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I'm looking at these LED replacement bulbs for the interior of my sweet conversion van. I'm looking for a more efficient alternative to the BA15 bulbs that are in there already. These bulbs appear to be really bright, and I can't seem to find a lower lumen LED light in warm white. I'm wondering if it is possible to unsolder or intentionally damage some of the LED panels to decrease the brightness of the overall bulb, or if that will disrupt the entire bulb.

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  • \$\begingroup\$ A simpler solution would be getting a different bulb. There are shorter ones with the same base. Or use an led panel with a modular base. \$\endgroup\$ – Passerby Sep 18 '16 at 3:53
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These assemblies have 18 LEDs on them, which I guess are connected in series of 3. All series are in turn connected in parallel. Desoldering 1 LED will disable the whole 3-LED block.

Try desoldering one of the LEDs and test to confirm.

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  • \$\begingroup\$ So in theory, if I desolder one of blocks of 3, then it should not effect the performance of the bulb, correct? Am I also correct in assuming that because each board is 3 chips in series and it's a 12V system, that each individual chip is 3V \$\endgroup\$ – user379468 Sep 8 '16 at 16:50
  • \$\begingroup\$ @user379468 if you desolder the whole block with 3 LEDs on it, you'll compromise the assembly mecanically. Those light are held together with nothing but solder blobs. \$\endgroup\$ – Dmitry Grigoryev Sep 8 '16 at 18:32
  • \$\begingroup\$ The original bulb was 75 lumens, this bulb is 350, was thinking of just desoldering all three of the side mount LEDs and re soldering the top circular board. This might seem crazy, but I cant find a lower lumen replacement bulb anywere \$\endgroup\$ – user379468 Sep 8 '16 at 20:02
  • \$\begingroup\$ @user379468 BTW, have you considered bulbs like these \$\endgroup\$ – Dmitry Grigoryev Sep 9 '16 at 7:07
  • \$\begingroup\$ No! but actually these bulbs are exactly what I was looking for \$\endgroup\$ – user379468 Oct 2 '16 at 16:26
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You could wire a resistor in series with the base. The lamps are claimed to be 2W so they should draw around 170mA from the 12V bus. Try about 10-50 ohms 1W to get the brightness you want.

Of course you will no longer be able to safely install an incandescent bulb, in fact doing that could cause the resistor to get dangerously hot. You could add a small resettable fuse (polyfuse) to prevent that situation.

As a bonus, the lamps should last much longer, especially in a warm climate. They are typically driven to within a millimeter of their lives because that saves the manufacturer money.

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  • \$\begingroup\$ not sure I understand the incandescent bulb comment, you are saying that if I modify the the actual light, correct? also wont that create allot of heat? \$\endgroup\$ – user379468 Sep 8 '16 at 16:46
  • \$\begingroup\$ I'm saying if someone later on, perhaps years from now, removes the LED bulb and puts an old-style bulb in there, the resistor will get really, really hot. It's a potential hazard because the socket remains compatible and if someone looks up the bulb type they'll find the incandescent. The resistor will not create any more heat than was there before- it will move some of it from the bulb to the resistor, but the total will be lower. This is not the same as putting a parallel resistor in there to fool the computer as is sometimes necessary. The resistor is in series. \$\endgroup\$ – Spehro Pefhany Sep 8 '16 at 17:04
  • \$\begingroup\$ A diode or two would work as well. \$\endgroup\$ – Passerby Sep 18 '16 at 3:52
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What you likely have here are 6 strings of 3 LEDs connected in parallel.
If you disconnect one set of 3 that should work.

If there were an LED driver then the current would be diverted to the other 5 sets.
> At this price point I am doubting there is a driver.

Each panel is likely independent of the others

Remove one LED from one of the panels.

I'm willing to bet only that one panel goes out and everything else will be fine.

If it dies then dissemble it to see what's under the hood.

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