What Wire Should You Use For DIY Solar Kits? Surprising Results!
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- เผยแพร่เมื่อ 3 ส.ค. 2023
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I have been using a line loss (voltage drop) calculator to size the gauge of wire to use for a 100' run out to some solar panels. The most common gauge of wire used in DIY solar setups are 10 and 12 AWG but I think that will result in a higher than desired voltage drop resulting in power loss. To ensure I make the right decision I am testing out 8, 10, and 12 AWG all in 100' lengths to compare side-by-side what losses I can expect.
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Your test is very simplistic. First off, the higher the voltage, the less your transmission losses. Somebody has said it already. You want to series your panels. Get the voltage as close to the max your MPPT can take. That means, that for the same wattage, your current will be much less. It is the current that dictates the size of your conductors. As long as your insulation is rated for the voltage. All the Solar specific cables and connectors I have found is rated for 1000volts. Your MPPT is nowhere near that. Its all in Ohm’s law.
If you use panels in parallel, you will need to fuse each parallel string. And, probably diodes. It depends on the specific panel how many volts they can handle. The long and the short. Series is best.
You didn't watch the whole video. He said as much in the end.
He's trying to avoid the High(er) Voltage legal requirements.. you can laugh at my comment... 'electric fence' [just spike it through.]
If you put the same panels in series then your current would be halved and your line losses would be a quarter. Then it would matter much less what wire you use.
Agreed. This video should have included a series connection. Nobody is going to run in two parallel. I expect the results wouldn’t be as exciting with parallel though. Also, most aren’t doing 100 foot runs.
@@ryanyoder7573 The results are still valid. They show the effect of Voltage drop over a distance. 100 is a nice number. Also, 100' to a ground mounted array would not be odd. Not all rooftops are in direct sun.
@@steveurbach3093 yes they are valid they are just way more compelling due to the low voltage used which produces a high drop
@@ryanyoder7573 I will run five in parallel. My system is designed to be 12 volts, and the controller can't do 24v, even. I will be using a shorter, 4 gauge cable.
It would be nice to have different design constraints.
@@jamesalles139Don’t forget to fuse EACH panel if you wire them in parallel! Fuse rating is the one written on the panel labels.
Total Amps and Wire Length are the controlling 2-factors. Short wire lengths allow smaller wire gauges. All this video proves it best to get a solar controller to handle as high VDC (48 VDC is better than 24 VDC which is better than 12 VDC) as possible (solar panels in series vs parallel) and keep amperage low as possible to the controller.
I think most marine equipment are also 48 V .. so it opens up appliance options that avoid conversion to 120VAC which means even less losses
The losses in the circuit are determined by the resistance of the wire and the electric current according to the formula P = I^2 x R . If the voltage is multiplied by 2, the current required to supply the same power to the load will be divided by 2. Therefore, the loss in the wire will be divided by 4, allowing the use of a thinner and cheaper wire.
@@nathanneimansweet. Thanx.
Using microinverters on the roof solves a lot of the design complexity of figuring out parallel vs series wiring of your panels, including what gauge wire to run. More important, they alleviate the issue of one panel being in shade taking down the output of a substantial part of the system. While the microinverters themselves add cost to an installation, they should save money in labor costs (assuming you are paying someone to install a system,) due to the simplicity of the wiring. You incur losses converting back to DC to charge a battery backup, to be sure. If you have short runs, no or very little shade, and are charging a battery with your solar, DC direct wiring is probably best. If, like me, you have areas of your roof that move in and out of shade during the day, long runs back to the battery and panel, microinverters are probably better overall - probably. That, and we don't actually SEE the sun in the winter for months at a time. First 10 days of the year this year we had 5 minutes of actual direct sun :D Basically, there are many ways to peel this banana, and everyone needs to find the right one for their situation :) Videos like this provide data to help make those kinds of decisions.
@@smarouchoc7300micro inverters are the bain of the industry. Enphase has worked the system to defend their optimizer/micro-inverter business territory. Making up requirements not even considered by other countries.m like "rapid shutdown".
Micro-inverters assume the power will be fed to the grid not stored local.
For my system they are completely useless even counterproductive.
Grid tied is great if you want to sell power for a quarter and buy it later for a dollar.
Unless you have shading, optimizers are a waste.
I want my solar power to work if the grid fails.
Still a newby in the solar community and I'm not very smart. I really like your videos because you teach and explain things down on my level of understanding.
Master electrician here. #2 , 4, or 6 Aluminum USE is less expensive than any of those you tested. I worked mainly with ground mounted panels and the lengths involved are a very serious issue. Go with at least 48 volt systems and layout to minimize lengths anywhere possible.
what is No. 2, 4, 6 for a cross section?
@@jensschroder8214c’mon now…do a web search, don’t bother the man after he gave us words of true wisdom. Sincerely.
But also , aluminum isn’t as good in tropical climates, especially here on the big island of Hawaii, where we have heat, moisture, sulphuric acid, hydrochloric acid, and salt. Aluminum turns into aluminum oxide here at an astonishing rate. Copper is much less prone to corrosion.
As the thickness of wire goes up, the cost increases exponentially. For something like this, I'd at least do the math on the alternative of running two hots and two neutrals of a thinner gauge wire vs one conductor of the thicker gauge. There are calculators on line that let you look at this alternative, e.g. how many strands of AWG X = 1 strand of AWG Y. Of course the best thing is to max the voltage and shorten the cable run as much as possible.
Why does this guy look like Johny sins?
