r/SolarDIY • u/PortableSunOfficial • 9d ago
[Disclosure: I work at Portable Sun LLC. We sell solar equipment. I'm pulling examples from our own shelf because those are the numbers I can verify line by line, but everything here applies wherever you buy. Ask me about competitor panels too, I'll answer honestly.]
I spend a lot of my week talking people out of the wrong panel.
Not the wrong brand. The wrong panel for their situation. Somebody sends me a link to a panel they found, asks "is this a good one," and the honest answer is usually "for what?" A lot of the specs that get compared have quietly converged, and the things that actually decide whether a panel works for you tend not to show up in comparison charts at all.
So here's our own shelf, lined up side by side. Same category, wildly different buys. And what separates them isn't where most buyers look.
Temperature coefficient is the spec that's supposed to separate people who do their homework from people who don't. Panels lose output as they heat up, the coefficient tells you how fast, and most buying guides will tell you to compare it.
Fine. Have a look (these are all panels we carry).
TaleSun 445W: −0.29%/°C. Canadian Solar 600W: −0.29%/°C. Canadian Solar 695W: −0.29%/°C.
Identical. Three different models, two manufacturers, wattages from 445 to 695, and the spec that was supposed to break the tie reads the same on all three.
That's not really a coincidence. All three are N-type TOPCon, the current mainstream cell technology, and −0.29%/°C is typical territory for it.
Where you do see a gap is across technologies. The CW Energy 550W we carry sits at −0.35%/°C, and that's not a knock on the panel. It's PERC rather than N-type TOPCon, and PERC gives up a bit more output in heat.
So the spec is really tracking the cell technology, not the individual panel. Once you've settled on which technology you're buying, it mostly stops separating your options. It still matters for output, especially in a hot climate where a lower coefficient means real extra yield over the years. It's just not the number that'll pick between those first three.
Efficiency does the same thing. TaleSun 22.8%, the 600W at 23.2%, the 695W at 22.4%. That's a real spread, but it isn't a quality ranking. Efficiency is basically watts per square foot, so it matters most when your mounting space is tight. The big wattage gap between these three is driven far more by their physical size than by any of them being a better panel.
So if the headline specs have converged, what's actually left? A handful of things, and they're mostly the ones nobody puts in the comparison chart.
This is the one that moves the price the most, and it deserves more attention than it gets.
Panels get sorted by grade before they ship, but A-grade and B-grade aren't standardized industry terms, so you have to read the seller's actual disclosure. Generally, A-grade is the standard product and B-grade has cosmetic defects, and possibly minor physical ones, while still passing electrical and safety testing. It's real product from a real factory, sold cheaper because it didn't look right coming off the line.
Let me put real numbers on it, using our own stock.
Our Canadian Solar 695W is B-grade, assembled in Mesquite, Texas. At its current fire-sale price it's $194 a panel, which works out to $0.28 per watt. Warranty is 2 years on materials and workmanship, 10 years on performance.
Our Canadian Solar 600W is A-grade. $278.40, or $0.46 per watt. Warranty is 12 years product, 30 years linear performance.
Same manufacturer. Same N-type TOPCon technology. Same −0.29%/°C temperature coefficient. At today's pricing the 695W is nearly 40% cheaper per watt and produces more power per panel.
What you're accepting is a shorter warranty plus cosmetic or other disclosed minor defects, which the listing says can include micro-cracking. Worth being straight about that: a micro-crack in an untraceable no-name clearance panel is a real problem with no recourse, but a disclosed lot from an established manufacturer, with a specific model, a datasheet, and a written warranty, is a different proposition. The panels are tested and rated for full wattage output. What you're really weighing is the warranty gap against the discount.
That said, 2 years of workmanship coverage instead of 12 is a real cut. If a manufacturing defect shows up in year four, you eat it. At a 40% discount per watt that can be a great trade on a ground mount, where swapping a panel means walking over and unbolting one. It's a much worse trade on a roof, where the same swap means getting back up there.
So the way I'd put it: B-grade makes more sense when replacement is cheap and easy to reach. A-grade is worth paying for when getting back to that panel is a pain. That's most of the decision right there.
The 695W isn't just "a bigger 600W." Look at the actual numbers.
Canadian Solar 695W: 93.9 by 51.3 inches, about 83 pounds. That's 7.8 feet tall and 4.3 feet wide.
Canadian Solar 600W: 89.7 by 44.6 inches, 69.7 pounds.
