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travellerw
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# Posted: 9 Feb 2022 09:35pm
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Welp.. Gonna be in trouble with the wife..
Found a deal for 3-5 year old panels.. 350W @ $150cdn per. I couldn't pass it up so I bought 4. Not sure I'm ready to be building a system yet.. but oh well.
I'll post details as I work through the build. It will be very traditional (no LiFePO4). FLA batts (8 6V) in a box by the panels, with a standalone inverter (1500W). Cabin will be fed 110V only (no 12V).
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Brettny
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# Posted: 10 Feb 2022 10:15am
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That's a prety good deal! I paid $75 for 230w pannels that where new but at a second hand store. I really only wanted 2 more (I had 2 230w pannels alreaty) but at that price I bought 4. I'm sure some day il need to replace a pannel or want to add in a string positioned different for winter sun.
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paulz
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# Posted: 10 Feb 2022 11:05am
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Quoting: travellerw Welp.. Gonna be in trouble with the wife..
She should be elated. My wife uses all the solar I can provide. 
Looking forward to watching your build.
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gcrank1
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# Posted: 10 Feb 2022 11:26am
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My wife 'suggests' you spend at least as much quality time with your wife as you do messing about with the solar system.
Or ensure the system 'doghouse' has comfortable room for you too.....
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travellerw
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# Posted: 10 Feb 2022 02:04pm
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Went to pick them up and the guy said he would knock $50 off if I took 5 instead of 4.. So I ended up with 1700W of solar for just $700 cdn. (DON'T TELL THE WIFE)..
Of course I was worried about them being stolen, but everything looks legit. He gave me his card and works for a solar installation company. Apparently they were from a commercial farm that had a fire in one section. Insurance scrapped all the panels on that string and replaced everything with brand new matching panels. This guy was instructed to destroy the panels and throw them in a dumpster. He and the other employees grabbed all the panels that were no where near the fire and took them home to be "recycled".
They all look good and are undamaged in any way and produce voltage. So I think it might have been the deal of the year.
Now I just got to get the cabin to a point where I can actually use a solar system.. LOL!
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gcrank1
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# Posted: 10 Feb 2022 02:26pm
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But Trav, you dont 'need' the cabin to play with solar!
LOL
Input end:
Wiring the panels in series is usually better than parallel.
Your Solar Charge Controller will need to be 'sized' to the output max, + some, for the array you use.
Fuse the array feed to the ssc.
Only go MPPT
On the output:
What voltage?
It isnt recommended to parallel more than 4 bats together.
Cheap GC 6v used to be about $100 each, some are reporting a 'battery shortage'; where prices go is......likely not down. So doing the voltage vs amp hours dance your target is what?
Remember that you can only use 50% of lead acid bat ah's, and 30% is far better for bat life.
With LFP you get easy 80%, often even to 100%, so you dont have to have as large a bat-bank as with FLA. I figure my 12v 100ah LFP is the equal to 300ah of marine deep cycle used to 30% and 200ah of GC used to 50%. And easily 2x the lifespan. Deducting the cost of a new, at whatever price this next year, FLA and one replacement of the complete bank pretty much pays for my LFP without any of the maintenance issues of FLA.
Your inverter at 1500w continuous/3000w peak is going to need Big Wires and Fuses. You can weld with the load!
I chose to keep the solar electric 'less' and whenever we need to run Big Loads the quiet inv.gen is started. It was waayyy less money than solar for the kind of power it puts out, and that power for us is not needed all the time.
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travellerw
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# Posted: 10 Feb 2022 04:14pm
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Gcrank.. I'm going to have to disagree with some of your suggestions based on the years I consulted but I appreciate the input.
You don't need to fuse the input side of a solar array if you have sized the wires properly. If the wires are sized properly you can literally attach positive to negative and they will just get slightly warm (even in full sun). It won't hurt anything to fuse it (just costs extra money). There are tons of solar installations with no fuses on the input side though! A switch/break is pretty common as it lets you disconnect the panels from your controllers easily.