Thank you for sharing your insights on wire thickness and cost considerations for DIY solar kits. It's important to find the right balance between wire gauge and cost efficiency. Maximizing voltage and minimizing cable runs are indeed effective strategies. By the way, have you heard about the Segway Portable PowerStation Cube Series? It's a versatile and reliable power solution for outdoor enthusiasts and RV lovers. It offers massive capacity, powerful output, fast recharging, and comprehensive protections. Plus, it's designed with Segway's UltraSeal Technology for waterproof performance. Check it out if you're interested!
This is why I chose an EG4 inverter. it can handle 500 volts mppt. so the amperage is 10 or less.
Does this guy have a second channel? I swear he looks like someone that does a lot of handyman stuff, outlets, wiring, etc.
Yep, this is my second channel and Everyday Home Repairs is the bigger one for sure.
Thanks. Running in series has its benefits given the cost of copper wire.
Yeah, Series is usually my default 👍 if possible.
this was really good. seeing real world results are better than calculating estimates! 🙂
The UnboundSolar calculator seems to be set up for AC current. AC current flows more towards the outside of the wire (skin effect) and doesn't make full use of the core of the conductor. DC current uses more of the copper in the wire and therefore has less loss. I think this effect could be contributing to the differences you see in your tests and what the calculator results show. I.e. the calculator will always overstate losses if you are using it for DC currents.
this is true. its a fulty test
This is a common myth. Skin effect only starts being a thing at radio frequencies from around a few MHz and up.
At 60 Hz it varies between zero and virtually indistinguishable from zero, so the full cross-section of the conductor is in play.
Interesting results. I knew the 8 awg would be better, but I didn't expect that big of a difference. Thanks!
You bet!
Sadly, approx. 2/3 of grid power from our local utility companies is lost during transmission (but yes, customers are still paying for the full 100%). With Solar on your own rooftop there is hardly any loss with appropriate wire size.
@@acordia91 Average grid losses are only around 5%, not 66%. The reason is because those overhead wires are running at much, much higher voltages. The basic trade-off is: double the voltage, halve the current, power losses over the wire wind up being only 1/4 rather than 1/2 because you aren't only reducing the current, you are also doubling the voltage.
The reason it works like this is because wire losses result in a voltage drop based on (current x resistance). But POWER losses are a function of (current x voltage) and not only did you halve the current, you also doubled the voltage so even though the voltage drop is only halved, POWER losses are 1/4th rather than 1/2 because that voltage drop is relative to a doubled voltage.
20+ years off grid. You should keep your wire runs under 30 feet and 8 gauge for12 volt. 10 gauge for 24 volt and 12 gauge for 48 volt. You can reduce loss by moving the controller and inverter closer to the panels and use an inverter to run 110 AC to your home. A shed works for that.
I recommend 24 volt in series and a run under 30 feet with 10 or 8 gauge wire for off grid.
@@acordia91nice observations.
This is a subject that doesn’t get covered often enough, nor with your great real world hands on demonstrations. Bravo!!
I'm a new DIY solar player. This video helped me know that wire gauage matters. Thank you.
We are here to help 👍
I tell you the bigger the better, but in terms of wire thicknes not gauge
Thanks I really like your tests!
HOWdy E-D-S, ...
THANKS ...
You just helped me JUSTIFY my usage of MARINE Grade "tinned" 8 AWG Pure Copper Wire from my FIVE arrays ...
6S / 5P Configuration = now 30 Panels ( eventually to be 6S / 6P configuration = 36 Panels ) ...
to my ...
All-In-One GROWATT SPF 6000T DVM-MPV INVERTER (about 75' length ) ...
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the WiSeNhEiMeR from Richmond, INDIANA
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Victron and Eton Electric have the most up-to-date wire charts the most advanced scientific research is used with when determining individual installment,
So simple but people want to make it harder by not following procedures. 🤔 😊😅
You are the first, very first, after many many views, that is addressing this issue.
I've seen solar systems with the solar panels hundreds of feet away from the charge controllers or switch, and no mention of voltage drop.
Kudos to you!
Only question I have is the difference in drop if you go only 30 or 50 feet.
Keeping in mind for when I want to add more solar panels in the future.....so plan ahead folks, if not already maxed.
Thank you for the video.
Yeah, most the guys with experience say go as big as you can afford when it comes to wiring. Most system want future expansion capability 👍
Drop @ 30 or 50 feet should be .3 or .5 of the results @100 feet, as the resistance is directly related to the distance.
This is also why you should go as high voltage for the long cables as possible.
I have a "off grid" 12v mppt inverter that accepts 56v input and i have open circuit voltage about 54v so there is little loss before the inverter.
Also my "on grid" inverter have 470v input
Always have as many panels in series as the inverter accepts (open circuit voltage, no load!)
We use 10ga wire in large systems where the wire is going hundreds of feet. No matter how many panels you put in series, the max amps is 8 amps, the limit of the panel itself. Amperage is the killer in line loss due to amperage squared times resistance, and the reason we jack the voltage way up. When doing the calculations remember the list for resistance is for 1000ft of wire.
Wow, nice job in explaining what this even means. This tells me that this industry is ALWAYS fighting physics. Wow!
From Leo: Look up whatever wire size that the charts recommend. The ampacity charts have been standardized since WWII. Don't forget to de-rate according to length and temperature if applicable. Then use 1 size thicker. That is how I sized conductors in industrial applications since the 1970's. Everything I set up is still running even in horrible conditions. Whatever you think you are saving today will always bite you in the long run.
Thanks for the feedback 👍
You seem to be confused about ampacity vs voltage drop calculations. There are times when ampacity matters a lot, and so maybe that approach worked if you were pushing those limits more than voltage drop. An example would be short runs of high amperage, higher voltages. At that point voltage drop is out of the picture and ampacity is the limit. But for solar panel runs, not likely. An 8 ga will handle 40 amps and stay cool enough but that doesn't mean it's a good choice for 35 amps @ 12v over 300 feet. Nor is upsizing to 6ga adequate in that case. Use a Voltage drop calc and don't worry about ampacity in this usage.
