Top 10 Beginner Mistakes When Building a DIY Solar System

today's video is the top 10 most common mistakes that beginners make when building their first solar power system also if you're not a beginner you might want to watch you might have formed some bad habits over time so let's talk about the most common ones so mistake number 10 is connecting a solar string to a device without checking the voltage if the voltage is too high you will destroy the device if the voltage is too low it will fail to operate and you will not believe how common this one is a lot of people destroy their solar charge controllers because they put too many solar panels in series and the voltage is too high or people use low voltage panels in parallel and they do not create a voltage high enough for the solar charge controller to do its job now you can avoid all these issues by checking the voltage before you connect it to the device every device has a working voltage range for example we have a solar charge controller here and there's a sticker on this side and it states minimum solar voltage is 120 volts DC and the max solar voltage is 500 volts DC but notice that it says VOC and that means voltage open circuit that's measuring the solar panels when they're not connected to this device so before you connect the solar string to this device be sure to use a voltmeter to test the voltage if it's within the working voltage range you will be good to go next problem is not enough batteries or solar panels a lot of people will discharge their battery to zero and then they're like what the heck there's zero volts my system is not functioning this battery is broken and then they'll call it the distributor and say what the heck you sold me a bad battery what really happened is you don't have enough solar panels or you do not have enough batteries also your battery should never reach a zero percent you should use an inverter or other devices that have low voltage disconnect and this is a very common feature on inverters once your battery Bank hits a certain voltage it will turn off the loads it will turn off the inverters output and this will ensure that your batteries never reach zero percent on my current system once they hit about five percent it turns everything off automatically if you do not have that you will put your batteries into safety mode and you will think that your system has been broken you'll have to use an alternator or a battery charger or something to wake the batteries back up again but again this is a very common beginner mistake and people think that their battery is not functional but that is not true now whether you have low voltage disconnect or not you should have enough battery power for a few days of backup if you don't you did not design your system well so check out my book or my other videos and I will teach you about days of autonomy and having a large Reserve capacity if your system is well designed it should never hit zero percent that's the whole point of a backup Energy System is that you need to have energy at any time so yeah please check out those resources number eight is building a system that cannot be scaled whenever you build a solar power system you have to think how can I add more batteries in the future and how can I add more solar power arrays because no matter what you tell yourself in the future if you're using this system every day you're probably going to want to expand it add more solar panels add more batteries it's just the natural way of things now some ways you can future proof your system to make it more scalable is number one having large bus bars that can handle a lot of current this will allow you to add more batteries whenever you please next use larger cables than necessary especially if you're going to be upgrading your inverter in the near future copper is not cheap and if you're buying new cables every time you get a new device you're going to be spending a lot of money next buying a solar charge controller that's larger than necessary will allow you to add more solar panels in the future or buying solar charge controllers with multiple inputs then you could add another string of panels during the winter when you need power during that time next mistake is low quality circuit breakers and not using the proper circuit breaker or fuse for the job for example this is a high quality circuit breaker but it says 42 volts DC maximum do not use this with a 48 volt system 12 and 24 volt systems can work great with this but nothing more than that next circuit breakers are rated for DC or AC applications this circuit breaker is rated for AC applications so I cannot use this to disconnect the battery or anything on the DC side of my system but this breaker can be connected on the inverter's output because that's alternating current a circuit breaker has to interrupt a Arc and a DC Arc is harder to extinguish than an AC Arc so for GC you have to get DC rated devices and this is a DC rated marine grade circuit breaker but notice it says 48 volt DC maximum if you look at the data sheet 48 volts is the limit if you charge a 48 volt lithium iron phosphate battery it will exceed this voltage rating so this is not appropriate for that either also realize that home circuit breakers are AC rated only do not use these for a disconnect for a large battery also fuse boxes should be high quality as well this is for low voltage DC like a 12 volt system and this is made by Blue Sea Systems this is a fantastic fuse box because if you go on Amazon there are lots of low quality ones and I would never trust those in a million years so spend the extra money and get a marine grade Blue Sea Systems fuse box or something that's equivalent next mistake is using copper clad aluminum these cables come with a lot of cheap Chinese inverters on Amazon and you want to avoid it like the plague these cables are a liability they can melt they can catch something on fire so avoid them at all costs you should only use copper and sadly I don't have any copper clad aluminum to show