Parallel vs Series. Lots of debates on this subject. It really depends on use case and the local environment. Series means smaller wires and a slightly more efficient MPPT controller. However, it performs much poorer in shaded or cloudy environments. Since its cloudy often here, and the batteries will be located under the panels (short wire runs), I'm leaning to parallel. I also like the safety factor of parallel. If I was to run all 5 panels in series, that would be about 250VDC in full sun. Easily enough to kill you pretty quick, but at the very least hurts like hell (ask me how I know).
Actually a big part of my plan is to keep all the electronics and batteries in a steel container under the solar panels (about 15 ft from the cabin). The only thing going to the cabin will be a 120V feed wire (that goes to an automatic switch for inverter or generator) and a control wire for the inverter. This will keep all the 12V cable runs very short (like 2 feet). More importantly the steel box will be sitting on a gravel pad. That way if anything went wrong and a fire started while we are away, it will be contained to that box and not burn down the cabin!
I debated on the battery choice a ton. It would be a different story if we were living full time on the batteries. However, LiFePO4 is still too cost prohibitive in my opinion for a weekend cabin. The prices here in Canada are still very high (about $700/100ah for a decent brand). I can still buy GC2 batteries for $100 each. So for $800 I can get 880 Ah (say 400 usable). 8 6V batteries is 4 batteries in parallel (as 2 are series to get 12V). Its dead simple 130 year old tech that doesn't require any fancy electronics. More importantly, I don't have to worry about charging in the cold (messing with heated batteries or power wasting heaters). Those GC2 batteries in my 5th wheel trailer are still going after 12 years (they did sit unused for 5 years with periodic charging though). The 6X6V bank on our boat was used for 2 years by us, then 3 years by the boat we donated it to. When we had it, we cycled almost %50 every day. So the life should be adequate for cabin use!
Damn this post is getting long.. Anyway.. I have just opened this can of worms and it will change as I move along (I'm sure). Its interesting as all the systems I built when I consulted were marine systems. In a marine environment you build to super high standards with only quality brands (like Victron or Mastervolt). I'm more free to pick some cheaper components and not try to squeeze every Ah out of the system!
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Brettny
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# Posted: 10 Feb 2022 04:43pm
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Quoting: travellerw I debated on the battery choice a ton. It would be a different story if we were living full time on the batteries. However, LiFePO4 is still too cost prohibitive in my opinion for a weekend cabin. The prices here in Canada are still very high (about $700/100ah for a decent brand). I can still buy GC2 batteries for $100 each. So for $800 I can get 880 Ah (say 400 usable). 8 6V batteries is 4 batteries in parallel (as 2 are series to get 12V
This is also why I chose FLA. Cheap, simple and work in cold. Even if I beat the hell out of these GC2 batteries (about 500 cycles) it would take me 8yrs to kill them.
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gcrank1
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# Posted: 10 Feb 2022 05:28pm
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Different ways to slide down the hill (using a winter analogy  ) shows smart folks can come to different conclusions for what is right for them.
You have the advantage of hard earned and learned past experience, newbies dont know what they dont know and the jungle gets thick quickly.
My wife did acknowledged today that she likes the way ours works now, even though she wasnt so fond of the process and my 'distraction' with it.
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travellerw
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# Posted: 10 Feb 2022 08:39pm
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Quoting: gcrank1 Different ways to slide down the hill (using a winter analogy ) shows smart folks can come to different conclusions for what is right for them.
%100 true!
LOL.. I think I would like to have a drink with your wife.. She sounds like a hoot!
So I have been doing some more thinking.... and I'm pretty sure I will be going with a 24V battery system. The cabling is smaller and I need 1/2 the solar controllers (which is big savings). Its interesting since on boats we shied away from 24V as other items (like lights, fans, windlass, ect) cost way more. However, since I will only be running 120V inverted power to the cabin I really don't care about the battery voltage.
Sucks a little as 3 weeks ago I got a great deal on a pure sine wave inverter.. Alas its only 12V.. So I will have to sell that and buy a 24V one!
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Brettny
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# Posted: 11 Feb 2022 08:40am
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What benefit are you thinking of in 24v vs 12v if you alreaty have the 12v inverter? Typicaly any negitaves are in line loss. With you only sending 120v I dont really see any losses in 12v over 24v.
