In this post I wanted to show you this 24v, 4000 watt 10kwh diy solar generator I built to replace the 12v system I have been using. This 24v Sungold Power Inverter with a built in charger is the star of the show in this DIY Solar Generator. Be sure to watch the video below. You won’t believe the surge capacity of this inverter. I’m also going to run a stress test and push it to the max.
This post is more of a summary of this new 24v DIY Solar Generator. Watch this video for the complete review.
This is the 12V system I am replacing. How to build your first DIY Solar Generator – Complete Review
If you are a beginner, check out this link el=”noopener”>>DIY Solar Power Generator Concepts and Equipment – For Beginners
The Build
The primary reason I built this 12V DIY Solar Generator was primarily for power outages. But I did not want to just let it sit here unused waiting on a power outage. So I decided to start using it to save a little on my electric bill. I was running extension cords all over house and my family and I decided we did not like that. So I put in a manual power transfer switch where I could with a flip of a switch, go from running a circuit on grid power over to running that circuit with my DIY solar generator. I could just as easily switch it back to grid. Its a 10 circuit transfer switch and I’ve been running several things off of solar full time for a few months.
I’ve been running almost all the lights, the main entertainment area where our TV is, my upstairs office and occasionally other circuits based on if we were getting some good sun that day. I could of course power my refrigerators and freezer if I needed to during a power outage. I will also put a link below to the video where I explain all about the transfer switch I installed.
Transfer Switch For Solar Generator – Emergency Backup Power with Gas or Solar Generator
So why am I moving to a 24v system? There are a few reasons.
– I wanted to move up to a 4,000 watt inverter because I wanted to increase the number of things I could power at the same time. I was occasionally going over the 2000 watt inverter limit and it would trip and everything being powered by the inverter would turn off. That could become irritating depending on when it happens.
– Another reason was wire size. If I moved up to a 4000 watt 12v inverter, I would have to use giant even more expensive wires. I would have to double my wire size. I was using a 1/0 AWG wire. By moving to a 24v 4000 watt inverter, I was able to keep the same size 1/0 cables.
Some of you may wonder why I didn’t just go up to a 48 volt DIY Solar Generator. Then I could even use smaller wires. Well, I could certainly have done that. But I chose not to for a few reasons. Even though I have learned a great deal, I still am rather new at this. Anything under 30 volts is considered safe. When you move up to 48 volt systems, that could possibly kill you. I wanted to get some more experience under my belt with a 24 volt system and at some point in the future, I will most likely move to a 48 volt DIY Solar Generator. I would just have to replace a couple of components and wire the batteries in series instead of parallel.
I decided to keep the 12v system mostly intact so I have a backup system I plan to use it or other videos.
This 24v DIY Solar Generatorwas going to take up more of a footprint than the 12v so I measured the area where I wanted it to go and I cut a piece of 3/4 inch plywood to mount it on.
I took quite a bit of time deciding on a Layout. I did not really want to go through the back with any wires if I can help it. So this is the layout I went with.
I laid out all the pieces and thought through it carefully before I mounted anything.
I learned in the 12v build that it makes more sense to lay out your components, measure and make your wires first. Then connect them temporarily before marking the drill the holes for mounting the components.
If you don’t do this. sometimes when you mount the equipment, then try to build the wires for it, the wires might not actually fit as you though they would. They would come out a little short sometimes and too long other times. I ran into this several times when I built the 12v system. Then I would have to unmount that piece, then re-drill and mount it again.
As you can see here, I decided to go with two MPPT charge controllers. For those of you wondering, Yes, you can do this. It works fine. I’m sure there will be some tweaking to the settings as I move forward and learn more about how they are charging.
The main reason I went with two charge controllers is because I have two solar arrays in two separate parts of my property. This also provides redundancy if one of the charge controllers stops working, I can at least have some solar power coming in.
The charge controller on the top right is a BougeRV 40amp MPPT solar charge controller. I have 800 watts on my mobile DIY solar array which I did a video on. I may eventually replace this BougeRV charge controller and replace it with another Victron. The Victrons can actually talk to each other and I really like the Victron mobile app interface. I will probably get the 150v/60amp Victron charge controller.
