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May-17-2021 04:27 PM
Gdetrailer wrote:rlw999 wrote:Gdetrailer wrote:
One of the pictures does show the backside of the circuit board, it is using a simple resistor current limiting setup which severely limits the voltage range.
I see 16 transistors on the board (can't make out the part number in the picture, but they are labeled Q1-Q16 and each has 3 terminals, so I'm assuming they are transistors). So they almost certainly have constant current drivers for the LED's that will likely work well over typical 12V charging system voltage levels.
Transistors and resistors perhaps, but no switching constant current regulator what so ever. You can make a simple series pass "regulator" with a handful of resistors and one transistor but a series pass regulator is very inefficient, wastes a lot of energy as heat and unless you throw in something like a zener diode for creating a rock solid reference voltage that series pass regulator will eventually pass more and more voltage and current..
Those also could be linear 3 lead regulators but that also would be pretty wasteful as they are the same as a linear series pass transistor regulator just without the need for external parts support.. But three lead linear regulators with proper design should be noise decoupled with capacitors on input and output leads which I don't see..
Switching constant current regulators will have more than three leads and require more parts support plus RFI filtering (inductor and capacitor filtering) which is not present on those boards..
They are however cheap enough to "experiment" with but as one review mentioned about 14V perhaps a bit more for top voltage.. RV three stage converters typically will have a bulk charge voltage of 14.4V-14.8V, one or tenths of a volt more can mean life or death to poorly designed LED light assemblies. Once LEDs get near the max current, it takes much less voltage variation to burn them out from over current as they will draw more current at an extreme rate.
For the less than $30 for qty of 20, it isn't much risk other than the need to change the LEDs at a faster rate as they may have a shorter usable life..
May-17-2021 04:25 PM
d1h wrote:
If I did get these to try I'm really torn on the color to get. Warm white seems like it might give a little more homey atmosphere inside the RV. Natural white might be a little less yellowish. I'm sort of hesitant of getting the super white in fear of giving the appearance of a sterile operating room.
May-17-2021 04:23 PM
May-17-2021 03:53 PM
Gdetrailer wrote:
Transistors and resistors perhaps, but no switching constant current regulator what so ever. You can make a simple series pass "regulator" with a handful of resistors and one transistor but a series pass regulator is very inefficient, wastes a lot of energy as heat and unless you throw in something like a zener diode for creating a rock solid reference voltage that series pass regulator will eventually pass more and more voltage and current..
May-17-2021 11:56 AM
rlw999 wrote:Gdetrailer wrote:
One of the pictures does show the backside of the circuit board, it is using a simple resistor current limiting setup which severely limits the voltage range.
I see 16 transistors on the board (can't make out the part number in the picture, but they are labeled Q1-Q16 and each has 3 terminals, so I'm assuming they are transistors). So they almost certainly have constant current drivers for the LED's that will likely work well over typical 12V charging system voltage levels.
May-17-2021 11:35 AM
Gdetrailer wrote:
One of the pictures does show the backside of the circuit board, it is using a simple resistor current limiting setup which severely limits the voltage range.
May-17-2021 11:26 AM
May-17-2021 11:20 AM