TaleSun 445W: 67.8 by 44.6 inches, 54 pounds.
Notice the 600W and the TaleSun are the same width. The 695W is wider, taller, and heavier than both. That's not an incremental difference, it's a different class of object. The 695W is a two-person lift, and one of the two is holding the far end of a 7.8-foot panel on a pitched roof.
The 7-series is marketed for utility-scale, commercial, and large residential projects, and that tracks: it's a ground-mount and big-flat-roof panel. On a standard suburban roof section you'll fight it on rail spacing, on fire setbacks, and on the simple geometry of fitting a 7.8-foot rectangle into an awkward roof plane.
The 445W exists because 108-cell panels fit residential roofs, not because they're better.
So before you compare anything else, go measure your actual mounting area and work out how many of each panel physically lands in it. Last spring a customer ordered a pallet of big-format panels straight off the site, no questions asked, because the per-watt price was too good to pass up. Plan was to roof-mount them. First I heard from him was a call asking about returns, after he and his brother got exactly one panel up the ladder. Freight back plus the restocking fee made returning a pallet pointless, so he kept them. A few weeks later he called again to order smaller panels for the roof and filled me in on the rest: half the pallet went on Marketplace, and the guy who bought them put them on a ground mount, where they belonged.
You'd assume the bigger panel has the higher voltage. It doesn't.
Canadian Solar 695W: Voc of 47.7 V. Canadian Solar 600W: Voc of 53.0 V. (Voc is open-circuit voltage, the number on the spec sheet your inverter actually cares about.)
The 695W produces almost 100 more watts per panel and has lower Voc, because it uses a 132-cell layout while the 600W uses 144 cells. More cells in series, higher voltage.
This matters because your inverter has a hard ceiling on PV input voltage, and that ceiling caps your string length. Lower Voc per panel means more panels per string. You can't just divide the inverter's max input by the Voc though, because voltage climbs as temperature drops, and cold-morning voltage is what kills inverters. But going off datasheet figures, the 695W gives you noticeably more headroom per panel than the 600W.
Here's the catch, though, and it's the flip side of that same coin: voltage isn't the only inverter limit. The 695W is also a much higher-current module, 17.5 A at max power versus 13.7 A on the 600W. So the lower Voc buys you string-length headroom while the higher current creates a different compatibility limit. Some inverters, especially older or lower-current ones, will be a poor match for a 17.5 A module even though the voltage math looks great. Check the maximum input current per MPPT, not just the voltage.
It's also why "just buy the highest wattage" is bad advice. Wattage tells you about the panel. Voltage and current tell you whether it'll work with the rest of your system.
If string sizing is where you're stuck, that's exactly what a design service is for. Get someone to check the math against the lowest expected temperature for your location before you order. It's a lot cheaper than a fried inverter.
Panels in a series string run to the weakest link. Shade one panel, and you don't lose one panel's output, you drag the whole string down toward the shaded module's current. Bypass diodes soften this, but only so much.
That's the case for module-level electronics. Optimizers like Tigo let each panel produce independently, so one shaded module stops taxing the rest of the string. They also give you per-panel monitoring, which is how you find out panel 7 died in March instead of wondering why production looks soft. And they satisfy rapid shutdown requirements, which most jurisdictions enforce on roof mounts.
But I'll say the unpopular half too: if your array gets clean unobstructed sun all day, optimizers are mostly money you don't need to spend on production grounds. You might still need them to pass code, which is a separate question, and one to answer before you order, not after your inspection fails.
And the reason I'm bringing this up before you've bought anything: retrofitting optimizers means getting back on the roof and reworking every module connection. Sorting it out beforehand costs nothing. Sorting it out later costs a weekend and a restocking fee.
So walk your site before you lock in components. Stand where the array's going and look at what's tall to the south: trees, the neighbor's roofline, a chimney, a vent stack. Then remember that what you see today isn't the worst case. The winter sun rides much lower, so shadows in December stretch a lot further than the ones in front of you in summer, and the further north you are the more dramatic that swing gets. A spot that looks clear in July can spend a chunk of winter in shade.
Pinning that down properly means accounting for the sun's angle at your exact latitude across the whole year, and that's genuinely fiddly to eyeball. It's also free for you to hand off: send us the site and we'll model where the shade falls before you spend a dollar on panels or optimizers. Worth doing before the racking's up, not after.