The charge controller on the top left is a 100v/30amp Victron MPPT charge controller. It currently has up to 600 watts coming in. I just have these panels leaning against a fence until I build something to mount them on. This charge controller can only support up to 100 volts so I can only add one more panel there if I stick with the same panels I am using. But I can add about 3 more panels on this BougeRv which can take up to 150 volts. I’m actually under paneled right now. I will expand as I can afford to do so over the next few months.
I decided to use this distribution box in the top middle to hold the PV input breakers. It’s not required. I just thought it looks nicer. I have two 20amp breakers in this box. There is actually a small DIN mounting rail inside. I have one breaker for each solar array. I mainly use these breakers to turn off solar input when I need to work on the system. I actually have a 15amp fuse outside on each solar array. I may go with a third solar charge controller at some point in the future. Not sure yet.
I have two portable Bluetti 350 watt solar panels I keep stored away. If for some reason the batteries were running really low, and I needed more solar input to charge up the batteries, I could just quickly deploy the portable panels and connect them into the third charge controller. I have not decided if I want to do this yet or not. If I do, I will most likely create a video on it.
The output from the charge controllers go into this distribution box where I have a 32amp circuit breaker for the Victron 30amp charge controller and I have a 40amp circuit breaker for the 40amp BougeRV charge controller. These protect the rest of the system if something goes wrong with either charge controller.
The output from this box runs into these bus bars. I decided to go with these high quality Pike Industries tin plated solid copper bus bars. These bus bars are rated up to 400 amps.
I have this battery disconnect switch here below the bus bars so I can easily isolate the batteries in case I am working on the system or perform and emergency shutdown. This battery switch is rated up to 275amps with intermittently hitting up to 455 amps.
I put a piece of paper up here for anyone other than me that needs to shut down this system. I went over it with my family already.
Between the battery switch and battery bank I have this BlueSea ANL fuse holder with a 250amp fuse. This is a high quality fuse holder and fuse. Much better than what I was using. But also more expensive of course. I will most likely upgrade to the Class T Fuse in the future. 24v systems is as high as you can go with an ANL fuse. You need to move to a T-class or mega fuse when going to a 48v system.
Off the negative wire coming from the negative bus bar, I have the Victron Smart Shunt which I use to monitor the battery state of charge and see how much the battery is either being charged or discharged through the Victron mobile app. This shunt is rated up to 500 amps. This is a nice shunt. The only downside is that if I am standing here, I can’t just look at the SOC, I have to open the mobile app. I could purchase some additional expensive Victron equipment if I wanted so I could have a nice little LCD display mounted up here.
Now we come to something you don’t see as much with DIY setups like this. In parallel setups like this, you typically just see the negative coming from this battery and the positive from this one going to the bus bar. Instead of that, I am using bus bars for the battery bank here. If you have rack mounted batteries in a cabinet, you sometimes see bus bars mounted inside the battery cabinet that all the batteries connect to with just the two wires (positive and negative) coming from the battery bank to the system. This is basically what I have done here. You don’t see people doing this much, but the power queen manual for these batteries actually says to do it this way.
These bus bars are 3 stud nickel plated solid copper bars and rated up to 600amps.
These two batteries are the power queen 24v 200ah batteries. Each battery has a 200amp BMS. Putting these two batteries in parallel like this gives me a total of 24v 400ah or 10,240 watt hours. These two batteries are the equivalent of 8 standard 12v 100ah batteries. These things weigh 80lbs each. I built this table to hold the batteries as well as my Bluetti AC/200 max underneath. I did not enclose it. Maybe I will do that in the future.
One nice thing about getting these 24v batteries is that if I do move to a 48volt system in the future, all I have to do is wire these in series and then I have a 48v battery bank.
These wires between the batteries are 6 AWG and the recommended size according to the power queen manual. It is crucial that all of the positive and matching negative battery wires between the batteries and the wires going to the battery bank bus bars are of the same size and length. Otherwise, if you don’t do this, you batteries could become un-equalized over time. And one battery may age faster.
These batteries have a 5 year warranty and are rated to 100% DOD (depth of discharge) after 4000 cycles. That means that if you discharged these batteries down to zero and recharged them fully every day for over 10 years, they won’t lose any of their charge capability. They only go down to 80% DOD after 16 years. That’s just crazy. I will most likely move to some better battery technology in the future before these batteries wear out.
