Hello all,
Ive been lurking for several months, marveling at the collection of intelligence displayed here. I am also amazed at the friendly manner in which questions are answered, and lessons are taught. The willingness to teach, rather than shove opinionated theories down a posters throat is simply not seen anywhere else. You should all be very proud of this forum.
My question involves the retrofit of el-cheapo Chinese LED flashlights (Harbor Freight), to work as headlights for my 5 year old grandsons Gator. I have used these flashlights as-is for many weeks but it has become a PITA to change batteries because the lights were left on. The flashlights are a bit difficult to reach, for turning off & on, as well. They are, however, the perfect size for mounting behind the previously fake headlight lens, and at $7.95 each I cant build and house a similar unit for anywhere near the price. As I have installed a pair of 12V 5AH SLA Batteries, in parallel, to operate his other accessories, controlled by a key switch he uses religiously to operate the drive system, I decided to try and operate the headlights from the same source.
Digging around the shop I found several NTE 1929 3-pin adjustable regulators, and the typical box full of assorted resistors (I swear Im going to get more organized one day soon). I ASSumed that I remembered how to hookup a simple regulator but obviously I dont or I wouldnt be here asking. NTE offers no application data, and I dont deal with component-level electronics enough to know when I can safely substitute typical ancillary components from other devices (ie: LM317), and use their application data. My degrees are Electrical not Electronic.
Flashlights for headlights (2) 32 White LEDs each, connected (I ASSume) in parallel
Powered by 3 AAA batteries in series (4.5V).
Operating voltage when running on the AAA batteries = 3.82 V (Off = 4.54 V)
Operating current when running on the AAA batteries = 340 mA (10.6 mA per LED ???)
* These things are BRIGHT for only 10mA - maybe the array is multi-level and they are NOT all in parallel? *
Regulator NTE 1929 3-pin adjustable in a TO-220 case, 5 to 35V input, 1.2 to 33V @ 3A output, mounted on 2 back-to-back Heatsinks
Vref=1.2 to 1.3V, 1.25 typ. I Lmin=0 to 10mA, 3.5 typ. P D=15W
http://www.nteinc.com/specs/1900to1999/pdf/nte1929.pdf
Desired supply 12V 10AH SLA Battery with the possibility of the lights being turned on while the battery is being charged (impatient 5 year old).
Charger output = 13.8V at 40% battery discharge state.
I am unsure whether I need voltage or current regulation with this setup. I do feel Ill need some input filtering as the wire runs are in excess of 6 ft, crammed in small wireways with high current conductors, and the source supplies a water pump (to squirt ME with), a red strobe, a siren (to annoy everyone), and several auto-style control relays. In my previous attempts, I did see some noticeable oscillation in the regulator so I feel output filtering is also in order.
I have searched this forum for similar applications, and can find nothing close enough to be comfortable using. I dont have to use the NTE 1929, but since a dozen or so were just lying around by golly they just aught to work! I have a reasonably complete test equipment inventory, and can check anything you wish. Im just too rusty and dumb at this to complete the project without some serious hand-holding.
Sorry for the long post, and thanks in advance for your help
Ive been lurking for several months, marveling at the collection of intelligence displayed here. I am also amazed at the friendly manner in which questions are answered, and lessons are taught. The willingness to teach, rather than shove opinionated theories down a posters throat is simply not seen anywhere else. You should all be very proud of this forum.
My question involves the retrofit of el-cheapo Chinese LED flashlights (Harbor Freight), to work as headlights for my 5 year old grandsons Gator. I have used these flashlights as-is for many weeks but it has become a PITA to change batteries because the lights were left on. The flashlights are a bit difficult to reach, for turning off & on, as well. They are, however, the perfect size for mounting behind the previously fake headlight lens, and at $7.95 each I cant build and house a similar unit for anywhere near the price. As I have installed a pair of 12V 5AH SLA Batteries, in parallel, to operate his other accessories, controlled by a key switch he uses religiously to operate the drive system, I decided to try and operate the headlights from the same source.
Digging around the shop I found several NTE 1929 3-pin adjustable regulators, and the typical box full of assorted resistors (I swear Im going to get more organized one day soon). I ASSumed that I remembered how to hookup a simple regulator but obviously I dont or I wouldnt be here asking. NTE offers no application data, and I dont deal with component-level electronics enough to know when I can safely substitute typical ancillary components from other devices (ie: LM317), and use their application data. My degrees are Electrical not Electronic.
Flashlights for headlights (2) 32 White LEDs each, connected (I ASSume) in parallel
Powered by 3 AAA batteries in series (4.5V).
Operating voltage when running on the AAA batteries = 3.82 V (Off = 4.54 V)
Operating current when running on the AAA batteries = 340 mA (10.6 mA per LED ???)
* These things are BRIGHT for only 10mA - maybe the array is multi-level and they are NOT all in parallel? *
Regulator NTE 1929 3-pin adjustable in a TO-220 case, 5 to 35V input, 1.2 to 33V @ 3A output, mounted on 2 back-to-back Heatsinks
Vref=1.2 to 1.3V, 1.25 typ. I Lmin=0 to 10mA, 3.5 typ. P D=15W
http://www.nteinc.com/specs/1900to1999/pdf/nte1929.pdf
Desired supply 12V 10AH SLA Battery with the possibility of the lights being turned on while the battery is being charged (impatient 5 year old).
Charger output = 13.8V at 40% battery discharge state.
I am unsure whether I need voltage or current regulation with this setup. I do feel Ill need some input filtering as the wire runs are in excess of 6 ft, crammed in small wireways with high current conductors, and the source supplies a water pump (to squirt ME with), a red strobe, a siren (to annoy everyone), and several auto-style control relays. In my previous attempts, I did see some noticeable oscillation in the regulator so I feel output filtering is also in order.
I have searched this forum for similar applications, and can find nothing close enough to be comfortable using. I dont have to use the NTE 1929, but since a dozen or so were just lying around by golly they just aught to work! I have a reasonably complete test equipment inventory, and can check anything you wish. Im just too rusty and dumb at this to complete the project without some serious hand-holding.
Sorry for the long post, and thanks in advance for your help