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Small Cabin Forum / Off-Grid Living / Solar Advice

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# Posted: 21 Feb 2016 10:37
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I am planning on putting a simple solar system in my remote cabin to be supplemented by a generator.
Just looking for some feedback on my proposed system. I will be using a 100W Coleman (or possibly 2) solar panel with a Coleman 12V-30A PWM charge controller feeding into 2 deep cycle batteries. The cabin will be for very intermittent use (hunting and snowmobiling) so I will transport the batteries in when using so they will not be attached at all times (due to cold temperatures). The plan is to run both the batteries and the generator input into a pure sine wave inverter then wire the inverter into the electrical panel. I will be running a limited amount of LED lights, a gas fireplace fan, and a TV/receiver. I have a couple of questions on this setup?
1.) If I run the generator during the day for say an hour or so, will this help to charge the batteries for use during the evening and night (i.e. fireplace fan, TV)?
2.) Is there any switch required between the inputs to the inverter (solar panel and generator)
3.) Suggestions on an economical inverter make and model?
4.) Can I use the non-inverter generator to feed the pure sine wave inverter to run electronics?
5.) Suggestions or feedback?

Solar_diagram.JPG

groingo
Member

# Posted: 21 Feb 2016 10:48
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First thing, do you have good unobstucted exposure for your panels, have you done an energy audit to see just how much power all your appliances will require, do you own a Killawatt meter to do just this, once you know this you can confidently build your system around your requirement which regardless what you come up with you should at least double or in my case quadruple due to many cloudy days and limited exposure, for starters.

Jebediah
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# Posted: 21 Feb 2016 11:13
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Quoting: curt

I will be using a 100W Coleman

The coleman 100's are on sale right now 40% off. They "usually" go on sale every spring for 60% off at CT.

MtnDon
Member

# Posted: 21 Feb 2016 16:53 - Edited by: MtnDon
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Quoting: curt

1.) If I run the generator during the day for say an hour or so, will this help to charge the batteries for use during the evening and night (i.e. fireplace fan, TV)?
*** You need a battery charger. Power the battery charger with the generator. If it is necessary to run the generator because the batteries are too low for just the solar, or it's cloudy or whatever, run the generator first thing and let the solar fonish the charge later.

2.) Is there any switch required between the inputs to the inverter (solar panel and generator)
*** Solar PV charges the batteries via the charge controller and then an inverter sends 120 VAC to the cabin circuits. .... Generator charges batteries through the separate battery charger. No switches there. Batteries can still power the inverter; again no switches, etc. .... But if you want to directly power the AC circuits in the cabin with the generator you need a means to connect the generator safely to the cabin and by-pass the inverter. The simplest method is with an automatic transfer switch, next best is a manual transfer switch. That switches / transfers between inverter power and generator power.

3.) Suggestions on an economical inverter make and model?
*** Depends on how many watts you want / need, what devices you need / want to power.

4.) Can I use the non-inverter generator to feed the pure sine wave inverter to run electronics?
*** NO. Generators supply 120 VAC (240 VAC with some). Inverters run on DC input and produce 120 VAC output. (some 240 VAC). You can not mix the generator AC output with the inverter AC output. It is either/or.

MtnDon
Member

# Posted: 21 Feb 2016 17:42
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Quoting: curt

I will transport the batteries in when using so they will not be attached at all times (due to cold temperatures).

If you use a well made reliable charge controller transporting the batteries is a wasted effort and possibly dangerous too boot. A good charge controller will not overcharge the batteries, but will keep the batteries fully charged. A fully charged lead acid battery will not freeze until -90 F or so.

razmichael
Member

# Posted: 21 Feb 2016 18:09
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About to say the same as MtnDon. i leave mine at the cabin all winter (Quebec - very cold at times). Never had any problems with them even though I know that the panels will spend time snow covered. During the winter they will continue to power a couple of motion sensors connected to LED outdoor lights but this has very little impact. This is not to say that I do not worry every spring on the first visit.

I'm assuming the cabin is already wired for 120 which is why you plan on running everything from an inverter rather than sticking with a primarily 12V system. For a very small system 12V might be the simple way to go, along with a cheap inverter that is off for most of the time.

As described by others, you need a transfer switch, battery charger etc so another consideration is going with an Inverter with those features built in. Obviously more expensive an inverter but when you add up all the separate components, extra wiring and complexity, it may be worth it. I use a Xantrex HF1800 which has an autotransfer switch (turn on the generator and it switches over from the batteries) plus a smart charger. Note however that this model is a modified sine wave (not that I have anything that needs a pure sine wave).

rockies
Member

# Posted: 21 Feb 2016 19:13
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I certainly don't know much about designing solar panel systems (gasp), but the one thing I would like to read more about in the forums is how to properly house the system. I have read that the batteries have to be in a separate enclosed area (like a little lean-to shed attached to the side of the cabin or maybe in a small shed away from the building) but also that the space should be insulated and yet have a vent to the outside in order to allow off-gassing from the batteries to escape.

There is always lots of discussion on the types of panels, invertors and generators to buy, but maybe a thread on how to properly design the space to hold the equipment is needed?

DaveBell
Moderator

# Posted: 21 Feb 2016 20:59
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We need to improve the solar page to stop regurgitating the same info over and over.