Before I hooked up these batteries to the systems I followed the instructions in the power queen manual and equalized the batteries. Basically the steps for this is to separately charge each battery to full. I used the built in charger on the inverter which I am about to get to. Then connect the batteries together in parallel using these 6AWG wires. Then leave them alone with nothing else connected for 12-24 hours to equalize. Then you can connect the battery bank to the system. Power queen recommended doing this equalization every 6 months.
The wire size between the inverter and battery bank is 1/0. I got this from the Sungold Power inverter manual. It says to use 1/0 for this model. I also ran my own calculations to confirm. This windy nation 1/0 battery wire has a maximum amps rating up to 285 amps.
Now to the inverter/charger. This is the Sungold Power 24v 4000 watt pure sign wave inverter with charger. This thing is a beast. It weighs 54 pounds. This is the single phase model, not the split phase model. It also has a UPS feature when it switches between battery and grid power. It can do this in under 10ms.
The inverter is what they call a low frequency inverter. You mostly see high frequency inverters which most DIY’ers use. Sometimes the inverter won’t even mention it. If it doesn’t it is probably a high frequency inverter. A low frequency inverter has some advantages and disadvantages. The advantages is that it can handle huge surges for up to 20 seconds. This inverter is a 4000 watt inverter and typically you see that it can handle a surge up to double that. But this one can handle a surge up to 12,000 watts for up to 20 seconds. It does this by having a huge transformer inside. This is why it weighs so much more.
Low frequency inverters are supposed to be more reliable and run a little cooler. There are some downsides though. As I already mentioned, Low frequency inverters are heavy because of that transformer. They also typically have a higher idle consumption. When I disconnect everything and only have the inverter running, the battery shunt shows its drawing 60 watts just sitting there with no load. That is definitely on the high side. You need some extra battery and maybe an extra panel or two to make up for this if you are planning to leave this on all of the time.
It does have a power saver mode. This is good if you only need to use it from time to time. When power save mode is on, it only consumes about 25 watts. It does this by checking for a load every 30 seconds. If it detects a load, it turns on the inverter. I believe you can change this to check every 3 seconds. Low frequency inverters are also have a slightly lower efficiency than high frequency inverters.
One of the biggest features I like about this inverter is that is has a built in adjustable battery charger. Using this little dial, I can adjust the amount of amps it charges at. I can adjust it from 0 to 50amps. You can also choose the battery type here. I initially chose Lithium Iron Phosphate since that is what I am using, but after reading the battery manual, the recommended charge parameters better matched the “Lithium/Sealed Lead Acid” setting. I reached out to Sungold power and told them what battery I was using and its recommended charge parameters and they agreed that that setting could be used.
This inverter/charger has 5 dip switches where you can configure it. There is no bluetooth connectivity. Switch #5 is to configure between battery priority or AC priority. In AC priority mode, it will bypass the inverter and battery and only use the battery and inverter as a backup source if AC input is not available.
In battery priority mode, which is how I will use it, it will always use the battery and inverter to power the loads. However, if the battery voltage hits a low battery voltage trip point, which I have set at 21 volts, it will stop drawing from the battery. It will then use the AC input (which could be grid power or gas generator) to supply the load and charge the battery. Since it has a UPS feature, you won’t even notice this. It also a generator start feature if the voltage gets too low. When it does hit this low voltage trip and switches over to AC input, it will start powering the loads from the AC input as well as charge the battery. It will continue to charge the battery until it is full, then it will switch back to inverting from the battery again.
These details are very important to pay attention to because you want to make sure the wire you use for the AC input is big enough. You don’t want to create a fire. As I mentioned, once the low battery voltage trip happens, It will bypass the battery and directly power the loads as well as charge the battery from what comes in through this AC input here. That means that the wire you use to power this 120v AC input needs to be capable of handling up to rated capacity of this AC input.
On this model, that AC input can handle up to 40amps. It has this AC input breaker here on the side which is rated at 40 amps. Your typical 12 or 14 gauged wire you typically find in houses will not work for this for this AC input. They are too small. So you can’t just plug this into a standard wall outlet. You need to at least use 8 gauged wire on a 40amp circuit. Your typical house circuits in your breaker box are only 15 or 20 amps. I ended up hiring an electrician to install a new 40amp single pole circuit in my house breaker box and he ran 8 gauged wire over to the AC input of this inverter. 8 gauged wire is rated for 40amps. This is now safe.