you for this video in past videos I talked about this more in detail so I'll have those linked below but it's a wire that looks like copper but it's actually aluminum and you can tell by when you cut it you can see the shiny aluminum on each strand on the inside but it looks like copper on the outside and technically this is safe to use if you know how to use it but most beginners should avoid it like the plague whenever you use aluminum you have to understand that aluminum expands and contracts at a different rate than copper and when you have the two connected you're going to run into some issues terminals can go loose over time and the conductivity of aluminum is not as good as copper so you have to use a thicker wire in cheap Chinese inverters that come with copper Cloud aluminum cables will typically be undersized and people will run into problems by using the cables that it comes with so right when you get those things you want to throw them in the trash and make your own cables out of copper now number five will make some of you guys angry and it's soldering large lugs this is incorrect when you have a large cable and a large lug and they are both copper you want to crimp with the proper tool and that will create a gas tight connection that is mechanical and this is superior compared to a solder joint and this is for quite a few reasons first of all a mechanical connection with a cold weld means that the metals become one they are sharing electrons and it has the lowest resistance path for those electrons to flow with solder you have a dissimilar metal flowing into a space there's lots of surface area for that conductivity to occur and it is sharing electrons but it's going to be at a higher resistance than a crimped connection a mechanical connection will always be superior to a solder job there is no question about it this also applies to corrosion some people say oh if it's soldered and it's a marine environment it will be better that again is false use a dry copper lug a dry copper cable terminate it and then you use marine grade heat shrink over that and you will have zero issues until the end of time also every manual for low voltage DC Electronics especially for marine it says to crimp I've never seen anyone say in a professional manual anywhere to solder a large gauge cable that is not correct and if you think about it just for solder to flow effectively you need to get that joint really hot and you're going to damage the insulation of the wire and you might not even get it hot enough a crimp on the other hand is stronger and you know that it's been done correctly and you can check a crimp you can saw in half and see how all the metals cold welded together and that is better that is a strong connection but this will not stop some of you I know that some of you guys love soldering for some reason I love soldering boards but on cables absolutely not that's illogical so yeah you need to stop doing that number four is messy wiring jobs and this is crucial I've seen this when people build batteries they just have this nest of wires on top of all of these exposed battery terminals that is not safe also having more than three lugs to a single terminal is again not ideal you need to space your stuff out and organize it you should be able to see every conductor and if you can label it that's even better also bundling too many wires together especially with zip ties if you have lots of high current conductors wrapped together they will not be able to dissipate heat as they're designed if you have a freestanding cable it can dissipate heat and it will stay at a low temperature if you have lots of wires bundled together that heat will not escape and you will get hot spots and that can cause fires or other problems melted insulation and other things so let those wires breathe let them be labeled and let them be color coded and nice make it look good number three is improper wire gauge sizing and this is a massive issue when building your first system if you are building with copper you need to find a chart that shows the max ampacity of the copper that you're using to ensure that it can carry the current to your devices from the battery from the solar panel any connection in your system it needs to have a large enough cable to carry that current and this is called the max ampacity of a conductor there are charts available online that show you how much current a conductor can carry without getting too hot technically copper can carry a lot of current but it will get so hot that it will fry everything around it or catch something on fire so you need your copper running at a good temperature and the best way to avoid issues is to oversize your conductors or use whatever is recommended by the manual for your device and this is very important with any device that has the sense voltage from your batteries if you have an undersized cable it will throw off the voltage readings and it will not work properly for example with the solar charge controller I will use the largest size copper that will fit safely in that terminal and I will keep the cables as short as possible so please read up the charts read my book watch my other videos and size your cables properly now I need to make this clear with the solar charge controller because this is where people screw it up the most the battery connection for the solar charge controller look up the max size cable you can fit into this terminal safely and use that and keep those cables as short as possible and you will have zero issues and every device has a manual with recommended cable sizes so please read the manual also in sizing cables for an inverter if you have an LF inverter and you're running inductive loads such as large Motors it is preferred to have the largest cable you can fit on that thing just so that you have a nice cool running cable and the voltage sensing capabilities for low voltage disconnect work properly so yeah try to oversize everything you can but do not oversize it to the point where you're causing a problem