Think of volts as the speed of the water through a pipe and amps as the diameter of the pipe. If you need to put 1,000 gallons of water an hour through a pipe it's going to have a much easier time if you up the speed of the pump but if the pipe diameter is too small you will get have to much pressure build up (resistance/heat in the solar cable). Always go as high a voltage as you can.... the money you save on the smaller cabling can be put towards a more modern up to 450v inverter.
Thank you father
Ive done real world tests and concluded that yes distance plus amps affects gains from thicker wire. But you want to consider average amperage not optimal. First of all, you will only get 80% of rated in best case. Second, thicker wire makes less difference when you need most efficiency- when its shaded and output drops to 30%...so optimizing for sunniest hours may not get you much over the whole year. That money may be better spent increasing your panels for cloudy winter days. Consider that for most overall yield per dollar.
Yes. Our solar systems from 1 to 20 megawatts in MA only consider 7 months of optimum solar. The other 5 months of winter are a bonus. And our 10ga wires run hundreds of feet from 500volts in 2013 to the 1200 volt systems now in 2024. The important thing for homeowners is to not cheap out and be sure they're using PV wire...and of course having a licensed electrician install the system. In MA only licenses can even touch solar.
@@Icehso140 Wow! At 500 volts (and even better 1200) the calculation shifts dramatically. Your professionals know what they are doing to bring up the voltage from the panels.
People doing smaller systems should understand that three things affect the wire size calculation: the voltage (often 100 or less), the watts delivered (again, I think 80% rated or even lower to save $) and the distance. Again, I contend that you don't need to care so much about maximum efficiency on the best days of the year at noon. You need sufficient efficiency on the medium days that are more numerous in your area when the power produced will be good but less. Optimizing wire gauge for the the highest possible output that you only get when there's more sun than your system is designed for is not usually the best use of funds. Exceptions would be maybe running AC on the sunniest days or a grid-connected system that pays back. But good to recognize that seeing that 80% of panel rating may only happen for short periods and when you least need it. Might make more sense to spend that money on more panel for the shorter or cloudier days. Of course, it's an iterative process. More watts bigger wire...
@@ceeweedsl Thanks for the reply. I played with a battery backup/inverter setup for running my furnace for a few hours. Cost: one battery, 2500 watt pure sinewave inverter, battery switch...$700. Add 2 panels and charge controller...another $300. But I have nearly unlimited funds...as long as my wife doesn't see this. LOL But if someone can add a panel or two, it would be good, and Amazon has a pair of decent panels for less than $200. Buying used panels that are still good works to. Solar technology has increased efficiency times 3 over the last 10 years, and the panels we installed 10 years ago are still working within warranty. As they get switched out ,they become viable used panels for homeowner projects. (As long as a licensed electrician supervises the installation. )
Solar wire comes in two flavors. 4mm2 or 6mm2. Both are rated for 50amps and 1000v and are tinned copper to stop the black death. Most inverters are rated at 16amps and 500v. They would have to be in series at 9amps per panel. Just keep connecting your panels until you hit the max Voc of 450v. 9amps and 450Voc. 4000watts per string. Some Charge Controllers MPPT will have 150v but 50amp. These are ok for short wire runs on DIY systems. Renogy Rover type chargers for RV's.
Why not keep the EcoFlow in a cabinet or shed 10ft away from the panels; then run A/C to the house at 120vac? The much higher A/C voltage 'line loss', will be able to run much farther and be negligible (a endless point of contention between Tesla and Edison).
There are so many different application that a longer run could be needed. If you can keep it short that would be preferred for sure.
Stream cold will affect the lithium batteries
I own a couple of meters similar to what you used. I've noticed what the meters show for the same source can vary a bit. This might contribute to at least some of the difference seen with the calculated values.
I think you are right. I am thinking about stepping up the testing equipment. Do you know of any higher quality power analyzers with a wide range of voltage and amperage capability?
@@everydaysolar For what I am doing, I couldn't justify more expensive meters, so I can't recommend anything. I did get some cheap "voltage reference" devices to test my meters, but they only go up to about 10 volts. Until you get better gear, you might try repeating the test with the meters swapped, then average the results.
@@everydaysolar Use A-B switching and operating conditions as stable as possible. Connect one device to the A side, note its results, swap to the B side, and note the results, swap back to the A side and note the results again, ensuring they read the same as before. If not, try again. Do this multiple times so you get at least three sets of good results at a given light level. Repeat at different light levels. Your records and a bit of work in Excel will allow you to cross-calibrate the two devices - "correct" the readings of the B device to match the A ( which you chose as the "standard").
Yes, when testing electrical values, it is best to repeat the test multiple times, pulling the test probes off and checking again. Rubbing them on the contacts as you watch the meter readings. A lot of electrical and electronics pros do it. False readings are quite common from faulty contact of the probes.
@@gregvanpaassenI’m sorry, what are the A and B sides?
Another way to calculate efficiency loss is the look up the resistance of your wire (and multiply by 2 for round trip resistance) or simply measure it with your ohm meter if you have one. Then, instead of the usual power calculation of volts times amps, you can also use resistance times amps squared. Use the amps number from the power monitor nearest to the panels and multiply by the resistance you measured (or obtained from Google). The lower currents that i observed in your measurements accounts for the lower than expected efficiency loss. If you repeated the test with the 2 panels wired in series, your efficiency losses would be half of what you measured for the parallel configuration. Because temperature voltage losses especially in the summer can have a confounding affect on power (and thus interfere with determining is the wire is the major culprit), you should use the Power = I (amps) X R^2 (ohms) equation when looking at wire losses. Conversely in the winter, the max voltage of the panel can be quite a bit higher than what the ratings are on the back of the panel, and thus also confound trying to see what the wire gauge affect is. Nice video! I also use 100 feet of 8 gauge when hooking up my portable panels.
