Parallel unregulated 18650 box mod

Hi, I am new to the forum so I hope this is where this goes...

I am about to build a unregulated box mod with:
replaceable fuses
mosfet
internal master switch
volt meter

I am probably going to use a pair of Sony vct4, have a troll V2 on the way and have a few questions I thought someone on here could answer

- What Mosfet is best? should I use two in parallel? do cheep ones last?
- Does anyone use replaceable mini auto fuses in their box mod? how did you mount(pics)?
- Best circuit design? (have seen a few variations on the internet)

Any help is appreciated

I’m also building my first unregulated box mod! I also have some questions so posting to follow. I got my mosfet from Monolithic Scatter and you can get them with a 15k resister pre-installed and heat shrink wrapped, which makes things a bit easier, as my soldering game is not quite on point yet. The wiring diagrams I’ve seen only show one mosfet, so I’m not sure 2 is necessary.

As for the fuses, I’ve only seen one video where a guy used them, and they were hardwired in. Once they blow, you’d have to rewire new ones. So I have no clue about that but if you find them can you post it on here?

I’m doing a parallel 18650 in a Hammond box. Started the wiring and I was wondering, have you connected the drain negative lead to the 510 yet? I got the positive lead soldered in nicely, but the negative lead is supposed to connect to this copper 0 ring that sits on the threads of the 510 connector, and that ring sits flush with the inside of the box. Won’t that creat a hard short? Or does it matter? I can’t seem to find any pictures that show it very clearly, so any info or pics you have on that would be appreciated.

Also my internal master switch has 3 terminals to connect wiring to. Do you know which 2 I should be using?

Thanks!

A reply
thanks

I am pretty sure that Putting 2 Mosfets together in parallel just halves the load that they have to bare.

Still working on the fuse situation, leaning toward glass fuses held in pcb fuse trays... I will let you know

The master switch is an on/on I assume, so you solder to the middle and one outer. Check with a multimeter set to ohms - put the two leads where you wish to connect and then switch back and forward, it should zero out in one position (no resistance- closed/on) and be infinite in the other (disconnected- open/off)

With the 510 connector, the base of it will be up against the box anyway so I am assuming the box is usually grounded out with this type of build. I wish an experienced builder would chime in, I am used to building drones and guitar pedals but never built a mod.

peace,

Kyza

Oh, good call on using the multi meter to check the on/off switch! Smart idea. Yeah I’m new to the electronics game, only things I’ve ever built are bonfires and shoddy wooden furniture haha. Anyway thanks for the info, was super helpful. What type of enclosure are you using? Here’s some pics of what I got going on. Just finished yesterday. Not the prettiest thing on the inside, I need to practice more on my soldering and stuff, but it works! Onto the next one, this time more do dads and maybe put some paracord over the wires to spiffy things up. Cheers!

Welcome to VU, both of you. Good to see folks building unregulated parallel mechanical mods. A favorite of mine so will be camping on this to see your progress. Before proceeding, do please be careful and not blow yourselves up.

With that said, here is some info to help you on your journey.

Here is a wiring diagram similar to the design you are working on. If it were me, I would skip glass fuses and opt for automotive fuses, they are less expensive and you can buy a fuse tray that makes replacing them easier in the case you get in a bind.



On ebay you can search for motley mods. They make some battery trays with on/off button slots and so forth to make your first build tidy.

Hope this helps and please use shrink wrap on your solder points and exposed wires and make sure everything is nice and tidy (no positive wires touching anything on the body, etc...). Another bit of advice. When you go to fire it the first time, use an atomizer unbuilt and with only one of your positive or negative of your volt meter leads screwed into the RDA base. If something goes wrong, clearing the short is simply removing the one lead. I still do this after many years of building and it helps, we all screw up periodically.

Good luck, keep us posted on progress and dont die. Building your own mod is fun and rewarding. You will always love it.

Thanks for your input jwill, really appreciate it. I am working pretty much from that findmyvapes diagram


AKmtnvapor, I am in Australia and so everything got way to expensive through any other source than straight from China ):
So, I have a 2-4 week wait on all my parts. I am using a china made 1560b clone as my enclosure, hopefully it is thick enough to sand down to square as I cannot bare the "hammond lean".

I could not find any good micro blade fuse trays so I have ordered pcb mounted glass fuse trays. I may receive them and realise that I wand to keep looking for a better option. I have magnets for my enclosure on the way as well as all the wire I need, a battery tray, digital volt meter, switches and 2x IRLB3034PBF mosfets.

I am looking forward to my first coil build also! I plan on building dual coil .2 in my troll so I am looking around for a good example of a velocity style deck build to this resistance.

will keep you posted,

Kyza

You can get the fuse tray at any automotive store for a couple of dollars. They are way better than glass and will not expose the contacts upward toward the lid.

could you send me a pic of what you mean?

Can't see the image :-(

All the ones I have found stand no chance of fitting in a 1560b

https://www.yachtbits.com/blade-fuse-holder-block-2-way


https://www.bluesea.com/products/5023/ST_Blade_Battery_Terminal_Mount_Fuse_Block

Nothing to add just following cause I like seeing home projects

Good luck with it kyza and be safe