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Small Cabin Forum / Off-Grid Living / Local solar panels for sale.
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Link44
Member
# Posted: 2 May 2022 13:53
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Craigslist fellow has multiple sanyo/sharp and suntech solar panels for sale at .50 a watt. I've been reading reviews but I thought I'd ask opinions here. Maybe someone has real world experience.

Thanks

travellerw
Member
# Posted: 2 May 2022 15:30
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Those are good panels. $0.50/watt is a "decent" price for used panels (that are not too old). I paid about $0.42/watt for 5 year old panels. However that was a VERY good deal.

Since its not a super good deal, I would make sure you have the system planned out before buying. How many panels, serial vs parallel, solar controllers, ect ect! Its better to build a system as a whole instead of buying panels and then trying to "make them work" (which is what I'm trying to do now).

gcrank1
Member
# Posted: 2 May 2022 16:22
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Can you get a cell-phone shot of the spec panel on the back?
All that info is important to figure out if they will be suitable.

Link44
Member
# Posted: 2 May 2022 17:49
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I asked for a picture of the specs, well see what that has to say.

Link44
Member
# Posted: 2 May 2022 18:32
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Here is the solar panel info.
IMG955120.jpg
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travellerw
Member
# Posted: 2 May 2022 21:12 - Edited by: travellerw
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Those Sanyo panels are %19.4 efficient. They seem to date from about 2008-2011. They would be my choice for sure.

Not sure where the panels were used, but its possible they have lost some capacity. They might only produce %85-90 of their rating now. However its also possible that there has been no degradation (I had 20 year old panels that still produced more than rated). If you view them you want to view them in good light and look at each of the cells for any brown discoloration.

Now be aware that those Sanyo panels are high voltage (like 65V) and designed for rooftop in series. 2 panels in series is 130V and you need to be careful as 130V DC is SPICY. You will need to spec you solar controller properly.

Nobadays
Member
# Posted: 2 May 2022 21:26
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Look for snail trails as well... little lines that look like snail trails you can see from the front. This is often due to the backing starting to separate. Often it does affect the performance right away but eventually will. Any visible separation, peeling on the back is not good.

The used panels I have are 4-5 years old and there has been little to no degradation. I do test output on all I install and try to match them up if there 8s a bit of voltage drop.

Santansolar.com has been a source I've used for several years. The 250w panels I have were $50/$.20 per watt. They have increased in price now to $63/ $.25 per watt. Unfortunately if you can't pick them up, shipping can be costly. Costs just as much (was about $350 more or less anywhere in the US) to ship 1 as it does 10. People sometimes do group buys.

gcrank1
Member
# Posted: 2 May 2022 21:53
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Great! Now you have hard info.
How many panels available?
Is it all or nothing?
And now the biggie:
What are your desires, but more important, what are your requirements. Ie, have you done an 'energy audit' to figure out what you think you would like vs what is practical and Affordable. Ime, the audit creates the base line, then I at least increase that by 50%; even better if you double it.
Why? more power costs more money. if your needs x 2 are 1Kw/24hrs do you want to pay for 4Kw potential?

Link44
Member
# Posted: 2 May 2022 23:36
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There are several of each panel available.

Quoting: travellerw
Those Sanyo panels are %19.4 efficient. They seem to date from about 2008-2011. They would be my choice for sure.


I'm curious why these would be your choice. Any thoughts for a charge controller? I also dont want to just buy panels and then have issues piecing a system together.