That is a ridiculous pain in the butt. Just do it correctly and use a VDI chart that you can find on Google.
I think it's P = I`2 X R
That's great and all if you're retired and have all kinds of time on your hands. Or you could simply use a VDI chart and be done in about 30 seconds.
20+ years off grid. You should keep your wire runs under 30 feet and 8 gauge for12 volt. 10 gauge for 24 volt and 12 gauge for 48 volt. You can reduce loss by moving the controller and inverter closer to the panels and use an inverter to run 110 AC to your home. A shed works for that.
I recommend 24 volt in series and a run under 30 feet with 10 or 8 gauge wire for off grid.
A shed costs a lot more and is WAY more work than conduit and heavier gauge wire. Though a small enclosure for a combiner box at the panels is very practical, but the combiners are generally set up to be outdoors. So they don’t need a totally weather proof enclosure like an inverter and charge controller will. That makes a BIG difference in time money and effort. Plus, the batteries need excellent weather protection, and you don’t want your batteries a long distance from the inverter or your breaker box, or the end use point(s). So in my case I don’t put panels on my roof because that is a whole can of worms for installation and roof repairs/replacement short and long term. I have a nice exposed hill that I put my panels on and it is just simpler to run 4 AWG into a weather proof cement board cabinet close to the cabin with the controller/inverter/ batteries.
@@5400bowen You are still going to have significant loss at any long distance with 4AWG.
@@solarcabin the numbers from many experts disagree with you…4 gauge for 50 feet carrying 72 volts at up to 1980 watts from the panels…quite sufficient. And do you know that the wire gets thicker as the numbers go down? You keep mentioning 10 and 12 gauge..that is WAY smaller than 4 gauge…way smaller…
@@5400bowen Off Grid 20 years teaching people to install solar and yes I am very aware of how wire gauge works. You will still have loss at at any significant distance with that gauge.
The Gauge of wire has absolutley nothing to do with voltage, using that as a method to size a conductor is a dangerous road to walk.
VDI chart works great. I always run my large ground mounted solar array wire runs in DC, and I keep my operating voltage up around 500 V DC.
Yeah, if you can crank up the voltage and keep current as low as possible that is ideal 👍
Off topic: Noticed your shirt, and I own a 1958 house in south Florida that my parents bought new and I was raised in. Over the years, more so recently, every outlet in this house, or switch that's ever been upgraded, or replaced due to wear and tear, has been found to have been taped originally back in 1958 when the house was built. Not trying to start an argument, or anything, but just thought I'd throw that out there for grins and giggles... Good test in this video. Thanks.
Hahaha, don't worry I won't get worked up either way. I just made the shirt a while back because of a few videos I did in the past there were no shortage of passionate people on both sides of the argument.
Better to put panels in series to provide higher voltages. Power loss = I^2*R. double the current and your losses increase by 4.
Yup, most people forget the square.
Perhaps the device he is charging cannot handle the higher voltage.
The current flow is what is charging the batteries. parallel panels allow for more current and faster charging times. The solar charge controller regulates the amount of current delivered to the battery it recharges. I
@@zaneenaz4962 Battery charges have a current regulator (something like a constant current regulator) Batteries are never charged directly using the PV voltage as it too high. the Battery charger will step down the voltage and supply higher current for the batteries. Basically it will use a Buck step-down converter will will drop the voltage and supply more amps than the PV panels can provide.
@@zaneenaz4962 Not really true.
With an MPPT, what matters is POWER. The MPPT is a buck converter which will convert that power into current.
If you have 2 panels of 10A each and 25V they can be wired in series as 50 V at 10A or in parallel as 25V and 20A. The POWER is the same either way: 500W. The MPPT will convert them both into the same number of Amps at whatever the battery voltage is (ignoring slight differences in efficiency at different voltages). Ignoring losses, that would be about 41A at 12V.
@@cccmmm1234 The power transfer is noted, but would you not also be increasing the resistance when the panels are in series? ....and the buck converter efficiencies are typically below 90% (another source of loss) As the systems scale up i suppose these loses drop off as lower percentage of the overall system. Leaves me to wonder if my 300W systems might not behave like your 500W.
It's quite a balancing act! The MPPT in the power bank will set the optimum VmP at the point of entry; the panels themselves will be at a lower VmP due to the voltage drop over the feed-wire system. This will mean that the panels will not be operating at their optimum MPP. Next, the power-bank will have a conversion efficiency curve for different DC input voltages; changing the input voltage due to the loss on the feed, will alter the efficiency, and how hot the MPPT gets. For my home DIY off-grid system I used short separate runs with the thickest wire I could afford, before the cost outweighed the benefit. From an engineer's point of view, efficiency is important; from the amateur's point of view, does it work?
That was just for 12v. Now in a 24 or esp a 48v system. The wire gauge isnt near as much of a Factor. Great video thx
With an eco flow delta pro, the max amperage you can get is 13A. The MPPT is not capable of taking any more.
Further: Putting the Panels in Series (2x the voltage, 1/2 the current) will reduce the loss to 1/4 (3%for 12 AWG and 1.5% for 10AWG).
Plus:
The max Power you can get with 2x360W panels in parallel is 40,95Vx13A=532,35W
The max Power you can get with 2x360W panels in series is 81,9x8,79A=720W
Need to do this type of testing on a perfectly clear day. Additionally, always wire up your series/parallel solar system to give you the highest voltage acceptable for your inverter to get the lowest losses.
