naiefelyemeni 0 Posted October 23, 2015 ok i checked the calculator online and with more Amps the greater the voltage drop?? i thought its the opposite? so thats why im getting ****ty picture on the cameras! http://www.calculator.net/voltage-drop-calculator.html?material=copper&wiresize=84.22&voltage=12&phase=dc&noofconductor=4&distance=180&distanceunit=feet&eres=1.5&x=26&y=9 Share this post Link to post Share on other sites
the toss 0 Posted October 23, 2015 Can I suggest you read up on Ohms Law. Share this post Link to post Share on other sites
naiefelyemeni 0 Posted October 23, 2015 Can I suggest you read up on Ohms Law. thanks buddy, so i got to power those cameras locally correct? Share this post Link to post Share on other sites
ak357 0 Posted October 23, 2015 Can I suggest you read up on Ohms Law. thanks buddy, so i got to power those cameras locally correct? http://lmgtfy.com/?q=Ohms+Law Share this post Link to post Share on other sites
the toss 0 Posted October 23, 2015 Not neccesarily. The biggest mistake people make is they think a 5 amp supply "pushes" out 5 amps. The current a power supply delivers is determined by the load applied ( ie the camera ) Cameras are all different and require different currents for optimal performance. So for two different cameras a power supply may deliver 1 amp for camera A and 2 amps for camera B. It is the current through a conductor that determines the voltage drop. So if camera A is powered by 100m of cable having a resistance of 0.01 ohm / m (total loop resistance of 2 ohms) and is supplied by a 12V power supply then the voltage drop from power supply to camera would be current (1A) times resistance ( 2ohm ) for a total drop of 2Volts. Now if camera A was replaced with camera B it would be 2amp times 2 volt resulting in a 4 volt drop. It doesn't matter if the power supply is a 5 amp supply or a 500 amp supply as long as it can deliver what is required. Share this post Link to post Share on other sites
naiefelyemeni 0 Posted October 24, 2015 Not neccesarily. The biggest mistake people make is they think a 5 amp supply "pushes" out 5 amps. The current a power supply delivers is determined by the load applied ( ie the camera ) Cameras are all different and require different currents for optimal performance. So for two different cameras a power supply may deliver 1 amp for camera A and 2 amps for camera B. It is the current through a conductor that determines the voltage drop. So if camera A is powered by 100m of cable having a resistance of 0.01 ohm / m (total loop resistance of 2 ohms) and is supplied by a 12V power supply then the voltage drop from power supply to camera would be current (1A) times resistance ( 2ohm ) for a total drop of 2Volts. Now if camera A was replaced with camera B it would be 2amp times 2 volt resulting in a 4 volt drop. It doesn't matter if the power supply is a 5 amp supply or a 500 amp supply as long as it can deliver what is required. i see.. so how am i going to figure out what i need. this is driving me nuts.. is 3 185 foot runs and the rest are shorter runs. using 1 twisted pair for pos power and 2 pairs for negative using a 30amp box only 11 ports used.. how come the far cameras are suffering? i thought 185ft is nothing? and 30 amps is enough? Share this post Link to post Share on other sites
tomcctv 187 Posted October 24, 2015 Hi for that run your going to need 3 twisted pair for pos and neg. Then your 30amp power supply ..... How many output does it have ? Share this post Link to post Share on other sites
naiefelyemeni 0 Posted October 25, 2015 Hi for that run your going to need 3 twisted pair for pos and neg. Then your 30amp power supply ..... How many output does it have ? Yeah I'm hitting my head for not Doing That now I gotta go to half the cameras and change up the wires.. It's a 30amp 18 port.. I'm only using 11 ports.. I've done most of my previous installs using 10amp -20 amp boxes using all ports no problem? But never this long.. Maybe 120feet this install pushing 170-185..and using cat5 for first time.. Share this post Link to post Share on other sites
tomcctv 187 Posted October 25, 2015 It might be a 30amp power supply but each outlet is only 1.5amp Share this post Link to post Share on other sites
naiefelyemeni 0 Posted October 25, 2015 Yes but those cameras draw at most 1 amp.. So what do you think? It's probably voltage drop Since its only on the farthest cameras.? And you think adding one more wire for the positive will Make the difference? On the calculator it said it would go up 1 volt , that's good enough? Share this post Link to post Share on other sites
tomcctv 187 Posted October 25, 2015 Yes but those cameras draw at most 1 amp.. So what do you think? It's probably voltage dropSince its only on the farthest cameras.? And you think adding one more wire for the positive will Make the difference? On the calculator it said it would go up 1 volt , that's good enough? Voltage is not your problem it's your amps Your camera might only be 1amp ..... But you will need 2 to 3 amp for that distance ..... And also take into account IR Share this post Link to post Share on other sites
naiefelyemeni 0 Posted October 25, 2015 Yes but those cameras draw at most 1 amp.. So what do you think? It's probably voltage dropSince its only on the farthest cameras.? And you think adding one more wire for the positive will Make the difference? On the calculator it said it would go up 1 volt , that's good enough? Voltage is not your problem it's your amps Your camera might only be 1amp ..... But you will need 2 to 3 amp for that distance ..... And also take into account IR I'm confused, the Voltage calculator says The higher the Amp Load the bigger the voltage drop?? I'm very confused here.. Share this post Link to post Share on other sites
the toss 0 Posted October 25, 2015 Yes but those cameras draw at most 1 amp.. So what do you think? It's probably voltage dropSince its only on the farthest cameras.? And you think adding one more wire for the positive will Make the difference? On the calculator it said it would go up 1 volt , that's good enough? Voltage is not your problem it's your amps Your camera might only be 1amp ..... But you will need 2 to 3 amp for that distance ..... And also take into account IR I would re-think that statement Tom. The current does not change throughout a series circuit. The current that flows at one end is the same as what flows at the other end. The flow of this current through a resistive line causes a voltage difference from one end to the other - the greater the flowing current then the greater the voltage differential. This is what the OP is having trouble with. Its probably no use to you now but normal practice for longer runs is to go with 24Vac power & cameras (no earth loop issues either) Share this post Link to post Share on other sites
naiefelyemeni 0 Posted October 26, 2015 Yes but those cameras draw at most 1 amp.. So what do you think? It's probably voltage dropSince its only on the farthest cameras.? And you think adding one more wire for the positive will Make the difference? On the calculator it said it would go up 1 volt , that's good enough? Voltage is not your problem it's your amps Your camera might only be 1amp ..... But you will need 2 to 3 amp for that distance ..... And also take into account IR I would re-think that statement Tom. The current does not change throughout a series circuit. The current that flows at one end is the same as what flows at the other end. The flow of this current through a resistive line causes a voltage difference from one end to the other - the greater the flowing current then the greater the voltage differential. This is what the OP is having trouble with. Its probably no use to you now but normal practice for longer runs is to go with 24Vac power & cameras (no earth loop issues either) Ok it seems to be a ground loop or Interference that's messing up all these cameras.. I'm using now 12 different power sources boxes , wall warts mix and all cameras are clear now?? I didn't want to go through 32 wires to see which ones has the interference.. But it looks so messy now.. : ( but customer is happy now or at least that's what I Think lol Share this post Link to post Share on other sites