So it is possible that the charger on this unit is never even used since I am using Battery Priority and it will only turn on if the battery drops below the low voltage trip. However, If I need to I can easily charge the batteries from grid or generator power simply by flipping switch 5 over to AC priority mode and it will then charge the batteries using the AC input. I like this flexibility.
Now you might be thinking why use grid power at all. Just use gas generator. I thought the same thing. If I want, all I have to do to do that is to switch out the wire into the AC input to a wire coming from a gas generator. But that is a little bit of a hassle and manual intervention. But right now, I don’t even have a gas generator capable this much power. So for now, this is what I will use. I may switch over to generator input at some point if I get a larger generator.
The inverter has these two outlets that I could use. But I’m using the 120v output terminal to run up to this NEMA L14-30R 30amp outlet. I’m using a 30 amp extension cord over to my transfer switch. The extension cord said it was capable of handling 7500 watts. My transfer which has 10 120v circuits that I decided was the most critical in a power outage. I’ve been running about 6 of these circuits full time for things such as most lights, my upstairs office, smoke detectors, kitchen counter appliances such as a toaster oven and air fryer. And the clothes washer. It handles all those beautifully. I’ll put a link below to the video where I talk about the transfer switch.
Testing
I put this system through a small stress test and check for heat. I pushed the system to just over the 4000 watts. I did not want to push it to the 12000 watt surge limit because I’m not sure I can even do that, plus I don’t want to blow my fuse. Those fuses are expensive.
Watch the video for the complete test.
I only discovered one wire above the battery switch that got about 110 degrees Fahrenheit. That’s not real hot, but hotter than other wires which stayed in the 80 – 100 degree range. My garage was about 80 degrees when I ran the test.
Its a good idea after a test like this and after everything cools down, to check all of the connections to make sure everything is still tight.
Let me know what you think about this 24v DIY Solar Generator in the comments.
I put the links below to all the components I used to build this DIY Solar Generator. Some of the links below are affiliate links. If you click on those links and make a purchase, I will get a small commission without costing you a penny more. That would go a long way to help me keep making posts and videos like this.
Other videos:</b></p>
DIY Solar Gene
rator Setup for Beginners – https://www.youtube.com/watch?v=lQ_3_9nPYFM&t=1084s</a></a></p>
DIY Solar Gene
rator Setup Complete Review – Beginner Friendly – 12V – https://www.youtube.com/watch?v=g6gKLMm70Cc&amp;t=52s</a></p>
<p>DIY Solar Gene
rator Transfer Switch – Power Outages and Every day Use! – https://www.youtube.com/watch?v=3Mj57MB8AWo&t=1s
Affiliate Links:
SungoldPower Inverter/Charger – https://amzn.to/3XMJwho
PowerQueen 24v 200ah Batteries – https://ipowerqueen.com/products/power-queen-24v-200ah-lifepo4-battery-built-in-200a-bms?ref=ProficientPrepper
Victron Energy 30amp MPPT Charge Controller – https://amzn.to/3Wmm23A
BougeRV MPPT Solar Charge Controller – https://amzn.to/3Ljw27k
Battery Switch – https://amzn.to/3MFtUrR
Windy Nation Welding/Battery Cable – https://www.windynation.com/products/1-0-gauge-black-red-welding-cable
Victron Energy SmartShunt – https://amzn.to/3ofTJFC
4 Stud 400amp BusBar (red) – https://amzn.to/44DIJRN
4 Stud 400amp BusBar (black) – https://amzn.to/44g4YOd
Breaker Distribution Box – https://amzn.to/3POIC1B
PV Isolation Breaker – https://amzn.to/3MFpAZG
Blue Sea Fuse Holder – https://amzn.to/44fgE3r
Blue Sea 250amp fuse – https://amzn.to/46zSrXr
Battery Bank Bus Bars – https://amzn.to/3O8OXUI
BougeRV 200 watt Solar Panels – https://amzn.to/40itNa4
30amp Extension Cord – https://amzn.to/3DarEDi