Thank you for running your real life experiment. I noticed that your running stranded cable. How would it compare to solid core wire?
higher voltage less loss. also keeping your wires as short as possible also helps.
Thank you from central Texas
You bet!
A reply I did to another’s comment: A shed costs a lot more and is WAY more work than conduit and heavier gauge wire. Though a small enclosure for a combiner box at the panels is very practical, but the combiners are generally set up to be outdoors. So they don’t need a totally weather proof enclosure like an inverter and charge controller will. That makes a BIG difference in time money and effort. Plus, the batteries need excellent weather protection, and you don’t want your batteries a long distance from the inverter or your breaker box, or the end use point(s). So in my case I don’t put panels on my roof because that is a whole can of worms for installation and roof repairs/replacement short and long term. I have a nice exposed hill that I put my panels on and it is just simpler to run 4 AWG into a weather proof cement board cabinet close to the cabin with the controller/inverter/ batteries.
The Delta Pro will only use 15 amps, which means that it current will be limited to that level throughout the circuit regardless of the voltage.
I've used No. 10 wire casually between 100 watt panels. The sum runs into heavy aluminum outdoor wire. 21 volts runs through long wires into regulators, one per battery set delivering 12 - 13 volts into lead batteries. The solar wires are long and the battery wires are short. No problems with efficiency.
Does electricity run THROUGH the wire
or along the surface of the wire wire ?
@@andrew_koala2974 Through. The voltage loss between your solar panels and your charge controller means a lot less than between your controller and your battery.
@@andrew_koala2974 The phenomena of electricity takes place outside of the wire
Thanks for the video. Very interesting test. Ive always wanted to see that in the real world. However I would definitely be going for the 12 awg, especially if the runs are small and they very well could be, with Panels located directly above your Solar chargers. I dithered for ages, 18 years ago when I first installed my off the grid house worrying about the gauge of wire. Turns out line loss is the absolute least of your worries and is easily fixed. A couple of extra panels will cover any line loss. Wiring 12 gauge and higher is significantly easier than any of the lower numbers for a DIY. Anyone fought with Crimp lugs on fine stranded 8 gauge wire 😞 Having said that though... Cabling between your Batteries and Inverter should be as big as you can possibly get. Double them up if possible. That's where you will get the best value in your cabling. Your Inverter will love you for it.
Are you meaning run two leads instead of one when you say double them up? Or double the gauges? Because the first one is something I’ve been saying (and of course have known) for a long time. When I ran my Romex 75 feet from the post inverter breaker box, I did just that. Two ten amp wires can carry 20 amps, and connecting them at either end is perfectly fine. Imagine the multi strands inside insulation. It is the same thing. And better for heat dissipation. Nice clear correct info, by the way.
Yes running 2 leads to give you a great big lead is a great way to solve lack of instantaneous power. I had a problem with a 5KW inverter that had the recommended size battery leads that kept going into fault mode with any sudden large motor load. I doubled the Cables and the problem went away. Very easy to do in an existing installation as well because you can keep your down time to a minimum, and 2 smaller cables are normally cheaper and can give a larger square area of cable. In this situation I was looking at installing soft starts on the motors but didn't need to. (Still keen to try them out though, so I may still do one anyway) 🙂@@5400bowen
@@garyrussell5559 I also heard that electricity runs on the outside of wires, hence multi strand wire (did I already mention that about multi strand?). Two smaller wires have more surface area for that to happen. It never occurred to me that a double lead was better for high surge devices, seems peculiar. But like my brother said, electricity is magic! And you of course saw what I said about running two strands of Romex because it was rated at 50 feet at my power levels and it is a 75 foot run? The rest of your reply is so pleasantly accurate! Aloha from the big island of Hawaii!!
Agreed. Real world amperage is usually much lower than rated. Especially Winter and cloudy days, morning and afternoon.
@@ceeweedsl Very true, and one of the most disappointing things you discover when completely Off Grid is that in Spring, summer and Autumn, your battery bank is normally fully charged before noon and the solar is pretty much dumped after that. In winter however I could triple the amount of solar panels and still struggle to charge my batteries on most days. My last array of solar panels I installed are completely for the winter sun and are almost upright. Panel angle lets you squeeze that last bit of current. I've found with Solar, when you miss, you tend to miss by a mile 🙂
Good video! If i try to put too many amp through 10awg wire, could it start a fire?
You rock! Thanks so much for this video! 😀
Happy to help!
082723/2041h PST 🇺🇸. Thank you for the presentation on simple and adequate PV cells setup. Yes, it’s so true to venture out to connecting to 110AC system and automatic changeover switching, which is all too much for layman and myself ( electrical engineer)
I have a similar set up 800W PV array and 2X12.80V@540Ahr LiFePo4 Battery, and 1200W inverter. All equipments are VICTRON. Here, in CA , we don’t experience load shedding or Blackouts. But it’s better to possess such a system, than not.
I’ve watched your electrical systems wiring etc, a lot. Thanks again. Best wishes.
Hi and how to solder the thick dc cables to the xt60i or do u use anderson plugs for the pro
Good info. A dc power supply may be thought to use for a consistent supply voltage and current availability for future tests.
Yeah, that would help compare apples to apples. Thanks for the feedback!
Would have been nice to see loss in series under 50 feet of wire which most people use! But, this was very informative! Thanks
Say my three large panels in series where pushing close to 150v to my DP and I wanted to get that down to a safer level. Could I increase wire length or use 12 or 14 gauge wire to drop the voltage to a safer lever? Would it affect the Current also and lower my total watts going into the DP?
