Voltage regulator and heat

[ishtob]

planning on using a 5v 1.5A voltage regulator for the economy sound board. My current setup is 7.2V li-ion battery pack. How much heat would be generated from this step down? should I bother with a heat sink?

[Ari-Jaq Xulden]

I would say yes. I would also make sure your regulator is rated for the 1.5A. Since your use li-ions I would suggest a capacitor setup as well

[Hasid Lafre]

You should be fine with just mounting the regulator to the heatsink for the lux, you wont need a capaciter.

Why would you even need a capaciter?

[ishtob]

what is the cap for?

[Ari-Jaq Xulden]

It prevents surges from the battery to the regulated board. An unexpected surge, say from another driver board ramping up for a clash effect on the lux, could fry the hasbro board.

[Jedi Jo-Dan]

Capacitors are generally used on analogue voltage regulators to insure that they do not oscillate and put high frequency signals on the regulated power. With short leads and lithium batteries the source impedance should be low enough there shouldn't be a problem on the input side without one. However, it never hurts to put a small electrolytic cap on the output side. I suggest that a 10uF, 25 volt tantalum is perfect for the job.

[Lord Dottore Matto]

planning on using a 5v 1.5A voltage regulator for the economy sound board. My current setup is 7.2V li-ion battery pack. How much heat would be generated from this step down? should I bother with a heat sink?

Why? Just use one 3.7V Li-ion and need the other crap you won't.

[ishtob]

well.. my li-ion battery is a pack, and i go the charger for it too, just didn't want to have to get another changer.

[Novastar]

Everyone has different opinions, but...

I would *NOT* bolt the regulator to the LED heatsink. In this case.

Why not.

Because you're shunting off "7.2v" (8.4v) to 5v... which can be up to 3.4v (!!) of energy to be spitting away into heat! That is a FLOOD of power for the regulator to be working with--in my opinion & experience.

I would think it'd be better to regulate to 6v. It'd be a lot less heat for the thing.

[Lord Dottore Matto]

well.. my li-ion battery is a pack, and i go the charger for it too, just didn't want to have to get another changer.

dude, a 1aa battery pack costs less than a dollar...and electronically, it is the most efficient solution for what you want to do. If you insist on a regulator, listen to Nova and use a 6V instead of 5 to help reduce the heat bleed off.

p.s. you can still charge those trustfires one at a time on your charger...

***edit- I see, you have a pre-made pack, not trustfires! Well then, use the 6V regulator...***