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paulz
Member
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# Posted: 11 Feb 2022 09:35am
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Quoting: travellerw Parallel vs Series. Lots of debates on this subject. It really depends on use case and the local environment. Series means smaller wires and a slightly more efficient MPPT controller. However, it performs much poorer in shaded or cloudy environments.
Due to partial shading of a series array? Or, with both arrays in total shade will the parallel still perform noticeably better?
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travellerw
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# Posted: 11 Feb 2022 10:20am
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Quoting: Brettny What benefit are you thinking of in 24v vs 12v if you alreaty have the 12v inverter? Typicaly any negitaves are in line loss. With you only sending 120v I dont really see any losses in 12v over 24v.
The big benefit is that "most" solar controllers are rated in AMPs on the output side. So for example a 100/50 rated controller is good for 640W of solar if your battery bank is 12V, but that same controller is good for 1280W in a 24V system. This means you will spend roughly 1/2 on the controllers. Since I need controllers for 1700W of solar, its a pretty significant savings (well worth selling the inverter I got and replacing it with 24v).
The second benefit is the size of cables on the output side. Everything can be smaller (and less expensive). In my case this won't be a big savings as all those runs will be very short. Still some savings though.
Quoting: paulz Due to partial shading of a series array? Or, with both arrays in total shade will the parallel still perform noticeably better?
In both cases the parallel array "should" perform better (in total shade, both would produce almost nothing). However, the type of panels (mono or poly) can affect this a little bit. Series wired arrays are good for a roof installation with a clear line to the sky. Shading is minimal (just passing clouds) and the smaller wiring (and lower losses) make sense and saves you money since your runs are usually pretty long. However, in a smaller array with shorter cable runs, parallel wiring makes more sense (usually).
For my installation, its really splitting hairs though. I'm willing to bet that the differences in average produced power between either install would be minimal, at least in summer. I'm guessing the parallel install will perform better in winter with some snow coverage.
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travellerw
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# Posted: 11 Feb 2022 10:23am
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Here is a video showing shading effects on a system in both parallel and series.
https://www.youtube.com/watch?v=1qD3mN8VotQ
Of course this is not a lab based scientific test, but its pretty valid. I'm not a fan of these youtubers either, but it was the best video I could find on the subject!
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Brettny
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# Posted: 11 Feb 2022 10:46am
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Quoting: travellerw The big benefit is that "most" solar controllers are rated in AMPs on the output side. So for example a 100/50 rated controller is good for 640W of solar if your battery bank is 12V, but that same controller is good for 1280W in a 24V system. This means you will spend roughly 1/2 on the controllers. Since I need controllers for 1700W of solar, its a pretty significant savings (well worth selling the inverter I got and replacing it with 24v).
That is true. Didnt think of that.
I plan on adding a second CC to my system for the redundancy of it. The cost difference between 1 big vs 2 smaller isnt that much. You can also setup pannels in different directions this way. For me my pannels dont see alot of sun, 2-3hrs in the summer. I actually get more once the leafs fall.
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travellerw
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# Posted: 11 Feb 2022 10:56am
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Quoting: Brettny plan on adding a second CC to my system for the redundancy of it. The cost difference between 1 big vs 2 smaller isnt that much. You can also setup pannels in different directions this way.
That is a common design in the marine world. Panels are broken up into strings with each string having its own controller. Not only does this provide redundancy, but when shading happens on one string it doesn't take down the whole array. As you can imagine on a boat shading is an issue (mast, boom, rigging, ect).
At our property I'm actually pretty lucky as I have a perfect spot for the panels facing south that is open for about 200 yards.
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gcrank1
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# Posted: 11 Feb 2022 01:25pm - Edited by: gcrank1
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Are there 24v PWM SCC's?
350W panels at what VOC? Gotta watch the input volts to the SCC.
It was recommended to me that whatever my panel wattage ratings were that I calc 70% of that as real-world.
Being in a poor solar exposure I only have e, se, and a little s sun until about 1pm at 43* lat., fixed grd mount to maximize for spring & fall equinox. That has given me 3 seasons of decent solar gen given the limited hours I can pick up. Then the tall pines hurt, though even with some spotty shading my MPPT screen still shows I gain some.
