DIY 13kW 48V Offgrid Solar System: How to build it from scratch!

so this is my workshop solar power system and over about three months it's generated three megawatt hours of power but it's pretty ugly and it's not that powerful it only outputs 5000 watts there's not enough space here to build a real system because i want to be able to power my mini split air conditioner and my tesla at the same time so we're going to start with the blank slate and build a new system from scratch and this is what we're going to use instead we have two lv6548s we're going to parallel the input so they're both going to be connected to one battery bank and then we're going to program them to communicate so that they can have a split phase output that way we can run 240 volts and supply a panel and this is the wall that we're going to mount these inverters too i already have some concrete board or hardy board against the wall and that's in case an inverter circuit were to fail and excessive heat were to develop this would ensure that i do not burn down my workshop and typically when these inverters fail they'll make a large show and lots of smoke but not that much heat is generated so this is a good safety measure but typically it's not required and these inverters are ul certified so it's really not that big of a concern to me i just like to be extra safe after we're done mounting the inverters i'm going to add this panel we are going to supply the output of both inverters to this single panel and once we wire up the inverters then we're going to stack up some batteries down here i want to keep the inverters as high as possible so i can fit a lot of 48 volt batteries below them so first i'm checking the manual to see the distance i can safely put these inverters so that they have adequate cooling and right here it states 20 centimeters from side to side and that's eight inches so we need to have eight inches of space between the two inverters and this hardy board is held in place with a couple of screws going into the studs and on this system i want to have an inverter an inverter and then the panel over here that way my solar conductors can flow in from this side and then all of my ac outputs can go out from this side these inverters are mounting with two screws so we're going to use these drywall anchors that can handle 106lb pounds each inverter is 51 pounds so this should work great so i measured that the inverter is this wide but i want to move it over just a little bit so i can actually have one of the screws into the stud and then over here we'll have a drywall anchor then we're going to mark where the other one needs to go and luckily hardy board has these lines and it makes it very easy to line up components [Applause] and it's holding nicely but drywall anchors always scare me man i don't care what the weight rating is i don't trust them so now we need to ensure the second inverter is eight inches away from the first inverter i'm going to mark it right here you guys should try these things out they're really nice now i remove the front plate from both inverters and we're gonna put two mounting screws into the back now we're gonna add the distribution panel on this side so this is eight inches so we're gonna mount it right here this doesn't need to be on the hardy board but it's nice to have it on here anyways nice i wish we had a stud to mount this to but it's just not in the right spot at all so i just got back from home depot and i thought i was going to use non-metallic flexible conduit but they were out of conductors in different colors but they did have 6 gauge so cables so we're going to use this instead this cord has two conductors in a ground so three conductors total and we're going to use this to connect each inverter to the panel individually each inverter will supply one leg of the split phase output so each inverter will supply each bus bar and then we're going to bond the neutrals and the grounds at the main panel so let's get started this should be pretty easy so here is the ac input and then we have a large hole below it we're going to use a clamp connector and screw it down right here and the cable fits nicely so now i need to strip this cable now you're going to unscrew all of these terminals all the way and carefully feed them in without hurting the conductors then we have a line neutral and a ground so the black is going to be the line the neutral will be white and green will be the ground this is a tight fit it said it can handle up to four gauge but this is very tight still with six so i got them in there but that was very difficult probably the most difficult part of this whole project so far after these are tightened down then tighten down this now this cable needs to supply the panel so we're going to simply run it over here and connect it to one of the bus bars we're going to secure this cord to the hardy board so you want to have a little bit of a bend in it to measure it properly and to reach one of the bus bars we need this length of conductor so we're going to cut it right here we need to strip a lot of this insulation back so that we can reach this neutral and grounding bar so we're going to strip it about here and i did the wrong size breakout for the hole so we're gonna have to come in from the side actually so first inverter hot lead we'll supply this bus bar in the ground in the neutral connect right here now i'm going to repeat the process from the second inverter over to the second bus bar on the panel now inverter 2 is connected so we have inverter one hot inverter two hot both neutrals from both inverters are bonded right here and then i couldn't fit the grounds into the screw terminal so i added some butt splice connectors and connected them over here and over here now that the inverters are connected to the panel we're going to add a communication cable between these two inverters and these are the cables that come with the inverters for a split phase output you do not need these ones all you need is the communication cables and this is the parallel communication board so all you have to do is simply plug these in but you're probably going to have some slack and these are pretty ugly try to organize it so it looks nice and honestly i think this is the ugliest part of the system it just looks so nasty but there's no other way that i can think to do it now that the ac wires and communication cables are completely set up we can add a battery and some circuit breakers for each inverter and each inverter is capable of outputting 6500 watts so if we divide that figure by 48 volts nominal for the battery we get 135 amps if you multiply this by 1.25 we get 170 amps or 169 and to add some headroom for surge i would say a 200 amp fuse or circuit breaker would be appropriate for these inverters and it says typical max amperage is 153 amps so you can size it to your application if you're not using the entire output capacity of this inverter you could use a 150 or 120 amp depending on your situation for me i'm using lithium iron phosphate and the nominal is 51.2 volts and if you multiply that by 150 amps we get 7680 watts so for me i'm going to use a 150 amp circuit breaker for this system we're going to use current connected bus bars [Applause] [Music] ah so what we need to do now is add a battery and turn these on unfortunately my large 48 volt batteries i ordered for this system have not arrived so we're going to put four 12 volt battle boards in series to supply the system with 48 volts now before you connect your batteries you need to be wearing safety glasses next both circuit breakers should be in an open position this will allow current not to flow through it now connect the batteries now that