Silly test, because line loss per foot and current is all known and in online tables. They are very easy to use, so you can find out what your system line loss will be for each gauge wire. These test high line loses are because there is very high current flowing through the wire. In a real DC system, you want series wiring so you have as high a voltage as your inverter can handle. The current would be about 8 to 9 amps (whatever a single panel puts out). That will minimize your line loss.
My 5 KW array uses two series strings, with 12 panels per string. Each string feeds it's own MPP inverter channel. That's about 430 volts at 8 amps, well within my grid-tie inverter specs. My line loss is minimal with 10 gauge wire.
Why didn't you use the 4.53A in your calculator that your meter was showing? What I do is have a battery at solar panels with an inverter hooked up to it then use a normal 14ga outdoor extension cord to run power inside to charge house batteries.
On any solar system you should run the highest voltage your inverter can handle, as the higher the voltage the efficiency is much better on smaller wire. I can run a 6270 watt array at 466.5 volts at 13.44 amps. This allows me to run 100meters on 10awg with only a 2% voltage drop. All this means is the higher your voltage is the lower your resistance(aka amps).
Agreed 👍 thanks for the feedback!
This is important, well done.
Thanks!
it's all about voltage drop
Great testing! You did mention a series configuration but you never tested it. The thing about going in series, which I don't think you mentioned, is that you cut your losses to 1/4, not just 1/2.
So if you go back to that calculator and put in 12 AWG, 40V, 16A, 100ft, you get a loss of 15.8%. The equivalent series configuration would be 80V, 8A, and if you plug that in you get 1/4 of that: 3.95%. And that's with 12 gauge.
For a whole-home system it is far better. Now you are running 240VAC with micro-inverters, or in the 400VDC range with a string inverter. The percentage losses with 12 gauge wind up being 1.32% @ 8A and 240VAC, or 0.79% @ 8A and 400VDC.
This just goes to show, going for the highest possible supported voltage massively reduces wire losses.
That said, I use 10 AWG for all my panel-side cabling. Actually it is even a bit thicker since it is 6mm^2 cable and 10 AWG is 5.3mm^2. I'm just a bit of a perfectionist. I just like the feel of the cable.
Thanks for the feedback and I would like to test a higher voltage as I agree that is a more practical and smart solution. The little power analyzers are pretty limited in the amount of voltage they can handle so that was the limiting factor for this test. I am thinking about stepping up to some mid-grade testing equipment which would expand the capabilities.
(this phenomena is also why people are moving away from 12V battery packs and to 48V battery packs for new ground-up builds. Because the losses and heat in the compartment at 48V are just 1/16th losses and heat at 12V). Now that 48V LFP battery packs are so easy to find.)
You should use standard wire cross sectional area of mm2. The Dawg you use is obsolete, especially having smaller numbers mean larger cable.
Have you ever found an inline watt meter than can handle 120-150V for the Delta Pro? I'm running my 12 EcoFlow 100W panels as 6s2p and would love to see what numbers look like.
I keep mine under 2%. The tables are based on a temperature coefficient, high temperatures create more resistance, therefore more voltage will drop more. When the voltage drops the wire heats up giving you more resistance. Hence the voltage drops even further.
Over time this can be a problem.
Good to have some empirical data as well. I would suggest however that you do each of the tests twice and swap locations of the EcoFlow meters just to eliminate calibration differences in them.
Not a bad idea, thanks for the feedback.
It would be interesting to see how accurate the meters are.
I was going to comment a similar idea, I have found I would rather like an existing comment then to duplicate a comment.
I wind up duplicating a lot because I haven’t read all the comments and replies yet. This video and comments are a cut above.
Very informative 👍. Thanks
You bet!
I measured my hundred foot run with 10 gauge wire and it came out to 0.61% Percentage of Voltage Drop with the calculator you're using... Not too bad
Tx mate...nice test....i learned something
You bet!
The calculated losses are probably higher because they take into consideration temperature change of conductors exposed to heat accumulation either by heat generated by current or from heat from weather and the sun and enclosed conductors in conduit or hot attics. heat increases resistance and would increase amps.
good show, but would have been good to let folks know that increasing panel voltage is a great way to reduce line losses (and therefore downsizing gauge of wire). This is the case since line losses are proportional to the SQUARE of current but only directly proportional to panel voltage.
Yeah, that would have been a good addition. I was keeping the voltage low for the power analyzer limitations so it was a bit misleading as compared to what you would setup in most real work applications.
Can only speak for my system, but went with 10 gauge for a bit under 120ft and it would have run me 33% more to run 8 gauge, more expensive connectors as well, and only would have save a few % in line loss, put that money into a few more panels and grabbed more power overall....your mileage may vary....if you are going above 20amps on the line then I would step up to 8 gauge with a run like that.
*I did a HIGH VOLTAGE array and ran 12 ga wire for about 50 feet*
When drawing over 3,000 watts there is not enough voltage drop to affect anything (maybe 1 volt max)
However. I'm running a 330VDC system. So thats only a 10 amp draw on the wires 😁
My system can produce upmto 5000 watts but it rarely utilizes as high as 4kw and at 5k I'd still be just 15 amps
My system is a 21S 2P
I run the exact wire you have links to (8AWG). Where do I get MC4 Connectors that will accept 8AWG? Do I need special crimpers for 8AWG MC4 connectors? I would like to get a very good quality crimper as I am doing everything myself as I have a large property and my panels are ground mount. I asked DIY Will but he is getting a bit big for his britches..... and didn't answer. I need to shorten my 100-foot wire lengths on several strings to get max efficiency and so need to have the 8AWG MC4s and the really good quality crimpers. Thank You!!
