Series box mod small problem

[frickensk8er]

Ok so I'm deff not new to building I just have a question that maybe someone better could answer I just built another box series to be exact and my current wire is getting hotter than I would like and my mosfet is getting warmer as well I know it's not my build on the Addy because it's at . 4 and that's about 21 amps nothing dramattic

 

[BunnyKiller]

what are your batteries rated for amp wise?? if they are rated for 20 A then you are pushing the limits on the batteries... remember, series batteries increases voltage but the amps stay the same example... 2 @ 4.2V @ 20 amps in series = 8.4V @ 20 A

also, it is really desireable to have the mosfet attached to a heat disapating surface, the tab alone really isnt enuf to remove the heat generated by the chip especially inside a box with no airflow...

 

[frickensk8er]

30a batt is what they are

 

[Podunk Steam]

I'm no Hammond box master by any means but I'd clean some paint and sync your mosfet to the box. 12 gauge is rated for 20amps at 120 volt, that's 14 gauge in there?
It's a little late but I go for surface area with my solder joints, splaying stranded wire out a little to get the surface area and I use a silver bearing solder for a little more conductivity. Always make a good mechanical bond before soldering, I use Hemostats after bending the wire so there is pressure against what I'm soldering to. Both pieces being solder have to be heated enough to bond as well.
Batteries rated at 2500 mah and 30 amps I find questionable.

 

[Mau]

indeed dont put heatshrink on the mosfet itself let the backplate rest on the metal of your box also keep in mind your batt sag and the specs of your mosfet hope it was helpfull

 

[Podunk Steam]

I guess I could have been clearer with that.

 

[ConcreteBob]

Indeed, a broad solder connection is important. Also, wiring size. Which wire, specifically, is getting hot? I'm guessing your negative lead, if the mosfet is heatingtoo.

 

[ConcreteBob]

Also, those HE4S are fine for what your pushing. I maybe would be iffy on Efest or something like that, but LG has excellent quality control, and I trust their ratings. Plus, I've read several independent tests of them, and they're right in line.