I have revised previous thoughts of how much I'd like to power. I believe I need 360 watt/hr a day.
5- 9w led bulbs 3hrs a day
1- 50w tv 2 hrs a day
1- 31w ceiling fan 4hrs a day.
All on 120v. I was looking at a Victron inverter.

https://www.google.com/aclk?sa=L&ai=DChcSEwiOjvHmssL3AhVBwsIEHZTPBrEYABAHGgJwdg&ae=2& sig=AOD64_2gGExMphdjJXCjKmq1OFxU3ySBWw&ctype=5&q=&ved=2ahUKEwiK2ebmssL3AhU3LTQIHW2zAg QQwg8oAHoECAEQFg&dct=1&adurl=

gcrank1
Member
# Posted: 3 May 2022 10:36 - Edited by: gcrank1
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Is this for full time/long term off grid living or a 'recreational'/hunting cabin a few days then home again?
As you consider solar keep in mind that although panel cost per watt is down the other components are not and the 'go-withs' required to complete the system add up to more than one thinks.
Then that 4-5 hours/day of solar power has to be 'stored' somewhere. The storage; ie, battery costs can be considerable!
Reason I ask is that your simple, low draw use is not unlike what ours has been the past 3 years. The system was 6 x 102W panels, 2 series/3 parallel for 24vdc into a MPPT charge control. It converts to 12vdc to lead acid batteries. That all worked, but about 1-22 I bought 2 LFP 12v/100Ah batteries (as my old LA bats needed replacement anyway). Game changer!
Thus far this spring I have not activated the solar at all, we go to the rec cabin with a mostly fully charge LFP, hook it up inside to the 12vdc to 120vac Pure Sine Wave (PSW) inverter and flip the switch; ta-da, elec!
Not on a charger At All.
Fwiw, I just brought the one bat home we had left and used for 9 day trips, some 36 hours of pretty steady draw from a ceiling fan, any 9w led lights we want (are you really going to be running all 5 of your lights? We sure dont need to) and the occassional usb or tool charger.
The bat finally got down to 12.8 under load so I left bat#2 there and brought bat#1 home to recharge (probably could have got another day trip put of it).
The way this is going; ie, getting 2-3 times as much power out of the LFP bat(s) vs LA, I may not even need to have solar.
So, what Im getting at, with the power requirements you say at the cabin and depending upon how much you are there, you may not really need solar either?

Brettny
Member
# Posted: 3 May 2022 10:52
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I paid 32cents a watt for 235w pannels. New on the pallet but left outside for a few years. Found them on FB marketplace. I needed 2 but got 4 and prob should have just bought 8. A spare matching pannel is never a bad thing to have laying around.

travellerw
Member
# Posted: 3 May 2022 11:38
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Quoting: Link44
I'm curious why these would be your choice. Any thoughts for a charge controller? I also don't want to just buy panels and then have issues piecing a system together.


The other panels are less efficient (16ish and 18ish), so you would require more square footage for the same wattage. The other panels are also older tech (2005-2010). Those Sanyo panels are also a good known brand. The higher voltage is more efficient for an MPPT controller to handle.

As to a controller. I'm partial to Victron as they are reliable, reputable and well priced for what you get. One 75/15 could handle 3 of those panels in parallel.

Now with all that said, I agree with Gcrank. You could probably get away with a portable power station and not worry about solar. First I would ditch the 9W LED bulbs as those are pretty high draw. There is now good 5-6W alternatives (Phillips 60w equivalents, 800lm). Second, not sure why you need all 5 bulbs on at the same time. Seems pretty wasteful. Changes there could probably cut your Wh/day down to like 250. A 1500Wh power station would power you for 6 days. Even at your 360wh number its still over 4 days.

A Bluetti 1500Wh power station runs about $1000. You are going to spend WAY more on a solar system, plus all the time spend faffing, tweaking and learning. Just some food for thought.

Link44
Member
# Posted: 3 May 2022 12:52
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We will definately be part time for now. Someday may spend all summer up there but not until I'm retired. I'd like to start my own campground and be my own camp host someday.

I'm sure we wont have all 5 lights going ar once but I dont want to underestimate what could be.

I'll look into that Bluetti power station. I may be getting caught up in the "everyone's going solar" a bit. I do like a deal.

Right now we dry camp in a trailer with a driveway gate solar panel to keep our 1 deep cycle topped off and run a 2k watt generator to watch a movie.

