A step toward completely off grid!

[MPaulHolmes]

All the stuff came from home depot or a cheaper equivalent part from ebay:

3/8" bolt through square washer, screwed into those unistrut spring things:


Push into unistrut channel, then rotate clockwise 90 degrees. It won't let you rotate it counterclockwise:




Torque that sucker down! The panels can take it!:

[MPaulHolmes]

Two clamping points per side:


I had to get sort of ghetto/creative for the ends. haha:

[Jyden]

Originally Posted by MPaulHolmes

OK I went with photobucket. I think they'll show up now...





I just used some square washers that are 1/4" thick to squash each panel down at 4 different points. I should get a picture of that part.

There were about 15-20 mph winds today and there's not even a hint of wobble. I think they will be fine in really really fast winds, at least I hope.

U better get som diagonal cross beams on that thing to resist wind etc, or it might tumble over.

[MPaulHolmes]

Ya, I'm going to add some 2x4's. I got the grounding lugs and #6 wire threaded through all 12 panels and then drove a big grounding pole thing like 8 feet into the ground, so I officially won't get shocked by touching the frames now, not that I would have anyway. I also drove another grounding rod into the ground next to the shop, where the AC box thing is going with all those "20 and 30 amp trip circuits" inside it. I also just got 250 feet of 10/3 underground feeder cable. I'm going to put outdoor plugs near the house so I am not messing with the house wiring.

I got a small protoboard soldered together for a DC voltage monitoring circuit. (seemed like a good time for a new paragraph, but I was never very good at knowing when to do that). I'm just going to feed the output of that to probably the throttle position on one of the DC controller control boards that I had done for the "1000 amp controller". That will be the MPPT charger control section. I've done up a driver section for a 600v 600amp IGBT half bridge. Since I'm just doing a buck converter, I'll only need the single module. The copper sheet is here, the 500uF ring capacitor is on it's way. I probably need another 8 6v batteries since I have enough power to charge the 48v battery bank at over 100 amps when the ambient temperature is over 100 degrees. Not a good combination. Maybe I'll make a little battery box and put a super tiny air conditioner inside it.

[MPaulHolmes]

I just went ahead and made a whole new board for the MPPT solar charger. It monitors solar voltage, solar current, battery voltage, and battery current, and "temperature" of whatever. It powers 2 contactors, and has 2 precharge relays that are good to 450vDC at 10amps. It also has onboard precharge resistors. The power section should be good to charging 400v at 300amp or so with adequate cooling. The inductor is only rated for 200amp continuous, so if you want to do the whole tesla charging thing, you'll need a slightly bigger inductor. None of this of course is at all relevant, since my array can only charge at around 5.6kW. haha. And my golf cart batteries would be none too happy charging at 300 amps, and I don't have 375v worth of 6v batteries either.

[thingstodo]

Originally Posted by MPaulHolmes

I just went ahead and made a whole new board for the MPPT solar charger...

Oh, I see ... you just CREATED ANOTHER BOARD!!

Someone like ME would make it fit into the existing design to avoid fabrication, testing, debugging, et al.

You amaze me ... and speaking of that ... what news? Any news?

[MPaulHolmes]

Hello! The boards will be here in about 5 more days I think. I just got an aluminum plate tonight from Ebay. 12" x 24". Not the most space conserving, but that's OK. Tonight I'm also doing the power section layout, and figuring out where all the holes go in the aluminum plate. Then maybe tomorrow I'll write the gcode.

Also, the 250 feet of 10 gauge 3 wire (plus a ground wire) got here. It's the direct bury kind. I'm running that from the shop to the outside of my house, and I'll plug in our 3 window air conditioners to it. It was 110 today I think. You can actually feel your eyelids burning in the shade. It's a very weird feeling. Also, I was racing a road runner today in the car. Those things are pretty quick. Also, my son made a trap, and it actually caught a weird desert squirrel creature today.

Also, I got some of those solar panel connector plug things. I'm going to do 4 parallel strings of 5 panels each, which makes for a voltage at peak power of 175vDC at around 40 amps. I could have done 2 strings of 10 panels, but a peak voltage of 450v was going to be a problem for the off the shelf "universal input" AC-DC for the control voltage that I ordered yesterday. It can take any DC voltage from like 110VDC up to 370vDC, and puts out 15v for the control board and powering the igbt driver. Oh ya! All the parts for populating the control board and the driver board arrived today. And I already have the igbt half bridge that will function as the switch/freewheel diode in the buck converter.

Also, I ordered a combiner box that can take up to 12 inputs and can have a single 1000V 1000amp output I believe. It's a monstrosity, but was really cheap on ebay.

[MPaulHolmes]

Here's the 200amp continuous 300uH inductor:


Here's how I'm getting the control voltage for it. It will do around 50-400vDC (you read that right! DC! Even though it says AC. ya!) input, 15v output. Bootleg ghetto Chinese. Cheap, but evidently reliable. I've heard good things about MeanWell. Once I use them for a while, I can say "I know you, Mean Well." Or I could say "I know you mean well". It's basically the same thing.

Here's the copper poop. Oops, I mean copper sheet. LOL. Get it? sheet? hahaha:


Here's (here're??) the remaining cables necessary to turn the array into 4 strings of 5 panels per string:

[MPaulHolmes]

A close-up of the connectors. They just snap together! Rated for wet or dry.


12" x 24" x 3/8" aluminum plate:


5 Mil Kapton tape. And ONLY like $50. barf. Good to 18,000 Volts of isolation!:


Input fiter capacitor. 600v 500uF. I threw it up in the air against a white wall, and snapped a picture really fast. It's not a stock photo. I'm not lying.

[MPaulHolmes]

I finished building the MPPT charger. I'd go install it and test it out if it wasn't 119 outside right now. The voltage monitoring is working well. It was pretty noisy and had an offset of a few volts. Now, it's accurate to +/- 0.05 volts. So, since my output needs to be around 55.2v when done charging, it will stop around 55.15 or 55.25. That's good enough. There's just a tiny bit more wiring to do. I'll start with 1 string of 5 panels, for a total power of 5*280 watts. First, I'll charge the batteries with the inverter off, and then I'll turn the inverter on at the same time.