DIY Solar panel setup on a budget

Discussion in 'Hobby Engineering' started by Mathuisella, Oct 15, 2013.

  1. rainwulf

    rainwulf Member

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    Yea not having much luck with the relays. They click but sometimes dont actually work. not particularly happy with that, as it could cause a link between the inverter and house mains. Currently pissed off.

    Do you have any links to these discussions?
     
    Last edited: Feb 11, 2018
  2. heller44

    heller44 Member

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    Even if you had no issues with that relay module, in the event of a welded contact / relay failure / driver fault, you would have the same issues. My opinion is this isn't the right way of doing this, throwing the set in parallel. Maybe an auto transfer switch could be used instead? There are some very cheap ones advertised, they might not be awesome, but might be a better idea..
     
  3. rainwulf

    rainwulf Member

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    yea i am rethinking this idea. Something that needs to throw both contacts at once, instead of relying on 2 individual relays.
     
  4. Recharge

    Recharge Member

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    dude..... that is so freaking impressive.... wow, just wow. :thumbup::shock:
     
  5. rainwulf

    rainwulf Member

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    Thanks.. still not happy with it. Last night the mains flickered on and off to the ATS, and when it came back on, and even told the relays to close to switch back to solar power (the ats itself is mains powered), it didn't switch, and left the main load on UPS. Going on a relay hunt, i need 4 dpdt relays that are preferably clear.
     
  6. vk2fro

    vk2fro Member

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    Pffft TNT just delivered 500W of solar panels - exactly half my consignment - how do you loose a 1.6x1m box weighing 40kg's? :p
     
  7. aussie-revhead

    aussie-revhead Member

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    rainwulf

    That looks like a lot of work, out of the realm of most diy-ers and would cost a fortune for a tradie to do (if you could find one that could be bothered)...

    Nice work.

    :)
     
    Last edited: Feb 12, 2018
  8. rainwulf

    rainwulf Member

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    Thanks revhead. You referring to the panel mounts?
     
  9. aussie-revhead

    aussie-revhead Member

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  10. JabTronic

    JabTronic Member

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    Unfortunately I can't find them, not sure what I was searching for at the time. I think most people would recommend using those relays to switch a contactor instead. I also noticed some people recommend solid state relays but be weary of the common Fotek SSR available on ebay etc because there are many counterfeits out there that melt at high loads eg fake Fotek SSR's rated at 40A people are opening them up to find only 12-16A rated triacs inside them. I have a 40A unit here which came included with another product and the SSR is a fake, they are pretty common. The fakes work fine for small loads eg 10A but it's recommended they are mounted on a heatsink regardless. Crydom or Kudom SSR's are supposed to be more reliable but you're looking at $40+ea
     
  11. rainwulf

    rainwulf Member

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    Yea definitely NOT going to use an SSR to switch between house mains and inverter 240 volts.

    Most SSRs fail closed, and that would directly link the house 240 volts to my inverter. I dont think that would do it any good, and that's ignoring the massive safety aspects.

    I have located a set of clear case 240 volt 10 amp relays that have linked contacts. It means that if one of the contacts welds itself, the other contact wont close to the other side, rendering the 240 supply isolated. They are 8 bucks each, but luckily only need 4 of them to do the switching. I do have a set of the DC fotek SSRs but that was going to be the plan for switching DC to the inverter, but i haven't implemented that plan yet.

    Today i recieved my 4 port usb charger modules : https://www.ebay.com.au/itm/4-Port-...026118&hash=item3ae7559c3f:g:thsAAOSw3YJZP67~

    I am designing the 3d printed case for them now, they will be situated at places that our phones/tablets spend most of the time, so they will charge from solar instead of from house mains, eliminating that particular phantom draw.

    The final aim for my entire project is to have as many things running of DC if they use plugpacks, or of the core inverter depending on the battery bank level.

