Want to experiment with small GT / MPPT setup

Thanks Bill -

Sometimes curiosity just gets the better of me.

On a more serious note...I have come by a damage solar panel that I thought I would use to learn about GTI's and their MPPT tracking feature. Sort of getting my feet wet long before diving into a serious solar system investment.

I am trying to match a micro Pv system of about 300~500 watts @ 28v~30v to a micro scale GTI. Is there any scientific approach to select a GTI that would maximize the AC watts produced. I know a little of the basic theory of the MPPT tracking and how it improves output but have yet to find a way of putting the theory to practical use in sizing a GTI to this micro pv system.

Any assistance, references, etc. would be appreciated

Thanks again

PS: Maybe this should be moved to a new/different thread...If So...Please place it where it belongs..and give me a link...thx

Comments

  • BB.BB. Super Moderators, Administrators Posts: 32,607 admin
    Re: Want to experiment with small GT / MPPT setup

    qis_mo,

    Hopefully you can find this thread. ;)

    Ideally, the MPPT / GT Inverter is already "optimized" for AC power output based on defined input (voltage and current) and safety requirements by NEC/UL (NRTL).

    Because these are regulated devices--You probably should not plan on playing around with them (making any changes) unless you are planning on scraping them when you make a mistake/are done. Sort of like I would not expect you to experiment with a Square D 15 amp circuit breaker, then install it in your home power panel.

    So, what is it you are interested in? The MPPT side or GT inverter side?

    If it is MPPT, you could purchase a small (15 to 30 amp) MPPT controller and connect it to a DC battery bank. And play with it as much as you want. The voltages are relatively low (not the 600 VDC maximum you may get with larger GT inverters). And you are isolated from the utility grid (legal). Note that batteries can output 100's to 1,000's of amps into a dead short--So you still need to be careful.

    http://www.roguepowertech.com/products.htm
    Morningstar Solar Charge Controllers

    If you are interested in the GT Inverter side--You could get an Enphase micro GT inverter unit (around 200 watts, I believe they are "sealed"). Or get one of those unapproved GT units from EBay (may be Hybrid GT/Off Grid units available too--those that do GT but support a battery bank and off grid applications too) and see what they do (not very reliable, may overheat if operated >50% of rated power).

    Enphase Microinverters for Grid-Tie Solar Systems

    If you want a "real" Hybrid Inverter system, Xantrex and SMA make some very interesting units (these are 4-6kW sized inverter systems):

    There is probably not much you could do to "improve" the MPPT function unless you are planning on designing your own system.

    But evaluating several systems before you buy a bunch (building a solar village)--Probably not a bad idea. Pretty much, the more you pay, the better the devices.

    We can probably be more helpful if you can give us more information on your requirements. Giving "generic" answers may end up confusing you more than if we tailor answers to your needs instead.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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