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Solar (heating or electric) / Re: Solar News
« Last post by dang on Today at 09:28:06 AM »
I think someone has not factored in the immense scale of their national rail system..

There are 12,000-plus scheduled passenger train routes scheduled daily, 5000 of its 10,000 locomotives are diesels. Appears each passenger car has its own little diesel power source for local lighting, venting and safety loads. India has 65,000~ passenger coaches...  If even 50% of them have aux power AND this saves one gallon of diesel a day then that is 12 million gallons of diesel unburned over a calendar year. Then how about the man-hours saved fueling & servicing the diesels plus the reduced fuel losses from spillage and lowered number of preventable accidents & equipment failure counting on an environmental perspective...

More factoids: seating capacity of the Indian Railways 5 million yet they will transport 23+ million people a day.

http://24coaches.com/indian-railways-facts-and-figures/
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India is rolling out trains with solar-powered coaches that’ll save thousands of liters of diesel
https://qz.com/1030696/india-is-rolling-out-trains-with-solar-powered-coaches-thatll-save-thousands-of-litres-of-diesel/

Typically, the numbers quoted don't add up.  Even building in optimistic  factors, there is no way the panels are going to come near anything like the fuel savings quoted. The energy the panels produce even when given every possible benefit, Production and hours per day assumed best possible case, every day, does not come near the energy content of diesel for the savings amount claimed.

Hope the indians know what they are getting into... or not be going to be able to get out of!
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Of course liquid fuels would still be needed for trains, semitrucks and airplanes.

India is rolling out trains with solar-powered coaches that’ll save thousands of liters of diesel
https://qz.com/1030696/india-is-rolling-out-trains-with-solar-powered-coaches-thatll-save-thousands-of-litres-of-diesel/

NASA Unveils Plans for Electric-Powered Plane
https://www.nytimes.com/2016/06/18/science/nasa-electric-plane-x57.html

Elon Musk Tweets Electric Semi Truck Will Debut in September
http://www.motortrend.com/news/elon-musk-tweets-electric-semi-truck-will-debut-september/
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Solar (heating or electric) / Re: Solar News
« Last post by lighthunter on July 18, 2017, 04:25:26 PM »
Right on! I dont have knowledge on slr mfg effects to environment but unless thats a deal breaker we(the ppl) are stupid not to fill rooftops with panels. Its wasted sun realestate  anyway not to mention you can double the use as roofing material. reduce size of HV transmission lines. It seems like a no brainer. Of course liquid fuels would still be needed for trains, semitrucks and airplanes but He is right!


Great read! Thanks so much for sharing this with us!!!

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Oztules / Re: guess who bought a power jack inverter
« Last post by lighthunter on July 17, 2017, 06:32:04 PM »


Can I still run this in split phase adding the second tranny?

I wouldnt do it any other way (unless of course i lived where split phase isnt used)
I dont know specs of each unit you want to team. If specs are all same (volts in,volts out,split etc) then ans is yes you will still have split with more power available.

One thing must not b forgotten tho, with 12v conversion the 12v current is phenomenal.
applying ohms law at face value, 2kw of AC power is 2000divide by 10.5v = 190Amps. Now double that for 4kw so 400A DC for the fets to carry. They have some pretty great specs like 180A per and there are 24, right? Well its an H bridge so you only get to count 1/4 or 6 pieces, then the to220 package they seal em in is only realistically good for 100 give or take an everybody has an opinion, so you have 600A to play with but they will make some heat at even 400 continuous. So keep in mind fet limits.

When considering connecting transformers together think of each winding as a battery for purposes of connecting.  You can connect 2 batteries + to + and - to - and get double the current capacity so long as voltages are identical. Same is true for transformers. You can also stack voltages in series on a transformer same as you can with batteries, taking into account current ability of windings, polarity and voltages.

Im guessing since you asked, one unit is split phase and the other is not. In that case you could add a winding to the non-split unit and make it identical to other unit.   Or you could just add it on as it is. That would beef up power capacity of one of the two split phases while leaving the other with no change. That is certainly an option. Then if you had mostly 120v loads, you would balance with more loads on the stronger side. Unbalancing a split phase really hurts efficiency though, thats another subject.


Also, realistically will I see any improvement to heat or output?
That all depends on your use and setup. If you are normally under 2kw and above only for short spurts chances are you dont have a heat issue and if you do its nothing a high performance fan wouldnt fix. Longer higher output, yeah anything you do to improve cooling helps.

Power handling? The resistance of the primary winding and the lead wires are the biggest limiting factors of power capacity. To get around that problem, you either configure things for higher voltage or lower the resistance by paralleling primary windings and lead wires with more copper. So yes you will imlrove power and efficiency (under higher loads) by adding another transformer. Not sure how u think it b expensive to go up in voltage. I think a 24 or 48v cntrl board can b had for $65 cant remember for sure an 24 irf4110 fets are maybe $15. If you really hate working with boards, you can use small side cutter an clip all 3 fet leads and bolt new fets in and solder overlap leads. Then again if the fets you now have can handle the voltage you wouldnt even have to change those. There are always many options and choices. You have to go with what your needs are and what you are comfortable with.  A running solar setup is always better than one thats not. Upgrades can be well worth it but I think Solomon wrote in the Bible somewhere that its good to grab on to the one without letting go of the other. I guess i never asked anyone what that meant but in our day you might apply it by leaving one inverter original and taking the lesser value unit and modifying it with higher voltage, new fan (some are like tubines) and a winding modified toroid. The single phase units can be made into split without much trouble. 

All fun stuff :)


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Here's Elon Musk's Plan to Power the U.S. on Solar Energy . . .

https://www.inverse.com/article/34239-how-many-solar-panels-to-power-the-usa
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Oztules / Re: Using old grid tie inverters to charge batteries
« Last post by oztules on July 17, 2017, 04:59:09 PM »
Yes Pete,

The GTI runs the house and charges the battery if the sun is out, and the house is using less than what it produces.... when the battery approaches full we can now throttle it back.

As we had full control and a micro involved, I figured we may as well do the three stage charging as well if light permitted.
Using the 8010 homebrew as the inverter, but a PJ would work just as well.

I think I make my own problems just so I can try to solve them.

....oztules
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Oztules / Re: Using old grid tie inverters to charge batteries
« Last post by Pete on July 17, 2017, 04:48:52 PM »
Hi Oz, well I have to admit that having a small solar system I have not come up against the high current problem you have to deal with. I only have around 30 amps at 12 volts to control. I have seen the high prices of MPPT controllers and steered clear of them though.
I am guessing that you are using the Grid Tie inverters to feed power to the PowerJack ( using it as the charger) or directly into the house when required.
Is that what you are doing?
As I really only dabble in repairing things that used to work, I don't have the info in my brain to design or change things much. Just Oh it used to work, so It should again.
Cheers
Pete
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Steve / Re: My Scratch Pad
« Last post by MadScientist267 on July 17, 2017, 03:00:00 PM »
LOL Yeah... turned out this one needed some additional.. ahem convincing... but it's now been beaten back into submission, and is test driving one of two methods I want to try for handling an offset that showed up in the ammeter. Looks more promising than ever tho with each swing... I must have gotten it backwards for one of them and it didn't fancy the claw...? Lol

Getting there tho yep
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Steve / Re: My Scratch Pad
« Last post by bj on July 17, 2017, 07:22:05 AM »
  Hammer works Steve.  Had good luck threatening with my 50 ton press as well. ;D
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