Online... mostly!

      Okay, so I finally got the 24V system up and running. It took a lot of goading to get the wife on board and help but we did it! The panel mounting system had to be built which is where I needed my wifes help (I will admit it right here... she is a better carpenter than I am, but I rock in the electrical and mechanical world!). Together we built the frame that is being used to support our panels. After the frame was built we then hefted the panels up and I went to work making and testing connections.

      The image below is looking up at the solar panels right after we had their initial installations completed and I had connected them to the charge controller. As you can see we used a wood frame made from 4x4's and 2x4's. The panels (I still have to clamp them down) will be clamped to the frame using non-conductive, non-metallic clamps. The entire reason behind using a wood frame was to eliminate several potential issues. The first of which is a possible ground/short condition between the panel frames and support frame. Next is the sheer cost of either buying or building a frame out of metal, and third bi-metallic corrosion is a serious issue that can occur which raises it's own list of issues.

3- 300W / 24V Helios 7T2 panels

      If you look just below the middle panel you will see the combiner box that I put together with all the guts connected. I thought we were going to place the panels up higher on the roof but the wife said no, let's try them here first. So I evaluated the area and agreed it would be perfect for both summer and winter collection. The only issue is an apple tree which we will be trimming soon. Otherwise we are getting excellent performance from the panels where they are right now. The next image is a side view, and there you can see the apple tree I referred to earlier. Also you can see the upper locking board we are using to ensure the panels don't go any where.

      One thing about where we live is the wind during the winter months can rip through our property at speeds as high as 80mph in gusts. And that means if it isn't locked,tied, nailed or glued down... it will end up in the neighbors yard. Anyhow the lower frame is metal and we chose to build the connections to the ground out of metal for the strength then we used wood for the upper frame to tie it all together. This weekend I will be installing the ground / lightening arresting system for the panels so as to protect them in storms. We don't get many electrical storms in our area and if we do it's usually one flash of lightening, a big ass boom then a ton of rain.

3- 300W / 24V Helios 7T2 panels side view.

      In the next image is another view of the combiner box. I still have to seal the penetration holes I drilled for my cabling but I am waiting for another couple of weeks while I tweak the system and verify performance. A lesson I learned on my 12V system. The one thing that will happen is the combiner box will be moved to a different location and the lead wires out will be shortened which will increase my efficiency while reducing loss even more. As it is I have already over engineered the system to the point that my theoretical loss is less than 1%. I had a friend who is a retired electrical engineer come up and look at my system, look at my design drawings and specifications and the first thing he said is the way I have it designed and built is that if I see more than a 1% loss he would be surprised.

Home made combiner box connected and providing power

      A bit more on the combiner box, I may have covered this already but I will do it again just for learning purposes. The combiner box it nothing more than an 8x8x4 plastic junction box. I bought two DIN rails and two lugs for the larger cable (4AWG). Then I went to West Marine and bought three 15A DC rated circuit breakers. You're gonna love this, the circuit breakers are held together as a group by a piece of plastic I cut out of a yogurt containers. Then each breaker is wired into the positive leg DIN rail. The solar panels are then each individually connected to a breaker. Now this allows me to isolate panels as needed for what ever reason I may have. It also provides over current protection in the event a panel surges, which I was told can possibly happen in colder weather.

      The totals cost for making my own combiner box is around $50-60.00. And it provides the connection point with protection I need plus I have a more intimate knowledge of how my system is put together which allows me the ability to trouble shoot and repair my system much faster.

      Okay this next image is the battery house again, with the cheapo inverter I am using for the interim. What you are looking at are 8 USA 6V 380AH batteries configured in a series (24V) parallel set-up that provides a total of 760AH or 18,240W of power potential. Normally this would entail using a 24V inverter as well, BUT since getting said inverter at a price point that I can pay has been proving quite the pain in the ass, I have temporarily set-up a 12V 1500W inverter to run our fridge. It works just fine but the problem is when you do this the two batteries selected drain faster than they charge... I found this out this morning when I was told by my wife that she heard an alarm from the battery house. I didn't hear it until I was 8' away (damn being deaf SUCKS! Or not :-) ) So this morning I had to change the connection points and set up the charger to recharge the two batteries we have been using. Word of advice... don't do it.

      Now before anyone says anything, I am still working on getting things put together so no it's not the best or cleanest looking set-up. But one or two more good weekends and it will look more presentable and be cleaned up. People who know me know I can't stand this kind of mess but... it's a work in progress at the moment.

      Now on the inverter issue, I finally resolved this issue this morning. Originally I had ordered this inverter here --> Tripp Lite PowerVerter® Plus 2400W Industrial-Strength Inverter with 2 Outlets from Provantage but due to a comedy of errors (I didn't think it was very fucking funny!) the inverter was back-ordered with no known date of delivery. SO I found the same inverter on Amazon for about $50.00 more but it will be here tomorrow and will be installed tomorrow evening after I get off work.

      Now some more really good information I learned. When I started this project I went in with very little knowledge or experience. I didn't know how to really get things going  but as I have been moving deeper into the solar / off-grid world I have learned a lot through experience. And one area I made a mistake was in sizing my inverters  and my initial system designs. Oh no the system I have is more than capable of doing what I need, but I goofed on my fridge calculations. And I realized that this weekend when I fired my fridge up. In my earlier posts I said 1-1/2 to double the amp rating should be factored in for your fridge or any motor start up. Man... I was not even in the ball park!

      So I have a Kenmore refrigerator it was purchase in 2006. Not very old but very efficient! When I was gathering my data for the system design I overlooked how many watts this thing consumed while running. I did the math and according to the math I should be pulling 4.9A at 588W of power... nope! So when this fridge is running it draws 1.69A at 202W and that's for about 10minutes after starting up. Once it's settled down it pulls 1.37A at 164W! For a front load fridge that's 6-8 years old! Not bad! And now that we have insulated it even more, the run times should be reduced. Now back to the area where I screwed up... the start up of this fridge is a whopping 13.8A at 1660W!!! That's to start the fridge! I was WAY off in my estimates. I was also off in my run time consumption. According to the Kill-a-Watt over a 24hr period the fridge burned 2.3kWh of power.

      Now looking at the system I have in place I got the solar capacity perfect (it will carry the remainder of my load as well as the fridge) And daily I will be driving my batteries down to an estimated 25% which is perfect! And so long as we have average solar days the system will produce that and more. But the whole point of this particular diatribe is when you are dealing with compressors or high load motors, give yourself about 40-60% for start up demand, the idea is to ensure your inverter can handle a massive current surge without tripping on an over current fault. The reason I say that is an 800W inverter is more than enough to carry my fridge but the startup current exceeds the 800W inverters capacity and so it's a non starter. The 1500W inverter I have right now... it can take the fridge start up but that's it. I can't have any other loads on that inverter.

      But tomorrow it won't matter as I will be installing the CORRECT inverter that is designed to handle the load AND work with the system voltage. I think that's all for now, I will make another entry once I have things cleaned up with the system and I have more actual use data. Kill-a-Watt... use them! Serious you can't manage what you can't measure folks.

      Okay... here is the system drawing I have with some of the material requirements annotated.