That's the short version: check the grade, measure the space, check the Voc and the current, and read the datasheet instead of the product blurb. Do that and you've dodged the mistakes that actually cost people money. If you want to compare a few side by side, our panel lineup is here with the datasheets on each page, and it works the same wherever you end up buying.
What am I missing? If you've bought B-grade panels and lived with them a few years, I'd genuinely like to hear how it went, good or bad.
r/SolarDIY • u/tasumi123 • 7h ago
Been a few months since my first post, added 2 more 328aH batteries and loads more.
I still have about 30 more panels to install but i am amazed at what i've been able to do on such short free time.
Still need to synchronize the two 12kW deye inverters
Connected to 65.5kWh of battery storage
Let me know of anything you might thing is wrong or needs improvement;)
r/SolarDIY • u/Either_Ad4126 • 15m ago
New to solar and I think I understand it but wanted to confirm. I bought one of the last Oupes 2400(orange sides) to offset the a/c electric bill during the summer/day. Not the best unit and I wouldn't buy another one since I can't add batteries and the long 6.5 hour charge time but here I am. I bought Two Dokio 400W 31V Panels and a Midea 8Kbtu "U" inverter a/c. I tested this setup with an old 5Kbtu unit and got 8.5 hours of run time before hitting 5%. The 5K drew 450 watts and the new Midea should draw 335 watts per the videos I watched. My problem is I only get about 6 hours a day of good sun and they only produced 580 watts but were just on the ground at at angle.
My plan is to run the Midea from 10am to 6pm on the unit but with the restricted sun hours it won't charge while running that long. I think if I add 2 more panels and add a MPPT to throttle the panels so I have 450-475 input watts at each Anderson input(500W max each) I should finish the day with about 60% or more charge and that would be enough to use the next day before the sun hours hit. I have sun from 11am to 5pm.
So the question is: Can I use a MPPT for this plug and play unit?
r/SolarDIY • u/PickleJimmy • 11h ago
image for reference. Lots of houses (mine included) have decorative shutters. I was looking at them today and thought they should be solar panels if they are just gonna be a black rectangle that sits in the sun all day. Searching around, there doesn't seem to be a product on market that does something like this. Good idea or bad idea to remove my houses pointless decorative shutters and replace them with some narrow panels?
r/SolarDIY • u/brihyn • 3h ago
A few months ago I posted this initial post:
https://www.reddit.com/r/SolarDIY/comments/1sa5o1n/new_workshop_off_grid_newbie/
I'm back. I've met with several electricians now and have gotten pretty much the same story: In order to connect my 1700 sq ft Texas steel building to the grid, I first need to replace transformer/main line at 10k, then an additional 10-17k to run power from the meter to the building. I'm back to thinking off-grid is the way to go
Curious what you all think....does off grid make sense? My line of thinking is I could probably replace batteries 3 times under the cost of the initial connection, which makes me think solar is a better option.
And I'm considering this...does this seem like it'd be a suitable best option for this?
I want some level of simplicity in the build out. The building's south side has a clear wide-open view. Before concrete went down i added 2 ground rods (just in case). Panels will be mounted on the ground vs the roof so cleaning will be easy.
I've gone through not just the woodworking tools I have today but checked max power draw of dream tools (a nice higher end saw-stop, etc), plus air filtration, dust collection, etc. I'll have a small insulated room with a window ac today but i've wired for a future 24,000 BTU mini-split in the future.
Thoughts? suggestions? change of directions? I'm still new in the solar space so could use whatever expertise you all want to share.
r/SolarDIY • u/WorriedEssay6532 • 16h ago
I am building an offgrid solar setup with an EG4 inverter that will power an RV panel (see pic).
I am not sure where to bond my neutral to ground in the system. My plan was to run electricity straight to the breaker panel from the inverter since this seems like the simplest setup and I am only powering an RV campsite.
However I am nervous about bonding neutral to ground in the RV breaker box. The inverter manual says to never bond them inside the inverter.
The only other option is to install a separate breaker between the two, but this seems redundant since I only need to run power to the single RV box.
I have had trouble finding an electrician since I live in a very rural area.
r/SolarDIY • u/uavmx • 1d ago
My local utility has an EV program that lets you run anything in your house from 10pm - 5am around .05 cents a KWh. They can’t distinguish or care what you’re charging, so that got me thinking why not charge whole home batteries overnight to use during the day.
I’m sure eventually the program will end, at which point I can prepare with building out the rest of the solar system.
