This item came up in a search on ebay for LIR2032 which is a rechargeable lithium cell. I bought it to take a look inside to see what sort of charging circuitry is used for the cell.
I'm afraid it's not very exciting. At first glance it appears that the control of the LEDs and the cell voltage management is all integrated onto a single chip that is a resin blob COB (Chip On Board). The light is clearly not waterproof and is unlikely to handle adverse weather with dignity. the charging port is a common small power-jack connector which was a bit dodgy and is likely to inject any trapped rainwater directly into the case when used.
But hey. It's cheap and kinda works, so if you're prone to losing your bicycle lights then this might be a viable option. It also contains a removable LIR2032 cell which is handy.

9 thoughts on “Inside a usb rechargeable bicycle warning light.”
  1. Avataaar/Circle Created with python_avatars JX567 KH553 says:

    I just made cheap front lamp with li-ion charger module[2cmx2cm/1A-TP4056],old 3.7V/1200mAh battery from phone and 3W/350mA cree LED[driver in PCB].Works bright [200lm] and fine,cost about 3$. ;D

  2. Avataaar/Circle Created with python_avatars Jusb1066 says:

    can you teardown/review a USB electronic lighter? they can be bought from ebay about 1.50ish, there are only scant reviews and no teardowns of one on youtube

  3. Avataaar/Circle Created with python_avatars Joshua Hutton says:

    what leds did you order god that will last you along time

  4. Avataaar/Circle Created with python_avatars SeanBZA says:

    I was guessing the charge circuit is the red led in series with the 5V supply, with the 1V5 drop of the LED and some resistance doing the charge current voltage and current limiting. Will charge the cell to "around" the right voltage.

  5. Avataaar/Circle Created with python_avatars Siskin's Bits and Bobs says:

    Nearly didn't see some guy on a bike the other day. He had a really dim poundland rear light and nothing on the front. I saw what sort of lighting he had, when I watched him lock up at the supermarket. He spent more on the lock than the light. I would have spent more on the lighting, but I'm fairly lax about bike security.

  6. Avataaar/Circle Created with python_avatars Seán Byrne says:

    I can just imagine someone trying to load this in their Blu-ray player to try out the "Smart blu-ray charging" feature… =)

  7. Avataaar/Circle Created with python_avatars The Hawk Ness says:

    Who's your LED supplier? 

  8. Avataaar/Circle Created with python_avatars BigGoucho says:

    Seven thousand LED's? New project you're working on?

  9. Avataaar/Circle Created with python_avatars haroldtplopps says:

    im rather hoping to see a 7k led bike light. 

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