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my 12v dc power supply

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snazzy c

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i designed a 12v dc power supply from a 12v battery of 45Ah. i used it to power devices each of 11v dc and cummulative current of 4A. am using the battery for the loads 24 hours and also charging it 24 hours steadily. i provided a heat sink for the regulators but they are still heating up. is it that the load drawn by the devices are too much for the circuit or battery, Or that the steady charging and usage at the same time is not good! pls help!
 

How can I ever hel when you omit posting a schematic, or at least more info than that. What's going hot you said? The battery is hot?
 
the regulators together with the heat sinks are heating up.
 

I suppose your using linear regulators? how are they configured (schematic) and what voltage are you supplying them with? This could be why they are heating up.

also, you are essentially running a 4 amp load from your regulators with the battery there as a back up. A 4 amp load on linear regulators will make them *hot*.

I would suggest looking into designing a switched mode power supply - they are much more efficient and wont heat up like linear regulators will.
 
check the charging section , what is your charging current?
 
snazzy c said:
i designed a 12v dc power supply from a 12v battery of 45Ah. i used it to power devices each of 11v dc and cummulative current of 4A. am using the battery for the loads 24 hours and also charging it 24 hours steadily. i provided a heat sink for the regulators but they are still heating up. is it that the load drawn by the devices are too much for the circuit or battery, Or that the steady charging and usage at the same time is not good! pls help!
Click to expand...
As i understood your post, The problem may be the regulator. When you have a 12 volts source which is a 45 Ah battery, and a load which is supplied with 11 volts 4A, why a regulator is used as the load can be directly powered.
To keep the battery in constant charging, the charger capacity must be more than the load current used, or the battery gradually fails.
Cheers
**broken link removed**
 
maybe your power supply should have a sinking resistor biased towards ground or maybe apply a thermal paste between regulator and heatsink.
 
my charging current from the 12v 45AH battery is 1.8A. Rem., am powering 3 devices each of 12v dc with a cummulative current of 4A (ie 2A, 1500mA and 500mA).
 

which part is getting heated , charger or output, your charging current is half of your requirement so there is a chance to draw more current from charging section, check this
 
rajudp said:
which part is getting heated , charger or output, your charging current is half of your requirement so there is a chance to draw more current from charging section, check this
Click to expand...
The charging current supplied to the battery is quite ok for normal charging and use. But in this case as you are drawing 4amps, the battery may drain fast than it gets charged. Also clarify which part of your project is heated.
**broken link removed**
 
the regulators i used are heated. is it still advisable to increase the charging current of the charger, say,4A to 4.5A.

---------- Post added at 00:27 ---------- Previous post was at 00:22 ----------

theb regulators are heated. but is it still advisable to increase the charging current of the charger, say, 4A to 4.5A because the battery is draining.
 

As i have mentioned in my previous post, i see NO need of a regulator. The charging current may be increased.
Cheers
**broken link removed**
 
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