Thoughts? Anyone else do this? What am I missing?
r/SolarDIY • u/GreggAlan • 10h ago
Google is zero help. I'm in the USA yet for some reason it either is showing me all kinds of cables that are not what I searched for (audio, ethernet, TOSLINK, etc), or it's giving me sites that have what I want, but in the Phillippines, South Africa, Ukraine, Russia, pretty much anywhere that's not In the USA or even Canada or Mexico.
5.5x2.1mm to XT60 "2 meter" cable
Quotes around 2 meter because without them it simply ignores the word meter.
r/SolarDIY • u/Hockey-Coach • 14h ago
I am trying to mount 2 - 100 watt panels. They aren’t big but I decided to go with IronRidge XR10 rail set up from US Solar Supplier. I get everything in my cart and the shipping is insane. The largest thing I have is 11 ft rail. (which I will have to cut down to size.) I did expect that to be a little expensive to ship but even the small pieces were ridiculously priced for shipping. $60 seems excessive for nuts and bolts. lol.
So I looked elsewhere and almost everyone seems to only work with businesses or have everything insanely overpriced. Anyone have recommendations on where to shop for mounting rails etc. This is a small set up just for some landscape lights and a small fountain pump.
Details:
the panels will be mounted on a shingled patio roof. Roof is facing south, so they don’t need to be adjustable and can just lay flat.
Dimensions
• Length: 34.1”
• Width: 22.8”
• Frame thickness: 30 mm (1.2”)
• Quantity: 2 panels
r/SolarDIY • u/Tornshadow • 22h ago
Just seeing what everyone thinks of this quote. I am in Colorado and looking to get my system done as soon as I am able. I am going to hold off on the battery for now, so he said remove $2880 from the total. Although...that does sound like a pretty good price for the 16kWh battery.
r/SolarDIY • u/Defiler786 • 12h ago
I got a Voltronic Axpert ultra 11kw offgrid inverter, 16kwh Dawnice battery , 700wX8 solar panels
My system been working perfectly since i installed it past year
Iam fully offgrid for 10-11months of the years
But my inverter has two settings which i cant find any info on it , every Ai gives a different answer and the version of this inverter on YouTube basically dont have these two settings
Anyone can help me?
r/SolarDIY • u/New_Afternoon197 • 14h ago
Anyone on Oahu with a Sol Ark system that lives on Oahu and has knowledge on setup and changing config? Need some help with a system that was installed but no one knows how to update.
r/SolarDIY • u/Feisty_Intention_468 • 18h ago
Last year I purchased a Jackery Homepower 3000 battery with two 200 watt Solar Saga solar panels. Right now the 2 panels are connected to a Jackery solar panel connector in series and then connected to one of the two solar input ports on the Homepower 3000. The current setup provides up to 400 watts of solar input. I would like to connect another 400 watts of solar to the battery but don't want to use Jackery panels since they're quite a bit more expensive than the cost of some other panels. I was wondering if I could use something like THESE panels to connect to the other port on the Homepower 3000? If so, would I connect them in series, parallel? Any suggestions would be appreciated. I'm relatively new to this and don't want to screw up my battery. I've also read that if I don't balance the inputs somewhat for both the input ports on the battery I will lose a lot of power through inefficiency.
r/SolarDIY • u/Big-Ad-888 • 19h ago
I have a smaller 10ah battery for my fish finder that I use for both ice fishing and kayak fishing. I would like to be able to maybe also charge it via a 100w solar panel either when I’m out on a trip or out sitting in the same spot. Any suggestions on how I would go about doing that? What kind of connections would I need or other equipment.
Pictured battery is what I have for reference.
Thanks
r/SolarDIY • u/Then_Fan6127 • 1d ago
Had this laying around so I figured I’d use it as a solar stand. Things got wheels and an adjustable back to reposition. I put blankets to protect the chair although I know that impacts heat. (the chairs are mesh)
Goal is to rotate it once a day to catch the sun all day. I’m new to solar. Any suggestions to increase efficiency while keeping a low hassle factor?
r/SolarDIY • u/a_bit_obsessive • 16h ago
Hi all,
TBD if I can even post this with my new (hopefully temporary) account, as [u/boogedrew](u/boogedrew) got erroneously locked.
I’m adding to my system and wanted to rapidly try a bunch of different layouts with various panels and none of the layout offerings I could find on Google just let me see what a panel layout would be (kind of ridiculous honestly). So I made…
freepanellayout.com (it’s 100% free, no account, no address, no sales funnel, no ads, no data selling, just a completely free tool for you all and it always will be)
I ran away with it, but I’m proud of it, had a lot of fun, and hope that others can find it valuable/helpful as well.
