LM317 voltage regulator R2 is getting very hot? why?

Regular low pressure lead acid cells cannot be charged by simply connecting them to a constant voltage, unlimited current charge.

I answered your questions about using an LM317 as a constant voltage, current limited charger. Including a link to a website that tells you all about charging lead acid cells. Please study it. http://forum.arduino.cc/index.php?topic=243044.msg1742390#msg1742390

calvingloster:

Grumpy_Mike:

Why can you not just charge a lead acid battery with a constant voltage of 14.1v

Because it will then take too much current.

You need a current limiting source until it reaches 14.1V AND then you do not increase the voltage any more.

Ok I get what your saying. But if I have a power supply that is 14.1v and supplies a maximum current of 100mA then it will be fine provided the 100mA is not more than 20% of the battery capacity? The charger might just get hot because it's working at its maximum rated capicity?

It's not a great idea maxing out the power supply all the time but as the battwey voltage rises, the current will drop as it approaches 14.2v, if you have a 100ma supply and the battery is rated 1000mah it will take 10 hours constant current, 11 or higher hours at constant voltage... (as current deceeases nearer to it's charge voltage 14 v)

How ironic… I had to Google what that meant.

JimboZA:

[quote author=Jack Christensen link=topic=243044.msg1741223#msg1741223 date=1401215132]
GIYF.

How ironic… I had to Google what that meant.
[/quote]

That’s the idea…

calvingloster: And I know that efficiency isn't going to be great but these are the only components I have!!! I can't just buy stuff like you guys recommend. I have what I have and I want to use it to make what I need. Even if it isn't the most efficient thing on earth.

My suggestion: Instead of devoting hour and hours of your energy to something that's never going to work very well, devote that time to finding a way to get stuff from eBay.

You must know somebody who can help...

fungus:

calvingloster: And I know that efficiency isn't going to be great but these are the only components I have!!! I can't just buy stuff like you guys recommend. I have what I have and I want to use it to make what I need. Even if it isn't the most efficient thing on earth.

My suggestion: Instead of devoting hour and hours of your energy to something that's never going to work very well, devote that time to finding a way to get stuff from eBay.

You must know somebody who can help...

Dude this is not about stuff! I will spend countless hours on this thing cause the whole point is to learn. I have a battery charger I don't need one, I'm trying to make one so I can learn stuff

I've tried to help, using the parts you have. You jumped down my throat and called me Mr Grumpy.

Good luck.