Btw, I saw something a while back regarding which way of mounting panels is better, horizontal or vertical, to min. the partial shading effect/the way cell groups shut down. Iirc hor. was better?
My conclusion based on my place is get the best array location you can right away to avoid shading if at all possible. (Ive moved mine 3x, and another to go!)
I have to use the MPPT and 24v setting on my SCC to get the 8ga. wire run from array to SCC. The PWM and parallel array was going to be way too many wires, combiner boxes, fuses (each panel or panel set in parallel is recommended, some required, to be fused as I understand it). 2S/3p simplified my set up big time, wish it could have been 3s/2p but my SCC couldnt take that input max with adding on a buffer for cold weather potential voltage spikes.
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travellerw
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# Posted: 11 Feb 2022 02:07pm
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Quoting: gcrank1 Are there 24v PWM SCC's
Not sure.. I will be using an MPPT controller(s) (probably Victron).
The panels have a 47V open circuit voltage (pretty high). So if I do go series I have to be careful, but Victron offers a 250/70 that could handle the whole array in series with a 24V battery bank. Victron controllers auto sense the battery voltage and many can be used in 12/24/36 or 48V battery banks.
If I go with a parallel install, I will do a "home run" from each panel to the box using the appropriately sized wire for the voltage/amperage of that panel (37.6 load voltage and about 9A). The longest run will be about 12ft (really 24ft since you must use the length of both positive and negative wires). I could get away with 10AWG with a 1.7% loss. All panels will terminate to a busbar (or 2) and then feed the controllers (with a switched breaker).
In a parallel install I could opt for cheaper controllers like 2 Renogy Rover 40A. Pretty big savings over the Victron.. We will see!
I'm probably overdoing everything but my brain is stuck in design mode at the equator. It was pretty common to have arrays that overproduced the rated watts down there. Up here, I bet I will be lucky to see %80 of the rated watts.
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gcrank1
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# Posted: 11 Feb 2022 05:27pm
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From what Im reading over at diysolar.com regarding current Renogy products Im not inclined to buy them.
If you havent, run the online tools for your lat. and conditions for insolation through the seasons.
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travellerw
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# Posted: 11 Feb 2022 07:51pm
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Quoting: gcrank1 From what Im reading over at diysolar.com regarding current Renogy products Im not inclined to buy them.
Thanks fella.. Looks like I have more reading to do!
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Bruces
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# Posted: 11 Feb 2022 08:27pm
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Not sure what the supposed issues are with Renogy lately ,I bought my 40 amp rover 2 years ago after will prouse tested it with several others and said it was a good unit ,I bought a 60 amp last summer ,my friend has a 60 amp and his brother in law has a 30 amp unit ,none have had a single issue or problem and we would all be happy to buy them again .There is another brand I can’t think of the name ,that’s the same units with bigger wire terminals and they are a few bucks cheaper ,I guess I would buy them the next time ,but no reason to not buy the Renogy rovers again .I hooked mine up and have not had to mess with anything on them at all ,not even once .I paid $140 CAN for my 40 amp rover ,$190 for the 60 ,I am very happy for the money with what I got .
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Steve_S
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# Posted: 12 Feb 2022 05:57am - Edited by: Steve_S
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Renogy = RUN Ohh Gee ! DON'T !
Many AIO's have Dual SolarControllers in them...
EPEver is a good "Value" Brand of SCC, Inverter/Charger etc. https://www.epever.com/products/
*PWM & Shaded panels do not play well together, MPPT controllers handle it far better. Setting up strings in a manner that reduces shade per string is always challenging as the entire string is affected even if a few cells on a panel are shaded.
Hope it Helps, Good Luck.
If your looking for an Ontario Retailer with decent pricing and are curious, check this out & peruse.
https://www.solarshoppingmall.com/MPPT-Charge-Controllers_c_21-1-3.html
Another in Toronto + Area who comes up with some really good deals to look at:
https://dnmsolar.com/productlist.php
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travellerw
Member
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# Posted: 12 Feb 2022 10:02am
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Quoting: Steve_S Renogy = RUN Ohh Gee ! DON'T ! Many AIO's have Dual SolarControllers in them... EPEver is a good "Value" Brand of SCC, Inverter/Charger etc. https://www.epever.com/products/
That is interesting. Things seemed to have changed.
