DIY Solar panel setup on a budget

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

  1. vk2fro

    vk2fro Member

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    Do you have a regulator between the solar panel and battery? if not your going to kill your batteries in short order. Even a PWM one is better than nothing, but an MPPT will get the most out of your panel.

    edit: Speed read - yes I see you have an mppt regulator. Nothing to see here. ;)
     
    Last edited: Nov 1, 2019
  2. Mark Leonard Reynolds

    Mark Leonard Reynolds New Member

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    Wondering how you went with this?
    Recently purchased some bib 260 Ah flooed lead acid batteries, and installed onto a SunGrow SH5K hybrid inverter. Early days, but seems to work well.

    Wondering if you implemented your plan?
    thanks
    Mark
     
  3. Recharge

    Recharge Member

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    for batteries that won't explode.. god knows how much these suckers cost though.
     
  4. vk2fro

    vk2fro Member

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    6 Cells per 12V battery, they're about $40-$60 a cell, the better ones are 40Ah so you'll need a few to make a substantial bank. Usually found hiding in their natural habitat of Aliexpress/Alibaba. :)

    Good thing about them is you can completely F**k with them and they don't care (as shown with the drill)
     
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  5. aXis

    aXis Member

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    I have those exact cells, configured as 12 x 40aH cells in series. Gives me roughly a 1kW pack at 26V. I got them a year ago and at the time they were about $700 for the lot delivered.

    See this thread here: https://forums.overclockers.com.au/...heck-interest-lithium-titanate-cells.1248813/

    I was going to build an active balancer for them and spent about $100 in parts, I have three quarters of the circuit built and need to get the motivation to complete it. So far they are maintaining reasonable balance with about 0.045V between the best and worst cell.

    Scariest part about them is they will push over 2000A if you happen to drop a spanner.
     
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  6. Recharge

    Recharge Member

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    that's a lot of A.... :o
     
  7. aXis

    aXis Member

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    Oh also forgot to say, they can supposedly handle 30,000 cycles - that's the man reason I bought them. If it's true, I might never have to replace them.
     
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  8. Recharge

    Recharge Member

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    and given you'd probably never full cycle them anyway, that's a very long time.
     
  9. ShadowBurger

    ShadowBurger Member

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    Hey lads. After a long time I can finally drop in on this thread as I've finally bought myself a house which is both practical for solar and actually mine to f*ck with :D

    I'm going to suss out retailers - I do know a sparky who is putting me onto a friend in the business. My hope is that I get a choice of inverter and panel. Anything else I should be asking for? I'd like to put batteries in, preferably nickel-iron, but we'll see how expensive that gets...

    This is the block
    [​IMG]
     
  10. OP
    OP
    Mathuisella

    Mathuisella Member

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    Yesss, go NiFe batteries.

    Fill the entire roof with panels in every direction :p
     
  11. heller44

    heller44 Member

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    I would suggest, you work out what you want to achieve with solar, before you even start looking at equipment.

    Do you want a reasonable ROI, or is it a long term toy/hobby?

    Hopefully someone from over there will have a better idea on the FIT you can get and how the calculations work out, financially.
     
  12. xc351

    xc351 Member

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    You Deffinitly want to put the most panels on you can. Eg 6.6kw with 5kw inverter.

    Yes it maaaay clip the top of it for like 15min per day.

    But 5kw of panels will produce 5kw of energy in perfect conditions add angles, direction if points, even temp, age, ect ect

    Then your brand new 5kw system will produce like a max 4.5kw.

    You also need to decide if you want God bang for your buck or pay a premium for "top teir products" I'd personally go good inverter (sma or similar) and cheaper panels as some panels are double the cost for only a small increase in output.

    My current place has a cheaper system (installed before I purchased the place) it goes just as well as my old place (now a rental)
     
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  13. rooster77

    rooster77 Member

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    you wanna buy a car? buy a roller! NO, buy a mini! no, buy a colorado! Umm... it depends on what your needs are. Are you looking to reduce your bill, or (depending on your state) milk the feed in tariff? If your state has crap feed in tariff, then producing more than you need is likely to cost you significantly. If you've just bought a house and don't have many bucks left over, then buying batteries is most likely not to be a good financial decision. Need more detail!
    (I've been responsible for working out the requirements for 3 family members, and each solution is different because of FIT, expectations and willingness to have an investment, and how heavy electricity users they are)
     
  14. ShadowBurger

    ShadowBurger Member

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    Thanks lads! I love the idea of batteries and it'll definitely be a bit of a hobby so I want something I can play with to an extent... I've seen some inverters with nice apps to check the system status from my phone from anywhere.

    Based on my average daily usage for december (250kWh total), I can build a NiFe bank with the capacity of half my daily usage - 200aH @ 48V - for about $8k including connectors and chemicals and all that. I'm hoping I could get a retailer to supply them so I'd be eligible for the $4.8K rebate I can see on the solar.vic.gov.au website. Anyone dealt with this? Are retailers likely to do that for me?

    Anyone here using a Fronius inverter? There's plenty of high level corporate marketing but I'm finding nothing in what they're like to actually use from an end-user perspective and how they can be configured. Will they support a NiFe bank? What is the wifi support / apps like?
     
    Last edited: Jan 5, 2020
  15. rooster77

    rooster77 Member

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  16. ShadowBurger

    ShadowBurger Member

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    rooster77 thanks so much for you input, that's awesome. Yep 250kWh was for the whole month and you're right, I haven't looked at the times of day when I use the power, I just halved it to aim for a rough capacity requirement. I figure the majority of power usage would be after hours but at least I have a ballpark figure to start from

    A 4kW system sounds pretty doable. Suggestions I've had from people with comparable houses / situations have suggested 5+ so i'll say 4kW is my minimum. It also sounds like I've estimated a fairly reasonable battery capacity, assuming most of that 200Ah specification is within the realistic daily usable discharge range of the battery

    In that image, north is up. Sorry should have specified. It seems like a big enough roof - I don't have dimensions but for approximates, it's a 700m2 block
     
    Last edited: Jan 5, 2020
  17. dakiller

    dakiller (Oscillating & Impeding)

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    You’ll need an inverter that does batteries, and that will be another 8k as well, on top of your array and inverters for that too. This makes what is called an AC coupled battery system. Dc coupled is the other type, but that is more viable for smaller setups.

    NiFe is terribly inefficient and requires constant watering top ups to run as well, that you will need a dedicated system to feed them water and require monitoring and maintenance.
     
  18. MUTMAN

    MUTMAN Member

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    talked to the Tesla mob yet ?
    their setup is fairly clever for on and off grid scenerios
     
  19. rooster77

    rooster77 Member

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  20. vk2fro

    vk2fro Member

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    Not to mention NIFE batteries arent cheap. But you'll only need to buy them once, same goes for LTO's if you treat them right.

    Member aXis can chime in on the LTO's.

    I didn't want to wait for china delivery of LTO's, so I went LifePo4. Presently a 12V system for my ham radio gear, but I'll grow the system as I get the money to afford each set of 4 LifePO4 cells.

    Battery voltage at a minimum should be a 24V system, 48V is preferred and thats what I am aiming for.
     

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