I have a few boost converters that are supposed to be 6A (Max) but I seem to keep burning up a resistor on the bottom of the unit. IDK much about SM resistors, it just says R010 on it, so IDK the value. Here are pic's of the unit but on the bottom of this one, it says 10M, but mine say R010.
https://www.ebay.com/itm/150W-DC-DC...A-Step-Up-Voltage-Charger-Power-/171907240597

There are 3 pins from an IC right next to it as well as 2 larger pins from the (inductor?) which make attacking a heat sink difficult though I could grind them down with a dremel or something. But even if I do that so I could put a small heat sink on it (like a 20mm x 20mm x 5-8mm), I didn't know if the aluminum would short out the two ends when it makes contact with the soldered ends - or if the thermal compound would also short it.

So, is there any way that I can stop burning these up? I'd also like to replace these resistors b/c I'll have 5+ dead units before long if they keep up at this rate.

I guess I could try to current limit the unit, but I'm not sure how. I've been using this to charge batteries with a 12v PC PSU (output of 12.32v), I was running at 28.5 the last time it burnt up and it's also done it at lower voltages as well, so IDK if it is the voltage that is doing it. I basically need multiples of 4.0-4.2v for charging lithium cells.

This last time I did add a 100mm x 100mm fan (taken from an old room heater, it moves a good bit of air) blowing air up from underneath. The sinks still get very hot, though the IC's don't seem to be burning up. The directions for the unit say to add "extra cooling" to run it at 6A, IDK if that means just a fan or what.

Any suggestions on what to do here?

 

Assuming it's a 10mΩ current sense resistor then it would be dissipating 360mw at a 6A output.

You might try mounting a 0.5W radial lead resistor with the leads bent underneath to raise the device slightly above the the pads.
That should work without burning up.

 

Be really careful charging lithium batteries, read this. It's not a good idea to just blindly dump current into them like you are.

Those are rated for 100W max output (150w with a fan), if you're sending more than that to your batteries then that's why these are overheating. A heatsink on the resistor would would help, or might just cause the next weakest link to fail. You probably need to limit the current. The simplest way is to add a power resistor in series with the load. The most efficient way is to add some sort of PWM controller in-between.

 

There are 3 ways in which heat can be removed from an object:

1. Radiation -- Unless you can make the resistor package black, you won't get much bang for the buck here
2. Conduction -- using an object with low thermal resistance and large surface area (aka a heat sink). Problem is making contact with the resistor package.
3. Convection -- move a volume of air (with a fan) past the object to draw the heat away. Viable

 

The air option is not good, its better to move water.

 

I guess I could try to current limit the unit, but I'm not sure how. I've been using this to charge batteries with a 12v PC PSU (output of 12.32v), I was running at 28.5 the last time it burnt up and it's also done it at lower voltages as well, so IDK if it is the voltage that is doing it. I basically need multiples of 4.0-4.2v for charging lithium cells.

Why? Do you read the news on lithium batteries? Do you really think you know more than engineers that have years of experience in the subject but still manage to start fires?

https://www.popularmechanics.com/flight/a17824/faa-lithium-ion-batteries/

Buy a proper charger.

 

This is a subject that should be on the forbidden list.