with the connection to the device for example putting a 4 Ock gauge cable on this little circuit breaker is a bad idea there's not enough space there for that much copper to be on this terminal so think it through and try to over gauge your wires when possible but do not do it to cause more problems number two is incorrect tools or low quality tools and this is huge do not use these cable Cutters to strip cables I see this all the time on YouTube and this is wrong you need to use a cable stripper to strip cables in nothing else now these are high quality cable strippers this one is made in Germany and this one is made in England these last for years and everyone Building Systems should have these on hand also small gauge wire strippers buy the more expensive strippers if you buy the cheap ones you're gonna have a bad time also high quality crimpers are just as important this is my favorite one I have a bunch of recommended ones on my website but yes spend the extra money and get the good tools I use this every single day and it works fantastic also if you're working with live batteries you should buy insulated tools these are insulated ratchets and these are high voltage rated screwdrivers please use this if you're working with current sources that you cannot turn off such as battery cells very important and even just pliers buy the electrical specific you'll find that there are little features on here made for electricians and if you know how to use them it will be very useful do not try to use a plier to crimp a connection you need to use a crimper always use crimpers for crimping and nothing else now this is expensive and I love my fluke but if you're a hobbyist you probably don't need to spend this much money you can get by fine with Klein Tools they have high quality stuff and it works great or commercial electric I like some of their stuff as well and these are Klein as well and they're made in United States and I've never had a single issue with my client tools so it's really good stuff now let let's say you're desperate and you need to strip a cable with one of these Cutters you can technically do it but if you're a beginner I recommend not doing it and waiting until you get the proper tools this is so crucial and honestly when you build your system you just have to do it right the first time and once it's done it's done if you make even a single mistake in an electrical system it can cause problems in the future every connection every piece of work that you put into that system needs to be perfect so that no problems will occur now number one most common mistake beginners make is loose terminals I go around systems when I check them out and I just wiggle the wires to see if anything is loose and sure enough almost always I will find one that I can yank out that is awful that can cause fires that can cause melted terminals that can cause problems with voltage sensing of the devices lots and lots of problems that people have is because they have loose terminal so you want to tighten it tight but you do not want to tighten it too tight so the best thing you can do is get a Torx screwdriver and a torque wrench this will allow you to hit the exact torque spec for your Terminals and I'll admit right now most people do not use these sadly I'm a lot of electricians get a good feel for it but that is no excuse we should all be using Torque screwdrivers to get the exact torque spec now what's tricky about terminal tightness is that you could have high quality components you could have high quality properly sized cables you could have the best circuit breakers in the business but if you do not tighten them properly you will have problems and it is the most common mistake I have ever seen ever now this is especially true for large lithium iron phosphate battery banks that people build with raw cells you have a lot of Terminals and they all have to be tightened perfectly so you do not have any issues also understand that over time a terminal can actually loosen itself up it it's always a good idea to re-torque everything every six months or so when something gets hot and cold the expansion and contraction can work this wire loose typically not these are high quality terminals in this victron but you need to check them to ensure that it is not loosening up over time especially if you have aluminum cables that's another issue those expand and contract at a different rate than copper and some of the terminals depending on how they are designed you might have some issues with them loosening up so yeah I like to check all of my connections every couple months to ensure that there is nothing that is going loose now something to help with inspection is to use a heat camera whenever I have a large battery bank with lots of terminals I check to see if there are any hot spots this will allow me to instantly assess if there is a loose connection and re-torque it also with any system having a heat camera is fantastic to see if a device is failing if the terminals that are connecting to the conductors are failing if a circuit break is failing or anything a heat camera is fantastic so a Torx screwdriver in terminal stick it in there put it to the right torque spec that's on the label and then tighten it down until it clicks and that will avoid most problems I've seen so many slower charge controllers with terminals that are loose it is crazy go up to a friend's system and wiggle the wires and try to pull one out if you can pull one out with your hand that means that something is not tight into the torque spec and that's pretty much it those are the most common beginner mistakes if you disagree and you think I missed something please let me know in the comments section below and I will see you in the next video thank you bye

Channel: DIY Solar Power with Will Prowse

Views: 504,526

Keywords: off grid solar, will prowse, diy solar, cheap lifepo4, top 10 beginner mistakes, beginner diy solar, beginner battery

Id: -3dNJAe8XEc

Length: 17min 39sec (1059 seconds)

Published: Thu Oct 27 2022