Small Cabin Off-Grid Solar Power System for Remote Cabin

[DanyO]

My parents asked me to put together a small Solar Power System for their Cabin. They don't have a lot of money to spend on it, so they asked that I get them the best bang for their buck for around 1000$. We're located in Atlantic Canada, so we are aware that we won't get optimal power from our solar panels.

Their requirements are fairly low, since they only need to run a Small 19in CRT TV, and 3 23W CFLs, for about 3hrs a night on the weekends. The assumption I made here is that I have a bigger battery bank, and smaller Solar capacity so that the batteries will have time to charge during the week. Currently the cabin is powered with a 1kW Gas Generator, which is way bigger than what they need. When solar power is installed, the generator will be as a backup source for longer stays.

Here are the parts I'm thinking of getting:
-3x 12v Deep Cycle Marine Batteries @ 130$ea (100aH per battery), in parallel. (http://www.canadiantire.ca/AST/brows....jsp?locale=en)
-1x 110w Monocrystalline Solar Panel @ 285$ (http://www.ebay.ca/itm/Pick-One-12-V...ht_9231wt_1049)
-1x 12v 30A PWM Charge Controller @ 110$: http://www.futurlec.com/Solar_Charge_Controller.shtml
-1x 600W inverter @ 60$: http://www.ebay.ca/itm/Bestek-600w-d...ht_3555wt_1064

Questions:
1. Other than cables, am I missing anything in the system?
2. Is that the correct system size for their needs?
3. Do you know of any better priced components that would give them more bang for the buck?
4. Any other comments on the system?

I'm a newbie here, so I thank you in advance for your patience.

Thank You.

[Naptown]

Without knowing the watt consumption of the TV and insolation for the location it's hard to tell if it's a large enough system. I would assume this is for a summer use cabin and not year round?
The charge controller you chose is way too big for the panel you chose. If you plan to add on in the future than go ahead with that one or downsize to a 20A.
The inverter is a modified sine wave inverter and may not play well with the CFL lights and TV. Spring for a true sine wave.
Lastly I did not notice UL or CTL listings or logo's on any of the equipment you were looking at. These will be necessary in order to keep the insurance company happy in the event of a fire or other issue.

[DanyO]

Power consumption of the TV is measured at average of 80W with Killawatt.

The cabin will be used from late spring to early fall, not during snow season.

[Sunking]

Their requirements are fairly low, since they only need to run a Small 19in CRT TV, and 3 23W CFLs, for about 3hrs a night on the weekends.

Questions:
1. Other than cables, am I missing anything in the system?
2. Is that the correct system size for their needs?
3. Do you know of any better priced components that would give them more bang for the buck?
4. Any other comments on the system?

I'm a newbie here, so I thank you in advance for your patience.

1. Sounds like you are going to fall short way short. Really need your exact location but Canada is not good. So assuming the TV uses 80 watts x 3 hours = 240 Watt Hours.
CFL x 3 x 23 watts x 3 hours = 207 Watt Hours
Total = 447 Watt hours round up to 450 wh.

Adjustment factor using PWM charge controller 2 x 450 wh = 900 WH/day.

OK for the battery you are going to need a capacity of 450 WH x 5 = 2250 wh.

At 12 volt battery = 2250 wh / 12 volts = 187.5 Amp Hours, round up to 200 AH
At 24 volt battery = 2250 wh / 24 volts = 93.75 AH round up to 100 AH

As for panel wattage we need to know exact location to determine the sun hours. To find the right panel wattage we take your adjusted daily watt hours and divide it by the minimum Sun Hours for your location. So we know the panels need to generate 900 WH/day. This is where you get in trouble with your location and budget limitations. In winter I can only assume you might get 2 Sun Hours if even that. So 900 WH / 2 h = 450 watts. Even in Summer you are in trouble. For example let's assume you get a good 5 Sun Hours in July. That means 900 wh / 5 h = 180 watts.

So the short answer there is no way a 100 watt panel is even going to come close to your needs.

