I constructed a power supply that steps down a 12v dc to ~3 to 3.2v dc.
Resistors are 1/2 watt
load: EL wire and driver
load current: 0.18A
load voltage: 3.2V
Regulator current: 0.19A (with load)
Vin = 12.7v (full charged lead acid battery)
Vout = 3.2v
Measured temp during the time period of 1 hour and 30 mins max's out around 63 degrees celsius and usually goes down to around 50+ degrees celsius then goes up again at max. Temp at 0 hour is 31.2 degrees celsius. Measurements are without heat sink.
Operation requirements:
It is required to operate 7 hours daily
I have already read the datasheet and slightly understood it. But I still need real world experiences and recommendations.
Question:
1. Is the degree of heat still reasonable specially for the required operation daily?
1a. If yes, can it possibly cause fire in the long run?
1b. If no, what are my other options? Given that 12v is the only source voltage.
I tried to drop the voltage before entering the LM317 Vin using a voltage divider from 12v to 9v. It works without load, when I attach the load the Vin and Vout voltage drops significantly rendering it useless.
Question:
1. Why is this happening? This is a part I am confused.
2. Is there another option to lower down the the source before it goes to Vin? I think 9v is the optimal voltage to drop, lower than that won't activate the LM317 (as I understand in the datasheet)
Resistors are 1/2 watt
load: EL wire and driver
load current: 0.18A
load voltage: 3.2V
Regulator current: 0.19A (with load)
Vin = 12.7v (full charged lead acid battery)
Vout = 3.2v
Measured temp during the time period of 1 hour and 30 mins max's out around 63 degrees celsius and usually goes down to around 50+ degrees celsius then goes up again at max. Temp at 0 hour is 31.2 degrees celsius. Measurements are without heat sink.
Operation requirements:
It is required to operate 7 hours daily
I have already read the datasheet and slightly understood it. But I still need real world experiences and recommendations.
Question:
1. Is the degree of heat still reasonable specially for the required operation daily?
1a. If yes, can it possibly cause fire in the long run?
1b. If no, what are my other options? Given that 12v is the only source voltage.
I tried to drop the voltage before entering the LM317 Vin using a voltage divider from 12v to 9v. It works without load, when I attach the load the Vin and Vout voltage drops significantly rendering it useless.
Question:
1. Why is this happening? This is a part I am confused.
2. Is there another option to lower down the the source before it goes to Vin? I think 9v is the optimal voltage to drop, lower than that won't activate the LM317 (as I understand in the datasheet)