LED Bulb with 11.5V battery

243

02:39:36

Just trying to make an old NiCd battery useful.

*Battery Voltage= 11.5V (max)
*Battery = 7.5Ah
*LED Bulb = 6 LED, unknown voltage/current/ configuration (solar panel that come with it was 9V)

Figure 1: (presently in use, Working)
Assuming each LED series has an (unknown value) resistor.


Figure 2: (Obsolute)
2 LED Bulbs are set in series to distribute voltage equally. No resistor.
Voltage drop= ~0.5V per hour.

Figure 3: (Old configuration)
1 LED Bulb with resistor. Will this works?
Voltage drop= ?

UPDATE:
Bulb has 6 LED (unknown voltage)
Wattage: 3W (as seen on amazon of similar product)

published 5 years ago

Raptor_Bash

5 years ago

LED without resistors are a Bad idea.

Robert_Kidd

5 years ago

You do need a current limiting resistor. Determine the working voltage and current of LED. Put the appropriate number of LEDs in series. Add their voltages together subtract this from your battery voltage, 11.5V in this case. Divide this voltage by the required led current to give you the resistor value.

Robert_Kidd

5 years ago

Note that you are using lamp symbols but talking about LEDs.

Robert_Kidd

5 years ago

For example, if you have 2V, 20mA LED’s then you could have 5 in series. So Resistor value = ((11.5-(2x5))/0.02= 1.5/0.02= 75 Ohm.

jorteron

5 years ago

Its a LED Lamp Light (like in closed bulb), its internal configuration is unknown. hoping it have resistor inside. So far it run/light up, not much bright thou.

Robert_Kidd

5 years ago

Do you have a manufacturer or part number or a link so I can look at led lamp?

jorteron

5 years ago

No. It is chinese made, no spec on its package or leaflet. Figure 1 is currently in use and its working. it was shot in the dark attempt.

Robert_Kidd

5 years ago

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