Feit electric LED lamp autopsy.

[momaka]

Re: Feit electric LED lamp autopsy.

Thanks momaka - I actually wanted to increase the current because my goal is to get a higher brightness from lower voltages allowing this bulb to run off a moderate number of Li-ion batteries. I do have the AP1910 datasheet, but I'm not familiar enough with electronics (yet) to confidently make connections between drawing and PCB. Your input was much appreciated.
...
Continuing on, I replaced the 4.7Ω resistor with a 2Ω resistor (I got smart and found a way to connect/replace without solder this time) and the current went to 147mA.

At this point, there a high pitched sound coming from the device...

Well, I'm surprised this actually even worked at all.

Generally, those boost converters are designed to work within a certain voltage input range. If the bulb was designed to work at 120V AC and you could still get it to work at 20V DC... that's one hella tolerant boost converter. Makes me wonder if this is a dim-able bulb.

The fact that you can hear it make high-pitched noise, however, is probably an indication that you're really pushing it to the limits. So it may be a better idea to either re-design the boost converter or somehow boost that 20V DC from the batteries to at least 90-100V DC with another circuit before feeding it into the bulb.

[RJARRRPCGP]

Re: Feit electric LED lamp autopsy.

By the way, what does the "1633" mean printed on the surface of the aluminum LED holder?

Looks like it was manufactured in week 33 of 2016.

[budm]

Re: Feit electric LED lamp autopsy.

So let me get this correctly, the original board use 120VAC to feed the boost converter that provide constant current of 40mA though the LEDs (all connected in series), so to use 20VDC source you will need boost converter that can boost the 20dc to get enough Voltage and provide constant current to dive the LED's.
Using the boost converter to boost 20V then you do not change the current sensing resistor to leave the constant current alone at 40mA. You will need to find boost converter that can convert 20VDC to around 160VDC to dive the existing board.
LED is the current device, you need to get it to Vf for it to start conducting current.
So what DCV do you have on that large lytics cap when you apply 20VDC to the board? How high of the Voltage did the booster circuit on that board boost it up to?

[4ces]

Re: Feit electric LED lamp autopsy.

The original bulb is the same or nearly the same as the one this thread began with... a 9.5 watt (60 watt equivalent) A19 LED bulb. I assume it will run less efficiently at 20V than it does at 120V, so as long as I keep the input below 9.5W I won't be overdriving the LEDs. I could measure the current but it isn't necessary as I know I'll be running it lower than it is designed for if I stay below 400mA input at 20V.

For interest sake-

There are 8 LED chips, each with 8 leds in them. (actually there is one chip that has only 7... you can see the bumps on the surface where the bulbs are). So 63 diodes in series, total voltage of 191V (before modifications)... I didn't measure the current but I infer it should be in the 40 mA range assuming 90% efficiency of the dc-dc conversion.

By the way, what does the "1633" mean printed on the surface of the aluminum LED holder?

[budm]

Re: Feit electric LED lamp autopsy.

What is the LED rating?
Are they all connected in series or series parallel combo?
It sounds like the original power supply has limit on how much current it can supply.

[sam_sam_sam]

Re: Feit electric LED lamp autopsy.

Ok but do not get carry away with the current because you do need to limit the amount current you are pushing through these LEDs because the more current push through them the shorter life span these LED light bulb will have if your LED do not have any sinks on them you will be limited how much current push through them

[4ces]

Re: Feit electric LED lamp autopsy.

Thanks momaka - I actually wanted to increase the current because my goal is to get a higher brightness from lower voltages allowing this bulb to run off a moderate number of Li-ion batteries. I do have the AP1910 datasheet, but I'm not familiar enough with electronics (yet) to confidently make connections between drawing and PCB. Your input was much appreciated.

So that means to increase current I need to decrease resistance at R9/R10. (I actually soldered at the capacitor and mosfet leads as they are larger, and with my essential tremor soldering is tricky enough as it is... any tricks on how to solder when you have shaky hands out there? I'm 40 but shake more than most 70 year olds

On my PCB R9=3Ω R10=10Ω (equiv is 2.3Ω)

First I added a 12Ω ohm resistor in parallel with R9 and R10. The device to took 63mA from the 20V battery. (measured input this time, as that was easier)

Then I added a 4.7Ω resistor in parallel with the new resistor I had just added and this resulted in draw of 92mA from 20V battery. (we are getting somewhere!)

Continuing on, I replaced the 4.7Ω resistor with a 2Ω resistor (I got smart and found a way to connect/replace without solder this time) and the current went to 147mA.

At this point, there a high pitched sound coming from the device... but much brighter! and it being dinner time, I decided I had learned enough for the afternoon

I think the final goal will be about 400mA@20V input to achieve the light output it was originally designed for. But something tells me, (the sound of it), boosting from 20V to the 200V operating voltage, and at those currents might require other modifications besides changing the sense resistance?

included shots of my setup for entertainment

[momaka]

Re: Feit electric LED lamp autopsy.