the batteries are connected we need to charge up the capacitors inside of each inverter and i'm going to do that with a pre-charge resistor and use the resistor to allow current to flow around the circuit breaker to charge up the capacitors after you wait for a few seconds then you can close the circuit breaker and that's it now we can safely turn on this inverter then repeat the process for the other inverter now both inverters are connected to a single battery bank we need to add the cover to each one and then we can turn them on well there we go we have power keep in mind when the output says 120 volts that means we have live connections in that panel so be very careful when you turn these on now let's repeat the process for the second inverter now we need to program these inverters so that they will communicate with each other so that they'll produce a split phase output and all we need to do is tell this inverter that it's 2p1 and that this inverter is 2p2 under option 28 on the settings menu and then we will turn these both down and then we will turn them back on again so that the settings are saved so to access the system settings we need to press and hold the enter button then we're going to press the down arrow until we reach 28 just like this and then press enter now this is inverter number one so we need to make this 2p1 and it won't let me change it so i'm doing something wrong and in the menu it says that this setting is only available when the inverter is in standby mode so we need to turn it off so press the off button and then go back down to 28 and then press enter and now we can change the setting and three p is for three phase oh why'd it turn off so it turns off too quickly for me to change the settings i just asked the distributor and i finally figured out a solution so what you want to do is leave the inverter on and then go into the settings menu and then go down to 28 and then you want to turn it off and then change this setting quickly and this is the first inverter so we need 2p1 and then press enter and then get out of here and then turn it on and turn it back off again and see if the settings have saved it should say 2p1 turn it back on again and it says 2p1 so we are good with this inverter now we need to change this one to 2p2 and then we'll be good to go the first hold down enter so now we're under option 28 we're going to turn it off and then change this to 2p2 120 and then press enter and then exit the menu and then it should say 2p2 now let's turn it off and turn it back on again and now it's off but before we turn it on we need to turn them on together so that they can communicate so we're going to turn them on at the same time it says 2p1 and 2p2 and they are both turning on at the same time now let's check if we have 240 volts at our panel and be very careful these are live conductors and from neutral to inverter hot number one we have 120 and from neutral to hot number two we have 120 but we only have 206 volts across the bus bars and i just found the problem so for the second inverter i put 28 120 but that's a 120 degree phase difference but we need 180 degrees phase difference so i'm actually going to go back in there and change it to 180 so it's a 180 degrees phase difference and then we'll have 240 volts here and here we go under option 28 it says 120 so we need to change this to 180 so turn off the inverter press enter change this to 180 there we go and now press enter then get out of this menu and we're going to want to turn them on and off again all right let's see if the settings save this time and it says 180 this time so we should be good let's test the voltage and we have 239 volts which is perfect so that was a bit difficult but now these are in sync and we have a split phase output now we need to connect some solar panels to these inverters there are mc4 inputs at the bottom where you can connect a single series string up to 250 volts open circuit and these 375 watt panels produce 49 volts open circuit so if i put five of them in series we will not exceed that max voltage input of the solar charge controller but i have six in series right now so i'm gonna have to remove one and typically the last panel is shaded more often so i'm going to remove that panel down there now we have five panels in series and we need to connect it to our solar charge controller and i'm going to use some mc4 extension cables to do that so first here's the negative conductor and then i'm going to connect the positive conductor and this is the other end of the extension cables first we're going to test the voltage because it's always a good idea to do that we have 190 volts which is perfect that is under 250. so now we just need to connect this to this inverter right here and because this is a single series string we do not need over current protection if we had multiple strings in parallel each one would need some form of over current protection device and right now it's charging and on the screen it shows 186 volts 2 amps coming in from pv array so 411 watts it's pretty cloudy right now but that's awesome it's actually working now i've made a second string of panels with 410 watt bifacials and again these go up to 50 volts open circuit on cold mornings so i put five together in series and then i connected it to the mppt and now i've connected both arrays to the first inverter and the reason they're both connected to this inverter is i already set the charge profile parameters so check it out so under option number one i have sbu number five is user setting so i'm not going to use lithium and i'm not going to use agm and under studying 26 which is max charge voltage or absorption i set it to 56.4 and under 27 for float i did 55 and for the cutoff of voltage for lithium iron phosphate i like using 48 volts and those settings work perfect for cycling lithium iron phosphate and in the future i plan to add more 48 volt batteries in parallel with these bus bars now that we have a battery and we're charging with solar i'm going to connect my air conditioner to this panel and this is my air conditioner it requires single phase 240 volts this is the cable that powers the air conditioner so we have two hots a ground and a neutral and we want to add it to this panel so we have a double breaker with 25 amps for each one but before we connect it we need to turn off the inverters and then check the voltage to ensure that the inverters are actually off and they are so first the ground and the neutral will connect right here and right here now that these are connected we can have the black and the red go into this double pole circuit breaker so loosen these screws now that the cover's on let's turn the inverters on now we have power so we can turn the circuit breaker on and now the air conditioner is running how cool is that it actually works so now we're using solar power entirely to power this air conditioner and that's pretty much it for this system all i have to do is add bigger batteries and then i'll clean up these cables over time i'll add more loads to this including my tesla charger and i'll add some more solar arrays to this inverter and i'll make future update videos showing you guys those upgrades so that's pretty much it let me know what you guys think below this is a pretty powerful system we've got 13 000 watts at our disposal and i plan to build a 30 kilowatt hour lithium iron phosphate bake to replace this small 4 800 watt bank so thank you so much for watching and i will talk to you guys soon bye

Channel: DIY Solar Power with Will Prowse

Views: 1,530,959

Keywords: off grid solar, will prowse, diy solar, rv solar

Id: 01qYerhorwU

Length: 17min 27sec (1047 seconds)

Published: Fri Aug 13 2021