    During the day, once the batteries hit absorb charge, there is an abundance of power, so my ATS will switch in all the things around the house that i can access with power leads, and this includes the TV and media center PC. The 24 volt ring bus around under the house will be tapped off to provide usb power, LED lights, desk lamps, aquarium lights etc. As the light drops in the evening, and while the batteries still have their excess surface charge ( i wish i had nickel irons batteries for this, as they can be overcharged extensively) the media center and TV stay powered switched to battery power until the battery bank hits 12.8 volts, which happens around 7-8pm. That way i can use the surface charge and run the tv of solar power for most of the time its on. Obviously this will all be monitored with the ATS and solar management program.

    So yea, going to be a fairly big project, but once its done, i will be able to monitor everything via a web page, and have the entire system take care of itself. It will prevent the batteries from going below a certain state of charge, and once they hit that level, all loads stay switched to house mains until the batteries can get a full charge in during the day, calculated with AH counting.

    The biggest issue with battery cut offs is that they often cut back in too early, and on a cloudy/overcast day your batteries never get that full charge they need (in the case of lead acid, lipo doesnt apply here).
    My system will know that if my bank hits 12.5 volts overnight, do NOT turn switch back on any load until the batteries have spent at least a solid 2 hours at absorb.

    Each day is a new day, so there will be flags for each days input and output power and voltages.

    its gonna be exciting! I will probably make the software for the arduino and PC open so anyone can fuck with it.

    I will also design an arduino based "IO" unit, so you dont actually have to be able to read your charge controller, as the arduino will be able to measure input and output currents, and panel and battery voltages, and make decisions based on that.
     
    Last edited: Feb 12, 2018
  12. vk2fro

    vk2fro Member

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    That would be awesome - so someone like me stuck with a charge controller that has no connectivity (even tho advertised as such) can actually walk away from it and still be able to monitor it :p

    TNT found the other half of my shipment. *phew*. Didn't think they'd be dopey enough to loose a massive box of solar panels :p
     
  13. rainwulf

    rainwulf Member

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    vk2fro, i have some parts on order from ebay, so i think a nice little packaged network enabled device that can give you info and stats would be decent?
    It will basically record temperature, battery voltage, charge current, discharge current, and have an output that will allow you to turn something on or off remotely, as well as at triggered voltages.
     
  14. vk2fro

    vk2fro Member

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    And of course have a wide input voltage range for those cool sunny mornings
     
  15. rainwulf

    rainwulf Member

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    As voltage goes up, accuracy will go down a tad, having to reduce say 200 volts down to a 5 volt range could impact accuracy a tad heh
     
  16. vk2fro

    vk2fro Member

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    Yes i found that with my cap bank. Ended up using a dedicated meter to measure the 900+ volts, and setting the divider up for more accuracy at the top end :)

    And this has got me thinking - I shouldn't be so afraid of the ~100ish volts that I will get from my 96 cell panels in series - after all I'm still here after playing with a 900+ volt cap bank that can dump 1000's of amps in a heartbeat if you touch something you shouldn't. Guess I am overly cautious :)

    The cap bank earned a few visits from the police. Blowing things up with it resulted in reports that sounded like gun shots. The firing scr looks like a hockey puck :p
     
    Last edited: Feb 13, 2018
  17. rainwulf

    rainwulf Member

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    Its something to do with your brain. you see a cap bank and go "oh fuck yea thats dangerous"

    you see solar panels and think "what could they possible do?"

    100 volts with the ability to provide over 10 amps is pretty damn lethal.

    I brushed the outputs of my panels in the afternoon SHADE and it gave me a pretty sharp tingle, even though they had barely any current, voltage was still up nice and high.
     
  18. vk2fro

    vk2fro Member

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    Ahhh but I have seen youtubes of open circuit panel strings pulling nice arcs - so I'm going to be careful with the pointy bits while up on the roof :)
     
  19. rainwulf

    rainwulf Member

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    Yep, when under the sun they can produce nasty arcs and will kill you without blinking.
     
  20. rainwulf

    rainwulf Member

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    I wish you could make electricity from humidity cos damn Brisbane wtf
     

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