Announcement

Collapse
No announcement yet.

Diodes and bypass diodes

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • inetdog
    replied
    Originally posted by cosuroca View Post
    Hello, sorry if I change a bit the topic of the post or ask somewhat out of place. But my question or ask is for Mike90250 and longwolf, I saw your posts and I really like your figures that they uses for show diode bypass.

    Mike90250 :



    In special longwolf, I'm student and I'm newbie in this topic, but I want to understand very well and try to use in my home some things...

    Well, my question or ask is about the Software that they use for make figures?, in special the use longwolf... What software they use for it?

    Thanks a lot.
    [COLOR="#B22222"]It is generally less productive to add a general request for info like this into a long dead thread on a different topic. In this case it seems like it might be appropriate since you are talking about specific graphics that are part of this thread. [/COLOR]

    Leave a comment:


  • aftabrrg
    replied
    how can I see your drawing?

    how can I see your drawing?


    Originally posted by longwolf View Post
    All right!
    Thx again Mike.
    And, because I know you like them, here's a pictorial view of the solution.

    Leave a comment:


  • cosuroca
    replied
    Hello, sorry if I change a bit the topic of the post or ask somewhat out of place. But my question or ask is for Mike90250 and longwolf, I saw your posts and I really like your figures that they uses for show diode bypass.

    Mike90250 :
    http://www.solarpaneltalk.com/showth...ll=1#post10700
    longwolf:
    http://www.solarpaneltalk.com/showth...ll=1#post11337
    http://www.solarpaneltalk.com/showth...ll=1#post11289
    http://www.solarpaneltalk.com/showth...ll=1#post10605
    http://www.solarpaneltalk.com/showth...ll=1#post10698
    http://www.solarpaneltalk.com/showth...ll=1#post10709
    http://www.solarpaneltalk.com/showth...ll=1#post10732
    http://www.solarpaneltalk.com/showth...ll=1#post10484
    http://www.solarpaneltalk.com/showth...ll=1#post10518
    http://www.solarpaneltalk.com/showth...ll=1#post10572

    In special longwolf, I'm student and I'm newbie in this topic, but I want to understand very well and try to use in my home some things...

    Well, my question or ask is about the Software that they use for make figures?, in special the use longwolf... What software they use for it?

    Thanks a lot.

    Leave a comment:


  • inetdog
    replied
    Originally posted by russ View Post
    ...hope you have you own Pancho Sanchez (think that was his name) to pick you up and put you back on your mule when you collide with the system.
    [FONT=Comic Sans MS]Sancho Panza, but who's counting. [/FONT]

    Leave a comment:


  • inetdog
    replied
    Originally posted by S0L0R View Post
    Designing an array of 18volt, 4 Amp, 172 Watt solar panels and need to decide what bypass diodes and blocking diode to use...
    When using a modern charge controller a blocking diode is not necessary or even useful. It just costs you power.

    Leave a comment:


  • S0L0R
    replied
    Diodes

    Designing an array of 18volt, 4 Amp, 172 Watt solar panels and need to decide what bypass diodes and blocking diode to use...

    Leave a comment:


  • Mike90250
    replied
    Bypass diodes are usually Schottky diodes, with sufficient power rating (and heat sink) to only have about .5V drop across them. At the MOST, I would go no more than 18 cells without a diode.

    Leave a comment:


  • bcroe
    replied
    Bypass Diode Function

    Originally posted by Mike90250 View Post
    You really should have bypass diodes, and you should
    re-site panels to avoid shade
    With no diode, any shade, anywhere on the array , will cut output way down, and
    the shaded panel will tend to overheat
    The issue of overheating seems to occur, when good cells develop enough
    voltage to force their current through a shaded or defective cell. The overheating
    would be at the non functional cell?

    Putting a bypass diode on each cell, would apply about 1V (diode drop) reverse
    voltage on a non producing cell. That seems to be accepted as OK for shade,
    don't know for a cracked cell.

    I don't see anyone putting a bypass diode on every cell. Short of that, the voltage
    applied to a non functioning cell will that of the other cells being bypassed by the
    diode, plus about a volt drop in the diode from overall array (bypass) current. So
    my question would be, how many cells (or how much voltage) can one diode
    safely bypass?

    There will be no panels on roofs here, in the country. But for now there are some
    convenient spots to put them. In one spot I see 200 to 800 W (clouds or sunny) till
    early afternoon, when the sun moves behind a grove of trees. At that point I am
    willing to have another similar array come out of the shade for the rest of the day.
    I am willing to duplicate those resources for the locations.

    To put up panels never shaded by all the trees, I would have to go 1/8 mile away
    from the house. That would happen if expanded to the 10 KW level. But first I
    would need a power handling system able to cover that distance with good
    efficiency, have a few ideas on that. Bruce Roe

    Leave a comment:


  • Mike90250
    replied
    You really should have bypass diodes, and you should re-site panels to avoid shade

    With no diode, any shade, anywhere on the array , will cut output way down, and the shaded panel will tend to overheat

    Leave a comment:


  • bcroe
    replied
    Bypass Diode Function

    As I understand it, these diodes are only used to preserve some power output,
    when part of a panel is shaded. This would be esp important with several
    series connected panels. So protecting the panel from destruction is not part
    of the function?

    In my case, I expect to lose a whole panel at a time (tree shadow blocks a
    panel at certain times of day). And I won't have panels connected in series,
    I prefer to operate around 30 VDC. So I really don't need bypass diodes?

    As for parallel connections, even a shaded panel generates pretty much
    full open circuit voltage. So if connected in parallel with another panel
    not shaded, I would not expect any reverse current in the shaded panel,
    as long as its open circuit voltage at least equals a loaded panel voltage.
    So no series diodes for each parallel panel are needed either? Bruce Roe

    Leave a comment:


  • russ
    replied
    You are pissing into the breeze - hope it does not get too damp! Please don't call it 'playing the devil's advocate' - you are simply breaking the rules which you have been made aware of and know the basics at least.

    Fighting city hall? Again I would not call tilting windmills fighting city hall - hope you have you own Pancho Sanchez (think that was his name) to pick you up and put you back on your mule when you collide with the system.

    Individual components of the system must be approved by UL or an equivalent agency.

    The UL didn't come inspect individual computers either - representative samples are tested and approved.

    No problem, you can certainly do it but don't whine when everything goes down the toilet sometime in the future.

    Russ

    Leave a comment:


  • solarrules
    replied
    Well I'm playing devil's advocate and "fighting city hall" at the same time, but if I pay a solar installation company to install an entire system for me, that system is not UL certified. Nobody from the Underwriter's Laboratories comes to my house to certify it.

    So I still may contend that the inverter is U.L. certified and therefore I can connect that to the grid.

    Leave a comment:


  • russ
    replied
    Wrong - the system is connected to the grid.

    Russ

    Leave a comment:


  • solarrules
    replied
    So technically, only my inverter is hooked to the grid, yes? (I like the enphase micro-inverters for going to the grid). My panel is hooked to the inverter. The inverter, which is UL-approved, is connected to the grid.

    Leave a comment:


  • Mike90250
    replied
    Generally, and always in the USA with the National Electric Code, only UL components can be connected to a house wiring. A panel to charge a camping battery, or a electric bike is fine for homebrew. Learning by doing is the best way, as you are finding out.

    Enjoy.

    Leave a comment:

Working...
X