This is a good example of why many installers now put an inverter at the panels, convert to 120Vac and that way they can use much lighter wire as copper is not cheap these days.
Put a few panels in series and you can get much higher voltages than 120.
My charge controller can handle 450 volts.
The use those micro-inverters to make it easier for themselves to design and trouble shoot.
I use 4mm², that is AWG 11. The new cables I have now bought are 6mm², AWG9½ - copper
100 feet are 30m. I don't have the cables for that long.
What is actually been drawn heavily affects what the panels produce... You plugged into a battery... So it's state of charge will change production.... Should hook them up to a heating element through the mop, that will put a constant pull... And you will also see how hot the wires get as well when under heavy load.
Thank you for this video!
A question, the analyzer you are using, I was wondering if it has the ability to record data points over an extended period of time? If it doesn't do you know of a similar solution for a similar price that does do that?
Thank you!
This one will just continually record the active session (session starts when you plug it in) but is limited outside of this basic functionality. I think you could pull this data from the device through the serial port into a Raspberry Pi or similar device to provide much more functionality like plotting out the metrics over time.
If you could datalog the voltage and amps through the testing period you'd be able to see why there is a difference between the online calculator and your measurements. What you want is the average value of the amps squared (amps * amps at each point) over the time interval. Take the square root of that [average current squared] number to get an "average" current value - and feed that back that into the online calculator. It will show a result that is a lot closer to your measurements. The growing difference in the loss % with each larger gauge wire is explained by the lower total Wh over each test interval. You would see the opposite trend in the closeness of the % loss number if you had a higher load for the 8AWG vs the 12AWG tests. Some rough calculations assuming a 40.5V constant system voltage (needs correction: all of your photos show actual voltage ~36-39V) show that if your trials were approximately 90 minutes for the 12AWG, 75 minutes for the 10AWG, and 80 minutes for the 8AWG - then the theoretical numbers from the online calculator match up. I think if you were able to fully load this system - receiving a constant 17.8A at 40.5V (721W) - the online calculator would be spot on versus your measurements.
Thanks.
@9:38 is where he lays out all the 3 different wires and how they perform.
You're welcome.
Thanks
Have you ever heard of the Shoals Plug and Play cables/system? Can anyone judge whether it makes sense to use it? Although they seem to be a bit more expensive, they are extremely easy to use and no professional installer is required. Installation is also said to be very quick and more energy efficient than conventional cables. What do you think about that?
They have cool products but I have seen their use case more in the large solar farm application where you can get rid of combiner boxes with 1 massive wire that has a bunch of leads coming off to each string of panels. Which of their products were you considering?
Interesting topic. By making measurements at the start of your cables and at the end of your cable you can narrow down to line losses, but you still need to consider the varying current flows. The 12awg starts with 12.9A and ends with 16.3A (why the wide range?).....the 10AWG starts with 4.7A and ends with 4.6A (more reasonable behavior). The greater the currents the greater the ohmic losses ! Line losses are lower with the lower currents.
Having worked with different batteries i've noticed they draw power from the PV-panels differently, so the state of charge of your batteries should be considered.....they should be similar across both tests. The lower the state of charge the higher the current flow when using a PWM-type solar charge controller. Have not had an MPPT unit long enough to test this, but i still can imagine similar behavior. My inverter experiences make AWG and wire type a high priority ----> th-cam.com/video/xK0L4dOMpSc/w-d-xo.html
Yeah, not a bad call out as a I think the 10 AWG test had a little more cloud cover and as such dropped the current resulting in a little less line loss than if the test had full sun. Overall I think the results are still valid within a reasonable error band.
And because the conditions differed, it invalidated the test. Current should have been equal and at the maximum design level to get accurate loss results. Cables will also have to be derated depending on how many cables are in the conduit and outside temperatures encountered, as all loss turns to heat and adds up, creating a safety issue if not considered. Is the conduit in direct sunlight, that's another thing to consider. Check the temperature rating of the cables as that needs to be considered also. Yes, there is a lot to consider for the DIY installer. @@everydaysolar
Could use some help still confused about the gauge wire where. I’m installing solar on my rv down to my delta pro in front of rv. Would 10awg be enough on roof to roof chase and then from chase to front? Also how about to the delta pro from my solar breaker? Do they make 10awg xt60 connectors?
You should be good with 10 gauge. Your runs are short and the Delta Pro maxes out at 15 Amps which the wire can easily handle without much losses over that length.
It all depends series and parallel configuration of your solar panels. Higher voltage = smaller wires lower voltage bigger wire. Most MC-4 connectors suitable for 10ga
Very interesting test, and very timely for me. I'm in the last weeks of finishing a house build and I plan on installing a solar array outside some time down the road. To that end I pulled a 100' length of 10 awg wire through the well pump access line (a 3" PVC line running under the slab) into my house. I've got a Bluetti AC500 solar generator that I'll be using at the house and in my 5th wheel (why I purchased an all in one system so I can move it between them when I travel). I've currently have a PV420 Solar Panel (again for use at home and in the 5th wheel) but have plans to install a ground mounted solar array with a lot more capability. Knowing what wire size I'll need to insure I get the most out of my array is a big question I had and you've pointed me in the right direction to figure it out, Thanks. I'm interested in learning more about what you have to offer so I also subscribed.
Design your array with voltage as high as your controller can handle and then your amps will be low.
270 volts and 20 amps through 100 feet (both ways) of 10 gauge wire gives a voltage drop of only 4.1 volts and less than 2% loss.
If you wire it differently you could get 66 volts at 82 amps and need zero gauge wire to get the same 2% loss.
The precept of this experiment was flawed in that it was designed to push a point that should be observed and accounted for but can be design to avoid instead of just throwing more copper at the problem.
