Page 3 of 4 FirstFirst 1234 LastLast
Results 21 to 30 of 36

Thread: 36v DC and SSRs

  1. #21
    Join Date
    May 2007
    Posts
    5,324
    Post Thanks / Like

    Default Re: 36v DC and SSRs

    If I'm looking at the correct schematic, this change does not need any modifications to the board itself (i.e. no cut traces and no jumpers), just installing different (and quite inexpensive) components in a different manner than the current instructions indicate. My suggestion is deliberately sketchy to see what reaction (if any) it gets from some of the other people in this discussion, and would be elaborated on later if appropriate.
    Phil

  2. #22
    Join Date
    Dec 2012
    Location
    Southampton, United Kingdom
    Posts
    102
    Post Thanks / Like

    Default Re: 36v DC and SSRs

    Quote Originally Posted by P. Short View Post
    If I'm looking at the correct schematic, this change does not need any modifications to the board itself (i.e. no cut traces and no jumpers), just installing different (and quite inexpensive) components in a different manner than the current instructions indicate. My suggestion is deliberately sketchy to see what reaction (if any) it gets from some of the other people in this discussion, and would be elaborated on later if appropriate.
    That sounds fair, and from my point of view, reassuring!

  3. #23
    Join Date
    Sep 2008
    Location
    Baulkham Hills, NSW
    Posts
    2,605
    Post Thanks / Like

    Default Re: 36v DC and SSRs

    My mod is quite simple. Lm7805 have a maximum operating voltage of 35v. So all I do is solder a string of power diodes to drop the voltage. Easy peasy.
    In your case, solder a string of 5 or 6 diode back to back (anode to cathode) connect the cathode to the top pad of C2 and the anode to the +ve of TB1.
    I use SMD diodes cause I have them in bulk. 1n4001s work well too.

    Sent from my SM-N9005 using Tapatalk
    [B][I]Matt[/I][/B]

    You too can become a Supporting member of DIYC.
    Check it out [URL="http://doityourselfchristmas.com/forums/payments.php"]here[/URL]

    I record my Blinky Flashy travels here: [URL="http://MyNoelLights.com"]MyNoelLights.com[/URL]

  4. #24
    Join Date
    Nov 2009
    Location
    Brisbane - Australia
    Posts
    944
    Post Thanks / Like

    Default Re: 36v DC and SSRs

    Quote Originally Posted by mutleyrover View Post
    Having re-read it properly I understand it now. I guess the downside is having to have a multitude of power supplies!
    I guess one obvious question is whether there are DC SSRs that exist that are able to take voltages higher than 30v?
    You can use a $3 DC-DC converter to derive the lower voltage for the controller, but make sure the input of the converter is rated for 36V else you'll be back to square one!
    www.da-share.com

  5. #25
    Join Date
    Jul 2008
    Location
    Pearland, Tx (sometimes) and anywhere on the globe the rest of the time
    Posts
    3,275
    Post Thanks / Like

    Default Re: 36v DC and SSRs

    Quote Originally Posted by David_AVD View Post
    You can use a $3 DC-DC converter to derive the lower voltage for the controller, but make sure the input of the converter is rated for 36V else you'll be back to square one!
    Just FYI guys, he has contacted me via email. The only way to handle 36V is to drop the incoming voltage for the Vreg or use a separate source for 5V rail. I thought about Matt's diode solution as well.
    WLC Ventures is now [URL="http://radiant-holidays.com"]Radiant Holidays![/URL]

  6. #26
    Join Date
    Dec 2012
    Location
    Southampton, United Kingdom
    Posts
    102
    Post Thanks / Like

    Default Re: 36v DC and SSRs

    Quote Originally Posted by Matt_Edwards View Post
    My mod is quite simple. Lm7805 have a maximum operating voltage of 35v. So all I do is solder a string of power diodes to drop the voltage. Easy peasy.
    In your case, solder a string of 5 or 6 diode back to back (anode to cathode) connect the cathode to the top pad of C2 and the anode to the +ve of TB1.
    I use SMD diodes cause I have them in bulk. 1n4001s work well too.

    Sent from my SM-N9005 using Tapatalk
    Am I right in thinking then that this allows the use of the higher voltage to pass through the board for the lights, but the voltage that's required to power/operate the board is reduced to a level that is acceptable?

