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Can I connect 4 LED strips to 9V cell phone power supply ? Answered

I don't know specifications of the LED strips all I know is that they are 12V, 30 cm long, supposed to be waterproof and they are blue light.
I've connected 4 LEDs in parallel to a 9V cell phone power supply with 200mA output...when i plug this whole assembly in it works - they all light up...how log will they last? From what i've read it seems to me that my power supply might not have enough wattage. Is the power supply going to die because not enough wattage or something will happen to the LEDs?


There is a big difference between connecting LEDs in Parallel and Series. Likely the LED strips are wired in series to make use of a 12V supply. Connecting them to 9V will not work or they will be very dimm. They are designed for 12V so they need a 12V supply.

Or the LED strips could be Series and Parallel. Depending on how many LEDs are in the string. You also need to know how much power is needed for the strips. If you plan to connect 4 of those strips together in parallel you'll need to know how much power is required to run them.

right, so that's my problem, the power supply that i have from an old cell phone has 300 mA so that there is only 2.7 watts...one strip needs approximately 1.8 watts, but if i connect 4 strips in parallel i need close to 8 watts...so what i'm trying to understand is what would happen to the power supply and to the strips...will the light be just dimmer than if i had a power supply with 8 watts or the strips will be ok but the power supply will be gone...thanks!

The strips will try and pull the power it needs. When the power supply exceeds it's max output it will fail.