@@ghz24This. Just bump the voltage up.
@@matthewtaylor3301 I think that's what I said.
Wire power losses all come down to the formula P=(I^2)R, since R (resistance) is fixed, I (current) is the most critical, reducing current will reduce your wire losses.
this is why want to get to ac asap. lower drops over distance. and smaller cable needed.
If there is regular loss in a traditional hundred foot extension cord from a wall socket, what is the loss for 100 foot cord to a 12 V solar panel?
Voltage drop = (2k x l x i)/Cm k= 12.9 for copper wire, l= 1 way length, i= current, Cm= area of conductor in circular mills
Great video, question, is there a in line meter out there that I could hook up to my 4 panel 1600W 196V that I could keep a eye on status that goes to my mini split
Thank you
I haven’t found one as I am looking for something similar for data collection on upcoming projects. The unit I was using is basically from the RC car and drone industry. If I find one you will see it being used on this channel 👍
Also i found this when running large loads & recharging batteries check along wires by hand for thin spots & defects. i had 2 spots where it was warm and hot. basically bad internal wire stretched thin during production... today things are just not quality made
I think you should repeat the test with a constant DC input power supply, instead of a solar panel. Always control for as many variables as you can, to get the most scientifically reliable and repeatable result.
No. This is not a test of wire performance - thats already been done. It is a test with real world factors in the mix. Thats the next step for more nuanced understanding and decisions.
The measured results don't match the calculator because the maximum amperage was used. Voltage drop increases as the load increases so, as has been mentioned, keep volts as high as your equipment can stand to minimize amps and voltage drop.
All systems I've seen set up was using 1awg wire on them no idea how much it helped with lowering the loss% I was planning to build a system and I was going to use the 1 awg also like the other set ups I've seen have you ever tested 1awg cable
Surprising results! You can calculate the voltage drop along the length of cable for any length of cable, any thickness of cable. You can do this before you spend any money buying cables.
One other issue to consider on the wire sizes is that when a wire is run over a roof, the wire can retain heat from the roof and you loose some power there too. 10 awg would be minimum for me on a roof to compensate for the additional loss.
And that heat cooks your wire. Even the metal is more quickly degraded from heat, and especially the insulation. Wire for outdoor use should be white.
run it through the attic. Yes, there's still some heat but not as much.
@@georgeperez4770 a valid thought. Or use white wire, or run it straight down as much as possible, or as I do with the cabins we build in Hawaii, use white roofing. But just look up videos on insurance and roofing companies reaction to roof mounted panels. When the roof needs replacing, yer gonna bleed hard. Some insurance companies have started refusing to insure homes with roof mounted panels…
For 100 feet even with this small two panel setup in parallel, I would go 4 or 6 gauge. Sure, costs a lot, but you pay for wire once, and it degrades over longer periods of time. But the losses are continuously reducing your power production, every minute of every day for years and years. Then there is durability and ability to add on. Add it all up.
MC4 connectors are the weak point - big wires to tiny connector - cut apart a mc4 and look at metal contact area - its a few square mm - similar to 3.5mm headphone plug -
- bigger contact area lowers resistance - I use polarized 2 blade connectors - 10x contact area -
3% is acceptable. But basically keep short and large CSA and adjust to suit de-rating if enclosed.
Follow the rule book.
So the best thing to do would be to Install an all weather Inverter like an SMA Sunny Boy close to the panels and A.C. to make the long runs to the point the power is needed. You have a lot less loss with AC vs. DC.
Yeah, not a bad plan 👍
I think some people might get the wrong idea. From the comments people are assuming that the fatter the cable the better. Which the answer is still yes but what if you have a small set up? If you have a smaller setup that has a lower power output with wires that don’t need to reach 50feet or 100feet getting a bigger wire can also cause power loss too? I’m talking about 13 amps 36 volts at a distance of 10 feet or so.
Or am I wrong?
Doesnt the first monitor add extra resistance that wouldnt normally be there on the second one?
+On cloudy days- when your really need the extra power, the losses will be less, and sunny days when you have more than enough the extra loss is fine.
I am currently devouring as much solar info for auxiliary power as I can; your topics are very relevant, and you deliver the content so it's easy to understand. You are appreciated. My EcoFlow Delta 2 is in transit. I'll be hooking up 2 190 watt HQST panels that will be wired in series. Does the length of the line (Let's say 100ft vs 50ft) affect the amount of loss?
Yes it does. Shorter run is always lower resistance. Bigger gauge means lower resistance per ft.
Thanks much. I'll be using 10AWG initially and adding another 30ft as soon as I get everything cookin'.@@MrBooMY3
Do yo have any videos on grounding solar panels? I just got an EcoFlow Delta Pro and purchased 6 200W solar panels. The EcoFlow, for now, is for backup emergencies so my plan is to set up the solar panels during an outage by tilting them but staying on the ground. Is it necessary to ground the panels in this situation? Also, my hope is to set up the Delta Pro such that i can start offsetting power and have it running all the time. My roof needs new shingles so i was thinking of building a system where each panel will mount to my fence so it can be rotated and tilted. Because this is a more semi permanent installation and the panels would remain outside that they then should be grounded?
I just did a video on a nice little ground mount and touched on the grounding at the end. Not sure that will be ideal for your 200W but depends on the size th-cam.com/video/IgeaQs1OUtE/w-d-xo.html
@@everydaysolar Thanks ! I was actually watching it when I saw your comment. Have you ever installed any solar panels on a wood fence? I really like the ground mount but I don’t have a ton of ground space. I am looking at ways to mount solar panels on my fence. I have 6 200 watt panels.
Good info.