[Naptown]

perhaps running the generator you have for an hour or two a day with a good charger would work also. At least it wouldn't be running at night when you're trying to watch the TV. Maybe an hour before they leave on sunday to bulk the batteries and the solar to top off the batteries.
Drop one of the batteries out of the equation and perhaps add one more panel or shop around for a 200W panel but keep it at 36 cells or you will be wasting power with the pwm charge controller.
An exact location is important to determine insolation.

[DanyO]

@Sunking
"Adjustment factor using PWM charge controller 2 x 450 wh = 900 WH/day."

Wow, that's quite the adjustment. If I used an MPPT charge controller instead, how would it change the calculations?

[Naptown]

@Sunking
"Adjustment factor using PWM charge controller 2 x 450 wh = 900 WH/day."

Wow, that's quite the adjustment. If I used an MPPT charge controller instead, how would it change the calculations?

1.5 x 450 = 675

however 2 days is only a 40% discharge if you bulk the batteries before leaving and let the solar top off you will be OK
consider also using 2 batteries and 2 panels. Still around the budget. At these power levels and if you are using 12v batter bank and 12V or 36 cell panels MPPT is probably not worth the added expense.

[Sunking]

@Sunking
"Adjustment factor using PWM charge controller 2 x 450 wh = 900 WH/day."

Wow, that's quite the adjustment. If I used an MPPT charge controller instead, how would it change the calculations?

50% or x 2 for PWM, 66% or x 1.5 for MPPT.

[Mike90250]

... The assumption I made here is that I have a bigger battery bank, and smaller Solar capacity so that the batteries will have time to charge during the week....

This assumption, started in the 70's, generally results in dead batteries in the 2nd winter.

Because the batteries do not recharge quickly, needing 3 or 4 days, they start to sulfate and loose capacity on day #2. If they lost 2% capacity each week, things are fine till the 2nd year, short days and long nights of winter get together and conspire to kill the system.

The key is to run the genset each AM, to re-bulk charge the batteries to 80%, and then you can leave and let the solar top them off.

[Pop Alexandra]

Panels work fine in most cases, but the amount of sunlight and the number of consumers also have a major impact.
_______________________________________
Alexandra from Summerwood cabins

Mod Note. Please do not include advertisement links in your posts. Another attempt will result in being banned.

[ButchDeal]

This assumption, started in the 70's, generally results in dead batteries in the 2nd winter.

Because the batteries do not recharge quickly, needing 3 or 4 days, they start to sulfate and loose capacity on day #2. If they lost 2% capacity each week, things are fine till the 2nd year, short days and long nights of winter get together and conspire to kill the system.
.

It also made more since in the 70's when solar was so very much more expensive than the batteries.
Now solar is much cheaper it make zero since to have an under sized array for off grid.

[djdalfaro]

Hi, I just want to throw this out there, because nobody has suggested it yet, and as a baby fresh newbie, I wanted to feel like I could contribute.

Why not replace their CRT TV with a LED TV (maybe even a 12v one), and replace their CFL lights with LED lights... That will bring the consumption WAY down. A quick google search shows that LED TVs use about a 25% of the energy as old CRT TVs, and LED bulbs about 75% as CFL. Just a thought.

So if you were to rerun Sunking 's calcs from above... you might get a better result.

[Sunking]

Panels work fine in most cases, but the amount of sunlight and the number of consumers also have a major impact.
_______________________________________
Alexandra from Summerwood cabins

Mod Note. Please do not include advertisement links in your posts. Another attempt will result in being banned.

He is a SPAMMER. Dug up a 6 year old post. Not hard to figure out to nuke him.

[SunEagle]

He is a SPAMMER. Dug up a 6 year old post. Not hard to figure out to nuke him.

If he was selling pv equipment he would be gone. He is just selling cabins but may have some input on the solar side. I have some patience.

[Sunking]

If he was selling pv equipment he would be gone. He is just selling cabins but may have some input on the solar side..

OK, my bad. I take it that means since I am not selling solar, then it must be OK if I sell Panama Red on the forum? Well actually it is more purple than red.