What rating of fuse to use???

[Slim Batz]

Hey,

I want to start using my 14500 mechanical tube mod with unprotected imr batteries ... I think I should at least incorporate a fuse between the positve battery terminal and the switch inside the mod head ... I use boge LR cartos on this mod. What I want is some expert feedback on what amp rating to use and whether is should be a fast or slow blow type. I was thinking 3.5amp fast blow, but I really don't know. Thanks in advance.

 

[hificat101]

Here is a good start:

http://www.cloudsofvapor.com/store/...od-fuse/1217-2-cents-for-safety-mod-fuse.html

 

[Slim Batz]

Here is a good start:

2 Cents for Safety Mod Fuse

Wow ... $9 for a fuse ... thanks for taking the trouble to post but no thanks ... sounds like it doesn't fit on a 14 series anyway. I will be installing the fuse inside the switch housing in this mod.

To be clear, I am not looking for a product, just some technical information on what rating/type is appropriate so I know which 75cent fuse to buy to get this done. Cheers.

 

[StrikeEagleCC]

If you're using LR cartos/attys, then your maximum current can be expected to be about 4.2V/1.5Ω=2.8A. Since cartos vary in resistance, and fuses have tolerance, I would shoot for something with about 3A or more holding current. I wouldn't exceed 5 though. I would go fast-blow because I like my batteries. There are also poly fuses that are thermal and auto-resetting. if the trip current is exceeded, it will overheat and open the circuit, and once it cools it closes again. These are commonly used on multi-cell packs as additional protection against shorts (in addition to the included circuitry).

EDIT: If you're using two batteries in series, double those ratings.

 

[breaktru]

EDIT: If you're using two batteries in series, double those ratings.

Actually the current with series batteries remain the same and one fuse will suffice.
Parallel batteries should have a fuse in series with each cell.
Same rating fuse will do. I use a 3amp hold rating and a 5 or 6amp trip rating PTC. (resetable)

 

[StrikeEagleCC]

Actually the current with series batteries remain the same and one fuse will suffice.

Oh, right. I didn't mean that two fuses are needed for cells in series, just that with the higher voltage, current could increase depending on the application. But I suppose most people wouldn't use a 1.5 ohm Atty on a 7V mechanical mod. Fire starter anyone?

Sent from my HTC Glacier using Tapatalk 2

 

[breaktru]

Oh, right. I didn't mean that two fuses are needed for cells in series, just that with the higher voltage, current could increase depending on the application. But I suppose most people wouldn't use a 1.5 ohm Atty on a 7V mechanical mod. Fire starter anyone?

Sent from my HTC Glacier using Tapatalk 2

Strike, current will not increase with 2 series batteries. Current will increase with 2 parallel batteries. A larger value fuse would be needed if putting the fuse in line with the load. I am saying is if you were using 2 batts in para then protect each cell. If batteries of unequal voltage are connected in parallel: the good battery will overpower the failed (lower voltage) battery, causing relatively large current within the battery.

 

[StrikeEagleCC]

I see what your saying, we're just on different pages. I am just referring to the fact that 7 volts will push more amps through a 1.5 ohm load than 3 volts will.