In Over My Head... Is this going to explode?

[RocketCat20]

I have the circuit described in the images attached. Please ask any questions you have. I just want to know if this circuit looks problematic to anyone. The LED includes a resistor and can handle the 24V. Thanks!

[coppercone2]

put a fuse

[RocketCat20]

put a fuse

Where and how big?

[RobertHolcombe]

Fuse the wire connected to the positive battery terminal, as close as possible to the battery terminal. This is purely to protect the wiring from a possible short circuit.

Fuse rating is based on the ampacity of the wire used, if not sure look up AWG ampacity table for reference. You don't have to fuse to the maximum ampacity of your wiring, eg; your wiring can supply 30A, but your circuit will never draw more than 5 amps during normal use - I would use a 7.5 or 10 amp fuse.

[coppercone2]

read the littlefuse documentation to get a more clear idea of how fuses work. it can get rather complicated to specify them optimally. the jist of it depends on inrush current, peak current/sustained current and life time of the fuse (you can theoretically specify a fuse to only work for 100 power up cycles for instance, but the tollerances of a fuse are probobly pretty large compared to numbers you normally associate with electronics). The more you overrate (assuming its not a specialty fuse like slow, medium, time delay, etc) the more cycles you can get from it, but the less optimal the protection it offers will be.

[mikerj]

You have your 5v Arduino supply connected directly across an ammeter, so smoke and flames are a definite possibility.