The bulb lights at 20 volts input, but it is dim... about 1.2W total. Can anyone point out to me where "R4" might be hiding as pointed out by user "capwizard"? (according to the AP1910 spec, not as labeled on the board itself)

Well, if we go off of this schematic that capwizard posted...
https://www.badcaps.net/forum/attach...3&d=1489578423
... it looks like R4 corresponds to the MOSFET Source resistor.

So on the two images posted here:
https://www.badcaps.net/forum/attach...1&d=1604380329
https://www.badcaps.net/forum/attach...0&d=1604380285
... that would be resistors R9 and R10 (they are in parallel) - at least this seems to apply to the board with the green PCB, since those two resistors connect between the MOSFET Source terminal and big electrolytic cap's lead. I can't tell if that's the case with the white PCB, as it's harder to trace it out.

With that said, removing either R9 or R10 should raise the resistance and thus decrease the current driven into the LEDs... but by how much, I'm not sure.

Hope this helps. Let us know what kind of results you get, though.

[stj]

Re: Feit electric LED lamp autopsy.

get a datasheet for the chip.

it's interesting that because of your shit mains voltage it uses a boost convertor.
in Europe the lights all use a buck or even linear regulator and are much simpler inside.

[4ces]

Re: Feit electric LED lamp autopsy.

Hi found this thread while searching around about the AP1910 'Universal High Brightness LED Driver Controller' in these feit bulbs. I also have torn a few apart, and I'd like to see if I can run a 9.5watt feit bulb on a 5 or 6 Li-ion batteries.

The bulb lights at 20 volts input, but it is dim... about 1.2W total. Can anyone point out to me where "R4" might be hiding as pointed out by user "capwizard"? (according to the AP1910 spec, not as labeled on the board itself) I want to increase the current setting... In my bulb, it drives the leds at about 42mA and 200volts across all 66 leds in series when on 120V ac input. At 20V DC input, it runs a much lower current (like 6mA ish) at about 180V output... I'd like to get closer to about 30mA (prob 195 ish volts) if I can by swapping a resistor or two. The first two images are from my own bulb teardown. The second two images below are just my reposts from the very first message in this thread.

[RJARRRPCGP]

Re: Feit electric LED lamp autopsy.

Ikeas LED bulbs are not as good as they used to be

I had a feeling that a person was going to say that they regressed!

[redwire]

Re: Feit electric LED lamp autopsy.

Ikea Ledare is their "high end" LED bulb, and RYET is the economy line. Almost the entire lineup is warm white 2700K. The way they fail slow flickering, it is the LEDs and heat.
Dimmables have an electrolytic capacitor.

[RukyCon]

Re: Feit electric LED lamp autopsy.

Ikeas LED bulbs are not as good as they used to be, i have an old 9.5w 600lm LED bulb i got from Ikea (for around 7$ which was a pretty good price at the time i got it) and it still works to this day after 5 or 6 years of near daily sevice in an enclosed fixture. However, i've seen their newer LEDs fail in their display cases.

[RJARRRPCGP]

Re: Feit electric LED lamp autopsy.

Ikea LED bulbs have a 1 year warranty, nothing extended. Blink flicker flicker

Weird! Because I heard good things about LED light bulbs from Ikea before, at least on an older article, with their "Ledaire" series?

I now think that they were possibly discontinued and replaced with an inferior version! Looks like shit's hitting the fan for Ikea!

[redwire]

Re: Feit electric LED lamp autopsy.

Ikea LED bulbs have a 1 year warranty, nothing extended. Blink flicker flicker

[japlytic]

Re: Feit electric LED lamp autopsy.

22 years life? Warranty, please!

[RJARRRPCGP]

Re: Feit electric LED lamp autopsy.

Apparently, not just for LEDs, the brighter, at least past a certain point, the lower the CRI! And thus, a trade-off. Thus, for brightness or for better CRI.

[redwire]

Re: Feit electric LED lamp autopsy.

I can't find a really bright LED bulb anymore, that is a reasonable price.

I gave up and bought Ali "12W and 18W aluminium LED bulb" for the workbench.
Inside is bead LED's on MCORE pcb, a dangling taped up SMPS. Something you can repair or mod at least and decent heatsinking.

The light is a bit narrow spot and lots of chromatic aberation (yellow donut), and cold blueish colour temperature. It's like all chinese LED lamps. Does not run too hot. The 12W is better than the 18W for quality of light, smoother more even spot.

You can buy just the LED's, MCORE PCB, heatsink, or a kit etc.

[goontron]

Re: Feit electric LED lamp autopsy.

IMO the best bulb was from philips, but they discontinued it for cost reasons.
it used blue/uv led's with a special phosphor loaded plastic casing.

the casing was relativly cool so the phosphor didnt degrade like it does on "white" led dies.

I beg to differ. Switch LED bulbs are the best. The only real downfall is the uneven light distribution pattern. Otherwise they are very well built, the electronics are housed in a cast aluminium finned case that acts as a heatsink, and the LEDs are oil cooled. I got one that has been in service for 5 years now and shows no signs of failure.

[stj]

Re: Feit electric LED lamp autopsy.

IMO the best bulb was from philips, but they discontinued it for cost reasons.
it used blue/uv led's with a special phosphor loaded plastic casing.

the casing was relativly cool so the phosphor didnt degrade like it does on "white" led dies.