Epever was total and utter trash 5-7 years ago. I have seen tons of failures on boats. I actually fixed a few by replacing the mosfets or bridge rectifiers. The original components were generic non-branded being used to the maximum rating.
They also had VERY poor MPPT algorithms. Any small amount of shade would make the controller hunt for the maximum power point often taking minutes to find it. The controllers would even randomly reboot on occasion. I actually have e-mail between support engineers and myself detailing the issue (which they were able to recreate). In the end I was told they couldn't fix it and I just had to live with it.
We started life on the boat with Epever (I was cheap). We ended up replacing them with Victron after all our electronics were destroyed in a lightening strike. Our average monthly energy harvested went up by %20 (guessing the better MPPT algorithms).
However, that was over 5 years ago! I'm guessing they solved many of those problems if they are still around as a company.
I have no experience with Renogy electronics (I have used their panels). However, I have done some searches (google and Diysolar forum) and can't seem to find any negative information about the Rover series. Does anyone have some specifics on their issues (aside from Renogy=Bad)?
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Brettny
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# Posted: 12 Feb 2022 06:23pm
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I have family that has a 80a EP ever CC and they have lived on that CC for a few years now
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gcrank1
Member
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# Posted: 12 Feb 2022 07:40pm
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Looking over different offerings these past couple of years it troubles me that so many have small, chinzy wire connectors, often smaller than the proper gauge wire for the max 'ratings' of the units.
That alone is enough to make me question the build of a unit, in fact, that becomes my first pass/fail of it.
Afaik we have no 'clearing house' for solar devices, there seems to be a plethora of cheaply made clones, even clones of clones? online. Its truly 'buyer beware'.
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Brettny
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# Posted: 12 Feb 2022 07:45pm
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Wire size depends alot on the run length and volts/amps. Do you have a specific CC in mind for that?
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paulz
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# Posted: 13 Feb 2022 08:25am
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I smoked a Renogy (not a Rover) CC with just a couple volts over the 100 input limit. Supposed to have built in protection, that didn't work.
I bought a new 20A Rover off a friend cheap, tried it a couple times just to keep truck FLAs charged, kept seeing E11 code (low battery) after a couple days. Haven't played with it much.
Have 2 Epever Tracer BNs, one in the cabin and one in the shop. Both have worked flawlessly, although Travellerw's talk about poor performance has me concerned..
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travellerw
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# Posted: 13 Feb 2022 09:31am
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This is a super old video (like 7 years), but shows the issues with the algorithm on the Epever. I'm not sure if this issue is just with the BN series or all of them.
https://www.youtube.com/watch?v=dFuZywwpfaU
Again.. This is MANY years ago and I have to assume they fixed these issues in later firmware. However, for me, all the firmware they sent me still had the issue which I just lived with until I replaced them.
I did find this quick comparison between the most common MPPT controllers. It seems to show what I found, that the Victron harvests more energy.
https://www.youtube.com/watch?v=j7DwgUGpI84
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paulz
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# Posted: 13 Feb 2022 10:32am
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Interesting, thanks. He does mention firmware update comments (in the first video) up to 2019 with no improvement. I wonder if I can check/update the firmware on mine, I'll have to look into that. When I click on the part 2 link at the bottom it just loads part 1 again.
I am severely hampered by shade, any help I can get would be worth it, even if it meant popping for a Victron.
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travellerw
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# Posted: 13 Feb 2022 10:44am
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We actually worked together to try and get EPEver to fix the firmware. Neither of us had luck in getting new firmware that fixed it.
Part 2 is just an overview of all the menus on the MT50. Part 2.5 is more interesting as he shows the performance when the panels are hot.
https://www.youtube.com/watch?v=Ws6WHHCfETg
As to the Victron.. I can definitely say they are good controllers and backed by good support. If something does go wrong, Victron has pretty much a no-quibble warranty. The only bad thing I can say about them is they do produce some electrical "noise" as they reduced the range of our VHF by about 1/2/
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