 400W Kit, which comes with the Xantrex inverter I mentioned above.

I appreciate any input.
 
What cellular system are you looking at, and what are you intending to do with it? I would consider looking at some of the marine stuff, as it is designed to run directly off DC power, so no need for a wasteful inverter.... (The electronics will be DC anyway, so you would just be inverting to 120VAC then the power supply would convert it back to DC. Skip all those steps for a more efficient unit. Check out Boatsense... There are a fewer other similar systems (names slip my mind right now), allowing for a few inputs of your choice, like door switches, voltage alarm etc.

I would skip the more expensive inverter/chargers - for the amount of time you would be running the generator to charge, just buy a simple 120VAC automotive charger. Be careful if you are installing a DC electrical panel that you have a lockout between the inverter and the charge switch, inverters don't like being put in a loop like that.

But the biggest question is what are you planning on powering from the batteries? You need to do a load calculation to determine how much output you need, to determine how much storage you need, to determine if your panels are big enough.

You may find this link useful.... (Have not used it, but has a decent looking calculator)

http://www.solar-electric.com/solar/calc/
 

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