What fuse to use? / where to get silicone cable 350°C?

[J.P.]

Greetings, my first post hire
So i'm planning to connect Bosch tool battery (18V) to Pinecill v2.
The adapter for battery comes with option to use fuse, but ones that are used in cars.
Question is what fuse would be the best one to put hire; like what voltage, amperage? I also heard of quality ceramic fuses...
I'm guessing using one that would brake if 24V or 3.8A is reached (just a guess )

Another question is there to be bought multi-core silicone cable (2 cores) that is same quality as one that Pine64 USB cables are made of,
so temperature heat resistance up to 350°C and super smooth feeling.

[DrYak]

So i'm planning to connect Bosch tool battery (18V) to Pinecill v2. {...} I'm guessing using one that would brake if 24V or 3.8A is reached (just a guess )

Disclaimer: I work in biomed research, I might get things wrong.

According to the specifications, Pinecil v2 is a 88W soldering iron. At 18V it would pull 5A to reach that power. So I would guess: take a fuse that trips at 6A, maybe? If more than that are pulled from the battery, there's probably a short on the cable and the fuse should trip to protect.
(check also the max ratings of your battery, and set max wattage accordingly on the pinecil).

Another question is there to be bought multi-core silicone cable (2 cores) that is same quality as one that Pine64 USB cables are made of,
so temperature heat resistance up to 350°C and super smooth feeling.

You mean you want something like the original USB-C  cable, on which you want to solder/attach a barrel for your battery?
- I've found silicon smooth cable on AliExpress in the past (mines were only rated up to 200C, you'd need to search for 350C).

- Otherwise, gut a USB-C cable and solder it directly on your contraption+barrel (you'd be wasting unused data lines and the two USB-C plugs, though).

- Otherwise, adding a car/truck "cigarette lighter" port 12V-24V charger that supports USB-C PD  and plug the original USB-C cable (the cig-charger will take care of negotiating voltage and amperage. Just use one whose input support the whole 12V-24V range (e.g. also compatible with 24V trucks) and not only 12V (not car only)).
(Use a real charger, DO NOT use a passive USB-C receptacle, IT WOULD BE DANGEROUSLY NON STANDARD. Normal USB devices expects to start at 5V, and negotiate higher voltage using USB PD or QC protocols. They shouldn't get straight 18V. If you plug a device that doesn't withstand 18V (e.g. a smartphone) you will certainly damage it).



NOTE: above links are the articles I've bought in the past, there might be cheaper/better offers by now (e.g.: my car charger is 30W only, there might be 65W or 100W by now?)

[J.P.]

According to the specifications below it can go up to 92W (24V-3.8A) on DC Barrel so I assumed that 3.8A is max thru DC Barrel.

Pinecil would maybe fry itself if he wanted to pull 5A to get 88W on 18V, maybe I should just put power limit in settings to 65W which should limit current to 3.6A on 18V, but I would really love to get that maximum of 92W on 18V.
As you said, max battery ratings are also important, but that info for Bosch battery I couldn't found anywhere.
___
Yes, for connecting battery to Pinecil I would use something like the original USB cable but without connectors, because I don't want cutting functional USB cable, but looks like I would need to 
Have found silicone cables as you stated but those aren't multi-core cables, meaning I would need to use two, which would look messy to me.

Using car-cigarette charger is interesting option, offering a layer of security and saving USB cable life. But I would still like to use DC Barrel connection without additional electronic in circuit.

[VaZso]

According to the specifications below it can go up to 92W (24V-3.8A) on DC Barrel so I assumed that 3.8A is max thru DC Barrel.

Pinecil would maybe fry itself if he wanted to pull 5A to get 88W on 18V, maybe I should just put power limit in settings to 65W which should limit current to 3.6A on 18V, but I would really love to get that maximum of 92W on 18V.

According to the image you linked, new tip of Pinecil has a resistance of 6.2 Ohm.
If you attach 18V to pinecil, it will draw I=U/R=18/6.2=2.9A and power will be P=U*I=18*2.9=52.26W, not more.

If you attach 24V as per the table above, current will be I=24/6.2=3.87A which has a power of P=24*3.87=92.9W

[J.P.]

WOW! Thanks for clarifying this mathematical equations , never really understood them.
Will put this all together and take some measurement, will also put 4A fuse in circuit just for precaution.
Will post results + pics. after its all done.

[J.P.]

Decided to cut open and use pine64 USB silicon cable.
Inside were 5 wires. Two of them much thicker (orange & black) and 3 slimmer (probably for data transfer).
Only two are needed for power, but I didn't want other 3 go to waste so have also used them as a power wires and just soldered them all together:
       

Haven experiment with fuses so i just left 30A inside.
Overview of setup:
   

Have measured maximum current draw with different tips.
With battery at max charge (20.7v), shorter tip (has lower resistance) had maximum current of 2.91A
while longer tip (has higher resistance) had maximum current of 2.29A