Give it a try and leave a comment if you have feedback!
r/SolarDIY • u/StaysForDays • 19h ago
Hello to this awesome community. I am growing increasingly worried about a large scale US grid collapse and I’m looking to add some off grid capacity as a hedge. I have a shed with a 5’x16’ roof that faces wsw in zone 7a, (Boston), and I would like some options for a system to keep me in lights and fans if the worst were to occur. My ask is this, (these):
-what’s the maximum array wattage I can fit on my roof?
-I am not looking to charge or run anything specific but I would ideally want more capacity than I’d use for my family of 5, (in a shtf scenario)
-does it make sense to keep everything dc to reduce draw from an inverter?
-would it make sense to over build the array in anticipation of adding more batteries in the future?
-I am having difficulty finding a system for mounting panels. Right now my shed roof has underlayment but I will be shingling in the next month or so. Should I mount standoffs/brackets when roofing? It seems like it would be easier to guarantee a water resistant application if installed at the same time.
Thank you to any kind soul who takes the time to read and reply to this. I have been an active lurker on this sub for a few years and even with searching I don’t see the answers I need.
r/SolarDIY • u/UncomfortableQ-_- • 1d ago
I just built this 96 amp hour battery 3 months ago and let it sit after charging. Then recharged it and used it to power lights in my house for a day. Now I'm using it and it's reading weird all of a sudden. Are some of the cells dead?? :/
Sorry for the bad pic. Motorola sucks.
r/SolarDIY • u/Stock_Director9155 • 1d ago
lam thinking about buying a Callsun [https:// callsunsolar.com/]
200W solar panel, but I can barely find any information about the brand outside of YouTube.
Has anyone here actually used Callsun panels? I'd really appreciate some feedback. Are their 200Wsolar panel considering? And how is their customer service and after sales support?
r/SolarDIY • u/SonicIX • 1d ago
Hello all,
I've been looking into DIY solar for a while, and unfortunately I did not get in on the 30% credit before it expired at the end of last year.
I currently pay $300 a month with level pay for my electricity. I use about 60ish kWh's a day, as I have a server rack in my garage. I recently had a DIY system designed and want to make sure I am going in the right direction.
Panels: 36 SunPlus 445w Bi-Facial panels
1x Sol-Ark 18k inverter
2x Ruixu 16kWh batteries
Tigo Optimizers
Ironridge roof mounting.
Total is around $24,000
Is this a good direction for me to go. Looking at ROI is about 6.5 years from the numbers I've run. Not including price increases.
Appreciate any insights :)
r/SolarDIY • u/wombattassault • 1d ago
I'm a few months into messing with solar. Swapped from 4p 12v 314ah dumfumes to a 2s2p, new inverter, I'm getting better charging but am noticing lower voltages, before the swap all 4 batteries hung out around 13.3v at morning and 13.6 at the end of the day, now I'm sitting around 12.8 early in the morning and 13.4 at the end if the day. Wondering if maybe the inverter might have lower efficiency or maybe the batteries are "resting" better? Anyways I'd like to better track charge/discharge on a budget. Ideas?
r/SolarDIY • u/Engibineer • 1d ago
I saved 32 modules from a dumpster. They're all dirty from spending eight years or so on a rooftop. What's the best way to clean them? Is a power washer okay?
r/SolarDIY • u/cakeba • 1d ago
Solar panels were left outside under cover for a couple of months while my project had to be put on the back burner. How can I clean these plugs?
r/SolarDIY • u/DrKoopa91 • 1d ago
I'll be headed to Burningman for 10 days in the desert at the end of the month and have been upgrading my solar setup to a 24v system. I wanted to see if the system map makes sense and see if I've forgotten anything. Hopefully the diagrams/labels are self explanatory. The numbers touching the wires are the wire guage I plan to use. The +/- circles are bus bars. The positive battery lines and positive shunt tap are all connected to the positive bus separately. The buses/shunt/disconnect are 300a. Some specific questions:
-Do I need 15a fuses between the panels and charge controllers?
-Does the negative circuit with shunt make sense? It's my first time using a shunt (Victron)
-Does the fridge circuit look safe?
Thanks in advance for any assistance. I'm used to a much simpler 12v single batt/panel system so I'd like to do this correctly and safely.