Someday we might want a small fridge. I know that blows eveything way out but it could happen.

gcrank1
Member
# Posted: 3 May 2022 12:59
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Ha, I dont think about All In Ones/Pwr Station stuff, Im a 'component guy'/diy sort....but yes, an AIO would be plug & play. My only requirement, at this point of battery technology, is for LiFePO4 (LFP) battery(s), the other 'lithium chemistry' bats are not as 'safe' nor as long lived.

travellerw
Member
# Posted: 3 May 2022 14:08
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Quoting: Link44

I'll look into that Bluetti power station. I may be getting caught up in the "everyone's going solar" a bit. I do like a deal.


Spend some time researching and figuring out features. Not all power stations are created equal, but much easier to understand than trying to build a complete solar system (its a steep hill). Many of the better stations have fast charge capability and can go from zero to 80% in like 2 hours. That means even if you do use all the power, you only have to listen to the generator run for 2 hours and you are back in business.

A fridge is definitely a game changer. A decent 4.4c.u. energy star mini fridge is about 600Wh/day (220kWh/year). A really good cooler and ice makes sense if its a temporary thing.

gcrank1
Member
# Posted: 3 May 2022 16:01 - Edited by: gcrank1
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We run a small old tube TV c/w integral VHS player off the 300W psw inverter just fine for a cabin movie now and then.
Tried a small 4.5cf compressor fridge, an old 12vdc/120vac absorption fridge and a truck-stop purchased back-seat 12vdc mini-fridge. All work much better if filled with frozen and pre-refrigerated stuff, otherwise they are a constant drain on the bat(s). We went with a Yeti-clone heavy duty ice chest (Walmart), it is great. Pretty much the same deal, fill with frozen and pre-fridged food and keep the lid closed, food lasts long, easy 4 days with my home freezer ice bottles so far.
Whenever you run the gen do you have an 'auto' bat charger topping up the bat? (dont use the puny 12v taps on a gen to try to charge a bat, waayyy low output). I only run my 1700/2000W inv/gen for short term, big draw stuff; like corded tools and the micro-wave if we want to have quick warm up left-over meals, etc.
All that said....if you make cabin life a similar, but upsize version of the dry-camping you have done the elec power thing will be easy and cost effective. At some point in time, after you settle into it all, you May want to look at solar IF you have a good exposure for such and Close to the cabin. Far away arrays and equipment means complications and expenses to wire run it in.

Brettny
Member
# Posted: 4 May 2022 07:36
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Quoting: Link44
Someday we might want a small fridge. I know that blows eveything way out but it could happen.

Running a fridge isn't that hard. I have a $1300 system that runs one including a $200 1kw inverter generator.

Link44
Member
# Posted: 5 May 2022 00:57
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Well I just found the Bluetti 1500wh power station for 800.00 on Amazon so its headed my way. Without the fridge I dont need anywhere near a 1000w inverter. It's also expandable so you can add over 3kwh to it for more capacity.

My wife said just do it and we'll test it out with the trailer hopefully this summer while building the cabin. The wife said go, so I went.

gcrank1
Member
# Posted: 5 May 2022 10:51
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Sounds Good! We will anticipate a product review and ongoing performance reports
With that and your little genny you should be well set.
Fwiw, there will always be used solar stuff/'the deals' showing up, dont rush into any. Do the research, define your parameters and buy to fit. Def Do Not buy because something seems a deal (ie, too good to be true) and try to cobble the wrong stuff together.

travellerw
Member
# Posted: 5 May 2022 14:46
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Quoting: Link44
My wife said just do it and we'll test it out with the trailer hopefully this summer while building the cabin. The wife said go, so I went.


If you connect it to your trailers shore power connection, be sure to turn OFF the breaker for the trailers battery charger. Otherwise you will be charging a battery with a battery and that is not efficient at all.

I would also play around with the trailers fridge (electric and gas). It would be interesting to see how much energy the fridge consumes. Mine has a 110W "hot finger" but it only runs about %20 of the time.

Link44
Member
# Posted: 5 May 2022 17:49
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Good point about the battery charger. I am very excited to start experimenting with it. We'll have the trailer up on the property by memorial day weekend. It will stay up there all summer and fall. It will be a great test.

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