My last and only Box Mod build

[Greigster]

Super-Shiny
Jase, do you need to use fuses with the SX350 board or does the board give its own protection against shorting/over heating?

Cheers

Neil

[Super-Shiny]

Greigster fuses can help against overheating and small things that have very little chance of happening, i think i am right to believe that having fuses can help against the main thing....putting the battery in the wrong way but with the SX350 board if you move the negative wire (which i have done) from the board and move it to the -batt solder point it makes the board have reverse polarity.

I would say for own use you don't need a fuse but if selling mods and to give the end user a feel for more safety then maybe use one for other things that may go wrong.

But saying that some of the big box mods coming out even being made by the top end makers don't use fuses.....jury is out on fuses.

The mod i am making right now i ain't using fuses, but to be honest a fuse ain't going to stop all problems......but there is the question is something going to happen, i ain't seen any mod so far with problems.

I have con-fused myself

[Cousin Itt]

Looking good. I like the semi matt black finish

One paint I have found to work well on ally is krylon . seams to stick very well with nothing other than a scratch finish. easy to touch up too as it blends really easy if you do light coats .

[piper1]

what size fuses are they jason

[Super-Shiny]

Jun 13, 2014 19:45:26 GMT piper1 said:

what size fuses are they jason

I ain't using fuses but these are the ones if you wanted to use some: Clicky

This is based on 2 x Fuses in parallel to give a total of 12amps of which the chip needs

Some info to also take into consideration:

Any controller board like the DNA30 or the SX350 should not allow a short circuit condition to persist that could cause damage. However, fuses can protect against installing batteries backwards and act as a backup for short circuits in the event there's a problem with the board.

Since you're pretty much covered for short circuits by the controller board, it's more a matter of reverse polarity protection which may or may not work with fuses depending on the controller board. Fuses do protect against reverse polarity with the DNA30, but can't say on the SX350 without risking a board to check it.

You could run without fuses and use a transistor for reverse polarity protection without a big safety issue. The SX350 may already have reverse polarity protection or it may not. If it does that makes fuses or any other protection redundant.

For those particular 6A fuses two in parallel requires a fault current over 20A for to trip them. That's a lot. Two 3A fuses in parallel would have a trip current close to 12A so they would still work, but they could possibly trip under maximal loading.

There's a range you can use between the trip and hold currents with PTC fuses. For two 3A fuses, you're right up against the minimum. For two 6A fuses, you're up against the maximum. You get faster trip times with a lower hold current, but you run the risk of false trips. With hold current at the maximal demand, you require the largest fault currents to cause a trip resulting in slower trip times and possibly failure to protect the circuit. 

[VapingBad]

Jun 13, 2014 19:07:14 GMT Super-Shiny said:

Greigster fuses can help against overheating and small things that have very little chance of happening, i think i am right to believe that having fuses can help against the main thing....putting the battery in the wrong way but with the SX350 board if you move the negative wire (which i have done) from the board and move it to the -batt solder point it makes the board have reverse polarity.

I would say for own use you don't need a fuse but if selling mods and to give the end user a feel for more safety then maybe use one for other things that may go wrong.

But saying that some of the big box mods coming out even being made by the top end makers don't use fuses.....jury is out on fuses.

The mod i am making right now i ain't using fuses, but to be honest a fuse ain't going to stop all problems......but there is the question is something going to happen, i ain't seen any mod so far with problems.

I have con-fused myself

Just to elbow in with a couple of thoughts bot reverse battery protection: you could wire a red LED with a resistor to light when the battery is inverted (if the board can stand it for a second or so that may do the tricK).  I acidently made my DNA reverse battery safe by having a flat -ve connection and all the batteries I have have heat-shrink preventing contact between -ve end and a flat surface.  I cheated with the Panasonic CGR18650CHs and put some heat-shrink on the bottom half, penny's from FT.

E: I'm such a cheap skate, maybe I should change my nickname to Steptoe