15a Resettable Fuses

[alcarl]

Hey all...I am about to build my first dual 18650 parallel box mod. I bought a kit that seems to have everything I need.

Hammond 1590gbk w/4 magnets
Cylindrical Battery Contacts, Clips, Holders & Springs 18650 DUAL THM BATTERY HOLDER
510 Varitube Battery Connector Spring Loaded Pin 22mm Stainless Mount Base
International Rectifier MOSFET MOSFT 40V 343A 1.7mOhm 108nC
15K Ohm resistor
12mm 1/2" Anti-Vandal Pushbutton Switches Anti-Vandal Authentic E-switch Nickel Plated Brass
Appropriate lengths of 4x 16ga & 2x 20ga wire

The only thing I see missing is the 2 15a resettable fuses. I was wondering how important these are. I typically don't build below .20 ohms and the pair of batteries I will be using will have the amps to support this build. Also, if these are needed, where can I get them? links if possible. Thanks in advance!

 

[drmarble]

The fuses are needed to prevent meltdown if you insert one of the batteries backwards. Without fuses each battery will drain into the other resulting in a HUGE current and very bad things will happen. Fuses also help if your coil shorts out. They aren't necessary but are a nice safety feature. Batteries exploding next to your face can be unpleasant.
I believe Mouser has 10 amp ones in stock. RGEF1000-2 TE Connectivity / Raychem | Mouser I just got some. They may have higher ones but I don't use high amp/low ohm builds so I didn't look.

 

[alcarl]

I think a 20 amp (2 10a) limit would be to low for me. I'd like to have at least a 30 amp limit being I vape around .20 ohms. Mouser is out of stock for the 15A. I see some 15A fuses digi-key so I think I'll grab a few of them. The part number is RF3037-000-ND. Is this the right fuse for my box mod application?

 

[BlueridgeDog]

You can stack them in parallel. I have four of these stacked:

2920L700SLPR Littelfuse | Mouser