  7. #27
    Join Date
    Jul 2008
    Location
    Pearland, Tx (sometimes) and anywhere on the globe the rest of the time
    Posts
    3,275
    Post Thanks / Like

    Default Re: 36v DC and SSRs

    Quote Originally Posted by mutleyrover View Post
    Am I right in thinking then that this allows the use of the higher voltage to pass through the board for the lights, but the voltage that's required to power/operate the board is reduced to a level that is acceptable?
    That is correct.
    WLC Ventures is now [URL="http://radiant-holidays.com"]Radiant Holidays![/URL]

  8. #28
    Join Date
    May 2007
    Posts
    5,324
    Post Thanks / Like

    Default Re: 36v DC and SSRs

    Quote Originally Posted by g2ktcf View Post
    Just FYI guys, he has contacted me via email. The only way to handle 36V is to drop the incoming voltage for the Vreg or use a separate source for 5V rail. I thought about Matt's diode solution as well.
    Where is the schematic for the boards that you are selling? If that board has two regulators in parallel (like the original DC SSR boards), there is another inexpensive way.

    First, do not install the 5V regulators that are mentioned in the BOM.
    Second, take a 5.1V zener diode and install it in place of the LM78L05 regulator (anode to the ground pin of the 'L05 footprint, cathode to the output pin of the 'L05 footprint). This diode might be a 1N5231A or 1N4733A, the exact part to be selected on the basis of working well at a low current level. This diode would not lay flat on the board, rather standing on end, so it might be a good idea to use a short length of shrink-wrap tubing to protect it.
    Third, take a 1.5K,1W resistor (selected for pushing 20mA through the zener with a 36V input level) and install it between the input and output pins of the LM7805 regulator. This part also ends up standing on end, so it should also be protected with a short length of shrink-wrap tubing.

    This potential solution should be prototyped of course. Its advantages are that it is relatively cheap, and does not require any cuts or jumpers to the board. The disadvantage is that the regulator is always dissipating 720mW of power between the diode and the resistor described above (when powered with 36V), and the value of the resistor would need to be changed if the input voltage is radically different from 36V.
    Phil

  9. #29
    Join Date
    May 2007
    Posts
    5,324
    Post Thanks / Like

    Default Re: 36v DC and SSRs

    Another zener diode possibility is a BZX79C5v1, which would allow the resistor value to be raised to about 6.2K, and the wasted power would be reduced by a factor of 4.
    Phil

  10. #30
    Join Date
    Jul 2008
    Location
    Pearland, Tx (sometimes) and anywhere on the globe the rest of the time
    Posts
    3,275
    Post Thanks / Like

    Default Re: 36v DC and SSRs

    Quote Originally Posted by P. Short View Post
    Where is the schematic for the boards that you are selling? If that board has two regulators in parallel (like the original DC SSR boards), there is another inexpensive way.

    First, do not install the 5V regulators that are mentioned in the BOM.
    Second, take a 5.1V zener diode and install it in place of the LM78L05 regulator (anode to the ground pin of the 'L05 footprint, cathode to the output pin of the 'L05 footprint). This diode might be a 1N5231A or 1N4733A, the exact part to be selected on the basis of working well at a low current level. This diode would not lay flat on the board, rather standing on end, so it might be a good idea to use a short length of shrink-wrap tubing to protect it.
    Third, take a 1.5K,1W resistor (selected for pushing 20mA through the zener with a 36V input level) and install it between the input and output pins of the LM7805 regulator. This part also ends up standing on end, so it should also be protected with a short length of shrink-wrap tubing.

    This potential solution should be prototyped of course. Its advantages are that it is relatively cheap, and does not require any cuts or jumpers to the board. The disadvantage is that the regulator is always dissipating 720mW of power between the diode and the resistor described above (when powered with 36V), and the value of the resistor would need to be changed if the input voltage is radically different from 36V.
    Phil, I do not have the schematic near me...but it is over on the Renard Plus website (just don't shoot me for posting that). But I do think you are 100% correct that it can be handled in that manner. The OP is the only one that has ever asked be about this question to be honest. However, I'm not thrilled about burning off 720mW just to drop the voltage though!
    WLC Ventures is now [URL="http://radiant-holidays.com"]Radiant Holidays![/URL]

Page 3 of 4 FirstFirst 1234 LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •